Stratigraphy, structure and composition of cement materials in north central California
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Authors Faick, John N.
Publisher The University of Arizona.
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Link to Item http://hdl.handle.net/10150/552261 BTRATigRAPHY^ STBlJCTyRE AMD GOMPOSITION OF
CEMEHT-MATEttlALE IM NORTH CENTRAL CALIFORNIA
5^ fA ■Tohn N» Faiek. ■ ■■■■v
A, Thesis Submitted to the Faculty of the:
; ;; v D e p a r t m e n t o f g e o l o g y :
M Partial Fulfillment'.of the Requirements For the Degree'of
. .'DOCTOR OF PHILOSOPHY ,
In the Graduate College .
* -. . : UNIVERSITY OF ARIZONA
1959
/ f j T ? 7 ^
STATEMENT BY AUTHOR
This thesis has been submitted in partial fulfillm ent of require ments for an advanced degree at the University of Arizona and is de posited in the University Library to be made available to borrowers under rules of the Library.
Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in their judgment the proposed use of the m aterial is in the interests of scholar ship. In all other instances, however, permission must be obtained from the author.
n / y7 ' ^ • / SIGNED:
APPROVAL BY THESIS DIRECTOR
This thesis has been approved on the date shown below: - ; " . ■' ■- . : ■ B'TB^IG EAPay? STBUCTUBE AND COMPOSITION QF CEMENT MATERIALS IN NORTH. CENTRAL CALIFORNIA
.'&.: v. / # ' a ' . . . .. :
. - - : - - ^ ■■ ■ ■■ ' ■ John N-" Faick
- : v A,-; V _ ., ^ABSTBACT ■ : ' ' , .
A geologic investigation was made in north central California
for materials from which to manufacture cement. Parts of the Sierra
Nevada and Great Valley provinces are included in the area investigated.
The area is underlain by sedimehtary and'.igneous, rocks ranging in age
from Silurian to Recent. Paleozoic shales,, sandstones, limestones,
and associated igneous rocks were metamorphosed, tightly folded, up
lifted and eroded'at theTlOse-of the:Paleozoic, These wer e again sub- '
merged in the Mesozoic when a nearly sim ilar sequence of rocks was
formed. The rocks of these two eras are grouped together as the f'Bed
rock series^ although they 'are separated .by a profound unconformity. . ; •
U plift during the Sierra Nevada orogeny and subsequent erosion caused
great amounts of m aterial to be removed from the Sierra Nevada and
deposited as . clastic, sediments in the Oreat Valley province during the .
Cretaceous and Cenozoic. Many deposits of calcareous materials are v : ' ' : :/:1 ' V - ; ; u . ■' ■■ present in formations of Carboniferous and Triassic age. Ba Plumas
. County two large deposits of Triassic age were mapped, "drilled, and sampled. The deposit near Genesee is the type locality for the
Hosselkus limestone. This large, relatively pure deposit is deformed, having been overturned, folded, and faulted. Near V irgilia is a deposit of argillaceous limestone.having a ,composition sim ilar to natural cement rock. Argillaceous, materials suitable for cement admixture occur in some of the Carboniferous formations and in post-Jurassic rocks along the;east side of the Sacramento1- Valley. Some Upper Cenozoic rhyolitic tuffs’ occurring in the .area have pozzolaaic' properties. TABLE- OF CONTENTS .
Page
n m o - O T c m M . d o O 0.0 o o o p o o .0 6 o o p o P o o o o o o o o o o o o 1 ;
,:; Purpose and Scope of Investigation-...., „.o.o.. ...» . 2 : F ie ld .•Wot’Jfe .«•»••• ••»•■•» • .«■*•«.• «•• v « • •• • •»; «.*• ® «• * • . 5 E a r lie r ^^^or 1c, o««*, • ©»© • ® © © ©, © © © © © © © * © © © © © © © © © © © © © © © © © © * 5 A cknow ledgm ents © © © © © © © © © © © .© © © © © © © © © © * .© © * © © © © ©_ © © © © © © ©. ■ 6
TECHNOLOGY AND' DEVELO PM ENT OF: CEMENT. . . © © © ©. © © © : .9 y .
Character of Cement Materials- © © . ■©©. -© .© O O O O O O O. O 0 .0 o t 9
' Historical Sketch of the Cement. Industry © © o o o o o p o o ®‘ o o t 14
, ; • ‘
GEOLOGY OF NORTH CENTRAL CALIFORNIA o o o o » o
General Geology o • o o o » o o' o o o o o o o o p *: 09 ’o. o o 0 0 o p o OOP P o o O, O' O 18
Geology of Cement M aterials o o: o o o oooe 0000 00000 o o 000000 25
Mode of Occurrehce of . Lim estone ,. © ©. © ©;..... o » 00 00 25 Minor Deposits of Calcareous Materials 2.6 Deposits of Siliceous and Aluminous M aterials ©',. © ©;. 29. P oz^olans ... © © © © © © © © © © © ©. © © © © © © © © .©.... © © © © © ©... © © © © © © © © © 31
GEOmGIC INVESTIGATION. OF -LIMESTONE.' ©... ©©.©©©© © © BB
GeOlogy of th e , Genesee Lim estone -Deposit . © ©;. © ©. © © © © © SS.
G eneral F eatures . . ©' © © © © © .© © © © © ©. 32
.Stratigraphy ©©©©.©.©. © © © -. .,.©©. ©, © OOOO 0OOOO 36
■ Reeve Meta-andesite . .;© ©... ©.... © © ©...... , © © © ©. © © 37 . Robinson Formation © © © ..©.,.©. © © ©-© © © © © © © © © © „. © 39
:;HOsselktiS:. L im e s tb n e :. > © © © © © © ©• © • * ' 6 OOO 40
. L ith o lo g y © © © © © © © © o«© © © ©©©a © © © o © © © o © © © © © © © 40 T h ickness © © © © © © © © © © © © © © © © © © © © © © © © © © ©. © © © .© 42 F o s s ils and ^^k.ge © © © © © © © © © © © © © © © © © © © © © © © © © © 43 . A lte ra tio n © © ©.© ©,© © ©.© ©© ©■©..© © © © © ©, © © © © © © © © © © © © © 44 / V ., -iv : - Page
Swearinger Slate ooooooooooooo©oeooooo®ooooo 44
Structure « > o o O O O O O O O 0 o o ooooooooooooooooo 45 ;
O.. 6 » O. O^ .» O O 0 :0 o o o' o o o o o. o o O 0 0 o o o o o o.o o o o O 0-0 o o o 45 ';
^ ' U e t t i l i t g 0 o o 'o o o o o o' O O O O O '0.0 O O O O O O O 0-0 oaoo oooo o oooo 48 Age of Deformation ..».««= .... 49
Geology of the T irg ilia Deposit o o o o o o‘ o o o ooooo o oo o o o o o o o o
General 'Features.. <. <.»»»..».«...... 50 Stratigraphy .....o...... o..o...... 55
Lower; Unit (Shale) ... „ O O O O O O O O O O 0 O O • o o o r o o o o o o o o 55.
Middle Unit (Virgilia Limestone) o e b "o o e Upper Unit (Metavolcanics) o o o o o o o 57 Structure-.' O V < o b o o o o o o o- b o o o o 'o o o- o o ,o o o' o o o o o’ o o‘ @ o o o’ o 57 Gomposition/of :Ayailable: Cement M aterials ,...... 59 ; .; Genesee Limestone ' Deposit =...... 59 . Bosselkus Limestone ooooooeooo 59 ; Swear inger rlnmestone o o o o o o o o o o o o ooooo e o ■62 . .V irgilia Limestone.Deposit:, ...... , ...... 62 lone For.mation ...... *...... «...... 73 Calavaras Formation ...... 75 Utilisation.'o£: Available Cement M aterials...... 78 Methods for Determining Composition... pooooooooooooo 79 Fiefd'Wethods- o o o o o o o o' o o o < o > '© Weathering Characteristics <5 o O 0 79 - Solubility Tests' . .., © O O O O O O O O O 0 o o o 80 Laboratory Methods . =«< O o o ® o o o o o o < ooo o ® e e o '81 ; b- o'o O o © o .0 o o o .0 o 0 0 © O. o «. o o © Page GEOLOGIC INVESTIGATION OF POZZOLANS., ooooo ooo oo o o 88 Introduction O O O O O OOO O o QOGOOOO OOOOO 88 Definition .,...,.....».... oooooooooa 88 Types of Pozmlans ...... v...... 88 Use of pozzolans'...... »..»»■..».»».. 89 Pozzolan'Materials .... „.. 90 General Features .»....»...... 90 Properties of Pozzolans...... vV...... 93 Classification of Pozzolan M aterials ...... 95 Classification by Pliysical Types ...... »...... 95 Classification by Activity Types ...... 96 Explanation of Activity Types ...... »...... 98 Summary of Activity Types ...... 104 Characteristics of. Pozzolans O-oo o ooo-o ooo o o o o 106 Geological Characteristics ...... v...... 106 Physical Characteristics ...... «« 107 Characteristics of Tuffaceous Material...... 108 Selecting and Testing Pozzolans ...... 112 Materials for Pozzolans in North Central California *»»... 115 \ General: Features o o o o o T u ffs A ...... O O O O Cr O O O . 124 ' Tuffs of the Tuscan Formation ...'»..». •*»«»...... 125 . ■ Tuffs of Oroville ...... 128 <: Unnamed Rhyolite Tuff ...»..»»»... ..«.. ..,«« 129 % , Geologic F e a tu re s ...... 129 pozzolahic Properties.-. 130 ,, Thffs ofG #ter '(Marysville) Buttes ..«.»»...-. , 130 Conclusions of pozzolan Investigation ...». 132 > - ' vi : Page SUMMAEY OF CEMENT MATERIALS. INVESTIGATION 134 BIBLIOGRAPHY 6 o o o. o 6 o o 6 o o b o p o o o p a o 6 b o o pop o .. 136 References Pertaining to Geology of North Central California =...«...... O » O • O O O O P O P 136 References Pertaining to Cements and Pozzolans ' 140 LIST OF ELATES P la te .Page 1« Geologic map of.South Peak, Genesee limestone, ■; deposit/ -Plunias'Cotinty^ California «.,..«... .in pocket 2«: Cross section of the Genesee limestone deposit, . '-■’■.A;. Genesee, California .. «> ...... ,.... in pocket 3, Cross section Of the Genesee limestone deposit, . ' ■ Genesee, California ...... «.> ....,...... , in pocket 4. Geologic map, V irgilia limestone deposit, Virgilia, C a lifo rn ia O P O 0 ,0 0 o 6 o o o o o o o o o O. o in p o cke t ■- . .■;:J f ig u r e s Fignre ■ ■: /' . ... ' Page 1. Inden map of north' central California .,...... - .. . 3 2. Map of California showing natural provinces ...... 19 3. Block diagram of part of Sierra Nevada ...... 23 4., Block diagram of a typical limestone deposit ... .•...... 23 5; Geologic map of a portion of northern California ...... 24 '6. Sketch map of north central California- ...... ; '27 ' ' . . : ' vii 'Figure; Page ■■'7 o General, view of the Genesee lim estone 0 0 0.0 O O O O o 6 o o' s 3.4 8. General yiew of Hosselkus limestone . 0,o e o e o o o o, « « o 35- 9. Geologic map of the Genesee limestone deposit . oo oooooo 38 10= - Sketch map- of V irg ilia limestone deposit . ======O e o e o o- o 53 11= V irgilia limestone deposit; section through d rill holes ■ ■ 1 and 3 = = 6 bo oo o o o o o o o o o o o o e o o o® o o o o o o 6.5 .12= V irgilia limestone deposit; section through d rill hole 2 .. . = 66 13= V irgilia limestone deposit; section through d rill hole 4 =«= 67 14= Effect of cupric nitrate stain on calcite and dolomite =... = = = 84 ' 15. Effect of cupric nitrate stain on. calcite and dolomite... = = = = 85 16. Approximate relationship between composition and specific gravity and refractlye index for natural glasses = = = = =. =. = 111 : ' EISTeF'TABLES Table'.’,;:;: ,. ' /' . - ; ' :: ' . ' - Page 1. P artial analyses of ^cement rock" in percent = = =.=.= = = = 11 2= Partial analyses of raw materials for various types of cem ents ...... 0 0 9 0 0 0 11 3= Summary of geologic history of northern California ax 4= Analyses of limestone on Limestone Point = =». O Q O O 0 O 28 v 5, Analyses fro m Swearinger form ation =. = = ='======-= = 63 •6. Weighted average core analyses of V irgilia limestone ... 68 7= Summary of weighted average analyses of V irgilia d rill CO re. O O O O O O O O O O O O P O OP o o o o o o o o o o o o o o o » o o o » o o o o o o o o ® o 69 ■ '■ ■■ ' y i i i ’ ’ ■ . ' ' Table Page , 8. Nummary of weighted average analyses of some : V irgilia surface samples ...... ,..;.., 69 ■ ■ • ; ,.. ■ : ■ ' ■ ■■■■ . :v.; • V . " 9, Analyses of composite core samples of V irgilia limestone. 70 ■ 10. Analyses of someTOne .sands,and'clays ..... >. 74 .11. Analyses of lone clay near Wicks'Corner...... 75 12. Analyses of fine sandy clay near.Pentz, California ...... 76 13. ' . Analyses of Calaveras shale and slate ..,...... -. 77 14. Composition of pozzolan .specified for Glen Canyon Dam . 96 ' 15. ; Materials, used as pozzolan. y...... 97, 16. Relationship of activity type and active ingredients in . ' y';pozzolanic materials .... .■«...... 99: 17. Group evaluations of pozzolans;...... v...... ' lie 18. Materials investigated for, pozzolanic properties ...... 117 19. Optical and chemical data of tuffs investigated ...... 11:8 20. Materials investigated for pQzzolanic properties ■...... 119 21. Strength tests of rhyolitic tuff in lim e mortar ...... ». 131 INTROBUCTIOH An inTestigation of the cement manufacturing industry in Cali fornia was initiated late in l956 to determine the feasibility of entry of the American Exploration and Mining Company into this industry. Since 1956, the staff of this or ganization and consultants r etained by it have made .detailed studies of manufacturing facilities and methods, distribu tion of producing plants, and the nature of the raw materials that have been used or might be used in the manufacture of cement. Existing power, fuel, transportation facilities, market conditions and sources of m aterial wer e investigated. This w riter, on joining the. staff of the company in June 1957, was assigned to making complete geological studies of two important limestone deposits to determine if adequate supplies of acceptable qual ity material is available. While field work was in progress members of the California .Department of Water Resources and the U. S. Bur eau of Reclamation, both With offices in Sacramento, California, suggested that a search should also be made for pozzolans to be used in massive concrete structures.'': Consequently, early in 1958 an. investigation of : pozzolans was initiated, this being conducted contemporaneously with the limestone investigation. The dissertation herewith submitted is based on the results of field and laboratory studies thus fa r Completed. a. Purpose and Scope of Investigation The purpose of this project was to determine if raw materials suitable for the manufacture of cement existed in north central Califor nia (fig. X). Justification for a cement manufacturing plant in northern California is obvious when it is realized the nearest plant now serving ; the area is near San Andreas^ about 50 m iles southeast of Sacramento. A ll other cement r equir ements must be met by shipments from outside sources. ' - - Efforts were cbncentrated:On finding pure limestone and shale or clay which could be blended in suitable proportions to make cement. Attention was also directed toward obtaining natural cement rock from which cement could be manufactured directly with little or no blending. ' •From the beginning it appeared mor e practical to buy the small amounts • ; V ’ : ' ' ■ - • • ' , ■ of iron ore, gypsum, and other materials required in the manufacturing process than to produce it from company owned mines. Then efor e, no effort has been made to locate deposits of these materials. . - : , ■' .••• ' 3 ' ' ' - • • " . 'With the M arybyille-Croville-Chico area under consideration / as the most important market area for cement/ the raw materials were sought within a reasonable or economic shipping distance of Oroville. It was considered feasible to ship either the raw m aterial to the manufactur ing plant or to put the manufacturing facility at the source of raw mate rials and ship the finished product. 3 Figure 1.--Index map of north central California Because limestone or natural cement rocks are scarce in north central California a comparatively large area was investigated. As shown on figure 1 the Area embraces parts of the Sacramento Valley on the west .and the .Sierra Nevada Mountains on the east. It extends from a few miles south of Sacramento to a few miles north of Red Bluff, The , area is approximately bounded on the west by the 122° 30r meridian with Baskenta. near the western margin and it is bounded on the east by the I20o 40f meridian with Genesee near the eastern margin. Obviously not all of this vast area could be studied in detail; however, all of the possible sources of cement m aterial were considered and most of the important deposits were visited, A few possible sources of limestone have not been visited because of their remote location and inaccessibility, The prelim inary studies indicated that two important limestone deposits situated within r easonable proxim ity of existing transportation facilities, justified detailed investigation. These two de posits, which w ill be discussed in this report, are near V irgilia and near Genesee, Plumas County, California. Clay and shale deposits were investigated as sources of. admixture. Pozzolanic materials oc- ■ cupy an important place in modern concrete works, therefore, these materials, were investigated .intensively and the results are also pre sented in this report, • . , 5 F ie ld W o rk Reconnaissance^type studies of the limestone resources of north central California were initiated by the American Exploration ’ and Mining Company during the summer- of 1956. Prelim inary geolog ical mapping of the Genesee ■deposit and exploration.by drilling was / nndertaken early in 1957 and sim ilar work was undertaken near V irgilia shortly thereafter. Oh June 1? 1957 the w riter started detailed geologic mapping of South Peak near Genesee#', and about September 10 of the same year was assigned to make a sim ilar examination of the limestone deposit near Virgiliao Geological mapping of both deposits was accom** • panied^by sampling nf.'the. outcrops*- •, Field work was discontinued during severe winter weather, at Which time maps and reports were prepared. In 1958 the w riter briefly examined many other limestone deposits in north central California and made a search for clay and shale admixtures# and for pozzolans. Earlier-"Work ■ 1 One-of the: earliest, of. many notable contributions is that of Whitney (1879) which gives a general description of the geology of the Sierra Nevada and other parts of California. This was soon followed by many more detailed, descriptions;, particularly in the writings of r Turner ’and p ille r during ’iwo decades extending from the late 1880*8 to about 1910, B iller (1893) contributed the firs t comprehensive report dealing with the rocks in the great Sacramento Valley, and Turner and .Lindgren described the M arysville Quadrangle in -1895, About the same tim e Turner (1894, 1896) was expanding our knowledge of the Sierra Nevada, The limestone near V irgllia was mentioned by M ills (1892) and was firs t described as part of the Cedar formation by B iller in 1895 Shortly thereafter B ille r (1908) mapped and named the Hosselkus lim e stone deposit near Genesee, In a notable contribution, Lindgren (1911) summarized the results of his own work as. well as that of Turner and B iller and other geologists who had pr eviously worked in the r egion, A report by Anderson (1933:) describes the Tuscan formation and another notable .contribution by Allen (1929) describes the lone formation. A com prehensive re p o rt by W illia m s (1:929) discusses the vo lca n ic events at Sutter (Marysville) Buttes and describes the tilted and eroded forma tions that surround them. vThe latest report of m aterial assistance to the w riter is an unpublished thesis by Creely (1955) describing the ge ology of the O roville Quadrangle. A ll of the. above mentioned reports were freely consulted in the preparation of this dissertation and are acknowledged in appropriate places. . : y -v- Acknowledgments ?" During the progress of the field work, the w riter has become indebted to many per sons whose efforts have helped make this report ' . ; ■ ■ : ■ ’ ■ ■. ■ : ' . . . • ■. 7 possible. The author especially, wighes to thanh .the Americazi Explora- tien and .Mining Company* on behalf of which the project was undertaken, and which has kindly per mitted the use of technical, data included in this report, and which provided financial and other aid in its preparation, ;■ Special acknowledgment is due JL K. Lindsay, form erly General Man- : ager of Exploration, and to his successor in this position, E, A. Scholz, for helpful suggestions and constructive criticism , especially from field conferences. Thanks are also due TV H, Googin for his suggestions re garding technical and, economic: aspects' of the: cement industry. Much credit is due to Joe Mathis, Geological Engineer, who prepared the topographic map of. South Peak, and made all necessary surveys at both ' ' the Genesee’and V irgilia limestone deposits,: and also supervised the ex- • . tensive sampling of the V irgilia deposit. To Lawrence Adie goes credit for his prelim inary geological mapping near Genesee. The assistance of H, Paulson who mapped the Virgilia, deposit on aerial photographs is gratefully acknowledged, ’ as'is the assistance of 0V ’Goudey for mapping part of the V irgilia limestone. The w riter is indebted to Messrs. E. A, Scholz, T. E. googin, L. Adie, F. T. Johnson, and A. G. Horton for reviewing parts of this report. The w riter owes a debt of gratitude to M r s. Sandr a Wood and: M iss Carol Jenkins r espectively for typing the prelim inary and final drafts of this dissertation. Valuable suggestions wer e made by Olaf Jenkins and Oliver Bowen of the California Department of. Natural Resources, Division of 8 Mittea. Others were made by T« H. ’TutM llP Concrete Engineer^. Sacra mento and Alan 0*Neil,; Geologist; O rdville? both with the Department of Water Resources,, State of California, : • 0 Dr. R. L. DaBoiS; Tucson, Arizona^ deserves gratitude for petrographic examination of materials, collected during the investigation for natural pozzolans. The w riter is especially indebted to Dr. W illard •C. Lacy if or his 'encouragement,' as well as for his technical and scion- tific suggestions embodied in the report. Also gratefully acknowledged is the fine Cooperation received, from the faculty and staff of the Univer sity of Arizona, which made,this work possible. . ' TEC.HMJl^GY'-^HPf^DEVEIXJplCENT-OF CEMENT , C ' - , , Character of Cement Materials . Cement is manufactured'froiri lirn'e, carbonate with which ig mixed the desired quantity of clayey m aterial consisting of silica (SiOg)? alumina (AlgOs)? and iron oxide.(FegOg). This may be a natural m ix or ■ it may be man-made. .According to Eckel (1913, p .. 7) an argillaceous limestone containing approximately 75. percent lim e carbonate and 20 percent of clayey materials (silica, alumina, and iron oxide) would be the ideal m aterial for use in the manufacture of Portland cement. This ideal cement.material is seldom found but rocks haying approximately the required composition for the manufacture of cement occur in several places. Remarkable deposits of argillaceous limestone in the Lehigh ■..: D istrict of Penns^yania ahdJKew Jersey are extensively exploited, and immediately prior to W orld War I supplied a little over one-third of the ■ V A ' / ■ ' ' , : • . ' ■: , ' • . ' “ ' '' entire Americah output of cement (Eckel, 1913, p. 48). ■ ; ; ■■'■■■ Rocks sim ilar to the Lehigh.r,cement rock” ' are used elsewhere in the manufacture of cement. The composition of rock that has been used or that might be used in a new manufacturing plant, is shown by 9 10 several partial analyses given in table 1. , It is to foe noted that the analyses in table 1 are of ?tcement rock, " an argillaceous limestone, and represent the natural rock that in composition nearly approximates the kiln feed used in most cement manufacturing plants - In present-day American practice five general types of cement* are manufactured; each serving a special purpose, as follows: V... : ' t - ' / ' . / " ■ ' ■ .■;■> ; ; ' ... ' ; . ' ■ ' ■ ■ ' ■' ■ ' Type I: - For use In general concrete construction when r special,properties specified^# types 11, HI, IV, and V 'Vv 'arenotTeQuired.: '; ; ..Type U: - For use in general, concrete construction ex posed to moderate sulfate action, or where moderate heat of hydration is required, ^ , Type n i: - For use-when high early strength is required. . y .- ' Type IV: - For /use when a low heat of hydr ation is r e- - qu ire d . ' Type V:. - For use when high sulfate resistance' is re- ' ’ quired. For purposes of comparison and evaluation, analyses of raw materials used in various types of cement are given in table 2. In addition to the five main types of cements shown above sev eral special-purpose cements are manufactured. Pozzolan cements * Reproduced from 'A. S. Th M. Standards,- Part S', Designa tion'C-I.50, p. 1, 1952, 11 Table 1„--Partial analyses of "cement rock" in percent. Range of Lehigh Lehigh Lehigh cement cement Utah California Type rock limestone 1 2 3 4 5 Silica 10-16 13,5 11,0 21.2 20.1 Alumina 2-6,5 5,0 3,5 8.0 10.1 Lime 73-81 74.5 81,0 62.1 63.4 Note: No o 1, 4, and 5 are quoted from Eckel, 1913, p , 49 , No. 2 and 3 from Blanks and Kennedy, 1955, p . 100, '‘Analysis includes both alumina and iron oxide. Table 2.--Analyses* of raw materials for various types of cements. ' ' Type I Type II Type III Type IV Type V Range Range Range Range Average Si02 12-15 13-15,5 11.5-14 14-17 12.4 Al^Oq 3-5 2,5-4 3-4.5 2-4 1.6 Fe2°3 1.3-2,5 2—4 1,3-2.5 1,3-4. 1.0 CaCOg 73-77 73-76 74-78 68-76 76.0 MgC0o 3-5.5 7,8 -5,5 1-5,5 3-5.5 3.5 Alkalies 0,5-1 0,5-1 0,5-1 0.5-1 0.5 ^Reproduced from Blanks and Kennedy, 1955, p, 100, ! ' /\ : ■ ■ ' . ' , : 12 (Lea, 1958, p. 18) are produced by grinding Portland cement clinker and a pozzolan, or by mixing together pozzolan and hydrated lime. Pozzolan is used: principally to prevent reaction between aggregates and the alkalies released by the cement, and serves a number of other pur poses which w ill be discussed in the section on pozzolan materials. High alumina cement is manufactured from limestone and bauxite to obtain a product that has a very rapid rate of strength development. White ce ment is a low-iron Portland cement that is white instead of gray. There are. many other special eements. . Due to its natural chemical balance the Lehigh district "cement rockn yielded Type I cenient with a minimum amount of mixing and blend ing,‘and occupied a favorable economic position during the early years, of the industry prior to 1910. Later, in order to manufacture Type n ce ment, according to Blanks and: Kennedy (1955, p. 101) producers in the - ar ea wer e required to change, the raw mater ial proportioning to the ex tent that d number of the limestone deposits were seriously depleted in a relatively short tim e and many producers were required to import high-grade .limestone to remain in production. ,/ ' -• Certain technologic advantages are obtained through the use of natural cement rock, according to' Eckel (1913, p. 48) and others. It is said to. (i) reduce costs because' a coarser grind can be used than with ■ other materials, (2) to require less fuel to make a clinker than by other materials, (3) requires less blending, therefore, lower handling costs ' / V - / ■ . ■ ; V 13: than other material®. Disadvantages of natural cement rook ar e (1) scarcity; suitable deposits are rare, lack of control over finished product except as provided by natural conditions= The above brief summary of the nature of materials used in the manufactur e of Portland cement is given as a basis for evaluation of an area near Virgilia, California where there is a large deposit contain ing limestone, and "cement rock .tr This summary also serves as a basis for evaluating the important limestone deposit near Genesee and likewise serves to determine the feasibility of using as admixtures the deposits of sandj ’ clay and slate - that are. available: in the,O roville -Pentz ar ea. As shown in the preceding pages the raw materials for making .Portland cement are calcareous and argillaceous m aterials that can be m ixe d -in such proportions, as to provide proper chemical composition within narrow lim its. Small variations in the ratios of the principle components of the mixture may be sufficient to alter the constituents .and properties of the cement, with possible undesirable results. Cal careous materials suitable for the manufacture of cement are compara tively rare in north central California; and discovery, exploration, and development pf these calcareous resources, as w ell as the necessary argillaceous materials is intimately related to the regional geology, a ' knowledge of which is essential in order to understand the problems of - exploring.for cement materials. Historical Sketch of the Cement Industry \ ,, Many excellent writings dealing with the history of manufachir ing and utilization of cement have appeared in the last few decades. Ex tensive h is to ric a l accounts a re given by E cke l (1913), Bogue (195.5), L e a (1956)5 and others. In the report which foliows/ a short chronological outline of/the history is included because it helps explain the geological problems incidental to the discovery and exploration of cement materials. According to Bogue (1955, p. 3), the first cement, which was made from calcined, impure gypsum, was employed by the early Egyp tians, and its discovery must have been made soon after the first intel ligent use of fire.. About 10 centuries ago, during the Greek and Roman periods, limestone was calcined and the quick lim e thus formed was mixed with water and used as a cement without other addition; but more generally, it was mixed with sand or other material to form either ''mortarmr concrete^ ; !; ; ;- 'v ; . : ■ It was early discoyered/that superior mortar- and concrete re - - suited from the use of aggregates containing certain volcanic earths. The Greeks Employed a volcanic tuff from the island of gantorin and the Romans used sim ilar material from Pozzuoli, near. Mt. Vesuvius. Bogue (1955,' : p. 3): quotes Vitruvius as stating that this m aterial "if mixed with lim e , and rubble hardens as well under water as in ordinary buildings,?f Prob ably this is the oldest recorded reference to hydraulic cement, i. e., a cement that- sets or hardens satisfactorily mider water. . During the Middle Ages, poor quality mortars were used. These are attributed to incomplete burning of the limey careless handl- ingj or insufficient mixing or consolidation of the mortar „ and to the absence of volcanic tuff. Quality again improved after the 12th to 14th centuries. This is attributed to thorough burning of the limestone and to the use of trass? a. m aterial occurring in Germany and having prop erties sim ilar to the .volcanic tuff used by the Greeks and Romans, . The results of significant research.by Smeaion? an engineer commissioned to rebuild the Eddystone lighthouse off the coast of Eng land? were announced in 1756, According to Bogue? he (Smeaton) ’’made the very important discovery that a hydraulic lim e (one resistant to the action of water) Could be obtained only from a limestone which contained a Considerable proportion of clayey matter . Burned gypsum decreased rather than improved the,quality? and a pozzolanic tuff from Italy was most beneficial. ” Thus? it was firs t ascertained that the near ly perfect hydraulic cement m ortar consisted of argillaceous limestone admixed with, pozzolana. This new hydraulic cement became widely known as Portland cement? because it was sim ilar to and was substituted for a popular merchantable stone known as Portland stone. By 1818 the French engineer, L. J. Yicat had discovered that Portland cement could be made from an artificial mixture of argillaceous rock and pure limestone. He noted that the properties of the cement could be controlled by controlling the ratio of the proportions of these raw materials in the .mixture. He also noted that the product possessed : superiod hydraulic properties' if considerable amounts of alumina or ferric oxide were present in the raw materials; in this case the product was called natural cement. ' ' , . The discovery announced by Smeaton in 175.6 was rediscovered, at least six times between that date and 1830 according to Bogue (1955, p. 5)o Processes remarkably sim ilar to Smeaton1-s were used by Joseph Aspdin to produce d product called Portland cement which he patented in 1824. Details of the patented process appear to have been deliberately concealed, and the.-Portland cement Industry as we know it today, was not founded until the mid-1800%. The firs t Portland Cement plants were in England arid others were- built in Belgium and .Germany about 1855. The firs t Portland cement was imported into the United States during the succeeding couple of decades. Construction of the. E rie Canal and other canals in the early 1800% created a demand for vrater-resisting mortars. The require ments were soon met by the discovery of cement rock at Fayetteville, New York and. other places from which natural cement, often called - ’ : ' . ' 1 - . . ■ - '■ " ■■ ■ r : - • ' hydraulic Cement, was produced. Notable among the early producers of. natural cement is David Saylor.' He found by analysis that his natural cernerit had a composition sim ilar to the imported Portland cement. Far ther experimentation by Saylor r evealed that he could sinter his rock at a high temperature and could produce an excellent product by grinding the clinker; thus formed. - Bis dement was patented in 1871 and after slight changes in the process, he made a uniform product equal in qual ity to the imported Portland cement. David Saylor thus is credited with starting the,Portland Cement industry in America. Although great ; strides are being made in cement technology, and production techniques are rapidly improving, the fundamental process of cement manufactur ing today is remarkably sim ilar to that used by the ancients. GEOLOGY OF NORTH CENTRAL CALIFORNIA. v': .. 4 ' '■ ■ '■ - '■ ' : t General Geology ' ■ The dominant physical features of northern California are two notable mountain ranges enclo sing the. gr eat. Sacramento ■ Valley5 the floor of which is nearly at sea level. Bordering the western margin of California, ar e the Coast Ranges, which have a width of about 70 miles arid rise to a maximum altitude of about 4, 000 feet. Inland from this range is the Sacramento Valley, or the Great Valley as it is often re ferred to? which.is bordered on the east by the majestic Sierra Nevada Range and on the north by the Cascade Range and Klamath Mountains. These natural provinces, and,the major rock.types of which they are . composed are shown on figure 2. This report is concerned prim arily with the Sierra Nevada because this range contains most of the calcar eous materials suitable for the manufacture of cement. Materials for pozzolans were sought in the west flanks of the Sierra Nevada and in the. Great Valley provinces. : ' The! Sierra Nevada is a single great range extending from the Mojave Desert in southern California to the Klamath Mountains in north ern California (fig. 2). It is about 400 miles long/ @0 miles wide, and the altitudes of the highest peaks are above 14,000 feet. Structurally figure 2 MAP OF CALIFORNIA SHOWING NATURAL PROVINCES — --— Area of investigation iSpEF MAJOR GEOLOGIC UNITS *.•*. Cenozoic volconics [• ' • '/I Cenozoic sediments 1 Cretaceous sediments 0 0 0 0 Jurassic Franciscan group FJTTTl Mesozoic-Paleozoic meto- morphic-gronitic rocks Kv= '^*1 Bosm-Ronges and Mojave & u Desert rock complex illf Original from California niv. Mines Kept. 40, pi. 8. M : / .. , : v 20 the range is a great block of the earth?s crust tilted westward and dipping . under, the alluvium of the Great Valley. ; Its broad western flank is scored by deep canyons through which run great rivers of which the Feather River is one of the most important. The stratigraphic record of the Sierra Nevada goes back only as far as the Silurian (jenkins? 1948, p. 23).. A fragmentary record of ' post-Silurian events exists in. the . sedimentary.series of rocks, in evi- denee of structural deformation, and in igneous intrusion. • A brief sum mary M the geologic history of northern California is given in table 3. The Northern Sierra Nevada province was occupied by an ex tensive inland sea during part of the Paleozoic, and most of the Triassic and Jurassic^ ^ silts, muds, -and marls deposited in these early seas have long since been metamorphosed to quartzites, shales, slates, ■ schists,, cherts, lim estones,: .and marbles. - - Considerable volcanism oc curred during the late Paleozoic and the igneous rocks thus formed were subsequently metamorphosed to greenstone; in many cases they are al most indistinguishable from igneous rocks formed during the Triassic and Jurassic. Jur assic sedimentation was accompanied by nearly si multaneous volcanism followed by folding and uplift of the sediments and by intrusion of ultrabasic and granitic rocks. The episodes of folding raised the sediments above sea level and compressed the strata into a. complicated series of folds trending from northwest to southeast (Jenkins, 1948, p. 23). These were 21 Table 3. Summary* of geologic history of northern California V .enloeir C m l ' l i r period fieolosir event Geolosir record ilu t o r y cl m an tjuarts mining Historical record Planer mining D re d g in g 2^4 billion dollars gold produced Hydraulic mining Shallow, hand planering Kreiirrectinn of anr.ent rhannrls and old Tertiary eurfame llix nographic feature* Continued faulting ' I ontmued baair volranir activity Vplift and faulting Inlervulram r utrrani* Andeeitir flown c,*,cealing old eurface Mehrten formation i andeeitei M loceiie Andeeitir lavas, breccias, ash. mud flows, covering all but the higher peaks and ranges Valiev Springs formation A ih fallB, co vering surface# £ (rh y o lite ) 1 O lig o re n e Rhyolitic a.th fails Ham #1 reams, covering channel# 1 lep-milion of large stream deposits of white quarts grav el (angular Ancient channels and sulwigular 1 and placer gold lone formstion Deposition of lone rimy, lignite. anH -.and 'in part marine) Ancient channels Keleaee »f gold from ro^k# and veins Old surface* Pale-irene 1 *ecav of rocka, formation of deep red soil D eep red soil Semi-tropical weathering Pirate streams rob east-floe mg -irranm rutting the Pre-Tertian V p p e r Divide and Great A'eetern Divide Chico formation C retaceous Tope of gold bearing vein* reached hv etoaion t on glomerate* sandstones, and shales many Depiwilion of sand and gravel in basin west ol Sierra Nevada miles in thickness (Great Valley) Kroaion ai d removal ol rocks 2 miles thick from top of Sierra Profound unconformity - [Infiltration of mineral bearing quarts veins into fractured rorks Quart# veins 3 c Metamorphism of older rocks on contact with granitic rocks Granodionte and related rocks ■ jL< Intrusion of grenitir hetholith I Dike rocks V p p e r • 2 i Folding, crushing and faulting S e rp e n tin e Z ® (Vpriae of sediments from inland sea basin M an pose elate Intrusions of serpentine rocks Amador volcanic group In ter bedding of basalt with sediments Ague Fna formation Marin# depoamon Logtown Ridge and Pen on Blanco formation V o lean iam Coaumnee and Hunter Valley formations L o w er Ju ra Marine depoeition Marine depoeition, including coral reefs Sailor Canyon formation Brock -hale V o leaniam Hoeselkus limestone Volcanic rocks Folding and unconformitv (Clipper Gap formation • e u | Delhi formation 2 § = 5 ( ape Horn slate 'ami Vr/m ian* Marine de|>oaition. including coral reef* • fi ® q u a rt at te 1 r ' F^atensive sedimentation throughout Sierra •Nevada province T y 1 g Kanaka conglomerate formation •- ~ — Tightner volcanic formation Blue Canyon marine formation I Devonian Marine deposition Taylorsville formation Montgomerx limestone Silurian Marine depoeition. including coral reefs Gnaaly formation O rd o v ic ia n ('a m h ria n Not known in Sierra Nevada Not known in Sierra Nevada J l l Reproduced with modification from Calif. Div. of Mines Bull. 141, - ■ 1 ■ ' ; v - ; ■■; '■ . 22 intruded by the Sierya Nevada batholith which either assimilated or pushed aside great masses of the sedimentary rocks which are now missing in many places. The remaining sediments were intensely metamorphosed. This episode of Late Jurassic folding, metamorphism, * and igneous activity represents the Nevadian orogeny. A ll Of the above-mentioned rocks— the sediments and volcanics, intrusive basic and ultrabasic rocks, and intrusive granites— form what . is commonly known, as the "Bedrock series” or "Bedrock complex" of the Sierra Nevada. Younger rocks, 1. e. , the.Cretaceous and Cenozoic . are found relatively undisturbed tow on the western flanks of the Sierra Nevada and rest unconformably on the deeply eroded "Bedrock series." This .unconformity repr esents: a long interval of erosion at the beginning of the CretaCepuSo Generalized geologic and topographic conditions are . . ■ ' . : '■ , . \ v , - ' . ;' illustrated by figure 3 and a typical deposit of limestone in the "Base ment complex" is shown in figure 4, The Cenozoic Was an era of in- b ,:- ^ ^'":'' '- -;,:- '.. - : b. - tense widespread volcahism, with the exception of the Eocene which was ;v- ;.'-a periodof intensive weathermg; under ■ humid sem itropical conditions at which time extensive deposits of clay, sand, and gravel were formed. Distribution of the most important geologic formations in the northern Sacramento Valley are shown by figure 5. Along the west' side of the area under consideration, the slightly ' deformed Cenozoic and. Cretaceous beds dip beneath the alluvial fill of . the Sacramento Valley, and .the "Basement complex" likewise is deeply 23 Block diagram to show tilting of the Sierra Nevada and its effect on stream cutting. Erosion, prior to tilting, planed down the surface and exposed the granite, leaving only occa sional fragments of the intruded metamorphic rock-bodies as roof pendants. The streams, at the point where they leave their mountain canyons and enter the Great Valley, form al luvial fans. (After Matthes, U. S. Geol. Survey Prof. Paper 160, 1930) dolomite replacement sill dike Figure 4 Block diagram of a typical California limestone deposit. The lime stone-bearing series consists of int erbedded schist, quartzite, and limestone which have been folded into a tight syncline or trough pitching away from the observer. The lower limestone member has been partly replaced by dolomite and the left limb of the structure invaded by a small stock of granitic rock which has sent out satellitic dikes and sills into the metamorphosed sediments. (After Bowen, California Division of Mines Bull. 176, p. 302, 1957). 24 Fig. 5. Geologic map of a portion of northern California. buried. Progressing northward from Oroyille, volcanic materials of the late Cenozoic become incr easingly abundant and deep accumulations of them conceal all of the ^Bedrock complex"' and most e f the Cretaceous^ Northward from the vicinity of Oroville, with the possible exception of the De Sabla-Sterling City area, limestones or other calcareous cement materials are practically non-existant until the southern flanks of the Klamath Mountains are reached in the vicinity of Redding. Geology of Cement Materials Mode of Occurrence of Limestone As indicated in the preceding paragraphs, calcareous rocks are to be found in strata ranging in age from Middle Paleozoic through Triassic. The Paleozoic rocks generally are referred to the Calaveras group of the Carboniferous. Actually, the Calaveras group is a hetero geneous assemblage of r ocks of Upper Paleozoic age and might even con tain rocks of Lower Paleozoic. Rocks assigned to the Calaveras have been found, to, contain Mississippian and Permian fossils at different localities. Apparently some Triassic rocks have also been assigned to it by mistake. : Although stratigraphic units are not precisely mapped, there is no doubt but what the most important deposits of calcar eous rocks in the north centfal California/ar ea' occur in the late Paleozoic and in the ' . ' Trias sic. Limestone deposits are relatively numerous in the Calaveras but many of them are small. These deposits were recognized as un usual features by the pioneer geologists working in the Sierra Nevada and almost without exception the more important deposits are shown on _ ; . their •geological maps. For example, Turner (1903) mapped many iso lated, lens-like deposits of limestone on the Bidwell Bar quadrangle. • , Calcareous deposits in the Triassic, in contrast to those of the Calaveras, are scarce but very large. In the area studied, two very .. large deposits, occur, namely' Genesee' and V irg ilia (also called ' ’’Pyramidal”). The Genesee deposit is a relatively large mass of com paratively pure limestone, whereas the V irgilia deposit consists of im pure shaly limestone approaching natural cement rock in composition. The V irgilia deposit occurs in the Cedar formation of Triassic age and is considered to be equivalent to the combined Hosselkus and Swearinger formations occurring near Genesee (Wilmarth, 1938, p. 381). The im portant deposits at Genesee and V irgilia w ill be discussed in consider able detail in subsequent parts of this report. The location of these .de posits is shown on figure 6. . Minor Beposits of Calcareous Materials - In addition to Genesee and V irgilia there are several, small de posits of calcareous rocks. One of the pur est is the deposit known as Limestone Point which is situated in a remote area near the head of 27 • P-20 RED BLUFF e P-2 • P-l CHICO ^P-Mo®P^l'2KS z) OROVILLE/X^i o Forbestown • P-« leva do Ci Rivejr, P-ITO Vw ” Area location MARYSVILLE X Genesee and Virqilia limestone deposits Folsom Reservoir o Numbers refer to samples collected for pozzolan investigation SACRAMENTO F ig u re 6 SKETCH MAP OF NORTH CENTRAL CALIFORNIA SCALE or MILES Mosquito Creek about 8 m iles '.northwest of V irgilia, . This' deposit crops out as a bold white promontory on the r idge between Yellow and Mosquito ' Creeks. It occurs as a lens in the Cedar(?)' formation which strikes' northwest and dips steeply, northeast. The limestone contains poorly preserved fossils and is relatively pure, except where it is intruded by an andesite(?:) dike near its northern edge. The deposit covers an area, estimated to be about 500 feet wide by 800 feet long. Chip samples taken along the crest of the deposit from south to north were analyzed as , ' shown in table 4. Table 4 .--Analyses of limestone on Limestone .Point. ' - ' . : > V . ..." ; .: ' : N um ber Sample .Length ' .C ac ' ’ , s% " MgQ : i ■ 215 ; : 51.,0 , . .1.2. ■ . 0.4 4 ■ ■■ ■ 200' :52.4 :'2. O'. 1.07 3 ' " 135 : / . 51.2 2 .3 ; 0.61 ; : . . . ' " - y ' 1 , - . . '; Reports by 'W illiam s (1929), Lindgren' (1895)^: and others .in- ■ dicate that limestones and other calcareous materials were present in the folded strata, on the south side of Sutter (or M arysville) Buttes. Therefore, this locality was examined as a possible source of cement , rock. Prelim inary Investigation revealed that considerable quantities .of fine-grained calcareous, sandstone, are present in the area. Analyses of a representative grab sample is as follows: :\ ' Q b O'-: ; 26,62 v Al»d3' 8.59 ' V. Si02 35.70 Fe|03 3.23 ' ■ This sample represents the Chico formation in the N W -l/4 sec. Slj. T. 16 H. 5, R . 2 E . > as shown by W illiam s . To make cement , this rock might be blended with, pure limestone, but none was found in the vicinity. Deposits of Siliceous and Aluminous Materials \ •' /' f , The Calaveras group contains many zones of shales and slates . . formed from the silt and clay deposited in the Late Paleozoic seas. These rocks contain silica- and alumina and in places a small amount of iron, and are acceptable as additives. These materials exist in considerable amounts near Pentz and are exposed in many places along the railroad ; ' ■ ■ ■ : ■■ ■'■ : ; ■ - ■ and roads as far as Indian. Valley about 10 miles northeast of yirgilia. ; ' v ^ 'r - % ... ■ " . ; : • . ■; : ■ ; ■ ' . ' - Considerable volcanic material was deposited with the shales and clays, therefore, the materials are not uniform in composition and care must be exercised to select beds of the desired composition. ' - - ' ' ‘ Clay’and silt having a composition suitable for an admixtur e . ■ ■ occur in the lone formation and possibly also in the Chico formation. Both of these are pr esent in the Pentz ar ea in considerable amounts and the lone crops out extensively between Pentz and O roville. The lone is often referred to as lone clay, but this is a misnomer as the 30 formation contains eoBSiderable material other than clay., Milch .geological work has been done on the lone formation and it is well known through extensive liteuature. A notable contribution was made by Allen (1929)„ The lone formation, of Middle Eocene, con sists of quartz sands, gravels,' clays, and lignite which lie along the western foothills of the Sierra Nevada for a distance of about 200 miles with the northern termination at Pentz, The formation is a product of intensive deep weathering and is remarkably uniform in mineral com- position and mode of occurrence. According to Allen (1929, p. 348), "The character of the Jon© sediments, their distribution and composi- tion, indicate delta deposits formed at the mouths of many westward- flowing streams. The presence of marine fossils in the upper part of the lone formation shows that it accumulated on the shores of an Eocene S e a .* . ' ■■ ■ • ’ ■ ' : ' .In the Pentz area. Lower Eocene rests raiconformably upon m ore-or-less indurate fossiliferous sandstone of the Cretaceous Chico '-thatis.exposed in a small area along D ry Creek (fig. 6); however, the contact is concealed by soil cover. These Lower Eocene Dry Creek beds consist of gray shales overlain by biotite sandstones that may be over 180 feet, thick. (Allen, 1929, p. 388), The lone formation rests con- - W v - . . X ' - ' formably upon the Dry Creek formation, and apparently is gradational with it. The lone formation is about 400 feet thick according to Alien (1929, p, 369). It consists of quartz-anauxite sands and clays and ■ 31 contains some: glauconite in the Coal Creek area north of O roville. The. soft sands and clays of the lone become finer grained toward the west. ,■ - .. : ... ■■. ' 1 , ' • ' . . . , * . . . - ■ ■ ' ; • ; The most .western exposur e: of . any consequence is near W icks Corner,' where lone clay was form erly used for making brick. ' . - - P o z m la n s In the area studied a search was made for pozzolans because of the importance of thesb materials in modern concrete structures. Because of the physical and chemical nature of natural pozzolans they were:sbught''ln the Cretadeous^ # of the Sacramento ■■' Valley rather than in the older rocks of the "Basement complex1 r in the Sierra Nevada. The materials that seem most likely to be used as pozzolans in the future are rhyolitic tuffs Of upper Cenozoic and clays from the lone formation. These m aterials are discussed in the section of this report, that deals with pozzolans. Localities examined and. sampled are shown on figure 6. aEOMXHC m ¥ESf IGATK)H OF LIMESTOHE Geology of the Genesee Limestone Deposit General Features to Plumas County many limestone deposits occur in several geologic formations ranging from the Silurian Montgomery formation to the Jurassic Thompson limestone (Logan, 1947, p. 267).; Most of these are small, and in remote, inaccessible areas, but large deposits occur in the mountains north of Genesee and near V irgilia (fig. 6). The most interesting deposit is the Hosselkus limestone which was named by .Diller ‘(1908, p. 30) for the old Hosselkus Ranch (now Grace Ranch), . at the community of Genesee in Genesee Valley. For practical and eco nomic purposes the term Genesee is arbitrarily assigned by the w riter to the large body of limestone situated about two miles northeast of the community of Genesee. No scientific connotation is implied by the use of this term as it previously has been preempted (Wilmarth, 1938, p. 808-810). The term Genesee seems appropriate for this limestone de posit although it actually is the type locality for the Hosselkus limestone and the Swearinger slate. The Hosselkus limestone underlies part of a prominent north- ' : ' • ' ; . 32 V ' ' ■ : . ' ' - . v : ■ ■■■■■.■■ 33 trending ridge between Hosselkus Creek and Indian Creek, and the ridge is divided by a low saddle into two prominent peaks—-N orth Peak and ■. South Peak— which also.are arbitrarily assigned terms. North and South Peaks are shown in figures 7 and:8. The limestone seems to thin northward and probably pinches out on the north slope of North Peak, but again r eappears as. isolated masses deeper in the drainage of HOs- selkus Creek. Another small isolated mass is exposed between South .. Peak and .Genesee Valley. The total strike length is said to be about six miles {Diller, 1908, p. 30), but the outcrops apparently ar e not con tinuous. The w riter had no opportunity to study most of the outcrops, therefore cannot satisfactorily -explain their discontinuity. In' the w rite rs Opinion the Hosselkus limestone was probably deposited dis- conformably on an uneven erosion surface, which may explain the len ticular character of the outcrop. The sim ilar lenticular nature of the Hosselkus also was recognized by D iller (1908, p. 31) in the Redding •: Quadrangle, Near Genesee the formation is obviously faulted in places and this may also account for its discontinuity. The stratigraphy^, structure, and lithology of all the outcrops ■ of the Hosselkus limestone, with one exception,, seemed comparatively simple and therefore were not studied. The one exception is South Peak which was mapped in considerable detail in an effort to understand the manner and extent to which it is folded, faulted, brecciated, and altered After deposition the limestone was uplifted, folded, and overturned. It 34 35 appears to have been subjected to a second, period of deformation ac companied by brecciatidn, folding, and faulting. Some of the rock has been alter ed by dolomitization and some contains r econstituted o r in troduced .calcite; ' ; - Stratigraphy As shown by D iller (1908, p. 3) in the Genesee area the Hos- selkus limestone is restricted in its occurrence. It is much more ex tensive and.better known in the Redding quadrangle. In the southwestern part, of the Lassen Peak quadrangle It is Included with other sediments in the Cedar formation which, w ill be described in this report under the ' Firgilla limestone deposit. . In the Genesee area limestone r epresents only the Upper Triassic and this consists of two formations—-the Hosselkus limestone and the Swearinger Slate which was deposited conformably upon it. The Hosselhus limestone was deposited unconformably upon the Robinson formation, with, which the.Reeye meta-andesite is. clearly, associated • (Diller, 1908, p. 32, 86). The stratigraphic relations are complicated by the fact that the beds have been overturned so that the older beds rest upon the younger and all formations exposed in South Peak have been in volved in folding and faulting. The stratigraphic units with which this report is concerned are as follows: ' ; Age Formation • Lithology Triassic Swearinger ghale and shaly limestone Trias sic Hosselkus " Thin-bedded .and massive crystal line limestone .Unconformity//J ’ Carboniferous Robinson Tuffaceous shale and sandstone • ■ Carboniferous Reeve Andesite flows and tuffs grading " into Robinson elastics . The distribution of the formations is shown on figure 9 and plate:!«, and: they are described below. • ■ . ' Reeve Meta-andesite .. Rocks, believed .to..’represent the.Reeve form ation are exposed \ in a deep r e-entr ent into the northwest part of South: Peak. 'Where ex posed these rocks are distinctly porphyritic and have white crystals set in dark, greenish-gray, fine-grained groundmass. The rocks are ' sim ilar to those described by B ille r (1908, p. 86) who says the forma tion is fragmental and contains a variety of well-preserved fossils and grades into sandstones of the Robinson formation. He also reports that, "In places the rock has been so squeezed as to develop a slaty structure, in which the phenocrysts of feldspar are drawn out long in the plane of the cleavage.n Between South Peak and Genesee Valley, B ille r (1908, p. . 86) found the Reeve formation occurring as definite flow and tuff in a long narrow belt bounded on both sides by fossiliferous beds of the Robinson formation. . Although poorly exposed in thevarea mapped by the w riter, 38 Compiled by J. N. Faick from maps by J. N • Faick and L. Adie LEGEND Hosselkus limestone I, I Swearingen formation i . i Robinson formation 1 I Reeve meta-andesite I i Dolomite S. PEAK Genesee limestone deposit, Genesee, California. S c ale , O______500 '______lOOO the; Reeve seems to contain both flow and clastic materiaL No fossils were, found in it by-the "writer, . ' Robinson Formation ; ; ’ : A little m aterial believed to represent the Robinson formation is exposed bn the west Side of South Peak, particularly in the shallow cuts along the road that gives access to diamond d rill holes 9 and 10 (pi, 1 and fig. 9), The formation is not well exposed,, but seems to consist principally of gray shale and fine-grained sandstone, M places it is red or reddish brown. Locally it contains some pyroclastic mate ria l that is remarkably sim ilar in appearance to tuffaceous material in . the Reeve meta-andesite. In a few places the Robinson is calcareous. D iller (1908? p. .26) reports the presence of several species of fauna but none were seen by the w riter, L. Adie (oral communication, 1959) found typical Robinson fahna: about. 400 feet south of d rill hole 5. As previously noted, the Reeve and Robinson seem to be inter- gradational with each other. D iiler reports the Robinson underlies the Hosselkus uncdnfor mably. A considerable time interval elapsed between the deposition of the Robinsonand Reeve‘Of the Carboniferous and the ■ Hos selkus of the Trias sic. Where exposed on the west slope of South Peak the beds of the Hosselkus and the Robinson are slightly distorted and angular differences in the attitude of the two formations could not be detected. Both formations participated in the deformation of South Peak but to different extent. The Bobinson appears to be crumpled, locally shear ed, .and brecciated to. a greater extent than the more com petent limestone, Hosselkus Limestone- ' ■ ' ,' " • ■ ..pithology ■■ v. • v : The typical Hosselkus limestone on a fresh surface is dark . bluish gray or black, very fine grained or dense, and breaks with a conchoidal fracture. Some of the material, however, is crystalline and this .ranges from gray to white on the fresh surface. The limestone weathers to a rough or hackly surface that invariably is light gray. In a.few small-areas the rock is dolomitic, in which case it is usually finer grained than the pur eTimestome,. weathers smooth, and is some shade of buff, tan, or brown on the weathered surface but is usually gray or light tan on a fresh surface. Three principal lithologic or physical types of limestone are pr esent on South Peak, On the north, west,; and southwest slopes the limestone Is thin bedded, flaggy or shaly with beds ranging from a small fraction of an inch to a couple of feet or more in thickness. In the vicinity of the saddle and- on a low ridge that extends south of it to the vicinity of ’ d rill hole 6, the: limestone is- massive? coarse gr ained,; and slightly banded with dark gray streaks in a light gray or white matrix. Similar but nearly white crystalline limestone also is found in sm all areas in the southwestern part of South Beak. This limestone was probably de posited as a thick massive bed but appears to have been bleached and recrystallised through metamorphism.-, Elsewhere, as on the north slope near the summit of South Peak some of the limestone has charac teristics that are intermediate between the two previously mentioned typeso This third type normally is distinctly banded with thin, parallel, discontinuous, planar, bands; in a medium -gray^ fine-grained, crystal line groundmass. In most places the bands are vertical or steeply dipping. They appear, to foe:nearly' parallel to the original bedding and: presumably are relict structures representing original depositional features of the limestone,, but appear to be modified by metamorphism. As the bands in most places appear to be parallel to the known or as sumed bedding planes they are thought to represent rock flowage or ■ gliding planes along which the linear and foliated character is accentu- ated by recrystallization. These platy features are very small; usually" they are about one-eighth inch or less in thickness and are usually from about two to six inches long. ' " Bedding planes of the thin-bedded limestone locally converge at-sm all acute angles as may be seen about 800 feet northwest of d rill hole 5 and in a sm all area mapped in the southeast part of South Peak : (pL; 1) .. ' ■Locally the angle of convergence of the strike of the beds is as great as 60 . The w riter attributes most of this convergence to crossbedding but recognizes that it may be influenced by folding or fault ing;, Numerous m inor folds are present in the thin-bedded limestone in the northwestern part of the west lobe. The writer believes that at least some of the limestone was deposited as a clastic sediment at relatively shallow depths. However, the presence of crinoid and ammonite re mains indicates deposition from warm, clear marine waters. . In a few places the thin-bedded limestone contains an abundance of small, round, quartz grains. One'small area containing considerable .quartz is about 300 feet northeast of holes 9 and 10, and another lies a .Short distance northeast.of hole 5. ■ These sandy zones can be traced only a short distance and probably were never extensive. The quartz Sand constitutes about 2 or 3 percent of the total mass of the sandy zones. These zones are shown on plate 1 and analyses of some of the m aterial are given under composition. Thickness ; • The thickness of the Hosselkus limestone varies considerably. Where measured by the w riter on the north side of the Saddle between North and South Peaks, the formation is 300 feet thick. There appears ' to be little Variation in tM s thickness in North Peak, but on the north side of it the beds thin appreciably and seem to pinch out a few hundred feet north of the peak, or they inay be faulted. The limestone is thickest on South Peak. To test the limestone and determine its probable greatest thickness, hole 8 was drilled nearly perpendicular to the beds exposed on the west side of South Peak, This is illustrated by plate 2, In this hole the indicated thickness of the beds is about 500 feet. Holes 8 and 10 drilled in the same general area tend to verify the results of hole 9. This thickness is believed to be reasonably correct. Although the beds may have been thickened by folding and rock flowage, there is no evi dence of duplication by faulting in hole 9. The w riter has been unable to confirm the .Statement b y,B iller (1908, p. 31) that the greatest thick ness of the Hosselkus limestone is about 140 feet. This is a little greater than the thickness of the formation in a sm all lens exposed a short dis tance north of the Indian Valley road, but is considerably less than the thickness of. limestone exposed on North and South Peaks. Fossils and Age ■ • The Upper Trias sic age of the Hosselkus limestone 'is well established by fossil'evidence reported by D iller (1908, p. 31). Good ' : fossils were not found by the w riter. Fragmental and distorted r emains of ammonites occur in some of the massive, moderately recrystallized ' limestone on the southeast side of the saddle previously referr ed too Round and pentagonal segments of crihoid stems are scattered through out some of the thin flaggy beds on the southwest and west sides of South Peak. Locally these are sufficiently:abundant to serve as markers by which individual beds can be traced short distances. 44 A lte ra tio n In places the limestone appears to have been altered by dolo- . mitigation. This has beep most intensive in a .small, incompletely ■ ; mapped area in the sontbeast part of South Peak. In this area dolomiiiza- tion has been relatively complete as shown by analyses included else where in this report. Several very small, irregular masses of dolomitic limestone occur in a broad, northwest-trending zone that crosses South .Peak southwest of holes 3 and 12. Only the largest mass of dolomitic limestone was mapped in this zone. Most of the dolomitic limestone oc curs in irregular light-brown or tan masses but some is found in narrow, short, discontinuous gash veins, either in limestone or in previously formed dolomitic material. The dolomite veins are white on fresh frac- ture and are easily mistakemfor calcite.' The origin of the dolomitic : material is unknown but it appears to be hydrothermal. In space it is closely related,to zones ef Structural'deformation. . gwearinger Slate ■, ,>.:B ^ - The Swearinger formation, which is referred to as slate by B ille r (1903, p. .32). underlies 'the eastern and southern slopes of South ;. Peak, and is conformable with and gradational into the Hosselkus lim e stone. .Because the contact between these two formations is gradational, it is difficult to map it precisely. The two formations appear to repre sent a period, of nearly continuous deposition. B iller (1908, p. 32) 45 ■ describes the formation as follows: The Swearinger formation is composed chiefly of dark slaty shale, sometimes becoming more or less calcareous and at others decidedly siliceous, but the thin beds of lim e stone or chert form only a small proportion of the whole mass. In the Side of the Swearinger slate adjoining the Hosselkus limestone thin lenticular beds of limestone be come more'abundant. They: are.generally dark, with ir- : regular cherty or sandy/layers?vand fossiliferons.'’ It is preferable to refer to the Swear inger as a formation rather than as:slate. Where observed by the w riter it is nearly black calcar- '' eons shale or shaly limestone. It lacks the characteristic luster, hard ness, brittleness,:-and cleavage of typical Slate. The formation contains abundant fossil fragments among which are some well-preserved fauna. D illor (19QB, p. 32) reports the pr esence.of Halobia, Monotis (or Pseudomonotis), Daonella, and Rhabdoceras. The age of the formation is established as Upper Trlassie. Some chemical analyses of the Swear- inger formation are given in this report under composition. The forma tion is relatively siliceous and in places, a few sand grains are found in , it. Locally the formation contains a small amount of disseminated pyrite. S tru c tu re F o lding In the Genesee area.the average strike of the formations is about N. 2’5° W. ‘ and the dip is from 50° to 80° west; however, in South Peak the beds have been involved in complex folding and faulting. The simple pattern of northerly striking beds, that dip Steeply west is com plicated by the fact that the beds are overturned so that the younger beds dip westward'foeneaththe,older beds. That the formations in some parts of Plumas County are overturned was recognized by M ills (189% p. 419) but conclusive proof was provided on the basis of fossils collected by B iller (1908, p. 31-34). By this means. D iller was able to show that the HosselkuS limestone is overturned and that it rests upon the younger Swearinger slate. These two formations are conformable and the con tact,bet ween them tends to pe gradational. The Reeve and Robinson, which are alsp overturned, now rest unconformably on the Hosselkus. AS pr eviously mentioned, South Peak is the locus of a large fold. Associated with it are a number of faults and much breccia which occurs in conspicuous, large, irregular masses. These features are r epresented bn plate 1. Inspection of the map: r eveals: that thin-bedded limestone is more or less restricted to the west and south sides of South Peak, that massive limestone is dominant on the east side, and that a prominent none of br ecciation trends irr egularly northwesterly across the central part of South Peak. - . . - Detail mapping of the bedding planes, or banding where bedding is not visible, ■ provides the best clue to the structure. At the north edge of the map the beds have a regional attitude, i. e., they strike northerly and dip from .- SO0 to BQ0 w est/ About ISO and-300 feet south of the north ■ edge of the map the beds locally are sharply folded and between the folds : V : . / 4T the dip is abnormally to the east. Southward from the last mentioned fold the beds have an early normal attitude until theybend westward into a prominent northwesterly trending, breccia zone. Beyond this breccia mass the strike of the beds turns westerly, thence southerly and finally easterly. The strike is approximately parallel to the con tour so f South Peak, thus indicating the existence of a large fold. The. :: thin-bedded limestone appears to have participated in the folding to a greater extent than the more.massiyd beds. Numerous minor flexures are pr esent in the thin-bedded limestone in the northwestern part of . South. Peak, The thin-bedded limestones in the south .-and western part .. of South Peak appear to have been forced northward over the more crys talline massiye rocks of the.. eastern part.. , ■ The western lobe has been arched pr domed with a few gently dipping beds preserved near the. summit of South Peak; whereas# steep ly dipping beds ar e found at both the north# west, and south margins. The character of the fold is illustrated by plate. 3. At the north margin of the lobe (pis. 1 and 3) some of the thin limestone beds are found to .dip-from-SO0-- to 50° south. These rest- on the Reeve and Robinson fo r- ;;v'- mations in an apparently normal sequence. The w riter interprets these unusual conditions as a second overturning of the beds due to drag in the lower part of the lobe# which has been moved northward by forces exerted -from: south-of the area mapped. F a u ltin g The folding, was accompanied by much faulting, but few faults are seen because they are obscured by large, irregular breccia masses. One northwesterly trending breccia mass previously mentioned marks the position of an abrupt change in strike of the thin-bedded limestone. It also marks the position of one of the most significant northwest-trend ing faults on gouth Peak (pi. 1). A prominent, north-trending fault that. lies about 400 feet east of diamond d rill hole 7 displaces the Swearinger- Hosselkus contact a considerable distance as indicated by plate 1. The ■ '■ ■ -. , '' ■ . ■. • ■. k ; south extension of this fault is lost in a,mass of breccia near hole 6. From the south side of South Peak another northwest-trending fault passes near hole 3V This fault appears to displace the Hosselkus- Swearinger contact and appears to be part of a zone of deformation along which the western part of South Peak was shifted toward the northwest. The actual fault plane is not visible but its position is indicated by an • irregular zone of breccia. A branch: of the fault or a sim ilar fault is e^bsed in a road cut 175i feet northwest of d rill holes 8 and 11. Near the summit of the hill, are three other northwest-trending faults. These are relatiyely conspicuous at the .Swearinger-Hosselkus contact but dis appear a. few hundred feet north of it. '; A prominent northwest-trending fault passes near d rill hole 5 ' (pL 1) and passes a short distance south of holes 9 and 10. The fault 49 displaces a block of the Hosselkus limestone in the southwestern part of the apea? but the amount of displacement does not appear to be great. The folding and faulting described above appear to have caused the accumulation of the large mass of limestone in South Peak. It can be shown on South Peak that limestone beds having an original strike length of '3j.8G0; feet have been compressed into a unit only 1, 600 feet . long. It is apparent that the total strike length of the Hosselkus lim e stone deposit in North and South Peaks before folding was about §<, 400 feet. This is exclusive of the; isolated bodies about which little is known. Most of the unusual features of the Hosselkus limestone can be accounted for by structural deformation. t Age. of'Defor mation : ,/ - The geologic history of the Genesee area is complex. The area was submerged and received varied sedimentary and igneous de posits throughout most of the Paleozoic. Near the end of the; Paleozoic the sediments were compressed, folded, intruded by igneous materials, and uplifted. After a long interval of erosion the area was again sub merged. and Trlassic and. .Jurassic sediments, were .deposited upon it. During the Neyadian orogeny the rocks were again compressed, folded, intruded by igneous materials, and again uplifted. Probably the strata ■ " ’ ■ » . ■ .V ■ -- , ; \ : - ■ . at Genesee were overturned during the Nevadian orogeny by forces generally thought, to have been exerted from the west. The area has been subjected to erosion and minor oscillations since the Nevadian. It is possible that the large fold in South Peak is related to the Nevadian orogeny, but in the. writer*s opinion it is more likely related ■ to later deformation. The west lobe appears to have been shifted north ward, over. m or e , competent beds. in. the eastern side of South Peak. Some : of the large,, irregular breccia masses associated with the folds are .looser unconsolidated;, and uncemented.: They suggest br ecciation of ":' ': brittle rocks at shallow depths. This criteria indicates a long period of ' erosion elapsed between the 'time, when the beds: were overturned and the time when the deformation of the: west lobe took place. This may have occurred during the late Cenozoic, but the problem cannot be resolved without more extensive field work, j Geology of the yirg ilia Limestone Deposit General Features At one time the yirg ilia limestone deposit was known as the Pyramidal deposit. It was form erly controlled by the Feather River Pyramid Lime and Cement Co. which was owned by EL C. Flournoy, , Quincy, California. A small amount of limestone from this deposit was calcined between 1919 and 192'7 and used for building purposes. The deposit is briefly'described by Aver ill (1937, p. 141) who cites analyses from Scott (private report) to show that the limestone and interbedded 51 : . ' . _ 1 ■■ , ' - ' V , ' shales have a composition sim ilar to Belgian natural cement rock and to other calcareous materials from which cement is made. The source of the m aterial referred to by AverllTis the small quarry and caved adit V near the south side of the Bush Cr eek road. In the headwaters of the Feather River? M ills (1892, p. 428- : 480) reported that' a large area was underlain, .by fossiliferous limestones .' that seemed to rest unconformably on pre-Mesozoic rock. Be recognized these limestones in the vicinity of Yellow Cr eek, Mosquito Creek, and Bush Creek. The limestones lie.inthe southeaster npart of-the Lassen ' ' Peak quadrangle mapped, by B ille r (1895). who assigned them to the Cedar formation, a name derived from the type section on Cedar Creek near'Bedding.. Begarding the exposures in the southeastern part of the Lassen Peak quadrangle D iller (I8'95, p. 2) reports as follows: Here, as on Cedar Creek, limestone form s an im portant stratum, and the Triassic fossils it contains show clearly that it is in the same horizon as the Hosselkus limestone and associated Triassic rocks of Genesee ; Valley. w ■ ' Turner (1894, p. 229-249) also considered the Cedar forma tion to be equivalent to the. combined Hosselkus limestone and Swear- inger slate exposed near Genesee, ft is interesting to note that at an earlier date B iller (1886, p. 404 and pi. XLVII) considered the rocks as part of the Auriferous slate '.series, a term then assigned to a large part of the "Basement complex. " This terminology was significant be cause erosion and disintegration of quartz veins in part of the Cedar formation furnished gold to old plae er mines on Rush Creek, Indian Creek, and Worth Fork of the Feather River, as shown by D iller (1895, p,a). ■ " ■ ; In the V irgilia area in the southeastern part of the Lassen Peak quadrangle the Cedar formation crops out in an area about 15 miles long and from one to three miles wide. The regional strike of the formation is about N„ 10o-20° W. and it dips from 40° to 75° northeast. Lime stone is the cominant constituent in a zone extending along the east side of Cherry Gulch from Rush Creek to the north side of Cherry Peak. Shale Is a prominent constituent at other places. Near the south end of the zone inter bedded limestone and shale having an aggregate thickness of 214 feet is exposed in a cut along the Rush. Creek road. These beds can foe traced northwestward about 800 feet to a point where they disappear beneath a prominent talus or debris 'slide (fig.. 10 and pi. 4), composed principally of metavolcanies. The main calcareous zone again makes its appearance north of the talus, thence extends northwest to the vicinity of Cherry Peak, a distance of about one mile. This calcareous zone attains a maximum thickness of about 900 feet. - ■ . % ’Withindhe area.studied (fig. 10) are three distinct lithologic rock types. Underlying the western part of the area principally near the main drainage of Cherry Gulch are thin-bedded shales and calcareous shales. Resting upon these are interfoedded limestone, shaly limestone, and calcareous shale. Both of these units; belong to the Cedar formation 53 CHFRRY nGURE to S K E T C H M A P V/RGILIA LIMESTONE DEPOSIT COMPILED FROM AERIAL PHOTOS ONCORRECTED FOR DISTORTION V* vV COMPILED BY H PAULSON CCOLOGY I - OH.FAICH H. PAULS OA/ CONTPOLt-U. MA THIS R E V IS E D or OSLF /SS9 APPROX. SCALE tsoo' LEGEND Metavoiconic Talus Netavoiccnics Limestone Shale of the Triassic,. Resting upon the Cedar formation and in places ap parently inter bedded w ith.it are. Jurassic metavolcanicSo The three rock units exposed witliin the area studied are briefly ■summarized as. follows: v Jurasisic(?) (Upper unit - Metavolcanics in (upper part grading downward ' - ... ■ (into interbedded pyroclastics(?)? (calcareous shale and limestone. Triassic (Cedar formation) , (Middle unit - Interbedded lime- /< : : (stone, shaly limestone and cal- ' (careous shale. ./ .V . . ■: - . ■ (Lower unit - Shale and calcar- (eous shale. Only the limestone and shaly limestones in the Middle unit are of particular interest as possible sources of cement rock. These w ill , be briefly ^discussed under stratigraphy. A noteworthy feature of the limestones and shales in the V irgilia -area is their transitional character, the . manner in Which they blend into each other from bed to bed throughout the stratigraphic section and also laterally along the strike. Apparently they change from: limestone and / shale and vice-versa with, considerable inter fingering of the different facies. Small scattered zones of tuffaceous sediments and other pyro clastic materialsiare locally present. The sediments represent deposi- . tion under m ildly fluctuating conditions dur ing the Triassic. Deposition vras culminated by extrusion of the Jurassic metavolcanics. ; 55 Stratigraphy Lower Unit (Shale) - . The lower unit studied at Virgilia. consists of shales and cal careous shales which in a few places include beds of limestone ranging in thickness from a few inches to several feet. The typical shale is gray to yellowish gray, very thin bedded, and argillic in character. The shale zone underlies most of Cherry Gulch (fig, 10) west of the area studied in detail, and was not examined critically except near the con tact with the middle unit. The most prominent limestone zone observed in the lower unit is several feet thick and is exposed in places along the footwall access road. It crops out in Cherry Gulch and on the south side of Cherry Peak. The shaly beds grade into the V irgilia limestone, or ' middle unit. ' - ■ ’v. ; ’ ' : : Middle Unit (Virgilia,Limestone) , The middle unit consists of pods, lenses, and beds of limestone interbedded with strata of shale, calcareous shale, and shaly limestone. ' Locally the shales are micaceous, and considerable portions are very carbonaceous. In some places the shales have the appearance of slates and phyllites, and the limestones are crystalline, thus indicating that locally the rock has been,subjected to slight metamorphism. The lim e stone norm ally is medium gray dense to crystalline rock that weathers to light gray, . Its lithologic -character ranges from very thin-bedded or : ■ ...... ■. ; . : ' ; ■ ' v slaty to thick=bedded: or massive limestone, and the quality ranges from very impure to relatively pure calcium carbonate. v'.;' - ; . ? . • : '■ ' ■ y ' . • ' - ■ The largest limestone bed is the hanging-wall bed that lies ju st : under the. metavolcanics and crops out prominently from the slide area " ■ • on the south to about Ridge 2 on the north (fig. 10 and pi. 4). It is about 100 feet thick. North of Ridge 2 the bed seems to become more shaly ■ and tends to blend with the intermediate shaly zone. North of Ridge 2 a wedge of shaly limestone appears to lie between the hanging-wall lim e- , stone and the metavolcanics which for m a capping over the depo sit. Nor th of Cherry. Peak in an unmapped area is. a prominent bed that stratigraphic al ly is. in the: .approximate position of the hanging-wall bed, but the two beds, probably ar e not connected. Another prominent limestone bed lies near the footwall of the middle unit and crops out from the south side of Cherry Peak to about 500 feet south of Ridge 3. This bed norm ally is about 125 feet thick but thickens to about 250 feet in Cherry Gulch. A few hundred feet south of Ridge 3 the bed tends to merge with shale and becomes part of the middle unit, & shaly limestone mass that extends southward to the Slide ar ea. The footwall bed tends to be lenticular and in places is definitely shaly. , \ In a few places,:. as on Ridge 2 and 3 and in the ar ea southeast of the talus, there are masses of volcanic materials that appear to be conformable with the enclosing strata in the lower part of the middle unit. Presumably these are pyroclastic materials deposited with the limestones and shales,, but it is conceivable that some of them may be intrusive sills or dikes. Upper Unit (Metavolcanics) : The upper unit consists of metavolcanics of an unknown thick ness. The upper portion has the. appearance of typical massive andesite and this grades downward into banded and schistose or gneissoid meta- . volcanic m aterial that in places is definitely bedded. At-the base of the upper unit are interbedded limestone, shale, and tuff(?) beds. Locally, near the" base of. the unit, the metavolcanics are conglomeratic^?); they ‘ . contain elongate or flattened pebbles ranging in size from a fraction of an inch to sever al inches across. The . conglomer atic beds observed range in thickness from a few* inches to about 25 feet, but are not every where present; the distribution is erratic. In places, as on Ridge 2, limestone beds as much as several feet thick appear to be interbedded with metavolcanics, tuffs, or other pyroclastic xnaterials near the base of the upper unit. The metavolcahics are probably Jurassic. S tru c tu re From a regional aspect the structural geology of the V irgilia limestone deposit is comparatively simple; however, in some local areas ' the geology is exceedingly complex because of folding and faulting. Beds of the Cedai* formation^ including the limestone beds, generally strike ■ Ho' 10o-40° Wo- and dip about 45° NE»,. but considerable variation in . : this attitude is noted. _ ' tEor pra.ctieal and descriptive purposes the deposit is divided ; into two parts, (1) southeastern and (2) northwestern. These are sep arated by a broad area of talus or. ’’slide” rock debris composed of meta- ’ volcanic ’.’cap rock, ” that slid from its nor mal position on Eagle Rock Mountain.. Undoubtedly the slide was caused by weakening of the rock ' : : by faulting, although evidence of the faults is obscured by talus, soil, and.vegetation.. •Field observations-indicate that (1) a north-trending fault or fold, now concealed by the talus, displaced the hanging-wall limestone a few hundred feet and,probably also- displaced the metavol- ■ canics with the east side down. (2) At least two and possibly more faults of a thrust nature appear to extend into the upper part of the slide from its east side, . . t i the Rush-Cr eek- area the beds have; been considerably de formed by folding, as revealed by anomalous strikes and abnormally steep dips.. ' Above hairpin curve, in the road east of the talus, both the footwall and hanging-wall limestone beds appear to be present in their normal position, but their dip: is flatter, than the average. In this area : the hanging-wall beds ar e r epeated because of faulting (fig. 10 and pi. Northwest of the slide area, the attitude of the beds seems to "■ . v ; 59 be about normal except for minor, relatively; unimportant^ changes in strike and'dip. . structurally the beds appear to be only slightly disturbed by faulting, which seems to be more intense toward the northern part, or •Cherry Peak section; . Folding and faulting appear to have been intense in ah unmapped area near the head of Cherry Gulch. ; , Nearly vertical .faults of small displacement that strike approxi mately parallel to the strike of the beds' are exposed between Ridge 1 and . Ridge 2.' On'Ridge 2 .and Ridge 3, are structurally disturbed zones that ■ mark the position of faults, and diamond d rill hole 4, on Ridge 3, was lost in a fault. Little could be learned of the amount or direction of displacement along these faults. From the data presently available, the observed structural deformation between the slide area and the gulch south of Ridge 3 does not appear to be 6f such magnitude as to seriously disrupt the continuity of the limestone beds. . Composition of Available Cement Materials Genesee Limestone Deposit . - • Hosselkus 'Limestone Presently available data indicate that, with minor exceptions, the.: Genesee limestone is •remarkably' pure- -■ Locations of carefully cut . •chip ' and channel samples taken across the edges of the upturned strata so as to be representative of the m aterial aye shown on plate 1- 80 Samples 400 to 410;Inclusive were cut across the most prominent sandy zone for the purpose of determining the composition of this materiaL The arithm etic average of the components in these 11 samples give an arithmetic average,, in percent, of: • • 2 ,7 6 ; -MgO 0..77-'. ■ . . ■ ' ’ CaO 53,3 v': . ' ; . AlgOg. 0,84 ■ ' Some of the purest limestone is represented by samples (426 tg 430 inclusive^ which give an arithm etic average of: , :,v ./:;S i 0 2 0.0: . '' i . ' .' MgO. : 0. 52 .^CaO .56,1:. : / ' AlgOg. 1.31 - : ^ ; . , : Another zone of pure limestone which is represented by samples 431- 437 inclusive contains an arithmetic average of: ' , / SiOg ’ 0,52- : ■ MgO - .0 .7 4 . :: ;, cao:: 55, 2. / : A I2O 3 0 .9 3 These analyses, which were made by Morse Laboratories, tend to verify numerous preliminary'random, chip samples which indicate that the rock has a high lim e content, except for local zones where it is magnesian. These zones' do not incr ease the overall magnesia content to seriously detrimental amounts for use in cement. A ll d rill cores and many sur face samples' were analyzed for magnesia which is found to range from nil to about 20 percent as indicated by a few hundred analyses. Worthy of note is a series of surface samples across the dolomitic zone in the southeastern part of the area, as shown on plate 1. ■ Samples SF 1 to 19 inclusive, taken across this dolomitic zone which is about 150 feet wide, ' . ■ ■, ■ ■ ■' / - ■ ■ , ■ 61 indicate an arithmetical average of 13.38 percent magnesia. These samples were analyzed:by Abbott A. Hanks, Inc., San,Francisco. Fortunately this dolomitic zone occurs only in the southeast extension of the main body of Hosselkus limestone. Of more immediate interest are the numerous small patches of dolomitic limestone that are found elsewhere-;in the deposit. These, are readily apparent' on the.surface because of the distinctive manner in which they weather to a smooth brownish surface of the weathered limestone. Usually these magnesian zones can be detected easily by testing with dilute acid which usually w ill not effervesce on the dolomitic rock. :A typical magnesian zone is represented by samples 418 to 423 inclusive (pi. 4). The weighted av- . or age of these samples^ as determined by Morse Laboratory, contains:. SiOg 0.0 MgO 6.0 • CaO,;: , 4 9 .3 ; ■; AlgOg '0.-82. It is worthy of note that the weighted average for all d rill holes excluding % and representing a total of 4, 945 feet of hole is 2.12 MgO. This may not be a realistic average magnesian content of the Genesee limestone because most of the drilling was in structurally deformed areas most likely to be dolomitic. The Hosselkus limestone deposit averages about .53 percent CaO, less than one percent each SiOg and AlgOg, less than 0. 5 percent FegQg, less than 0:. 5 percent combined alkalis, and about 2 percent MgO as indicated by assays from both surface channel samples and ■ diam ond;drill ■ cbr e sarnples the southeastern coraer of the deposit is excluded from this estimate, gwearinger Formation ' _ The' Swearinger has attracted little attention .during this investi gation because it was presumed to be too impure to be suitable for the manufacture of cement; however? the meager- data presently available suggest that it might be usable as an admixture. The Swearinger at Genesee is dark gray to black, carbonaceous* shaly limestone having a relatively high content of silica. Locally it contains considerable pyrite, of which the sulfur could be -deleterious; however, the iron might be beneficial. The few analyses of the Swearinger that have been made are:given in tableS^ ' v -'' - , - ' As is obvious in the analyses shown in table 5, the feature that is. most, detrimental and .which would probably prevent the use of the \ Swear inger as an admixture is its lack of uniform composition. Also, the ratio of silica to iron and alumina may be too high for an admixture. :;V- Virgilia.Limestone Deposit The largest part of the V irgilia deposit lies between the talus area on the south and the head of Cherry Gulch on the north (fig. 10 and pl. 4). In this zone a prominent bed of limestone about 100 feet thick rests upon a thick zone of interbedded limestone, shaly limestone, lim y shale, and shale. Near the base of this section ar e beds of r elatively 63' Table 5.— Analyses of Swearinger formation. F o rm a tio n Lo cation S i0 2 Fe20 3 AI2O 3 MgO CaO 0- 2E . Swear inger- ... ' , - v B osselkus ;; transition ■ zdne(?)" ' 16,18 0.-34 .2 ,1 2 - .2 . 06 . 4 2 .6 BBH#1, 2p-:52r ' Same as above ' 12.94 .0.41': 2.15 2.15 44.1 i © BDB #1, 52^86®: Same as above 6.58 0.31 ■ 1.39 ..2.25 ' . , : v '; " BDB #5, 0-24* ; Swearinger ;. 21.68 0.80 DDB #5, 24-45* Swear inger ' ' 32, 88 ■1.02 DDB'#5, 45-56* Swearinger 16.32 0.98 Southeast side of N. P eak Swearmger(?) . ■ 4 .2 3 . '2 ,8 9 S wear inger Spur Swearinger (?) 61. 54 2.3 4 8 .6 4 3.57 Epstein Tunnel (la s t 30®) Swear inger (?) 30.10 1.56 7.82 2.07 pure limestone which are referred to as footwall limestone. These beds attain their greatest thickness near the head of Cherry Gulch, but south , of it tend to be lenticular and discontinuous. Both the hanging-wall bed and the. footwall beds are relatively . pure, they contain 50 percent or more CaO and less than 10 percent : . ■ ' . - ■ ' ■■■ , . . . , . z impurities, mostly silica. The impure shaly limestone of the \ \ ■ 64' intermediate zone is shown by a great many analyses to contain from 40 to 50 percent GaO and from 10 to 30 percent im purities. To determine the composition of the V irgilia limestone deposit it was tested by four diamond d rill holes. Three of these were drilled nearly perpendicular to the beds, and one was drilled obliquely to the beds to test the hanging-wall zone. The d rill cor es were split and ana- :Tyzed»;:';idsoJ;'’several Ibies/of.'Samples, wm*'©.cut'-across the outcrop. . Sample intervals correspond to changes in lithology; each sample repre sents a specific bed or series of beds. having: sim ilar characteristics. Wherever possible^ the surface cuts extend from the metavolcanic hang ing wall to the shale fobtwall. The locations of the d rill holes and surface' - ■ ■ - ' ' ■ • ■ . : ■ - , - , 4; . - ; _ - - _ . . ■. , ■ . samples are shown on figure 10 and plate 4, and the holes are illustrated on figures 11, .12, and.13. A total of 1:63 samples of diamond d rill core - representing 2, 764 feet of hole and 265 surface samples representing 6, 665 feet of chip, groove, and channel samples cut practically normal to the:strike were..analyzed and evaluated to determine, the average com position of the deposit. Only the samples pertinent to this investigation are discussed below and are shown on tables 6 to 9 inclusive. The - weighted average analyses of the d rill cores are shown on tables 6 and . 7. The weighted average composition indicated by part of the surface samples is shown on table 8. Results of surface and d rill core, sampling are summarized as follows: Hole no 3 Inter bedded limestone and volcanics Limestone Sholy limestone Calcareous Shale S h a le Scale - feet Fig 11 - Virgilia Limestone Deposit. Section through drill holes I and 3 'Inter bedded limestone and volcanics Shaly limestone Calcareous Shale S h a le H o le no. 2 Scale - feet Fig. 12 - Virqilia Limestone Deposit. Section through drill hole 2 / Interbedded limestone tx' and volconics Shaly limestone Fault Shaly limestone Hole no. 4 Lim estone S h a le O lOO ZOO 3 0 0 4 0 0 5 0 0 111 ■ 1111111 I I I l S c a le - fe e t Fig. 13- Virgilia Limestone Deposit. Section through drill hole 4 68 Table 6.--Weighted average core analyses of Virgilia limestone Interval Distance SiOr, CaO MgO Al90q 15-75 60 18.1 40.0 0.31 75-137 62 16.8 43.7 0.67 137-151 14 20.2 40.8 1.72 151-209 58 24.5 38.4 1.35 209-339 130 20.2 41.1 1.23 339-380 41 23.5 37.6 0.89 380-437 57 12.7 46.1 0.78 437-460 23 14.9 42.2 1.19 Hole Noe 1 460-527 67 3.2 49.8 0.58 527-557 30 14.3 45.7 0.67 557-620 63 25.0 35.0 1.26 620-640 20 53.3 11.7 1.1 640-690 50 34.6 24.8 1.06 690-790 100 39.7 14.6 2.13 790-900 110 39.1 15.0 0.80 900-941 41 52.9 4.8 0.75 15-557 * 542 16.9 42.6 0.90 557-900 343 37.1 19.8 1.34 0-45 45 2.0 52.1 0.36 45-92 47 17.4 40.5 0.37 92-249 157 15.3 43.9 249-302 53 24.5 34.2 302-460 , 58 14.8 44.1 460-540 80 21.2 40.4 540-701 161 15.3 43.7 Hole No o 2 701-763 62 5.5 52.4 763-798 35 30.0 29.1 798-865 67 12.9 45.4 865-902 37 36.3 23.2 902-925 23 40.9 13.7 0-701 701 15.9 . 43.1 701-865 164 13.7 44.6 0-865 8 65 15.5 43.3 0-100 100 3.5 50.9 100-120 20 25.9 31.2 7.8 Hole No * 3 120-160 40 45.2 16.1 11.9 160-180 20 8.6 48.7 180-212 32 42.8 17.2 12.3 212-226 14 10.6 47.4 0-174 No recovery 174-435 261 15.3 44.8 Hole No e 4 435-521 86 29.3 31.7 521-579 58 18.6 41.9 579-664 85 40.3 24.0 174-664 490 22.5 38.5 69 Table 7„--Summary of weighted average analyses of Virgilia Drill Core Hole Noo Interval Si02 CaO A l 2 ° 3 * * 1 15-557 16.9 2.9 42.6 3 0-100 3.5 0.1 50.9 2 0-865 15.5 1 .7*** 43.3 4**** 174-664 22.5 -»=»=» 38.5 TOTAL FEET 1997 w ei gh t ed AVERAGE, 1 to 4 17.0 e. — e. 42,3 inclusive WEIGHTED AVERAGE OF 1, 2 and 3 15.2 2.0 CO CO Analyses by Morse Laboratories, Sacramento, Calif„ ** Data from composite samples„ *** Interval represented 0-701 feet, #*##jjrill hole incomplete; represents about 60 percent of section. Table 3 .--Summary of weighted average analyses* of some Virgilia surface samples Sample length CaO MgO Samples Si02 A12°3 in feet** VS 1-20 586 12.9 4.9 45.7 1.0 VS 45-53 VS 121-150 857 12.2 3.5 45.7 1.8 VS 153-172 944 10.3 2.5 47.8 0.8 VS 203-226 688 13.7 2.7 45.7 1.0 Total 3075 ft.*** Weighted Average 12.1 3.3 46.3 1.2 » Analyses by Morse Laboratories, Sacramento, Calif ornia 4HC- Approximates stratigraphic thickness 0 Incomplete Table 9 „ --Analyses'8, of composite samples of Virgilia limestone Sodium Potash D „ D o H o Footage CaO Si02 A12°3 MgO Fe2°3 Na20 k 2o No, 1 15-75 42.1 16.8 4.54 1.07 1.3 0.06 0.28 75-137 45.1 15.0 3.07 0.84 0.69 0.04 0.14 137-151 42.9 17.6 2.57 2.20 0.39 0.02 0,12 151-209 40,2 22.8 3.05 1.42 0.39 0.01 0.15 209-339 42.5 17.5 2.72 1.33 0.64 0.04 0.12 339-380 39 o 9 20.9 3.63 0.64 0.69 0.02 0.23 380-460 46.2 12.6 2.62 0.61 0.64 0.02 0.19 460-527 53.2 3.5 1.07 0.41 0.53 0.01 0.09 527-557 44.8 13.6 3.83 0.38 0.41 0.02 0.16 557-620 35.6 23.0 6.18 1.30 2.06 0.05 0.51 620-640 12.0 52.6 11.5 2.15 5.60 0.07 1.00 640-690 27.3 32.0 9.00 1.80 4.35 0.04 0.84 690-790 15.6 42.0 14.78 2.81 6.50 0.07 0,91 790-900 18.2 40.1 13.14 2.35 5.90 0.12 1.05 900-941 8.3 56.1 13.9 1^91 6.8 0.10 1.91 15—557 44.3 15.3 2.90 0.95 0.66 0.03 0.16 557-900 21.6 37.1 11.64 2.20 5.13 0.08 0.88 No. 2 0-45 52.8 2.6 0.44 0.38 0.84 0.18 0.10 45-92 42.1 16.6 3.68 0.52 1.08 0.10 0.31 92-249 46.2 14.1 2.2 0.64 0.96 0.04 0.14 249-302 35.0 24.6 4.12 0.88 3.0 0.07 0.61 302-460 44.9 14.5 0.54 1.16 1.38 Trace 0.13 460-540 39.3 20.4 3.47 1.30 1.01 Trace 0.19 540-701 44.9 14.2 0.54 1.33 1.14 Trace 0.12 0-701 44.1 15.2 1.72 0.98 1.26 0.04 0.18 in o CO o tsD No. 3 0-100 2.5 0.1 0.69 0.96 0.32 H -a Q ^Analyses by Morse Laboratories, Sacramento, California All analyses are weighted^. . ' ■ . : ' ' 71 _ Percent Percent Percent - 1 ; Cap ■ ' Drill core samples - ' . .. 15.2 43, 6 ■ . 2,:0 , Surface samples^ 12,1 . 4E,3 . . .. 3,3 It is to be noted that a difference of about three percent SiQg and CaO exists betweenthe analyses of the surface and,core samples. This may be due to differential weathering or to loss of some materials during core drilling but a satisfactory explanation is not evident, ■ To verify results of sampling and analytical work, as well as . to obtain additional data, many composite samples were prepared from the core from holes 1,. 2, and 3, The composite samples were prepared by combining proportional parts by weight of rejects from the core. Rel atively complete analyses were made and the results are given in table 9, Inspection indicates that the analyses of the composite samples check the analyses of the original samples within reasonable lim its customary in commercial work. The analyses' now available indicate that the average composi tion of the V irgilia limestone is about as follows: ' 45,0 percent daG ; : 1.0 percent Pe^Og . - : .^ -# 7 . do, f -giOg. v; y-.v ■ l.o do. ' MgO . -2.7. doi .AlgOg. . 0. 3 do. a lka lie s As previously mentioned the V irgilia deposit shows variation from bed to bed and also along the strike of individual beds, Within the main area of interest the average composition across the entire width . ' ' '■ ■■ . 72 of -the-deposit taken as a whole remains 'relatively constant for a strike length of about 5, 000 feet. A significant increase in the shale fraction takes place northward from about Ridge ,3 and the deposit changes to a 1 very thin-bedded or laminated calcar eous shale that is well exposed along the Cherry Peak road. ,-'in Ihe, C lW ry P'eW area'-the- entire strati graphic section of calcareous sediments seems to be represented, ap- parently.it is somewhat thicker than' farther; south, the 22. 5 percent SiOg in hole 4 is indicative of the high shale content in the upper part of Ridge 3. Because of drilling difficulties this hole was Stopped before penetrating the lower portion of the main limestone zone. Surface study and sampling indicate this lower sectibn contains more limestone than that, intersected in the drill hole. - ’ The most southerly limestone outeropj which is south of the talus hrea?'is . well exposed dm the Rush Creek road.. Her e a strati- ' graphic thickness of 214 feet of thin shaly beds interfingering with beds . of limestone from a lew inches to a: couple of feet thick are exposed be tween the shale footwall zone and the metavolcanic hanging wall. Along . the. Rush Creek road the beds strike N. 30 W ., about the average for the main deposit, but dip about 70° northeast. These beds are moder ately deformed and considerable vein quartz has been injected into them. The footwall and hanging-wait beds have not been recognized near Rush .Creek. The weighted average of 12 samples taken along the Rush Creek road to represent the entire section between the shale footwall and the metayolcanic hanging wall is 23.53 percent silica, 36/53 percent CaO, an.d 9o 9 perCent AlgOg, A sm ail amount of cement was made at th is . locality from 1919 to 1927. lone For mation The lone formation in the Groville-Pentz area was investigated as a possible source oi admixture„ It should be suitable for this purpose as it consists of clay and fine sand. Either highly siliceous'or aluminous m aterial should be obtainable by selective open-pit m ining: and theor et ically it would be possible to secure the desired proportions of silica -and alumina, by a simple wet classification pro ceSs, However, the high . , iron content of the lone might prevent its use in the manufacture of white cementas shown, by Bogue (1955, p : 25^; but would be desirable in most ’ tj^jes of cement., In the published literature there are many analyses of the clay . '■ : ’ - ■' Vr . ' ■ . ■ and sands of the lone, a few of which are given in table 10, In addition to the analyses given in table 10 others have been collected by the company-in the Qroville-Pentz area.,. Three •samples ■■ collected by F. T. Johnson near an abandoned clay pit about a half m ile southwest of Wicks Corner are given in. table 11. : During this investigation the w riter took some additional samples of the-line; sands and clays in the-Fentz area, but at present it is uncer tain whether all of these represent the lone formation or whether some 74 Table 10o- -Analyses'*’ of some lone sands and clays. j f 1 2 3 4 5 P i Si02 71.62 48.00 43,21 53.68 53.74 50.38 A1203) 18.62 35.56 40.21 24.2 31.59 32.49 TiO, ) i ' | Fe20 g 0.52 1.54 1.34 6.9 2.51 2.99 CaO 0.32 0.23 0.40 0.91 0.91 1,15 MgO 0.33 0.35 0.21 1.15 0.5 3 10 07 Na20 ) 0.63 1.10 0.20 0.64 e» eo go eo k 2o ) “H20 ) 7.59 13.60 14.83 11.6 10.19 11.29 +h 2o ) *A11 of the analyses in this table are taken with slight mo dification from V. Allen, 1929. They are described below„ No0 1- Average of five analyses of lone sand from Newman Pit, one mile south of lone, California No. 2- Plastic lone Clay, Jones Butte, 3 miles north- west of lone, California No. 3- Average of three analyses of Edwin Clay, Jones Butte, California No. 4- Average of two analyses, lone clay, Valley Springs, California No. 5- Average of three analyses of lone Clay, Lincoln Clay Products Co., Lincoln, California No. 6- lone clay, Gladding McBean Pit, Lincoln, California ■ ■ ' • 75 TaMe ll. --Analyses of lone .clay near. Wicks Corner. • , ' 2 ' ■ 3 ; 51.2 ;. ; 52.6 : . 57 .5 . : AigOg . .2.9.0, 29 .0 30.26 .■Fe^Gg / , : ; ' 5,26 : ; S . 6. ■ 3.5 4 CaO ■ ; 1.21 . ■ 'C'T/:: v MgO ' ' ' 0 .9 9 of them are assignable to the underlying Dry Creek beds. Analyses of ■ . : ■, - - - 1 4 ' . - ■ , V ,, ... the ean^les,are given in t#le'l% ^ il :\ - C'alavaras Formation:. - ' The Calavaras formation of the ’fBasement complex" in many places contains thick zones of shales, slates, quartzite, and other meta- sediments, many of which are considered to tie suitable for use as ad mixture. Four of these in the Pentz area were sampled by the w riter as ■ possible sources. of. silica, alumina, and iron. The analyses are given \ in tab le ,13. 76 Table 12<>--Analyses4*' of fine sandy clay near Pentz , California 1 R-2** CO R-4 R-5 R-6 R-10 Si02 72*6 57.2 66*9 61*6 66*9 71.4 A1 2°3 14.3 18*5 13*6 14*1 14*7 11.8 Fe2°3 3*77 7.48 6*06 5*9 5*45 . 5.49 CaO 0*35 0*82 1*98 0.46 0.58 1.51 MgO 0*52 1*59 1.97 1*01 0.96 1.25 Na2®3 0*36 0*53 1.30 0*37 0.83 0.63 K20 0*48 1.94 1*78 1.57 1.67 1.68 *Analyse s by Morse Laboratories, Sacramento, Calif* ^Designation refers to a special group of samples„ Area sampled is shown on U . S» Geol„ Survey, Cherokee quadrangle map, scale 1 = 24000, 1949„ Descriptions and locations of these samples are given below: R-2 Sandy clay about 500 feet northeast of P „ G 0 & Eo ditch tender's residence* Location near center of Sec 0 31, T 21 N, R 4 E* R- 3 Clay in road cut in SE l/4 of Sec 0 36 , T 21 N , R 3 E „ Same low hills as sample R-2 0 R-4 Fine sandstone in road cut 003 miles north east of old Pentz road; north side of first cut east of concrete bridge» Location S l/2 of Sec o 36, T 21 N, R 3 E 0 Sample represents 25 foot exposure of horizontally bedded fine sands with a few layers of pebbles 0 Slightly iron stained* R-5 Yellowish gray clay with black carbonaceous clay at base» Sample thickness about 15 feet* Location is road cut south of Wheelock ranch house about 1*4 miles northeast of old Pentz road; south edge of SW l/4 of Sec* 30, T 21 N , R 4 E. R-6 Sample represents 5 feet of fine sand resting on 5 feet of clay exposed on south side of ditch about 100 feet south of new road* Location NW 1/4 of Sec* 31, T 21 N, R 4 E. R-10 Sand and clay from Lucky-7 ranch* Sample from gully on SE side of hill 564* Location NW l/4, SW 1/4, Sec* 25, T 21 N, R 3 E* Table l3o --Analyses"5* of Calaveras shale and slate R-7** R-8 R-9 R-ll Si02 58 .1 75.0 70.2 59.2 A12°3 1 9.4 3.71 12.9 18.5 Fe2°3 8.51 5.01 - 5 ,. 60 7.78 CaO 1.05 0.23 0.35 0.70 MgO !2.96 1.36 1.65 3.83 Na203 b.14 0.26 0.18 1 .2 0 ; K20 1.83 1.91 1.91 2 .0 1 "Analyses by Morse Laboratories, Sacramento, Calif0 '"Descriptions and locations of these samples are given below. t - ' R-7 Clay shale of "Basement complex." Some of i material appears talcy. Sample represents southwestern half of prominent cut on new road; length of sample about 150 feet0 Location SW l/4, Sec. 30, T 21 N, R 4 E., 106 miles from old Pentz road. R-8 Slate of "Basement complex" in new road cut 2.1 miles from old Pentz road. Sample represents l/3 of cut southwest of meta- diorite (?) dike. Location North l/2 of the SE 1/4, Sec. 30, T 21 N, R 4 E. R-9 Dark gray slate of "Basement complex" in abandoned ditch on west side of C. A. Phillips ranch. Stratigraphic thickness of 25 feet sampled, total thickness unknown. Location South 1/2, NE 1/4, Sec. 30, T 21 N, R 4 E. R-ll Slate and clay shale from "Basement complex" in gravel covered area on east side of Wheelbck ranch. Approximate location East l/2, SW l/k, Sec. 30, T 21 N, R 4 E 0 I - . ' ' ' \ ™ - • Utilization of Available Cement Materials TWr& considerable iatitW materials for the manufacture of cement as is evident from the preceding discus sion« Cement could be manufactured from the Y irgilia cement rock, and if the carbonate fraction needs to be incr eased this could be done by the addition of pure limestone from Gehesee/ or froni high-grade limestone beds at V ir gilia, Limestone . Point, or possibly some other. deposit' ' ' ; ' . • .. If it is preferred to manufacture cement from Genesee lim e-. stone by the addition of aluminous material^ then the fine sands and clays of the lone or the shales and slates of the, Calavar as could be used. To the w riter it would seem preferable to use the lone because it could be easily obtained at a low cost. The w riter believes that by a simple process the lone could be made into a slurry, classified to obtain the desired sand-clay fraction, and added to Genesee limestone in the correct proportions for kiln feed. A typical average sample of Y irgilia cement rock containing : . 43. 84 percent CaO (78.3 percent'CaGOg) with siliceous, and carbonaceous im purities was submitted to a cement consultant for laboratory testing. ' He reported (written communication to A. ,K. Lindsay, January 18, 1958) this to be an excellent natural m aterial for the manufacture of high-qual ity low-heat cement for dams or other; massive structures. This natural high quality of the cement rock is attributed by him to the very fine grain /Size of the siliceous particles and the manner in which they are intim ate ly mixed with the carbonate. He emphasized that this factor is important because the m aterial would be easy to "burn" ■ and would require less; fuel than some other materials. He stated that some pure limestone, high aluminous clay and' a little iron should be added to the V irgilia cement rock to produce cement for present-day Type I and Type II requirements. Dr. R. H.' Bogue (private,report, December 31, 1957), con- . sultant, Washington, D. C ., has shown that cement could be produced from typical Virgilia' cement rock containing 45.0 percent GaO, 14.0 ‘ percent SIGg, 2.4 percent AlgOg, and 1.0 percent Fe^Og by adding only small amounts of Iron ore or other high iron material. ' ■ •Methods 'for Determining Composition ■ Field Methods' Weathering Characteristics . As the composition' of 'limestone is . exceedingly important in - cement manufacturing it is advantageous to have methods by which the composition can readily be; determined in the field.. This is especially important if the limestone tends to be dolomitic, as magnesia in excess .of about 3 percent is generally considered deleterious in cement. . . In many areas dolomitic m aterial can be distinguished by the ■■ ■ ■ . ; . ■ ; ■ ■ ; - so m anner in which it weathers. It normally ie fine grained, weather# smooth, and usually is some shade of buff, tan, or brown on the weath ered surface. Limestone, on the other hand, generally is somewhat coarser grained, weathers to a rough or hackly surface, and is usually some shade of gray or white at the outcrop. These distinguishing fea tures, which have been, used effectively by the w riter in several places, were found to be applicable in .mapping.the, limestone deposits at.Genesee Somewhat sim ilar observations were made by Heyel and Wiess (1949, p. 509-513] heat Sonora, Tuolumne County where grain size was found to be indicative of the character of the carbonate material. According to these authors "The magnesian limestoneTs finer grained, most of the individual grains ranging in diameter from 0.05 to 0. 3 of a m illim eter . In the limestone composed of nearly pure calcium carbonate, the grains ' : ' . - - " v • . : . - ' / range from 0. 5 to 5 m illim eters. " : ■ ' t*:'' Solubility Tests Probably the simplest and best known of all tests is for solu bility in acid, a test whichds described in most mineralogy books. -A . drop of acid placed on pure limestone or calcite w ill effervesce, but if the carbonate happens to- contain appreciable amounts of magnesia then', little or no effervescence w ill result. The test is influenced by the con centration Of acid, temperature of acid, temperature of the material tested, the mineral gram size, and the degree to which the mineral is shattered or pulverized. On moist surfaces the test is not reliable and may even be deceptive. Although of great practical value the test is not infallible. Laboratory Methods Abr asive pH . - gimple fleW'methods for , distinguisliing' m inerals have been de scribed by Stevens and Carron (104% p. 31-49) as abrasion pH tests. This term refers, to the pH of the solution that;results from the reaction between a mineral and the pure water in which it is ground. The pH is determined by'.means of pr epar ed indicator papers.- The pH range is : :: i. fro m 1 to 12, with most minerals being near neutral. Calcite gives an abrasion.pH of about .d o lo m ite 9 to 10, and . magnesite about 11, thus ’ enabling calcite to be quickly distinguished from the magnesian carbon ates. This. method should be an effective field test to distinguish lim e- / ; stone from dolomite. Miner al Staining : . - : .Home of the most reliable simple tests to distinguish, limestone from dolomite are stain tests. A number of staining tests have been developed to aid in identification;of some rock-form ing minerals.' -Stain ing does not necessarily identify a m ineral but classifies it as belonging ' ' \ / A '' ; , v- - ' . , ; ’ 82;.' ' to a special group of minerals. Any mineral which, with or without acid treatment, has, the ability to absorb staining m aterials lends itself . ; to study by staining techniques- This helps, to isolate, outline, and iden tify grains of the affected m inerals in thin section, polished surfaces, or hand specimens. Several staining tests are described below. Hematoxylin test. —An'early stain test was the. Lemberg m eth-:. od, a modification of which was used by Fairbanks (1925, p. ■ 120-127) to ' distinguish between calcite and dolomite. ■ By this.method a little hydro gen peroxide is added to a hot, dilute solution containing hematoxylin and aluminum chloride. The solution is allowed to ebnl and the . specimen is immersed in it for fiye minutes then removed, rinsed, and dried. The ■ calcite w ill be- deeply stained purple, while any dolomite w ill remain un-. affected... . ". - ■ . ^- - " . " . - b -' ^ ' .. - ' - '- 'h /. ' - ' - y- ' .. : - " " A slight modification of the Lemberg method is used by F. W. Peirce (talk given to the Dept, of Geology, Univ. of Arizona, May 9, - - - - "V . . . ' ■ : - ...... ' v ; - , ... v - - ■ ; 1958) who refers to it as the purple logwdod stain or hematoxylin test. By this method thin sections, and rough or,polished surfaces are. distinct- ' ly stained by immersion for three to five minutes in a solution contain ing the dye- To prepare the solution, dissolve 13 grams.AlClg or 23 ' grams AlClg. G'HgO and 2.0 grams hematoxylin in 200 cc of water and heat to boiling point (do. not. boil), Cool. and filte r the solution and' add. '. , 10 cc of three percent hydrogen peroxide to oxidize hematoxylin to . / . : . 83 ■; : . ■ ■ ' ' ■ , - : ■■■ . ■ hematein and dilute to 400 cc for use. Cupric nitrate test. ""Another staiiitiig procedure described by Peirce for distinguishing between ealcite and dolomite requires cupric ; nitrate for the staining medium. In this test the specimen is immersed ■ ■. .for 15 minutes in a solution prepared; by dissolving one-half pound of cupric nitrate in a liter of water and warmed to 120oF. The calcite w ill turn green, after which the specimen is immersed in a five percent . NH 4OH solution, at which point the calcite w ill turn blue but dolomite Will remain unaffected. Results of the test are illustrated by figures 14 : and 15. ■ • : ' , : . ■ ' ' ; ! .Ferric"chloride test. r-A very simple stain test is,described by Douglas, King, and .Misick (1944, p. 69=10) . In this test a large drop o f 10 perceht. (by weight) fe rric chloride solution is placed on the specimen to be tested. It is washed off after a minute or so and lim e stone w ill be slightly stained a light brown, whereas dolomite shows no . color: change. -, / : ' ' • • ^ Titan yellow test. --To confirm results of the ferric chloride test described in the preceding paragraph, Douglas, King, and M isick (1944, p. 69-10) use a solution containing titan yellow'and potassium hydroxide. This solution w ill cause pure dolomite to turn distinctly r ed but the color w ill be less evident if the magnesian content is low and the 84 85 z . «•. ;V ; 1=. material w ill r^m aia anclianged if magnesia is. not. present. . This is im practical as a field test because the solution r equires boiling. Ferric chloride-ammonium sulfide test. — A method first an- -/pounced by Fairbairn (1935, p, 31), and more fully described by Keller and Moore (1937,; p. 949-951) is used to, distinguish between calcite and dolomite. By this method a freshly cut or broken surface of the mate ria l to be tested is wet,.with water then immersed from 5 to 10 seconds in FeClg solution. It; Is,then thoroughly washed under a faucet to remove excess FeClg, and is then immersed for about the same length of time in ' ammonium' sulfide solution saturated with .HgS, probably (NB^S^S. The ■ specimeh is again washed to complete treatment. The calcite is stained distinctly black, whereas the dolomite, retains its original, light color. The ferric chloride-ammonium sulfide method of mineral iden- .. tificatibn is said to be practical because the staining occurs quickly and vivid contrasts in color are.developed. However, the'method proved unsatisfactory-in the Joplin district where - Smith (1943-, p. 420-422) ob tained some abnormal reactions between dolomite and ferric chloride. The calcite acted normal to the test but most of the dolomite, which > should have remained uncolored, yielded some black stain and. about 60 percent of it was all black. This abnor mal stain is attributed by Smith to the presence of iron sulfate produced by slight alteration of an ore Recording stain Tests A simple positive method of making permanent records of stain and etch tests ns mentioned .her e .hecansh it . is not widely known. As. de scribed by Pierce (see previous citation) the method perm its transfer of the stain to transparent acetate sheet; o r peer,.. To be effective the stain or etch test should be made on a Surface polished with no. 600 or finer grinding compound, Celulose acetate sheet having a surface partially dissolved in acetone is then placed on the stained surface. After drying the acetate is removed from the specimen and the stain remains perma nently attached to the acetate.. It may then be used for reproduction in colored photographs-or may be used for transparencies in photo-projec- ' tion, . It is said the image.may be enlarged as much as l s 00.0 times. , g e o l o g ic . I nvestigation o f p o z z o l a n s Introduction D e fin itio n .Pozzolans;, are natural, o r a rtificia l materials which, when added to mortar or concrete., produce a strong and durable product, A much quoted definition of pozzolan is that given in the IK 8. Bureau of Recla mations Concrete Manual (1956, 6th ed. ? p. '81), which defines a poz- • zolan as, UA siliceous or siliceous and aluminous material, which in itself possesses little or no cementitious value but w ill, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing ce mentitious properties, ” /. / ' -- '' : TypCs of Pozzolans Pozzolans can he. divided into two groups, (a) natural and (b) artificial. Natural pozzolans are chiefly materials of volcanic origin but also include diatomaceous earth, opaline shale, clay, and other ma terials. The artificial pozzolans are mainly industrial by-products, such as fly ash or slag, and products obtained by heat tr eatment of : ; ' V . ■ ■ ■ 89 natural materials, such as clays,, shales, and certain siliceous rocks. Some ambiguity of terminology exists and clear cut classification of the different types of pozzolans is difficult. For example, most natural pozzolans improve with calcination at medium to low temperatures and are often treated in this manner, but if heated to the point of fusion so that the integral components are changed by reorganization or reconstitu tion then the pozzolan is regarded by most investigators as being a rtifi cial, Ground brick and tile are examples of artificial pozzolans, " Use of Pozzolans Pozzolanic materials used in cement, mortar, and concrete have a favorable reputation derived from practical experience through out the last 20 centuries or more. Their use is especially advantageous in large massive concrete structures. such as: dams and marine installa tions. Some of the benefits! to be derived from the use of pozzolans as 'asvfollowss' I. Alkali-aggregate reaction can be greatly retarded or ; prevented. - '■ ' / 2. Resistance of cbncyete to attack by sulfate-carrying waters can be increased greatly. % '3. Seat generation'.in massive structures can be reduced. Y - ; ■ ■ ■ ■, • • ' ' ' 4. Savings in portland cement can be made. 5. v'i Cost of the,cement constituent may be reduced. 6. Tensile strength of concrete can be increased. . Tc P e rm e a b ility of concrete .can be reduced. ;8c, ^PropOTSsB' o£ the:-m ix']b^ hardening, such as work ability and tendency to segregation and. water gain/ can. be improved. . ■ A few disadvantages may accrue from the use of pozzolans. The water requirement may be increased with a subsequent increase in shrinkage on drying. MieienZc, (ISSO, p. 20) states that the compressive . strength of concrete and its durability under alternate freezing and thaw- ... ing is deer eased by adding; pozzolans. - Also, the . r ate of hardening and development of strength might be seriously retarded, and a few pozzolans have',been .found to inerease the alkali-aggregate reaction. Nevertheless, the advantages of pozzolans are so great that their use in concrete con struction is rapidly increasing, and it is anticipated that the use of ce ments containing pozzolans w ill gain impetus and w ill displace str aight Portland cement in many instances, according to Mielenz and others <1950,. p. 2 1 1 9 5 1 , p. 827). '' 1 Pozzolan Materials General Features The terminology applied to pozzolans is somewhat confusing because of differences in American and foreign usage, and because dif ferent terms are sometimes applied to nearly sim ilar materials. Further more, some of the most widely used pozzolans are products of volcanic eruptions wMeh display marked variation from place to place and are difficult to1 differentiate and- identify.: To prevent -confusion in, this re- 1 port some of the more frequently used terms are explained below, with particular reference to their' application as pozzolans in California. Volcanic tuffs are frequently used as pozzolans. These tuffs -are indurated .pyroclastic rocks of grain SiSe generally finer than 4 m m ., i. e., they are the indur ated equivalent of volcanic ash or dust. The tuffs used as pozzolans are porous, consolidated, or unconsolidated ma terials which commonly show evidences of alteration after deposition. This group includes the original pozzolans of Italy, trass and tuff stein of Germany, santorin earth in Greece, tetin in the Azores, tosca from the Canary Islands, and other materials less well known. Rhyolitic tuffs are preferred because of their high content of silica, but materials having the composition of dunite, trachyte, and dacite may constitute : ' _.-■■ ■■; ■ - ' ' : - ■ - ' r ; - acceptable pozzolans. Mot a ll tuffs’ possess pozzolahlc properties as w ill be shown in subsequent parts of this report. -Sedimentary rocks.used as pozzolans include the diatomites or- diatomaceous earth, which in Europe are also known as kieselguhr and t r ip o li '(Davis, ,1049, , p. 5). These rocks-are composed of the siliceous skeletons of diatoms deposited from either fresh or sea water, and often are mixed w ith sand and clay. Diatomaceous earth is often referred to by a trade name Moler or M o-ler in Europe and as Lompoc in the United States.. At one time it was commonly, but incorrectly, called infusorial 92 earth and tripolite (Howell and others, 195?, p„ 149). It is not to be confused with the American tripoli (Heinz, 1937, p. 911), which is a. . fine-grained m icro- to crypto- crystalline porous silica formed as an ■ end product of weathering and leaching of siliceous limestone or chert. This tripoli is little.used as a, concrete admixture. Many siliceous shales form significant sources of pozzolanlc . m aterials,: especially in California where they ar e widely used. The . . Monterey shale, Puente shale, Modelo, and other sim ilar formations of Miocene age are widespread in California, Oregon, and Washington. These are shaly formations containing opal, chert, porcelanite, and often bentonite. Strata of clay, shale, siltstone, Sandstone^ and diato- ";: maceOus earth are almost always presentde'close association with the ; opaline shale. In France a soft, porous, highly siliceous, sedimentary rock containing gelatinous silica'and clay is- widely usOd as a pozzolan. This is known as gaize (Lea, 1956, p. 364), if used in the natural state, but it is normally calcined and afterwards is called burnt gaize. The m aterial apparently is sim ilar to the opaline shales of the Pacific Coast States. The opaline cherts, sim ilar to those of the Monterey and Puente \\form ations are reported by Mielenz and. others (1949, p. 2.0), to be su perior to all other natural pozzolans, but most require calcining. '. Many industrial by-products such as furnace slag, ground brick and tile and other materials have long been used as concrete ad mixtures. ; These require special treatment before use, thus are ■' ; ■ ■■ . :v; ' • ' ’ ■ ■. ■ . - ■ . S 3 considered to be artificial and w ill riot be discussed further in this r e p o r t ; , - ... Properties of Pozzolans . Pozzolanic properties of natural materials depend upon their composition, physical characteristics, and the treatment processes to which they have been subjected during manufacture of the finished prod u c t The- mechanism by which pozzolans accomplish the changes in the properties of concrete are not fully known but the action according to . Mielenz and others (XSSI, p. 313), 'is part physical and part chemical. The fundamental property of a pozzolan is its ability to combine with lim e which is explained by the theories of base exchange and direct combination, the current views of which are Summarized by Lea (1050, p. 370-371). Chemically, pozzolans react with calcium hydroxide re leased by the hydration of cement and form stable compounds many of Which are cementitious. Those pozzolans which in h ib it or prevent ce- ■ - , ■ - - . - ■ - . . ment-aggregate reaction in concrete do so by chemical reaction with, or by absorption:of, the alkalies released by the.cement. The alkalies ■ (NagO and KgO) thus bound to dr by the pozzolan are unable to attack the aggregate, according to Mielenz and otherS (1951, p» 315)., Without ; doubt, many complex r eactions are involved in the hardening and setting of concrete. According, to Mielenz and others (1951, p.. 315), ’’Natural ' pozzolans owe their chemical activity to one or more o£ five substances; namely (1) volcanic glass, (2) opal, (3) clay minerals, (4) zeolites, (5) hydrated oxides of aluminium," It is generally agreed that all pozzolans must contain a relatively high proportion of silica, but there is mp clear line of separation between siliceous materials which are regarded as pozzolans and those which are not. Silica in the amorphous form is more reactive than in the crystal form, and the larger the crystal the less rapid the rate of reaction. Thus, the amount of vitreous, amor phous, or non-crystalline silica in a given material is probably one of '■ the,;be^t Means by wMch pozzolanie actiyity can be judged; but other fac tors are also.important, - ■ ' ■ . / : , ' . , Chemical composition is of little importance in determining pozzo!an!.o activity; and analyses indicate a: wide ■ range of acceptable materials," The range in chemical composition of pozzolans is appro priately summarized by Davis (1949, p, 4| as follows: . ' Though the predominating constituent of a ll of the ; .recognized pozzolans is Silica, many which exhibit sat isfactory performance contain as little as 40 per cent of this compound. A ll are relatiyely low in lim e and 'magnesia, and many of those'.which are regarded as the better pozzolans contain as much as 5 per cent, ' .; ,ahd some as much as 10. per cent, of the alkalies—— ' ■ • soda and potassa. .Some contain as much as 30 per cent alumina and some as much as 20 per cent of iron oxide. It seems to be'the:case thahthe presence o| at least a small percentage of the alkalies, in whatever ■ may be their compound form, is. beneficial rather than detrimental. It also seems to be the case that those . which contain. at least a moderate, amount of alumina and. some iron oxide are superior to those for which -the silica is of a high degree of purity,.. * In spite of the fact that chemical composition is not a satisfac tory criteria of pozzolanic activity, compositional lim its often appear in industrial literature .such as that issued by the Airox Company, Los Angeles,' California and by Basalt Bock Company, Inc., Napa, Calif or = - nia. An example of compositional lim its set by specification, which is typical of many pozzolans, is given in the Invitation, Bid and Award .Schedule (No. BS 5012,' 1958, p.' lS), issued by the U. S. Bureau of ■ . Reclamation for pozzolan for the .Glen Canyon Dam, near' Page, Arizona. The specification.; requires pozzolan having the composition indicated in table 14. ■ " y • - . Moran and CillllW d (l^^ 119) believe the compositional lim its expressed'' in specifications are to assure uniform ity within a ■.class of material, and,are'not.intended to be- applied to pozzolanic m a- . terials in general. Specifications sometimes are drawn to "fit" a known source of supply of\pozzolah.. % - C lassification of Pozzolan M aterials Classification by Physical Types M aterials’ used as pozzolans can be divided into several groups. A tentative classification with a few examples of each type is given in table 15. ' V- ' 'Z::-a ' ■ ■; ' ' " y ' . ' . Table 14/—Composition of pozzolam specified for Glen Canyon Dam. H a tu ra l ■ , Chemical composition pozzolan F ly ash- (percent) ■ (percent) Bilicon .dioxide (0iC)2) plu s alum inium ^ - oxide (AlgGg) plus ferric oxide (FegQg) not less than ...... 75.0 " -1'. ’ . 75.0 ■ ' ■. ' - - - - "y - . - - . .. , : v - - ■ - Magnesium oxide (MgO), not more ' J' than ...... o .»*...... »... *..... : ; 5.0 y 5,0 ■ ' ' ' S u lfu r trio x id e (SO3), not m or e than ... f 4 .0 . 4 .0 .LOss on ignition, not more-tbW .1.: , '10.0 . . ' 5.0- ' Moistare content, not more than . . y . .. . 3.0- 3 .0 Exchangeable alkalies as NagO, not m o re than ...... *. >... . . 6 .;: ... 3 .0 3 .0 Classification by Activity Types ' ' In two notable contribiitions Mielenz and associates (1949, p. ' 43^92} 1951, p. 311-328) discuss the restilts of research on pozzolans conducted since 1933 by the Research and Geology Division, Branch of ' Design and Construction, U. 0. Bureau of Reclamation. Additional data are embodied in .Petrographic -Report No. Pet-9OB by Mielenz (1950). ' . - • Mieienz.:an,d others (1949, lO 51). offer a classification of natural pozzolans which divides these materials into six; parts as determined by the identity of the essential active ingredient. As shown by Mielenz and others (1951, p. 317), this classification avoids ambiguity of petrographic 97 Table l5o--Materials used as pozzolans Classification______Examples I, Natural pozzolans A e Volcanic or pyroclastic Materials Rock class:- Tuff, ash, pumice, obsid ian, scoria Pozzolan class:- Trass , tosca, tuffstein, santorin earth Petrologic classic Rhyolite,leucite, trachyite, phonolite B e Siliceous sedimentary rocks Diatomaceous rocks Moler (or.Mo-ler) Celite Tripoli, dia- tomite, Kieselguhr rottenstone, Inf us uri.al earth Siliceous (opaline) shale Salinas and Nespelen formation Monterey shale, Puente shale, Gaize II. Artificial Pozzolans . C0 Burned clays and shales Ground brick and tile. D 0 Industrial by-products Fly (fuel ash, Furnace slag, Burnt oil shale. ;; ■ ; ■ ■ \ 98 classification in which it may not he possible to identify the active sub stances/ gome difficulties remain, however, for it is difficult to clas sify mixed types or those that are gradational from one type to another» Furthermore, proportions of active ingredients may vary within wide lim its and pozzolanic activity of all pozzolans is strongly influenced by particle size. For these reasons designation of activity type w ill not indicate r eliably the quality of a pozzolanic m aterial (Mielenz and other s, 1951, p. 317); nevertheless, this classification provides a useful desig- " \ nation. Table 16, is adapted with modification from Mielenz and others (1951, p„ 317), to show the relationship of the activity type to the active ingredients in certain pozzolanic materials, . / ' .■■■ ■ ./ : ■ ' The order of classification of the activity types shown in table .16 is not intended'to indicate an exact order of decreasing relative re activity of the pOzzolans, nor of their importance, usefulness, or ap plication. Many factors, which cannot be shown in the table, determine the feasibility of use of pozzolans. These are discussed elsewhere in this feport,-,- - : ■ ■ v 'vy 'v ' ’ * . ; : . Explanation of Activity Types ’ 1,,.'••'^dtivity Type 1. --{Pozzolans: of Activity Type X, according to Mielenz and others (X 9 51, p'. 319), owe their activity prim arily to vol canic giass, the refractive index of which lies in the range from 1.490 to 1, 507, which indicates a silica content of about 70 percent, as shown Table10o--Relationship of activity type and active ingredients to pozzolanic materials i Activity type Active ingredient Pozzolanic material j i 1 Volcanic glass. Rhyolite pumicites and tuffjs Dacite pumicites and tuffs j 2 Opal Diatomaceous earth j Opaline chert j 3a Kaolinite-type clays Altered pumicites and tuffs Kaolin clays 3b Montmorillonite- Opaline shales type clays Bentonitic clay and shale Fuller * s earth 3c Illite-type, (hydfomica) clays Hydromica (illite) clays i j 3d Mixed clays Lacustrine silts and clays j containing vermiculite» biedellite-montronite» illite and kaolinite 3e Palygorskite Attapulgus clay 4 Zeolites Zeolitic tuff and ashes . 5 Hydrous aluminum oxides Bauxite 6 Non-poz zolans Onfv. of Arizona librnri” . ' . . . ; ' :100 - by George. (1924^ p. :365);0 According to Mielenz and others (1951, p„ 319)5, experience indicates that pozzolaiis' owing their activity exclusive ly to volcanic glass must contain at least 60 percent glass to develop satisfactory mortar strong^ and must contain 90 percent or more to control alkali-aggr egate r eaction in m ortar unless other active ingre- . diehts are present. ■; : C on verse ly5, not all highly siliceous volcanic ashes and tuffs ar e satisfactory pozzolans because: (1) they may demonstrate excep tional stability of the glassy fraction^ (2) they may be unusually coarse grained, (3) they may increase the alkali-aggregate reaction through re lease of alkalies from their own substance. Andesitic and more basic materials are inferior or wholly unsatisfactory in quality. Mielenz and - others (1901, p. ■319), say the trachytic and phonolitic . tuffs and ashes ; used since ancient times in Europe r equir e hydrothermal alteration with production of clays and zeolites befor e satisfactory activity is in duced. ' ■ ■■■ . ■ . ■ • Apparently most vitric tuffs, which are dominantly composed of glassy fragments, belong to Activity Type 1. Pozzolans of this type, especially pumice and tuffs, are the most common sources of natural pozzolans, especially'in the-western United States.. : Activity Type 2 .—Pozzolans of Activity Type 2 are diatomite • (diatomaceous earth) and cherts owing their activity to opal which is the ; .101 . 'actlyeviiairMieiit addorSyg 'to p. '52). These are the - most active of a ll natural pozzolans. Diatomaceous earth or diatomite is a friable earthy deposit composed of nearly pure silica which consists essentially of remains of the microscopic plants called diatoms. The physical properties vary widely because of the variation'in particle size and shape.. An obj ection- ■ able characteristic of this material is its high porosity which causes a high-water requirement:for a given workability of. m ortar and concrete. - This high-water requir ement causes a r eduction in cementing ability, strength, weathering resistance, .and increases drying shrinkage in concrete. .Mielenz (1850, p. 1 0 ), states that recent research suggests that the excessive water requirement may be controlled by use of wetting agents. . Professor G. E, Troxell and A. Klein, (oral communication, 1958) Berkeley, California, and others indicate the quality of the raw : m aterial may be- greatly improved with fine grinding and calcination., Although diatomaceous earths are improved by calcining, Lea (1956, p. ,363) suggests this may be due to dehydration of. the clay im purities,’ rather than to any effect on the diatom skeletons. Diatomaceous earth ordinarily is used only with great caution because of the high-water re q u ir e m e n t . .... : ’ ; . . ^ Activity Type 2 is also r epresented by opaline cherts. These possess the Inherent chemical reactivity of diatomite but are relatively free from the objectionable internal porosity which leads to high-water requirement. According to Mielenz ''(10S1, p. '3.22)' these are the most effective pozzolans available for control of alkali-aggregate reaction, and greatly improve resistance of cement to attack by sulfate-bearing water. The shales and porcelanites of the Miocene system of Califor nia.owe their activity to opal, or: bo# opal and biedellite, therefore are classified as both Activity Types 2 and 3b. These are widely used but re q u ire ' ca lcin a tio n a t. te m p e ra tu re s fro m 1, 000° F . to 1, 800® F . to r e duce water requirement and to induce maximum alkali reactivity. : ... • Activity; Type 3. —Several types of clay m inerals are included : in Activity Type 3. These include kaolinite, illite (hydromica), palygor- skite,. altered-Vermiculite, and montmorillonite type clays. . A ll clayey pozzolans must be calcined at temperatures over X, 000° F. to induce optimum activity and reduce water requirement according to Mielenz and others (1951, p. 322), and all require grinding to develop proper fineness Some clays are inferior or actually deleterious with respect to control of the alkali-aggregate reaction as- shown by Mielenz and others (1951, p. 222-223). Most clays used as pozzolans have a high- water r equir ement, . though.npt as high.as for diatomite, andlcarp must be exercised in their selection and use. Argillaceous silt containing illite and montmorillonite type clays (Activity -Types 3c, 3b), dredged from the bottom sediments of San Francisco Bay, California, were successfully used in the Bonne ville spillway dam and fishways, Washington and Or egon (Mielenz and . others, 1951, p. 3X8* Mielenz, 1950, p. ' 14). Recent research by Ruiz tm (1958) indicates that calcined kaolinite clays are excellent pozzolans. Activity Type 4. — Pozzolans of Activity Type 4 owe their ac tivity to the zeolites clinoptilolite/ ptilolite? analcite, and probably -others. These zeolites are found in deeply altered rhyolite tuffs and sim ilar rocks used as' pozzolahs. Much of the'European trass is of zeolitic characterj according to Mielenz and others (1950, p, 5). The zeolites present in the pozzolan w ill determine its characteristics, some of which are beneficial and others are detrimental if used in con- ■ ■ -V " ' V ■ -N •' ■ - , ' ' ' - ' • - Crete. ■ '..; ; -. Two examples of Type.4 materials having deleterious proper ties ar e described: from California and Wyoming. According to Mielenz and others (1951, p. 323), deeply altered- rhyolite tuffs from the Rosamond series near Monolith, California are about 80 percent cllnoptilolite.. M ortars prepared with this pozzolan - show satisfactory compressive and tensil strength and resistance to attack by sodium sulfate solutions. However, leach tests demonstrate : that the altered tuff w ill release alkalies to intensify the alkali-aggre gate reaction. Phonolite porphyry and analcite from Missouri Buttes, Wyoming, if used as a pozzolan, w ill release sufficient sodium and potassium to cause the alkali-aggregate reaction if used with susceptible aggregates. These examples are cited because many of the tuffs of northern California are potentially reactive and might have detrimental effects on concrete and mortar. However? T. M. TutMll (Concrete : Engineer, California Dept, of Water Resources, Sacramento^ Calif. ) . Bays tests of aggregates available in the O roville area indicate they are not alkali-reactive. Activity Type 5. --No test, data on pozzolanic properties of Acr . tlvity Type 5 are available to the w riter; however, Lea (1956, p, 366) ' mentions the nse of .banxite in some ancient mortars- in .Europe. E vi dently bnrnt bauxite form s an excellent pozzolan. - ■ Activity Type - -M aterials of Activity Type 6 include stable ' ' minerals which are essentially non-reactive with lim e ■ however, some pozzolanic properties might be induced by heating to clinkering tem per-: hires. The materials are most likely to be used as inert fillers in mortar and concrete. Apparently most lithic and crystal tuffs belong to this class. They are rarely used as pozzolans. Summary of Activity Types : v/ ^ , : ' Natural pozzolans owe their activity to five substances, name ly: (1) glass, ;(2) opal,' (3)'; clays* (4) zeolites, (5) hydrated aluminium oxides; and they may be classified according to these activity types. Each actiye . substance contributes characteristic properties'to the poz- zolan; consequently, it is possible from petrographic analysis to predict the pozzolanic nature of available materials and the need for special : ■ • . . ' : : '■ ; . ' . ■ ' : ■' ' 105' • processing. Chemical composition is relatively unimportant in deter mining pozzolanic activity. .■ ■ V': - ■ M aterials owing their activity to rhyolitic glass and opal (Ac- . tiyity Types .1 and 2) are the best sources of natural pozzolan from the / standpoint of strength development. Rhyolite ash or tuff should have a high proportion of glass with a.low index of refraction for satisfactory strength development. This class of pozzolan w ill Control the alkali- aggregate reaction if it contains an excess of 90 percent glass according to Mielenz and others (1951, p, 319). M aterials owing their activity to opal (Activity Type 2) and to kaolinite and montmorillonite type clays (Activity Types 3a and: :3h respectively) are the most promising for the ■ " ; » ' ' ■ / • ' ' ■ ' 'V V/; ■'■/ ... . ■ control of alkali-aggregate reaction. Opaline cherts of Activity Type 2 are superior to all other natural pozzolans? according to Mielenz and ; others (1949, p. 90). Oiatomaceous earth has an exceptionally high- ■ water requirement^ and therefore is considered to he a poor pozzolan; even though it is highly reactive. It is? however^ greatly improved by . calcination. Clayey-pezzolans. (Activity Types 3a to 3e inclusive) have : a relatively low strength development and the water requirement is high compared with, some other materials.: - Clays also show marked improve-' ment by calcination. Zeolites (Activity Type 4) are inferior because they have a high-water requirement and are likely to contribute alkalies . which intensify the alkali-aggregate reaction (Mielenz and others, 1951, p . 323). ... . ; : - Characteristics of Pozzolans : ■ ; • Geological Characteristics Only a few of the more significant or unusual geological fea tures that are especially app]lcahl#; to the study of pozzolans will: be ■ - discussed here; the detailed geology of most deposits is beyond the scope of this report. Most pozzolans are either siliceous pyroclastic rocks or siliceous sediments which are more or less stratified. They are, consequently, variable in composition, texture, and properties. Tuffs and pumicites, for example, often grade laterally into clays, shales, or sands with which they might be interbedded or intercalated. Sim ilarly the opaline shales and cherts, such as occur in the Monter ey and other formations of the Miocene in California, are associated with Sandstone and siltstone and other m aterials having little pozzolauic value. V ' • The most fr equently used pozzolans, those of Activity Types 1 • and 2, are confined largely to the Cenozoic and Quaternary formations of Western United States; however, some clay-like pozzolans range in age from Cambrian to Recent. Mielenz and others (1951, p. 324) in dicate .that-the paucity o r absence of pozzolans from older formations relates to progressive alteration and recrystallization of the unstable - - y a ,: ■■■■-..■ '■ ' volcanic glass and opal to mor e stable substances with the passage of time and influence Of geological processes. ' Most tuffs. and ashes seem to require post-depositional alteration td develop pozzolanic properties and the activity of tuffs seems to increase with depth of huriaL. Mielenz (1950, p, 5) indicates that re- cent ashes near Vesuvius are only weakly reactive whereas the older/ buried materials are much more reactive. Partial alteration, particu larly by hydrothermal action, may be necessary to develop pozzolanic . - activity 'whereas -intensive weathering during long intervals is- detriment^ ■ - ■ : " ■ ■ ■ ■ . al because; it reduces pozzolanic activity in most materials. y " a' ■ Physical Characteristics . Materials used for pozzolan must have a low specific gravity because of its use as a replacement of cement which has a specific grav ity of approximately 3.1.. The' absolute specific gravity of pozzolans -ranges from about 2.3 to 2* 8" therefore, the pozzolan occupies a greater ' volume than the weight-equivalent of portland cement (Mielenz, 1950, p. 2). A low apparent specific gravity or volume weight is a desirable characteristic of pyroclastic pozzolans. Volume weights were con sidered in the selection of pyroclastic pozzolanic materials in north central California, and the better materials were found to have very low volume weights. It is generally assumed that pozzolans should have some chem- ‘ ically 'combined water, but there is no agreement as to how much should • be present or how- important the water is. According .to Lea (1950, p,. 388) German specifications for trass require not less than 6 percent 108 combined water, this quantity being the amount lost on ignition after firs t drying to a constant weight at 98°, Mieienz: (1950, p. 5) states trass of good quality can be distinguished from sim ilar but inferior tuffs by its charaqterlstic content of more than ?' percent water; Amer ican practice usually does not specify the amount of combined water; however, most specifications, as for example those issued for the Glen Canyon Dam, perm it not more than 10 percent loss on ignition. Klein and Troxell (oral, communication, 1958) prefer materials having several percent loss on ignition. This would naturally include combined water plus any material lost on the destruction of carbonates or other mineral or organic matter . ■ Characteristics of Tuffaceous Material In north central California tuff deposits of different types are widely:distributed; therefore,'' these. w ill be discussed in considerable detail. Unfortunately there exists much ambiguity in terminology of pyroclastic rocks' and it is necessary to define some of the term s used \ in this report. In a. notable paper on the Tuscan formation (often re ferred to as Tuscan tuff) Anderson (1933, p. 222) gave a; definition which was adopted from Wentworth and W illiam s (1932), and which is followed with modification in the pr esent investigation. Ander soh's definition of a tuff, with slight modification, is as follows: Tuffs are indurated pyroclastic rocks of grain gen erally finer than 4 m m ., i. e. ? the indurated equivalent of volcanic ash or dust. If the grain is from 4 to 1 mm. 3 ■ the aggregate is coar;se ash? indurated^ coarse tuff, : the grain is. from '1 to 'l/4 inm. ?. the aggregate is medi um ash, indurated, medium tuff. If the grain is less than 1/4 m m ., the aggregate is fine ashj indurated^ fine tuff. Admixtures of clay and very fine ash are designated as tuffac eons clay. % ' Although the above definition is adequate as far as grain size and. degree of induration is concerned, it gives no clue as to the char acter or composition of the individual particles in a tuff. As the physical character and,' to some extent, the composition of tuffs is, of utmost im portance in pozzolans, certain qualifying terms' are used to classify, ex plain, or describe the materials. Tuffs are classified as vitric, crystal ■ ■ ■ ’ . ' ■ , . ■ ' ■: ' ■■■ . ... ' V '■ or lithic, depending upon their physical character . These terms are de- ■ fined in Glossary Of Geology and Belated Sciences, J.. V. HoWell,. Chair- man (195% p. 314, 180, and 70), from which the following definitions are adopted: V itric tuff: An indurated deposit of volcanic ash dominantly composed of glassy fr agments blown out during a volcanic eruption. The term should-properly be restricted tp tuffs containing more than 75 percent by volume of glass particles. '' - ' Lithic tuffs Tuffs that consist dominantly of crystal line rock fragments formed from quickly cooled volcanic materials giving the rock a fine grained structure and a crystal'fabric. It is an indurated deposit of volcanic ash in which the fragments are composed of previously form ed rocks; i. e. accidental particles of sedimentary rock, accessory pieces of earlier lavas in the same cone? or small bits of ejecta that first solidify in the vent and are then blown out. - ' c.. ' ' ; ■' 110 Crystal tu ^ .deposit o£ vdlcajilc ash dominantly composed of intratelluric crystals blown out during a volcanic eruption- The crystals usually are broken euhedra of the common phenocrysts of lava, and . ' may be: sheathed in an envelope of glass., . The term should properly be rsstrMed to tu% % per cent by volume of crystals. Of the Wfaceous m aterials only those having a high proportion : of glass .and.a composition approaching rhyolite seem to have high poz- ■ zolanic values (see p. 98, this report). The proportion of glass is re ferred to as the petrographic index by Mielenz (1950, p. 9, and table 1). Most vitric tuffs satisfy this requirement but lithic or crystal tuffs con tain little glass and usually have low pozzolanic values. Tuffaebous- m aterials used; for pozzolans should be highly s ill- . eeous, preferably at least 65 or 70 percent silica, although many poz- zolanS; contain much less. , The- silica content can be detected petro- graphically by measuring the index of refraction by methods established by George (1924j p. .3:58^Y2),- The relationship of the index of refrac- ’ tion of natural glasses to their composition is illustrated by figure 16. The index of the glass (recorded as n) should be about 1. 5. For many pyroclastic materials tested by the U.» S. Bureau of Reclamation, Mielenz,>(1950, table 1% and Mielenz. and others (1949, p. 46-47, and table 1), report indices ranging from 1.488 to 1. 507, thus indicating rhyolitic composition. Materials having higher indices are more basic in composition and have lesser pozzolanic values. In summary it can be said that pozzolans of pyroclastic origin should (1) have a composition I l l 6 2! N 1/46 F ig . 1 6 .Approximate relationship between composition and specific gravity and refractive index for the natural glasses. Dashed lines for specific gravity; solid lines for refractive index. After W. O. George. approaching that of rhyolite, (2) contain a very high percentage of s ili ceous glass having an index of about 1. .5, (3) have a low apparent spe cific gravity, (4) be slightly altered after 'deposition, (5) have a loss of. a few percent by weight on ignition. ' . ' ■ ^ > Selecting and Testing Pozzolans In north central California, a search was made prim arily, but not exclusively for pozzolans of volcanic origin. Other types such as the widely used opaline shales of Miocene age were not sought because they are not known to the w riter in the area of interest. No effort was made to find diatomaceOus earth deposits because of the unfavorable high-water requirement of this material. Although clayey materials are abundant in the area, they were examined and sampled as possible sources of pozzolans in only a few places because of. their high-water requirement. . • Explanation of the laboratory methods used in the selection and testing of pozzolans is beyond the scope of this report, but they w ill be mentioned briefly because most of the methods are complex, time consuming, and Unfamiliar to many geologists. Perhaps the most favorable criteria for a good pozzolan is a long history of successful use. as for example, the trass in Germany and the siliceous shales of / ■ ■■■; .■- ■ ' ■ ■ . ... : - California. Seldom is a successful history known; consequently, labo ratory techniques have been devised to determine the quality of pozzolanic 113 materials^ and to determine the. methods by which they must be.treated, to obtain optimum results. Various experimenters do not seem to be in complete agreement as to what constitutes good test methods. These change by improvement Of older methods and the development of new methods, and the requirements vary from job to job, depending upon the pozzolanic materials and aggregates available. The requirements of a pozzolan and the methods of testing and treating it generally are ex plained in the specification of a particular job, as for example, in the .Invitation, Bid and Award Schedule BS 5053 for the Glen Canyon Dam. ' - Further Information is to be found in Feder al Test Method Standar ds, Specifications for American Society of Testing Materials, and in the Handbook for Concrete and Cement (see specification C 263 and C 263: : , for examples). Probably the most comprehensive source of information about pozzolans is the '’Symposium on the use of Pozzolanic M aterials in M ortars and Concr ete, ” Special publication No. 99, American Society of Testing Materials, Philadelphia, Pa. hi this Symposium Moran and G illila n d (1949., p. 109-12.6) sum m arize, te s t m ethods fo r d e te rm in in g pozzolanic activity. The tests used are as follows: Tests on. pozzolans alone: ■ ■ ; /.- "v 1. Chemical composition 3. Solubility in different mediums ' < - ■ .3. Lime absorption . v ; - . 4. Optical methods a. petrographic analysis b. X-ray analysis ■ ^ : :; 114 Tests on pozzolan-lime mixturesr . 1 o/. T im e -o f se t te sts 2_0' Compressive and tensil strength tests 3; Determination of remaining TOCombiiied lim e 4. Determination of insoluble residues :Tests on pozzolan-portland cement blends: ' 1. Strength tests 2o Insoluble residue and uncombined lim e ' 3, ’ R.eslstaiiiee:tO;'leacMng . • ' ■ ■4. Lime solubility \ 5o Resistance to sulfate solutions 6. Reduction in expansion The tests listed above are discussed in extensive literature tin the subject. It is to be noted that at least part and possibly all these tests should be made on both raw and calcined materials, and often it is necessary to make the tests on m aterials calcined at different tem peratures so as to obtain optimum results. Another test having great promise, but not in the above list is the differential thermal, analysis1 . methods (Grim and Rowland, 1944, p. 65-76), developed in recent years. , ; .A ctivity of'individual rhyolite glasses, cannot be predicted pr e- - cisely from microscopic data or from chemical composition; however, the spacing of certain lines in am X-ray diffraction pattern can be related to potential alkali reactivity of glasses (Mielenz and others, 1951, p. 319). . : ; - :: ' - ■ : ’ The value on most tests has been assessed; on the basis of th e ir ■ relationship to strength values. However, strength contribution is only one of the qualities desir ed in a pozzolan and most m aterials should be 115 evaluated on a performance test based on the particular requirementso .; If both the nature of the pozzolanic m aterial and the purpose for which it is used are known then it may be possible to dispense with some of the above tests or to substitute others. For example the test for pozzo- : Ians in U. 8. Bur eau of Reclamation Specification: 1904 was designed for Davis Dam v/here the use of pozzolans was required to prevent alkali re action with susceptible aggregate (Mielenz? 1950, p. 16). The test is ■ seldom used except under sim ilar conditions, i. e. ? when the alkali- aggregate problem exists. U. 0. Bureau of Reclamation Speoification 1904' appears to be the same as A. % T. 1/E. C. 289-54 t ?' issued 1952, revised 1954. Problems in selection, testing, and treating pozzolans of all types are explained in a paper by Bauer (Oct. 1954, p. 41-46 and Nov. 1954, p. 83-86). Bauer?s ta.ble summarizing group evaluations of pozzolans is reproduced in table 17 without modification. . ; M aterials for Pozzolans in North Central California ' ' : -v: : t/;;^Oeneral Features. ' r . .Several beds of tuff, and-other miscellaneous materials were . investigated as possible sources of pozzolans in north central Califor nia. Distribution of some of the rock types investigated is shown on the geologic map in figure 5, A total of 29 samples representing dif- ferent types of materials were .collected, the locations of which are 116 Table 17. -Group Evaluations of Pozzolans* GROUP I G R O U P n GROUP III VOLCANIC O&mJP NAME ERUPTIVES SILICEOUS SEDIMENTS SHALES & CLAYS RHYOLITE & DACITE-PUML CITE3, TUFFS, DIATOMITE, DIATOMACEOUS SHALES & CLAYS WITH MANY ASSOCIATED ROCK TYPICAL (TRASS) SCORIA, CLAYS AND SHALES, CONSTITUENTS DERIVED FROM ALTERED VOLCANKS, ROCKS 8ANFORIN OPALINE CHERTS & SHALES SEDIMENTS & IGNEOUS ROCKS, ALTERATION BY HYDRO- EARTH TRIPOLI . THERMAL REACTIONS OR WEATHERING, LEACHING, ETC. ALTERED ASHES RHYOLITE (HYDRO-MICAS) (ALTERED PREDOMINANT GLASS OPAL IN OPAL IN (CLAYS) (BENTONITES) UXITES GLASS) ACTIVE 65-80% S10„ + DIATOMITE SHALE MONTMORIL- ZEOLITES KAOLIN ITES LONITES VARIABLE CONSTITUENT H A AW* 810% • nH$0 810% • nH20 Al%0j2Si0%2H%0 HYDROUS Ha,AIs(SK),) Mo A Kg) Al%0,4Si0,-H20 SILICATE 2HcO ANDESITE a n a lc ite ASSOCIATED GLASS, DACITE (May contain ANAUXITE HECTORITE PTELOLITE BETA HALLOYSITE VERMICULITE FORMS GLASS, BASALT trace of Alumina) CRISTOBALITE BEIDELLITE MUSCOVITE CLINO- GLASS DICKITE MONTRONITE PTILOLITE^ EFFECT OF USUALLY IMPROVED IMPROVED CALCINING SMALL GENERALLY MARKEDLY IMPROVED CONSIDERABLY OPTIMUM TEMP. FOR STRENGTH BELOW 1600°F. 1400°-1800oF. 1400o-1600°F. 1200°F. 1400°F. +1800°F. 1400°F. OPTIMUM TEMP. FOR ALKALI 1800°F. PLUS 1400°F. 1400°F. 140(FF. 1400°F. +1800°F. ISOtTF. ACTIVITY j COMPR. BELOW TO BELOW TO BELOW TO BELOW TO BELOW TO STRENGTH ABOVE ABOVE ABOVE BELOW 1-12‘MONTHS ABOVE ABOVE ABOVE REDUCTION Good, flow in INSUFFICIENT Excellent but EXCHANGE IN ALKALI TO GOOD Excellent Good Fair Poor EXPANS. used within limits ABLE SODA SULPHATE MODERATE RESISTANCE INCREASE HIGH HIGH VARIABLE DRYING X 1.3 CONSIDERABLE X 1.5 X 1.2 COMPARISON TO COMPARISON SHRINKAGE NORMAL CONCRETE CONCRETE NORMAL SHRINKAGE In small amounts WITH AHl NORMAL NORMAL NORMAL OR REDUCED ENTR. AGENT near normal KEL. GRINDING COST HIGH LOW MEDIUM MEDIUM REL. ACTIVATING NONE MEDIUM TO . COST HIGH MEDIUM J LOW TO MED. MEDIUM HIGH MEDIUM Condensed from U.S. Bureau of Reclamation Reports. Table by W„G. Bauer shown On figure For convenience in tMs discussion materials sampled are classified according to type as shown in table 18, and some physical, - chemicalj and optical data are given in table 19V Descriptions of the in dividual samples and the significant physical, chemical, and optical data for each are shown in table "20, Prelim inary examination indicates that only a few of these m aterials had sufficient pozzolanic properties to justify further testing. At present, as w ill be discussed later, mortar strength tests are available for only two Samples. ' Table: 18.--M aterials investigated fo r Pozzolanic.Properties.' Source of materials Sample number s Tuscan formation ■ P-9, P-10 Numlaki tuff ■ P-1, P-2, P-20, P-21(?) ’’Tuffs of;OroviUe,t: : : P-4, P-5, P-6, p-7, - P-8, P-22(?), P-20(?), P-27 Unnamed rhyolite tuff .P-3, P-2S, P-24, . P-26, . . " P-28, P-29 lone formation ; ' ■ P -1 1 , P -1 2 Sutter Buttes peripheral tuff P-16, P-17 • ■■ Sutter Buttes vent tuff -• . , . .. P-14, . P-15. : Sutter Buttes rhyolitic tuff P-18, P-19 . " S ierra Nevada tuff ■- ’ P-13 .- . Data presently available are insufficient for precise classifica tion of the pozzolanic. materials sam pled,It is possible that samples P- ;22 . and P-SB, in table;! 8," should be placed with the unnamed rhyolite tu ff, a te rm adapted fro m C re e ly (195.5, p. 108-200), and P -13 m ig h t - 118 Table190--Optical and chemical data of tuffs investigated Hygroscopic Loss on Per cent Index Volume water , in ignition, Number of glass* of glass weight percent in percent P-1 95 1 o 51 1.4 5.17 5.36 2 70 1.51 1.8 5.12 5.23 3 95 1.52 1.5 5.47 5.54 4 0 1.5 1.74 1.76 5 2 1.52 1.7 5.12 5.24 6 0 ea eo 1.9 3.34 3.43 7 -2 1.52 1.5 4.44 4.57 8 0 -» «■ 1.61 4.70 4.82 9 1 1.525 1.56 7.03 7.25 10 1 1.535 1.7 2.78 2.82 11 1 1.54 1.98 9.43 9.70 12 0 — «■ 2.00 10.80 11.01 13 -1 1.-512 1.90 6.64 6.79 14 0 «=» cm 1.45 3.08 3.15 15 0 O. 0 1.97 2.93 2.98 16 0 0 0 1.74 1.79 1.80 17 0 0 0 2.29 1.20 1.21 18 Trace 1.522 1.81 2.97 3.01 19 Minor 0 0 1.48 5.87 6.03 20 95 1.504 1.28 3.58 3.64 21 30 1.515 1.68 3.34 3.43 22 30 1.523 1.72 10.87 11.10 23 95 1.514 1.1 5.19 5.29 24 70 1.510 1.13 6.98 7.14 25 10 1.518 1.03 7.25 7.48 26 99 1.511 1.03 4.48 4.79 27 Minor 0 0 1.51 3.61 3.82 28 90 1.513 1.11 5.90 6.13 29 95 1.508 1.18 5.45 5.60 *Sometimes referred to as petrographic index„ TablegQ.--Materials investigated for poz zolanic properties No, ______Locality Description P-1 Wheeler Ranch, a few miles White fine-grained vitric tuff containing megascopic specks SE of Paskenta of biotite. Composition is rhyolitic with about 95% glass (n-1.51) which occurs in shards 9 Minerals present are anhedral crystals of quartz, plagioclase, sanidine -biotite apatite, hornblend and clay. Slight alteration. P-2 Quarry on former Numlaki A rhyolitic vitric tuff containing visible shards and black Indian Reservation about grains in a fine grained ground mass* Material is about 6 miles N.E. of Paskenta 70% glass (n=l.51) which occurs as shards and as partly devitrified masses * Minerals present are plagioclase, quartz, clay, aeginine-augite, sanidine and quqrtz. Slight alteration. P-3 Roadcut 2 miles E . of Light gray, fine grained vitric rhyolite tuff containing Oroville on Forbestown Rde tiny black specks that are probably hornblende * About 95% glass (n=1.52). Remainder is composed of fragments of quartz, plagioclase, sanidine, muscovite, etc* P-4 Marysville Road about 5 Dark grey medium-to fine-grained crystal tuff containing miles S o W o from Oroville some clay-like sedimentary material. Minerals are quartz, plagioclase, biotite, aeginine-augite, hornblende, apatite, and zircon. Also contains masses of hydrous iron silicates and ferriginous clay. .P-5 Roadcut about 1 mile S* Brown weathered fine-grained crystal tuff containing minor of Palermo glass (n=l.52). Composition is dacitic; minerals present are: quartz , plagioclase , biotite, augite , hornblende, rutite, apatite, clay, and hydrous iron silicates* Slight alteration. P-6 Wyandotte Creek where Brown stained sandy crystal tuff or arkose containing poorly crossed by Cox Lane cemented, subangular grains of quartz, plagioclase, hyper- stene, ziifccon, rutite, etc* Specimen is probably altered and reworked with inclusion of some sedimentary material* 119 Table 20o - -Continued No. Locality Description P-7 Marysville road, about 250 Medium gray fine-grained rhyolitic crystal tuff containing ft0 No of P-4 o, Sec o 35, about 2% glass (n=lo52)» Minerals present are quartz, To 19 No, R 0 3 So plagioclase, zircon, hornblende, biotite, and apatite® Some hydrous iron silicate and clay derived by alteration. P-8 Roadcut at Fox Ranch near? Light gray to tan, slightly iron stained rhyolitic crystal P alermo or lithic tuff with some admixed sedimentary material. About 10% devitrified glass associated with quartzite and volcanic fragments, quartz, sanidine, biotite, etc® and products of alteration. P-9 Above hydraulic pit about Medium gray slightly bedded fine-grained sandy, tuff admixed one mile N 0 of Pentz. with a little sedimentary material, Minerals present include quartz, albite, apatite, hornblende, orthoclase, biotite, hydrous iron silicates, zircon, and volcanic frag ments® About 5% glass (n=l®525) most of which is devitrified P-10 Same as P-10 but strati- Dark gray coarse-grained dacitic crystal tuff containing graphically higher a small amount of glass (n=l®535) and a few volcanic frag ments, Minerals are sanidine, augite, hypersthene, horn blende, plagioclase and ferriginous clays® Rounded grains suggest reworking by sedimentary processes® P-11 About 102 miles S eWo of Light gray, slightly iron-stained, clay-like Altered tuff Wicks Corner of uncertain composition® Traces of glass (n=l®54) and cryptocrystalline quartz, plagioclase, biotite, hornblende, clay, etc® P-12 About one mile Se of Light gray to pink, slightly iron-stained clay containing Wicks Corner 30% glass that is totally devitrified to cryptocrystalline aggregates® Minerals present are quartz, orthoclase, plagi oclase, rutile, tourmaline, apatite, and clay. Material is an altered rhyolite tuff. 120 Table20.--Continued No. Locality Description P-13 About one mile S.E. of Pale yellow rhyolitic crystal tuff containing a trace of New Brunswick mine, near glass associated with biotite, epidote, and zircon» Feld Grass Valley. spars are extensively kaolinized and sericitizedo Moder ately pulverulent. P-14 S. side of Braggs Canyon, Purplish gray, medium-grained indurated crystal tuff con Sutter Buttes taining sanidine, quartz, calcite, albite, biotite, ortho- clase, hornblende and clay. Some pumice is present in volcanic fragments as much as one-half inch across. P-15 Braggs Canyon, Sutter Buttes A crystal tuff similar to P-14 but somewhat finer grained and containing only a few small fragments of pumice0 P-16 East part of Sec. 16, T. Medium gray, sandy, crystal tuff of trachytic composition. 16 N., R. 1 E., about Abundant orthoclase and hornblende with lesser amounts of mile N. of Braggs Canyon albite, biotite, and apatite. Many crystals are evhedral. Road P-17 Quarry approximately Medium to fine-grained crystal tuff of dacitic composition. located in T. 15 N., R. 1 It contains albite, quartz, hornblende, biotite, etc., E .; near abandoned bridge but no glass. S.E. of West Butte Townsite P-18 Sutter Buttes, N. side of Medium coarse, sandy, light gray, crystal tuff consisting West Butte road about 4 of hornblende, hypersthene, albite , quartz , and biotite. miles E. of West Butte A little clay, traces of glass and some volcanic fragments are present. Essentially unaltered. P-19 Sutter Buttes, about 1 Fine-grained, yellowish-gray crystal tuff containing mile E. of sample P-18 quartz , hornblende, orthoclase, albite, biotite , volcanic fragments and minor amounts of devitrified glass. Slightly altered. 121 Table20o - -Continued Nop Locality Description P-20 A few hundred feet S c of Light gray vitric tuff containing 95% glass in irregular Tuscan Springs to elongate shards e Accessory minerals are hornblende, aegirine-augite, albite, and orthoclase0 P-21 Little Salt Creek where Dark gray, fine-grained, sandy crystal tuff of dacitic crossed by road to composition* About 30% glass (n=l*515) which is slightly Tuscan Springs devitrified and kaolinized• Minerals present are quartz, orthoclase, hornblende, biotite, hydrous iron silicates, and clay* Slightly altered* P-22 About 2 miles Ee of Oro- Nearly white, fine-grained, massive, pulvurlent crystal ville on Feather River tuff containing about 30% glass (n=l*523) which is slightly Highway devitrified* Minerals present are quartz, sanidine, albite, hornblende, biotite, tourmaline, and zircon* Material is an unaltered rhyolite tuff* P-23 About 2 miles E.-N.E* Light brownish, gray fine-grained rhyolitic tuff * About of Oroville 95% clear glass (n=l*514) occurring in shards and strings of blebs * Minerals present are quartz, albite, sanidine, apatite, biotite, muscovite, hornblende, clays, and hydrous iron silicates* P-24 About 2 miles S0E0 of Tan to buff, fine-grained, porous, vitric tuff containing Oroville white megascopic shards, About 95% glass (n=l*523). No alteration* Traces of quartz, albite, etc* P -25 About mile S e of P -24 Thin intercated beds of coarse and very fine grained white rhyolitic tuff; tan or buff on weathered surfaces* About 30% devitrified glass and 10% fresh glass (n=l*518)* Contains biotite, albite, quartz* Slightly altered to clay and hydrous iron silicates * 122 Table20o--Continued Noo Locality Description P-26 About 2 miles SeEe of Oro- Light brownish gray rhyolitic tuff bedded according to ville on Lover Wyandotte Rde grain size ranging from fine to medium* About 70% of material is glass (n=lo510) that occurs in irregular masses, shards, and stringers of blebs0 P-27 Near Oroville, SE^-, of Gray, very fine grained "silty” crystal tuff of rhyolitic NE Sec. 21, T.19 N., composition* Traces of devitrified glass associated with R.4 E. albite, orthoclase, quart z, biotite, and hornblende * Slight alteration* P-28 About 2 miles S 0 E. of Light brownish gray fine-grained rhyolitic tuff * About Oroville on road to Garden 90% glass (n=lo513) which occurs as irregular masses, Ranch shards, and blebs* Minerals present are quartz, sanidine, albite, epidote, and clays* Apparently altered in site* P-29 A short distance S0Ee of Light brownish gray rhyolitic titric tuff with coarse Oroville on road to shards in a fine-grained ground mass* About 95% glass Garden Ranch (n=l*508) which occurs in shards and streaks of blebs* Minerals present are quartz, albite, sanidine, biotite, hydrous iron silicates and clays0 123 124 be included with the rhyolitic tuff of the Gutter formation as described by W illiam s (1@29? p. 129-139). Accepted practice dictates that the "tuffs of O royille" (Lindgren, 1911, p. 26) be classified separately from the tuffs in the Tuscan formation, described by •Anderson (1933), : although they have many petrologic sim ilarities. As Shown in sub sequent parts Of this r eport, only the tuffaceous materials were inten sively investigated as possible sources of pozzolans. Only a cursory investigation of the clays was feasible because they require calcination to induce pozzolanie properties. ; y _ TuffS ' Tuffs are widely distributed in north central California. They '■< are genetically associated with Cenozoic volcanic activity in the Sierra Nevada and with the vast volcanic fields in the vicinity of Lassen.Peak, which are described by B ille r (1895) and:W illiam s (1931), and in Gutter (M arysville) Buttes described by Lindgr en (1895) and W illiam s :(1929). Several investigators consider the source of some of the tuffaceous ma terial to be unknown localities in the northern part of the Sierra Nevada :Battge<, far to the east and southeast of the area in which the tuffs now • ■ ' / \ ' -'y ' ; ' . - y-': ' . ' occur. The tuffs were deposited during the late Cenozoic and probably are to be assigned to the Miocene and Plipcene. The distribution, source, origin, and age relationships of the tuffs are reviewed by Creely (1955, p. 198-229), in an. unpublished dissertation to which the reader is . referred for a discussion of this interesting problem. In north central California the tuffs are of three general types, as dismissed below. Tuffs of the Tuscan Formation The most widespread is the Tuscan formation, often referred to as the Tuscan tuff, a: designation once •assigned by B ille r (1906) for the Redding region, but which is no longer preferred usage according . to Anderson; (1933, p .’223). The Tuscan formation is described.by Anderson (1933, p. 226), and others as being composed of andesites and basalts with the latter predominating. Interbedded with the lower ; part of the Tuscan formation, exposed on the east side of the Sacramento ; Valley and occupying a sim ilar position in' the Tehema formation on the , west side of the valley, is a distinctive bed of dacitie tuff described by Anderson '(1933,,p. 235) and others.■;' This is the Numlaki tuff, named for its occurrence on the Numlaki Indian Reservation. It is noteworthy that the Tuscan for mation has its, southern'lim it near Pentz (Anderson, . 1933, fig. 1; and this report, fig. 5). Southward between Pentz .and TOrovine little or no .tuff is exposed: ; ■ The Tuscan formation may be of utmost importance in various aspects of massive concrete construction projects in north central Cal ifornia. Eckel (1928, p. 581), in citing the work of B iller (1904, p. 177-179), calls attention to the possible importance of the use Of tuff from the Tuscan in the construction of large dams for irrigation or m water- power' In the Redding' region. Regarding this matter D iller '(1904 p. 177 and 179) states as follows: It is well known that a hydraulic cement of good qual- , ity may be made by: mixing ordinary lime with some sill- - ceous substance in such proportions that the interaction Of the two form s silicate of lim e and sets or hardens the cement,,. In parts of Germany a volcanic tuff called trass is largely employed for this purpose,,. The Tuscan tuff is sim ilar to the trass of the Rhine Valley, which is so extensively used in the manufacture of cement, and there appears to be no good reason why it might not be used in the Redding region for the same ' : : ^purpose, ' ' -r;; ' ■ - ■ • ' ’ . The possibility of using tuff from the Tuscan formation in ce- •• meat and concrete apparently warrants further investigation. Accord-; Ing to B iller (1904 p. 177): "The scarcity in northern California of hydraulic limestone or cement rock Suitable for the manufacture of ' hydraulic cement, creates a demand for the small quantities of such rock as exists and of other material which may be used for the purpose,H Whether- the tuffs from the Tuscan formation can be used in the manner prescribed by D iller remains problematical. Actually the Tus can formation contains very little tuff according to Anderson (1933, p. 2284 It is probably not more than 10 percent tuff, tuffaceous siltstone, and claystone according to Creely (1955, p. 208). Most of this material is andesitic or dacitic in composition and is composed of angular crystal and lithic fragments according to Anderson (1938, p. 229). The w riter's samples P-9 and P-10 are representative of some of the thicker beds of the finer grained tuffs in the Pentz area* . As'these are crystal or lithic tuffs containing little or no glass and generally lack alteration it is con cluded by the w riter that they would not make good pozzolans. Mielenz (185% p* 5) accepts Diller^s conclusions, and considers the Tuscan fo r mation to be a possible source of pozzolan. The problem of utilizing the tuffs from the Tuscan formation as suggested by D iller (1904, p. 17% and Eckel (1828, p. 581) is very complex* It has been shown that trass* with which tuff of the Tuscan has been compared* is a: ^highly altered zeolitic? trachytic tuff or vol canic mud” (Mielenz, 1950* p* 5), which differs from the relatively un altered material of the Tuscan. Howeyer* the tuff of the Tuscan forma tion contains rock and mineral fragments that M erriam (1952, p* 6) con siders to be deleterious from the standpoint of the alkali-aggregate re action. it must, therefore* also possess some pozzolanic properties. Strange as it seems* deleterious materials that cause the alkali-aggre gate reaction to take place, as for example opaline shales (Merriam, 1952* p. 6), also make some of the best pozzolans used tp prevent the .reaction (Merriam* 1952, p. 10). The difference lies in the manner of preparation and utilization of the m aterial. if the tuffs in the Tuscan formation can be shown to have sig nificant pozzolanic properties* which the w riter doubts* then somewhat sim ilar crystal and lithic tuffs near OroviUe* near Sutter Buttes, and in the Sierra Heyadas might also have, significant pozzolanic properties. Tuffs of Oroville - Tuff deposits are-comparatively thick and widely distributed in . file' vicinity of ■Oroville .and extend southward to Bear River. These, were designated the "tuffs of O roville'-by Itndgren (1911 ? p. 26-27). He de scribed-the tuff; as. "light-brown m aterial containing in places pebbles -of. , metamorphic rocks and also small white fragments of pumice which are found to consist of volcanic glass; locally these fragments are very small and the tuff looks more like a compact clay.n This tuff is clearly andesit ic in composition according to Cr eely (1955? p. 199), and was mapped by . him as Mefartea(?). . This appears to be the dominant m aterial in the low M ils of the piedmont in the Vicinity of Palermo, Bangor, and elsewher e. In discussing the "tuffs of O roville" Lindgren (1911, p. 27) says, nTMs, ■ series %as deposited on the .even slope of the- older (Neocene) formations, before the modern canyon of Feather River had been excavated but after the earlier lone formaW n had-been greatly eroded." Turner (1896, p .;. 540-542), and Anderson (1933, p.: -218) consider the Tuscan formation - . " : ;■ - - -. , : ; : v I - 1 . — ' ' ' ■ ■ ' ■ . . ' -' : . to be younger than an andesitic tuff series that is extensively developed in the central part of the Sierra.Nevada. Probably the andesitic tuff corresponds to the Mehrten(?) of Creely (1955, p. 199). Most of the /"tuffs of Oroville^ are crystal tuffs, which presumably have little or no pozzolanic properties. -Unnamed Rhyolite Tuff Geologic Features Another tuff occurs in small2 isolated patches in the Oroyille area where it is. described by Creely- (1955, p. 198-208), who refers to it as unnamed rhyolitic pumice tuff. Part of C reeps description is Reproduced Below:. , ' : The principal rock type composing this unit is vitric tuff, often interstratified with which are thin layers con taining abundant lapilli of white pumice. The tuff is char acteristically light-colored. Most of it is white, light - . - - gray # pale bu% though certain feeds are locally dis- - . colored'fey an orange-brown ferruginous stain. Much of the formation is thin-bedded and some individual units ex hibit excellent cross-bedding. The tuff is usually well- : ' Sorted, ’ and shows a ll gradations from silt and sand-sized " tuff to lapilli tuff. The finest-grained types are usually well- ■ : consolidated and "chalky" and consist almost entir ely of an- ; gular glass shards.- Under the binocular microscope, the shards are seen to fee delicately shaped, and consist of con nected,: thin, curying septa of ,clear glass . . . The coar ser- .grained tuff and lapilli tuff are extremely friable, and ' ' Crumble readily,under SligM'pressure. They consist - principally of volcanic glass in the for m of white, unalter ed pumice. The sand-sized particles and, lapilli are most ly angular to sufeangular, and some are subrounded, pre sumably reflecting-the aqueous transport to which the : : original ash was Slightly subjected. - Uapllll,- which meas- ; ure up to 4 centimeters, are generally concentrated along certain feeds, but most of the tuff contains scattered lapilli. Accompanying the pumiceous material in the coarser- grained tuff andlapllli tuff are small angular fragments- ; - w euhedral. crystM s b f quartz,- glassy feldsfear (sanadine), hornblende and hypersthene, with a few chips of dark, . dense, volcanic(?) rock. Undoubtedly the extent of the rhyolitic tuffs originally was con sider able'and the present restricted'.areal distribution is due to post- ' depositional erosion and masking by later deposits»• Creely (1955, pv 2.63) found the rhyolitic tuff to rest on andesitic mudflows of the Mehrten(?) formation without any marked angular-discordance ..and reports that it is overlain disconformably by the fluvial deposits of the Red'Bluff forma tion, Rhyolitic tuff is not present nearer .'Oroville where Red Bluff rests directly upon the-Mehrteri(?)- andesitic rocks according to Creely (1055, - p. 203). ■ - ■' ; ■ : ' V".-: t- , " Pozzolanic Properties ■ . - - . - Str ength tests Of lim e m ortar mixes using some of the unnamed rhyolitic tuff, both raw and calcined, were made for the writer by Wolf Gr. Bauer, Seattle, Washington. The results, shown in table 21, indW cate that it Is a. satisfactory pozzolan for some purposes if properly prepared. Probably better results would be obtained by finer grinding; however, additional special tests are necessary to determine if the ma terial w ill meet.use requirements. ' Tuffs, of Sutter (Marysville) Buttes Extensive tuff deposits surrOund the Sutter (Marysville) Buttes and a little tuffaceous material occurs within the Buttes. These tuffs are surprisingly sim ilar to some of the tuffs near Oroville, and Lindgren (1911, p. 90) thought it likely that ash showers from the volcano at Sutter . (Marysville) Buttes contributed to the tuffs near. Or oville.; However, ; . Table,21o —Strength tests of. rhyolitic tuff in lim e mortar. Fineness . 28-day p s i • Sample B la in e / 7-day PSI . 3.0 p e rc e n t Pv C. sq. CM. /gr. Lime mortar Repl. B-23, Raw " y 4.700 : :/. - ' .810. 3.000' P-23, Calcined at . 1500°F. ' ' 4900 845 3075 > P -2 0 , Raw' : 4800 .; >:/ : 850 y .3100 P-2.0, . Calcined at 1 1 5 0 °F . ' : 4600 ' .915 : 3125 Cement control 3160 .. this is hardly possible as pointed out by W illiam s (1929, /pi. 185), who r eports that the tuff beds thin appreciably away from the Buttes and at a distance of 4-1/2 miles the thickness is negligible; therefore, it is unlikely that any of the ash'traveled as far as Groville, ■ ' % Most of the tuffs in the low hills forming the peripheral area around the Buttes, as described by W illiams (1929, p. 178-180), are • fragmental andesites. These pyroclasties, according to Williams, are: Fine, sand-like tuffs, gray or buff in color, alternate with bands of la p illi tuff and coarse breccias, and ar e oc casionally divided by thin lenses pf detrital tuffs.... W ith rare exception they are of andesitic character I they are ’ indeed nothing but comminuted fragments of the andesitic laccolith... . The coarser ejecta .belong to the catagory of cognate lith ic blocks; the finer ejecta are crystal and lithic tuffs, in part detrital. • '/v, ' 132. ; On the south .slopes of Sutter (Marysville) Buttes, Williams (1029, p. 129-139) describes some rhyolitic and andesitic tuffs which he assigns to the lower portion of the Sutter formation of probable Low er Miocene, At this locality the Sutter formation' is about L 000 feet. thick. Regarding the Sutter formation and closely related beds, W illiams states they were derived from sources in the Sierra Nevada and can be correlated with beds' now occurring in the ^Sierra foothills, Williams (1929, p, 131) shows the basal beds of the Sutter contain considerable glassy rhyolite tuff ’’characterized by the presence of conspicuous frag ments of opaque, white pumice and shredded glass in a gray m atrix of fine rhyolitic dust and shards. ” As the descriptions of these rhyolitic tuffs satisfies many of, the requirements of pyroclastic pozzolans, two samples were collected by the writer for further study. Unfortunately these samples did not fit the description given by W illiam s so it is as sumed they are not representative of the tuffaceous portion of the Sutter formation. ■ ' . ' Conclusions of .r , : ' . ■ . . - ' ; ; : ' ' ■ " . ■■■ ' , This investigation reveals that pozzolans are being used ex tensively in large, massive concrete structur es and their use is in creasing. Most of the pozzolans being used in north central California • are obtained from opaline shales and sim ilar materials of Miocene age that are not known to occur in the area investigated, tetlds-ar'ea.it is 133 believed, that pozzolaais could be prepared by calcining some of the clay beds from the lone formation, especially those that are tuffaceous. Poz- zolans probably also could be obtained from some of the rhyolitic tuffs near Oroville, and from the Numlaki tuff. These possibilities are in-1 dieated by the high glass content of the tuffs, the low index of refraction of the glass and the results of afew mortar strength tests that are avail able. ■ if appears that the. tuffs in .the Tuscan, gutter, and Mehrten(?) formations, and most of the materials described by Lindgren as the 't’tuffs of O roville” are not suitable for pozzolans. This belief arises from the fact that these materials are crystal and lithic tuffs, having an andesitic or more basic composition; therefore,; probably have low poz-. zolanic values. The suggestion made by D iller that the tuffs in the Tus can formation are simular to the trass in Germany, and that it might be used in a sim ilar manner, warrants further investigation. BW M AEY OF CEMENT MATERIAL 1NVESTIGATIOH The area investigated for cement materials in north central California is underlain by a thick series of sedimentary rocks, igneous intrusives, and volcanics ranging in age from Silurian to Recent. Pa leozoic and Mesozoic rocks in the Sierra Nevada province: ar e often con sidered together as the ."Bedrock se rie s/’ although they are separated by a profound unconformity. Resting unconfor mably upon these are Cretaceons and Cenozoic rocks which ar e extensively .expoBed in the Great Valley province. Limestones from which cement can be manu factured are comparatively scares but numerous smali, widely scattered deposits occur in the Calavaras formation of late Paleozoic, and large deposits occur in the Triassic. A deposit of argillaceous limestone oc curs near V irgilia and an important deposit of relatively pure limestone is situated near Genesee, both in Plumas County. Both deposits are T r iassic; in'age and the. Genesee deposit is the1 type locality for the ' Hosselkus limestone. This deposit has undergone considerable struc tural deformation. The limestone contains about 53 percent CaO. The argillaceous limestone near V irgilia has a composition sim ilar to natural cement rock. It contains about 45 percent CaO, 13. 7 percent 810g, and .2. T percent .AlgOg, ; and about one percent each of MgO and FegOg. It' .. : - ; - i s 4 . ; ; . ■' ■ v . : n . ■ appears feasible to manufacture cement from either of these two lim e stone deposits with the addition of appropriate admixtures. Aluminous materials are available.in several places in the area, but. it appears advantageous to acquire iron and gypsum from other sources. Pozzo- lans, if needed, can be obtained from clay and tuff in the Sacramento BIBLtoGBAPHY ... References Pertaining to Geology of North Central California ' . • '' Allen> ¥« T = 1929,' A e lone formation of California: California Univ, Dept., v. .18, no. 14, p. 347-448, ■ • Anderson, C. A. ,- 1933, The Tuscan formation of northern California, with a discussion concerning'the.origin of volcanic breccias: GeoL Sci. Bull., v. 23,.p. '215-2#. - . Anderson, F. ;M.> 1933, Type area of Jurassic Knoxizillian series: Pan-Amer. GeoL , v. 60, p. 175-183.' Aver ill, C. V ., 1937, Mineral resources of Plumas County, Califor nia: California.Jour. Mines and Geology, V„ 38, no. 2. Bramlette, M. N ., 1946, Monterey formation of California and origin A ; of its siliceous recks: U. S. GeoL Survey Prof. Paper 212. Bowen, Q. E . , and.Crippen, R. A. , 1948, Geologic maps and notes along Highway 49: in Guidebook, The Mother Lode Country,' v" , Calif . Div. of Mines, Bull. 141. ' Clark, F. W ., 1924, Data of geochemistry: U. S. GeoL Survey Bull. :: : ' L , A . v ' . . . ,:' : : ■;V Clark, F. W., et aL , 19.15, Analyses of rocks: B. S. GeoL Survey Bull. 591. V: ; . . C ; . . ■ : - . ; ■ i3 6 ' ' . Creelyj 8. ? 1955,’ ■ Geology of the 'Oroyille .quadrangle, California: . Pho'D. thesis, IJiiiv. of California, Berkeley, Calif. ■ -Davis, :E. • F ., 19:0, The.Radiolarian cherts of the Franciscan group:... TJniy. Calif. Pebl. Dept. Geol. 8ci., v. 11, p. 285-432. D iller, J. S. , 1886, Notes on the geology of northern California: U. $. /Geol. Snrvey Bull. 335 p. 23.' . - . 1883, Cretaceous and Early Tertiary of northern Califor- : nia and -Oregon: - Geol. Soc. America B ull., v. 4, p. 205-224. ' . ; . 1895, XJ. 8. Geol. Survey Atlas, Lassen Peak Folio (no. . . 15). . ' . V ’ . . •’ ' . . 1904, Mining and'mineral resources in the Redding quad rangle, California in 1903: U. S. Geol. Survey Bull. 225. , . . ; '1908, Geology of the. Taylorsville region, California: U. S. Geol. guryey Bull.: 353. , D iller, J. S., and Stanton, 1894, The.Shasta. Chico series: Geol. Soc. ' ■ ■ '' America Bull., v. 5, p. 435-464. Douglas, G. V. ? King, A. M ., and.Misick, J. D. ,. 1944, Staining tests .. for dolomite: ’ Econ. Geology, v. 39, p .: 69-70.. Fairbairn, B. W ., 1935, Introduction to petrofabric analysis: Queens University, Kingston, Canada (mimeographed report), p. 31. ■ ' Fairbanks, E. E . 1925, A modification of Lembergts staining method: Am. Mineralogist, v. 10, -p. 126-127. ' . Heyl, Q> Ro j, and Wiese^ J. H, $ 1949, Geology of limestone near Sonora, Tuolumne County, California: Calif. Jour.. Mines and. Geology, v. 45, p„ 509-513. - Howell, J. , et a l., 19.57,. "Glossary-of geology and related.sciences^ '■ ' - Am. GeoL. Institute,. Washington,. B. C. Jenkins, 0. :P. 1932, Report accompanying Geologic Map of Northern - Sierra .Nevada: (including map): Calif. Biv. of Mines, Report / of the State Mineralogist, v. 28, no. 3, p. 279-298". ; (Editor), .1933, Middle California and Western Nevada; In- ternational Geological Congress Guidebook No. 16." • ’1948, Sierra Nevada .Province and Geologic history of the Sierran Geld Belt, in Geologic Guidebook along Highway 49, , The Mother Lode Country: "Calif. Diy. of Mines Bull. 141, p. ; :" ' 2 1 ^ 3 6 . V." '-, : d -" ; ■ ; ■ - ' . Eellery W. D ., and,Moore, G. E., 193"7, Staining d rill cuttings for calcite-dolomite differentiation: Am. Assoc. Petroleum GeoL Bull. , V, 21, pt. 2, p. 949-961. ’ *■ ■. . . - _ ' .Lindgren, Walde-mar, 1895, XL S. GeoL Survey Atlas, Marysville Folio ;; (no'. v l7 )...i ' ".. . ; 1911, The.Tertiary gravels of the Sierra Nevada, Califor- \ nia: U. S. Geol.- Survey Prof. Paper. 73. Logan, C. A ., 1947, Limestone in California: Calif . Jour , of Mines and. Geology, - v. '43, no. 3. ; . v ' ■■ ... ,r ; 139 M ills? Jo E- ? 1892, Rocks of the Sierra .Nevada of California: GeoL Soc. America BulL, v. 3o , : - PaSk,' A,', :-and Turner, D» # 1952, Geology and ceramic proper ties of the lone formation, Buena Vista area, Amador County, California: Calif, Diy. Mines Spec» Report No. 18. Smith, S. T. , 1943, Calcite-dolomite staining tests: Bean. Geology, ' V V . 38,- p. 420-422. ' - ' Stephens, B. By, and Carro% M. :Kr, 1948, Simple field test for dis- • tinguishing minerals by abrasion pH:-' Am. Mineralogist, v. . • ■. . S3, p. 31-49.: ■ ■ . ■ ■ Taliaferro, N. L ., 1942, Geologic history and' correlation of the Juras- . .. sip of southwestern Oregon and California: Geo!. Soc. America y Bull., v. 53, p, 71-112.. ' y ; -. ' . , 1943, Franciscan-Knoxville problem: Am. Assoc. Petroleum itireol. B u ll. ,' no. 27, p. 109-219. Turner, B,. W. , 1894,- The rocks of the Sierra Nevada: U. S. Geol. . Survey 14th annual report, pt. 2, p. 435-495. , ... ■- 1896, Further contributions to the geology of the Sierra Nevada: . Bv S. Geol. Survey 17th annual report, pt. 1, p. . , ." - - . .521-762. . , . . . , ■ ; 1897, tT. S. Geol. Survey Atlas, Bownieville Folio (no. 37). . , - 1903,- U. S. 'Geol. Survey Atlas, Bidwell Bar. Folio (no. 43).. \ . ' ■ , : 1 # T u rn e r, H.. W=, -and Lin d g re n , W aldem ar, 1895, U. S. GeoL Suryey . 'Atlas, Marysyille Folio (no. 17). - ■ Whitney, J. Do, 1879, The auriferous grayels of the Sierra Nevada: Mem. Mus. Comp. ZooL Harvard Coll., v. 6. . W illiams, Howell, 1929, Marysville Buttes: California "Oniv. Press, : Dept. 'Geol. Sci. Bull. , v. 18, no. 5, p. 103-220. y Wilmarth, M. G., 1938, Lexicon of geologic names of United States: \tT. S. Geol. Survey Bull. 896. / " Bef er ences. Pertaining to Cements and PozzolanS' Airox Pozzolan, 1956, an information circular by the A irox Company, ' Los Angeles, Calif., t A-l-A.- file 4-B-l. : American Soc. Test. Materials, 1949? Symposium on the use of pozzo- lanie materials, ih mortars and-cdncrete: Spec. Tech. Pub. ho. 99, Philadelphia. , ' 1952, Standards, pt.- 3, designation C -150. Basalt Pozzolan, an information circular'.by the Basalt Rock Co., Inc., , ' Napa, Calif. : A-B^ Y ' - : " Blanks, R. F ., and Kennedy, H. L. , 1955, The technology of cement and concrete: John Wiley' & Sons, New York, New York. Bogue, R. H. ,.1955, The chemistry of Portland cement: : 2nd ed. .Concrete Manual, 1956? U.' S. Bureau of Reclamation, 6th ed. , 141' Dayistj, R. B . 1949,; A r eview of pozzolanic materials and their use in concretesi in Symposium on use of pozzolanic materials in /. V mortars and concretes, Am. Soc. Testo M aterials9 Philadel phia, '• ' •" ’ ; V' V v ' Befcel, -E.. C.> 1913, Cement materialst XL S. GeoL Survey Bull. 522- Fears, F. K ., 1949, Bibliography oh mineral aggregates, annotated: compiled by Committee on M iner al Aggr egates. Highway Re- sea rch B oard, W ashington, Bo .C- , * .' V : G eorge, W. O ., 1924, The relation for the physical properties of natural glasses to their chemical composition: Jour. Geology, v. 32, p. 353-3:72. ' Grim, R. and Rowland,. R. A ., 1944, differential thermal analysis of clays and shales, control and prospecting method: Am. Ceramic Soc. Jour., v. 27, p. 65-76. Handbook for Cement and Concrete, U. 8. Corps of Engineers, W ater- ways E 2q)eriment Station, Vicksburg, Miss. ■ Heinz,' C. E. , ' 1937,Tripoli, in industrial minerals and rocks: Am. ' Inst. Mining, MetalL Engineers, New York, New York, p. 911-922. " ; ' • 1 Lea, F. M. , 1938, The chemistry of pozzplans: Symposium on the Chem istry'of Cements Prpc. j p. . 460-490, • Stockholm, Sweden. 1956, The chemistry'Of cement and concrete: London, _ _ _ . ; : ■ : : , ' ■ ; V ■; England, p. 637. ' Mathery Kafherlne, 1-958, Cement aggregate reaction—what is the problem: in Case Histories No. % Geol. Soc. America, p, ■ ■■ ^ ' McClean, W alter E. / 1954, Eozzolanic; materials and- their use in, con- ' ; • Crete pipe and structur es of the East Bay sewage, disposal pro- ' ject? East Bay Municipal U tility District, Oakland, C alif.: - Baper available from the author. . , Merriam, Richard^ 1952, Alkali-aggregate reaction in California concrete aggregates: Calif. Div. of Mines, Spec. Pub. no. 27, ■ . - p.: 3-10. ; ' . Mielenz, R. C., 1946, Petrographic examination of concrete aggregates: Geol. Soc. America Bull. ? v. 57, p. 309-318, pt. 1. ______1950, Materials for pozzolan, a report for the engineering . geologist: Pet. Lab. Bept.^ no. Pet. 90-B, B. S. Bureau of : Reclamation. ' Mieienz, R. C.., Greene, K. T ., and Benton, E. J.? 1948, Chemical test for reactivity of aggregates with cement alkalies: Chem ical Processes In Cement-Aggregate Reaction, Amer. Concrete - Lnst. Jour., v. 3.- • Mielenz, R.- G,, Greene, K. T., and.ScMeltz, N. C. , 1951, Natural . pozzolans for concrete: Econ. Geology, v. 46, p. 311-328. Mielehz, R. C., :^tt% P., and Glantz,, p. J., 1949, Effect of calcination on natural pozzolans: in Symposium on use of ■ ■ 143 pozzolanic materials in mortars and concretes,, Am. Soc. Test. , Materials,: Philadelphia. - Moran, W. T ., apd ,Gillilan.d? J. L. ,104% Summary of methods for '' determining pozzolanic activityi In Symposium on use of poz- zolanic materials in mortars and concretes. Am. Soc. Test. ■Materials^ FMladelpMa.., Firsson? L. V, 191 §3 The microscopical characters of volcanic tuffs: ' Am.-Jour. Sci. j. y. 40^ p. 101-211., Ruiz, A. L ., i058j: Effect of calcination temperature;on heat of solution - ; ' , \ . -of clays: 'Am.vSo^p Materials, October Bull., p. 51-56. Stanton, T. E ., Porter, O. J ., Meder, L. G.and Nicol, Allen, 1942,: California e^erience with the expansion of concrete through reaction between cement and aggregate: Amer. Concrete Inst. Jour., v. 13, no.•I. - Wentworth, C l K ., •■and W illianas,; ■ Howell, 1932, The classification and terminology of the pyroclastic rockSd National Research Council, Bull. 89, p. 19-53.; ; Unrv. of Arizona Libran 7 o PLATE. 4 GEOLOGIC MAP VI PC ILIA LIMESTONE DEPOSIT VIRGIUA. CALIFORNIA Gtalety J H fan A >«« — v h P a u /to r S u n n y m j: J. M at A it LtetNO V.\- — ' >- • O rtll Mat,, « V a r t K m ! » # * f A tt/tu P t o f hada — TMutt f 'mV. o f Arizona U b ra r ^ 7 PLA TE 2 A A' 4800'-i — 4 8 0 0 WEST D rill hole No. 3 EAST Drill hole No, 4 B r e c c ia 4700' 4700 Hosselkus limestone D rill hole No. 6 4600 4600' 4500' 4500 D r il l hole No. 10 4 400 4400' D rill hole No. 1 R o b in so n ^ x- ^form ation/ rJ-S rS'rS- S ^ ^ / 4300' 4300' 4200' 4200 Swearinger formation 4100 4100 Hosselkus limestone Hosselkus limestone Swear inger for rnation 4000 4000 3900' 3900' 3800 3800' ' Swear inger formation 3700 3700' 3600' 3600' CROSS SECTION OF THE GENESEE LIMESTONE DEPOSIT, GENESEE, CALIFORNIA 7a P L A T E 3 4 8 0 0 '-I r 4800' SOUTH NORTH 4700 4700' 4 600 4 6 0 0 INCOMPLETE 4500 4500' D rill hole No. 11 / Collar of hole 162 feet Hosselkus limestone / west of section 4400' 4400' D rill hole No. 9 at section 4300 4300' I Robinson and Reeve formations I undifferentiated 4200' 4200' Hosselkus limestone 4100' 4100 Bottom "of hole 225 feet Hosselkus limestone east of section 4000 4000' Swearinger formation 3900 3900 3800' 3800 3700' 3700' 3600' 3600' CROSS SECTION OF THE GENESEE LIMESTONE DEPOSIT, GENESEE, CALIFORNIA P LA TE 1