Detrital mineral studies of some Cenozoic sediments, Safford Valley, Arizona Item Type text; Thesis-Reproduction (electronic) Authors Mathias, William Francis, 1934- Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 24/09/2021 15:32:47 Link to Item http://hdl.handle.net/10150/551368 DETRITAL MINERAL STUDIES OF SOME CENOZOIC SEDIMENTS, SAFFORD VALLEY, ARIZONA j ' -oni- ■; ; ;:, .-v , • • . '-vva:-;-: i ^ :o rov,-: .l V William F. Mathias, Jr. •'} / \ > '• A Thesis Subfhitted to the Faculty of the In Partial Fulfillment_of.the Requirements - r' v : ■ 0 ForZth^ Degm eW ■/: - MASTER OF SCIENCE : .,'1 ’' -■ ■ : vi'. ‘ , :-v . I . - ...: In the Graduate College UNIVERSITY OF ARIZONA 1959 tSTHSMiaaS 0105:07133 EM03 3 0 P31uUT5 JAHSKILI JATiTiT^Q AWOSIHA tY3 JJAV OHOlOAd 7 0 • iL t2r:irij;u/I .3 rn^illiW srii oj bei3\%%8 aiaodT A GlnemsiiorJ^ g^sJo u 1 lj3ii'U3<I nJ ^ 'io 3 95dIIoO disubsiD erii nl AKGSIKA 3 0 YTI8 3 3 V73U 850 r 6 179/ / f-r? / ja STATEMENT BY AUTHOR This thesis has been submitted in partial fulfillment of re­ quirements for an advanced degree at the University of Arizona and is deposited 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 material is in the interests of scholar­ ship. In all other instances, however, permission must be obtained from the author. SIGNED: , APPROVAL BY THESIS DIRECTOR This thesis has been approved on the date shown below: p H « WILLARD D. PYE bate Professor of Geology T:;c-' "tii' v • : ;■ :: ;r . >:u , : : vV:- DETRITAL MINERAL STUDIES OF SOME CENOZOIC SEDIMENTS, :!.nd :::h;;,,:iv SAFFORD VALLEY, ARIZONA i:- - u.: .'.:V I G’.' v.f by, William F. Mathias, Jr. ABSTRACT More than 27 mineral species have been identified in Cenozoic sediments of varying lithology within the Safford Valley of Arizona. The mineral assemblages suggest the following possible sources for the basin-filling detritus: (1) acid igneous rocks, (2) basic igneous rocks, (3) high-rank metamorphic rocks, (4) reworked sediments, and (5) ex­ plosive volcanic activity. The high angularity and low stability of most of the heavy min­ erals suggests that the crystalline rocks of the mountains that flank the valley were the source of most of the detritus. The presence of glass and fresh euhedral volcanic minerals suggests that explosive volcanic activity has also contributed greatly to the detritus that fills the valley. The use of heavy minerals as a means of differentiation and correlation of strata must be based upon frequency of occurrence of mineral species, rather than on any major mineralogical changes. ii The uniformity of the general heavy mineral suite over a con­ siderable vertical and lateral range, and the characteristic lenticular and discontinuous nature of the Cenozoic sediments, may make the de­ termination of mineral zones difficult. ..................... • -v . ■ ' ■ .■ ' -'0 -- . ■' 1 :) T- - ri., "- 10 :0 i"; h'V-- . C .. 0, c. ' : . j ’ ini - o' A 2." r; 17 i:: 10 IB 1 7 JO v; Q. lvj:\rv Ml;:- : On . iii TABLE OF CONTENTS. ; . ........................................... .......... .. ..................... Page INTRODUCTION ...........--------.......................... 1 General Statement of Problem ................. r-4 v-4 03 IO CO b- l> l> 00 Previous Work . .... .............................................. Location and Geologic Setting of Area ............ Collection of Samples ......................... .. Acknowledgments ................................................... TECHNIQUE OF DETRITAL MINERAL EXAMINATION' Introduction ......... Preparation of Sample Counting of Grains .... LOCATION AND PETROLOGY OF SAMPLES .,..,,,.,........ 10 Introduction .................................................................................... 10 Sample A ............ 10 Sample B . ................................................................................., 12 • Sample C .................. 14 Sample Cr ......................... ............ .................................................. 15- Sample D ...........................^ 16 DESCRIPTIVE MINERALOGY OF SEDIMENTS ............... 17 Introduction ........................... 17 Light M in erals.................................................. 17 G lass..................... ...................;.............................................. 17 Gypsum .................................................................................... 18 M icrocline................................................................................ 18 Muscovite ...................................... •......................................... 18 Opaline Material 19 O rthoclase................................................................................ 19 Plagioclase ............... .............. ................................ ......... 19 Q uartz....... .................................... 19 Mineral Aggregates..... ................... ......... 20 Heavy Minerals ................ ._...■.......... 20 iv Page Apatite................... .................................................................... * 20 Augite................................................ 20 A xinite.........: ......................................... ................................... 21 Epidote ................................... 21 , Garnet .. i ....................................... ................................ 21 Hornblende (Brown) ............................................................... 21 Hornblende1 (Basaltic) .................. 22 Hornblende (Green)........................... 22 Hypersthene.............................................. 22 Monazite .............. 22 Olivine ...................................................................................... 23 R u t i l e ........................................................................ 23 Sphene...................................................... 23 Spinel......................... 23 Titanaugite............................... 23 Tourmaline................................................................................ 23 Z irco n ..................................*....................................... ............ 24 Magnetite .................................................... 24 Other O paques.............. 24 Mineral Frequencies .......................................... ...........'.............. 24 The Frequency Scale .................. 24 SOURCE OF DETRITUS............................................... 31 Inferences from Detrital Minerals ................ 31 Possible Source Areas...................................................................• • 33 SUMMARY AND CONCLUSIONS............................. 36 REFERENCES CITED ...................................... .-.............. 39 ' LIST OF FIGURES Figure Page 1. Index map .......................................................................... .. 3 2. General stratigraphic relationships of sam ples................. 11 3. Profile chart of light mineral frequencies............................ 27 4. Profile chart of heavy mineral frequencies.......................... 30 LIST OF TABLES Table Page 1. Light mineral frequencies............................................................. 26 2. Heavy mineral frequencies ............................................ 28 vi L'. ..--Vifv. M,,’ G ’ '.-:v.v'v fv::-!--rr r; ; • .G'X. -: 7G> . ■ . i INTRODUCTION Li" ■ 'G:.G-:.v :.r : v ■, :• »; c " G": ^ ■ L ' ;; G- G-<" General Statement of Problem The Safford Valley of Arizona is an inter montane trough which has been filled by a sequence of poorly to medium-well consolidated sediments of Cenozoic age. 0; G- a : ■ a: • i , ; , , , a This study is an investigation of detrital minerals within some of these Cenozoic sediments. , It provides further insight into the sources of the detritus that fills the Safford Valley. 'Gr ■ G ' G A - r." r:. v : v . - i ’. A:: • i :.; ", : i - A l A A ,A-*; , ~ Previous Work GiOA A,": A G " [’ ■■■■ ■ G' : •, . : -.G ' A' A-' ’ A , A ZVA V/aG laa ' A:G*AA, .;*A '>A A1 A G; a: a G The only other study of detrital minerals in the Safford Valley area was done by Van Horn (1957). He made a qualitative study of,the heavy minerals in order to, gain an idea of the source of some of the sediments..v a g ■ G a . -G a- . - , Studies of the ground-water conditions of, the Safford Valley _ were made between 1919 and 1956. Van, Horn (1957) gives an extensive bibliography which lists most of these works. - Knechtel (1938) discusses in some detail the geology of the,area. , -.gg-ga j a G • A" A A A . G a •; Aa: .a a, • :G ."A)f; laa'-*-GG: G G" A; GrAj A ;rz ''A .A vi: A GA: A ' , A a- ,A A A "A; G.A VGA G-A.. 2 Location and Geologic Setting of the Area ; i The area covered by this study lies within the greater Safford Valley along the Gila River from Coolidge Dam on the northwest, to the \ " junction of the Whitlock Valley and the San Simon