State of Washington Department of Natural Resources BERT L. COLE, Commissioner of Public Lands DIVISION OF MINES AND GEOLOGY MARSHALL T. HUNTTING, Supervisor Bulletin No. 58 CHEMICAL AND PHYSICAL CONTROLS FOR BASE MET AL DEPOSITION IN THE CASCADE RANGE OF WASHINGTON By ALAN ROBERT GRANT STATE PRINTING PLANT ~ OLYMPIA, WASHINCTON 1969 For safe by Department of Natural Resources, Olympia, Washington. Price $1.50 Errata sheet for Washington Division of Mines and Geology Bulletin 58, Chemical and Physical Controls for Base Metal Deeosition in the Cascade Range of Washington ( By Alan Robert Grant Errors noted in the p-inted text are listed below. The editors regret these and possibly other mistakes in editing. Page 12 Paragraph 5, line 2, "heliocpter" should read helicopter. 14 Paragraph 6, line 6, •programed" should read programmed. 15 Figure 2, 11 Ntesoic" in explanation should read Mesozoic. 19 Paragraph 4, line 7, "authochthonous" should read autochthonous. 22 Paragraph 6, line 4, "extension Ntesozoic 11 should read exten•ioo.o f 1l1e Mesozoic. 22 Paragraph 7, line 1, ''aforemention" should read aforementioned. 25 Paragraph 4, line 7, "Misch" should be changed to Vance. 25 Paragraph 7, line 7, "Totoosh, pluton" should read Totoosh pluton. 26 Paragraph 1, line 4, "classical" should read classic. 32 Paragraph 4, line 1, "alkaline" should be changed to acidic intrusive. 33 Paragraph 1, line 1, "alkaline" should be changed to acidic intrusive. 48 Une 3 of Figure 16 caption, "alkaline" should be changed to acidic intrusive~ 49 Paragraph 3, line 5, "Creasy" should read Creasey. 51 Paragraph 3, line 1, "Creasy II should read Creasey. 52 Paragraph 5, line 1, "degree atomic" should read degree of atomic. 56. Paragraph 1, line 1, "Table 1" should read Tobie 3. 56 Paragraph 3, line 2 , "feldpathi-" should read feld$pathi-. 57 Paragraph 1, line 1, "invironment" should read environment. 58 Paragraph 2, line 2, "classical II should read classic. 60 Paragraph 4, line 4, "formation if'• should read formation of. 60 Paragraph 6, line 2, "magmatitic" should read magmatic. 68 Paragraph 71 line 4, "si lfides" should read sulfides. 71 lDst paragraph, line 1, "structural, as'1 should read structural belt, as. 75 Figure 24, "Pre-Tertiory" In explanation should read Pre-Tertiary. 77 Paragraph 5, line 5, "there there is" should read there is. 79 last paragraph, item 4, "quartz dioritic" should read quartz diodfe. 86 Figure 30, credit for map should be given to Ellis, 1959 and Foster, 1960. 87 lDst paragraph, line 1, 0 complex that that" sheuld read complex than that. 89 Figure 31, credit for map should be given to Felts, 1939 and Heath, 1966. 101 Paragraph 3, line 3J 11 ingre$S or egress to the claim site'1 should read ingress to or egress from the claim site. 103 10th reference, 11Bican" should read Bichan. ~ •· .... -.. ..:--- -- -~ '"':. ·~ · ···~ .. •• - ......··- -tl!"-"W'I"'"- __ _ .. --.r ; .... FOREWORD The Cascade Range of Wash ington hos been the scene of mineral exploration and production for at least 11 5 years, since the first discovery of gold in the State- on the Yakima River- was reported in 1853. Although this discovery appar­ ently was occidental, or at least was incidental to exploration for a railroad route through the Cascades, the search for metallic ores soon was begun seriously and hos been continued to the present time. In the lotter port of the 1800's the mountains were "crawling with prospectors," and most of the presently known prospects in the Cascades probably hod been discovered before the turn of the century. The early prospectors were moder­ ately successful, and several million dollors 1 worth of gold and lesser amounts of copper and other metals were produced as a result of their efforts. Essentially all of these discoveries and the resultant production con be credited to the dogged per­ sistence and hard work of the early prospectors; only a modicum of credit con be given to conscious use of geologic principles. In the 1900's a few mines in the Cascades have hod records of production exceeding $1 million each in value; one, the Holden mine in the centra I port of the North Cascades, produced more than $66 mi Ilion in copper, gold, si Iver, and zinc in the 20-year period it operated. Relatively little has been published on the geology of the very large area that encompasses the Cascade Mountains of Washington, so there has been little opportunity to use geology properly to guide mineral exploration there. The Division of Mines and Geology was fortunate in being able to obtain the services of Alon Robert Grant to continue his already ex­ tensive studies of geologic controls for ores in the Cascades and to write this report of his findings published as Division of Mines and Geology Bulletin No. 58. Dr . Grant earned both his M. S, and Ph . D. degrees in geology from the University of Washington, basing his dissertations on studies of the geology of port of the Cascade Mountains. His academic studies, his work for 6 years as exploration geologist for a major mining company, mostly in the CtJscades, a nd subsequent work on this project for the Division, as we ll as independent investigations as a consultant, have given him an unparalle led oppor­ tunity to investigate the geology of these mountains and to discover which geologic features ore related to or control the occurrence of metallic ores in the Cascades. This report details the findings and conclusions resulting from his work. It should be helpful to other explorotionists in their efforts to find new ore deposits in the Cascades to help meet the notion's ever-increasing demands for metals. Mmhall T. Huntting, Supervisor Division of Mines and Geology October 31, 1968 [3] CONTEN T S Foreword ........................................................... ... ... .. .. ...................... 3 Abstract e • e • • e • e • • • • e • • • • e • e •et•• e •et•.• e • I e e e e • • e e • e • e • • e e e •. • e e • e • . e e e e e e • e e e e e e e e e • e e e • e e • e e e • • • • 9 Introduction . • • . • . • . • . • . • . • . • • . • . • . • . • • • . • • . • • • . • • . • . • . 10 Topography and glaciation .•... , . • . • • • • . • . • . • . • . • . • • • • • . • . • . • . • . • . • . • . 10 Access . .. ...• . .• . •.. , . ..• • .. • . ........•.• . •. , . • • • • • • . • . • . • . • • • . • • . • . • . • . • • • 12 Previous investigations . ..... •. ........ , . • . • . • • . • . • . • . • . • . • . • . • . • • • • • • • 12 Purpose of the study . • . • . • . • . • . • . • . • • . • • . • . • . • • • . • • . • • • • • • • • . • • • . • . • . 13 Li mi ta tions of the study •.. • •.... •.. , . • . • • • . • . • . • . • • • . • . • . • . • . • • . • • . 13 Field and laboratory work • . • . • • . • . • • . • . • . • . • . • • . • . • . • . • . • • • • . • • . • . • . • 14 Acknowledgments . • . • . • • . • . • . • . • . • . • . • . • • • . • • • • • • • • • . • . • . • . • 14 Geology . • • . • • . • . • . • . • . • . • • . • • • • • . • . • . • • . • . • • . • • • • • . • . • . • . • . • . • • . • 16 Geologic provinces • . • . • . • . • . • . • . • . • . • . • . • . • . • • . • . • • . • • • • • . • . • . • . • . • • • • • • . • • . 16 General considerations and definition of terms . • . • • • • • • . • • • • . • . • . • • . • . • . • • • . • 17 Outline of geology in the North Cascades • . • . • . • . • . • . • • • • • • • . • • • . • . • . • • . • . • • . • . • • . • 18 Outline of geology in the Central Cascades . • . • . • • . • . • . • . • . • . • • . • . • • • • • . • . • . • . • • • . • • • • . • • 22 Late Cretaceous-Tertiary intrusive activity • • • . • . • . • . • • • • . • • • • • • • . • . • • . • . • • • . 24 North Cascades • • . • • • . • . • . • . • • . • . • . • . • • • • • . • • • • • . • • • • • . • • . • • . • • • . • • • . • • • 24 Centro I and South Cascades . • • . • . • . • . • . • • • • • • • . • • • . • • . • • . • • • • • . • • • . • • • • • • • 25 Age corre lotion of intrusions . • . • • • . • • . • . • • . • . • . • • • • • • • • • . • • • • • • . • • • • • • • • • • . • • • • • • • • 25 Contacts • . • . • . • • • • • • . • . • . • . • . • . • . • • • • • . • • • • • • • . • . • • . • • • . • . • • . • • . • • • • • • • 26 Speculations on mode of emplacement and origin • . • • • • • • • . • • • . • • • • • • • • . • . • • • . • • • • • • • • • • • • • 26 Emplacement levels • .. • • . • ...• . .• . • • . • • , •••• • •.• • . ...••. •• • • •• • • • •• . ••••••• , • • . 27 Petrology • . • . • • • . • • • . • . • • . • • • • • . • • • • • • • . • • • . • . • . • • . • • • • • • • • • • • • • • • • • • • • • • . 28 C loudy Pass pluton ...... .... .... ............... ................... ....... .... 30 Structural analysis . .•..•..••.. •• . •. .••••• • , • . ••.• • •••••• . , •• • • . ••• .. • . •••.••.•• • • • •••• • ••• , •• , , ••• • 34 Regional structural relations ........... .. .... .. .. ..... .............................. .......... 34 North Cascades .. .•.•.•.••••.••.•••. • . •. •• ...• • • • •••••••••• • •• • • . • • , • , , , • , , • • , • , , , . , , , • , , , 37 Centre I Cascades •.... • .•.•.. ..... .... ...... .• . ..••.• . •••••• • • . • •• • ••• . •• • • . • .. • . • . • . • • • 38 Transverse structural belts • .•••••. .• • . • • , • . • .. • .. • .•••••••• • •••• ••.• .•. , • •••.• , , • , • . • • , , • , , , , 39 Cascade transverse structure I be Its . • .. ......• • • •• • • • . •• . •••.••• . ••. • . • .••• , •••• . ••• •• • 44 Structure I intersections • . • ..•.•..•.. • •••.• • . ..• • •••.•••• . ••• . ••• , , , , . , •• . , , ,