WYOMING STATE GEOLOGICAL SURVEY Gary B. Glass, State Geologist DIAMONDS AND MANTLE SOURCE ROCKS IN THE WYOMING CRATON WITH A DISCUSSION OF OTHER U.S. OCCURRENCES by W. Dan Hause} Report of Investigations No. 53 1998 Laramie, Wyoming WYOMING STATE GEOLOGICAL SURVEY Lance Cook, State Geologist GEOLOGICAL SURVEY BOARD Ex Officio Jim Geringer, Governor Randi S. Martinsen, University of Wyoming Don J. Likwartz, Oil and Gas Supervisor Lance Cook, State Geologist Appointed Nancy M. Doelger, Casper Charles M. Love, Rock Springs Ronald A. Baugh, Casper Stephen L. Payne, Casper John E. Trummel, Gillette Computer Services Unit Publications Section Susan McClendon - Manager Richard W. Jones - Editor Jaime R. Bogaard - Editorial Assistant Geologic Sections Lisa J. Alexander - Sales Manager James c. Case, Staff Geologist - Geologic Hazards Fred H . Porter, III - Cartographer Rodney H . De Bruin, Staff Geologist - Oil and Gas Phyllis A. Ranz - Cartographer Ray E. Harris, Staff Geologist - Industrial Minerals Joseph M. Huss - GIS Specialist and Uranium W. Dan Hausel, Senior Economic Geologist - Metals and Precious Stones Supportive Services Unit Robert M. Lyman, Staff Geologist - Coal Susanne G. Bruhnke - Office Manager Alan J. Ver Ploeg, Senior Staff Geologist - Geologic Joan E. Binder - Administrative Assistant Mapping This and other publications available from: Wyoming State Geological Survey P.O. Box 3008 Laramie, WY 82071-3008 Phone: (307) 766-2286 Fax: (307) 766-2605 Email: [email protected] Web Page: http://wsgsweb.uwyo.edu People with disabilities who require an alternative form of communication in order to use this publication should contact the Editor, Wyoming State Geological Survey at (307) 766-2286. TTY Relay operator 1(800) 877-9975. ~ Printed on 50% recycled fiber paper. Second printing (October, 2001) of 750 copies by Pioneer Printing and ~ Stationery Company, Cheyenne, Wyoming. Diamonds and mantle source rocks in the Wyoming Craton with a discussion of other U.S. occurrences, by W. Dan Hausel. ISBN 1-884589-13-8 Front Cover: Gem-quality diamonds recovered from the Kelsey Lake diamond mine in the Colorado-Wyoming State Line District, on the margin of the Wyoming Craton. More than 130,000 diamonds, including some of the largest diamonds in the United States, have been recovered from Precambrian- and Devonian-age kimberlites in the district. The largest stone in the center of this photograph weighed 14.2 carats. (Photograph courtesy of Redaurum Ltd. and Howard Coopersmith.) WYOMING STATE GEOLOGICAL SURVEY Gary B. Glass, State Geologist Report of Investigations No. 53 DIAMONDS AND MANTLE SOURCE ROCKS IN THE WYOMING CRATON WITH A DISCUSSION OF OTHER U.S. OCCURRENCES by w. Dan Hausel Laramie, Wyoming 1998 Table of contents Page Abstract ......... ............................... ........ .............. ............................................. .. .. ........................... 1 Introduction ....... .. .... ...... .......... .................. .. ... .. ... ... .. ... ....... .... ........................................................ 1 Diamonds and their host rocks .... .............. ......... .... ........ .. .. ... .................... .. .................................. 1 Diamonds..... .. .. .. .. .. .. .. .. .. ................................ .............. ............................. .. ...... .. ..................... 3 Kimberlite ......... .. ... ... ..... ... .... ...... ...... ....... ... ... ... .... .. .. .. .. ........... .. ........ ... .... .... .... .............. ...... 5 Lamproite .... ... ... ... ........... .......... .. ........ ... ... ... ... ... ... ... ... ...... .... ....... .... .... ... .. .. .. ... ............ ....... 5 Ultramafic complexes, lamprophyres, and related rocks .......... ...................... ............ .. ....... 6 High pressure metamorphic rocks..... ........................................................................... .. .. .. ... 8 Meteorites ... ... ......... ... ............. .... ... ... .... .... ... ... ... ... ... .... ... ...... .... ...... .... .... .... ..... ... ..... ...... ....... ... 8 Placers ...................................... ............................................................. .................................. 9 Favorable terranes for diamonds..................................... ................................. .......... .. ......... 9 The Wyoming craton ...................................................................... ................................................ 9 State Line district, Colorado-Wyoming.................................................................................. 13 Schaffer, Ferris, and Aultman kimberlites .......... ...... ...... .............. ............ .. ...... .. ............ 15 Kelsey Lake kimberlites ..................... ................ ......... .............................. ........ ............... 18 Chicken Park kimberlites ......... .......... ......... ........ ............... ....................... ........ ............... 20 Sloan kimberlites .. .. ... ..... .. ........ .. .. ............... .... ... .. .. .. ........................................................ 21 Nix kimberlites .. .......... ........ .. .................................... ..... .............. ............. .............. .. ........ 22 Maxwell pipes ........................ .. ....... ........................... ................... ..................... .......... ...... 23 Diamond Peak kimberlites ...... ................ ................. ............. ...... ................. .............. ...... 23 George Creek kimberlites ..... .................................... ............ .... ... ................. .................... 23 Kimberlites and related rocks and minerals in Colorado outside the State Line district..... .................................... ..... .................................... .............. 24 Baca County ........... .. ........... ............................................................ ........ .. ........................ 24 Boulder County .................. .. .. ... ... ................................................... ............ .. .................... 24 Custer County.. ... ... .... ....... .. ....... ... .... ... .. ... ...... .. ..... ............. ... ... .... ..... .... ...... ....... ..... ...... 24 Larimer County...................... .... ... .. .. .. ... ... .. .. ... ...... .... ................... .... .... .... ... ... ................. 24 Moffat County. ... .... ........ ....... .. ... .... ... ... .. .... ... .. .. ............. ... ... .... ... ... ... ..... ... .......... .. ........... 24 Kimberlites, lamproites, and related minerals in Wyoming outside the State Line district.... .......... ...... ...................... .............. .................................. ...... 25 Albany County... ..................... ............. ...... .. .. ..................................................... ............... 25 Campbell County .. .................. ................ .................................................... ....................... 28 Carbon County.............. .......................... ................. ............ ...... .. .. .... .................... ........... 28 Fremont County ........................................ .. ......... ........................................ .. ..... .............. 31 Laramie County .................................................... ... .. .... .............. ..................................... 31 Sublette County..... .................... ................. .. ... ................................... ........ .. ... ..... ............. 32 Sweetwater County ....... ................ ... ......... .... ........... .. ......... .... .. .... ... ..... .. .... ............. ... .... 32 Leucite Hills .... .... .. ..... ..... .......... .... ... ... ....... .... .. .. .. ... ........ ........... .... ..... .. ... .... ... ... ............. 34 Green River Basin anomaly ... ............................................................. .. ............................ 37 Teton County ......................... ................................ ... .. .... ... .. ....... ....................................... 38 Uinta County........ .............. ................... ... ... ................. ................................ ........... .......... 38 Bighorn Basin .............................................................................. ............. .. ....................... 41 Montana (Wyoming craton) ........ ............................................................................................ 41 Beaverhead County ................................... ... .... ... .... .......................................................... 42 Blaine and Hill Counties . .......................................... ........................................ ............... 42 Garfield County... .... ....................... ... .. .. ............................................................................ 42 Glacier County... ... .... ................. ... ... ... ... ...... .......... ............. ... ....... .. ...... ................. ........... 43 Granite County ... .... ... .... ................ .... .. .. ...... ... .... .... .. ................ ... .... ...... ...... ......... ......... 43 Lewis and Clark County ..... ....... ............. ................ ...... ....... .............. ...... ..... .................... 43 Madison County .. .... .. .......................................................................................................