PALINSPASTIC RECONSTRUCTION

OF THE

CAMBRIAN SYSTEM

IN THE GREAT BASIN

1980-1983

By

LINDA B. McCOLLUM

MICHAEL B. McCOLLUM

GEOLOGY DEPARTMENT

EASTERN WASHINGTON UNIVERSITY

Introduction

In late May, 1980, we set up a limited corporation (Cordilleran Geological Survey, Inc.) in order to receive funding for a three year project attempting to create a palinspastic reconstruction of the Cambrian System in the Great Basin, western US.  The task was fairly straightforward, take all of the available literature on this structurally complex region to form a palinspastic map and then test its accuracy by superimposing all of the available Cambrian stratigraphic columns on this newly generated base and see it the facies patterns were reasonable aligned.  The last step was to construct a series of time slices through the Cambrian and produce a series of paleogeographic maps.

 

The Cambrian System was chosen for the following reasons: 1) the lower Paleozoic strata were deposited on a passive margin after Proterozoic rifting and prior to the mid-Paleozoic and later tectonism, 2) the Cambrian system was well distributed within the Great Basin, being present in more than a hundred mountain ranges, 3) a well written synopsis of the Cambrian System in the Great Basin had recently been published (Palmer, 1971) and there was no comparable overview of the other lower Paleozoic systems at that time, 4) Dr. Richard A. Robison (Univ. of Kansas), a leading Cambrian trilobite expert, was willing to provide faunal identifications.  This project was funded contractually by Gulf Oil and Production Company, Houston, Texas.  Under this agreement, Gulf Oil had exclusive rights to the data up to one year beyond the exploration date of the contract, and then all data reverted back to the sole ownership of the CGS, Inc.  Dr. Grant Steele, executive manager of frontier exploration in the Great Basin for Gulf Oil, was our main contact and kept us focused on our goals through the three year contract.  The other major contractor was TerraScan, Denver, CO., and they worked in the post-Cambrian rocks and were fairly restricted to central Nevada.

 

George Marshall Kay added the term palinspastic (Greek meaning stretched back) to the geological literature in 1937 and referred this term to any depiction of the original position of strata in tectonically disturbed regions by “stretching back” the principal thrust sheets by the amount of foreshortening they had experienced.  Armstrong (1968) was the first to construct a palinspastic map of the eastern Great Basin to be used as a base for a series of isopach and facies maps for the uppermost Precambrian to the Permian strata in Utah and eastern Nevada.  Stewart and Poole (1974) had constructed a similar palinspastic map of the Great Basin region east of the Roberts Mountains thrust and later, Stewart (1980) used this same palinspastic base map in his Geology of Nevada.  The next serious attempt at a pre-Mesozoic palinspastic map of the eastern Great Basin was by Levy and Christie-Blick (1989).  The latest attempt at a palinspastic reconstruction of the southern Great Basin is by Snow and Wernicke (2000).

 

 

Field Research, 1980

We began our field research in late May by visiting one of the classic Cambrian regions in western Utah with Dick Robison, which included the House Range, Drum Mountains and Dugway Range.  In July, we began visiting Cambrian sections in the Antler orogenic region of north Nevada, which included the Battle, Shoshone, and Osgood Mountains.  In August we visited the classic Cambrian at Eureka, Nevada and then headed west to the Toiyabe Range and looked at sections both north and south of Austin.  We also spent a few day at the end of the month in the Bull Run Mountains.  In October we visited another classic Cambrian section near Pioche, Nevada and then traveled south for the winter months visiting section in the region between Bishop, California and Tonopah, Nevada.  In fact we had dinner A.R. “Pete” Palmer and Mike Taylor at the Rex Café in Tonopah on the evening of February 12, 1981; which was our last day in this region.

 

Field Research, 1981

We attended the GSA meeting in Hermosillo, Mexico in March and then visited the classic Cambrian section near Caborca.  In late April, we began a week long field trip showing Gulf Oil geologists the Cambrian sections from the White-Inyo Range area northeastward through central Nevada, ending up in Elko.  By mid-April we were looking at Cambrian sections in the Quinn Canyon, Grant, White Pine, and southern Egan Ranges and ended up back in the Pinon-Sulfur Spring Range with Keith Ketner (USGS) and geologists with TerraScan.  In June we began looking at Cambrian sections in northeastern Nevada, beginning in the metamorphic core complex in the Ruby Mountains and heading east to meet up with David Miller (USGS) who was mapping in the Toano Range, Pilot Peak, and Silver Island Mountains; and then headed south to spend a few days in the Deep Creek Range with Max Crittenden (USGS).  In mid-July we spent a few days looking at possible lower Paleozoic section in the Klamath Mountains near Yreka and then drove back to Elko to meet up with Dick Robison to look at Cambrian sections in the Cherry Creek Range, and northern Egan and Schell Creek Ranges.  We attended the 2nd International Cambrian Symposium in Golden, Colorado in August and spent time in early September discussing the results of our second year’s work at TerraScan headquarters in Denver.  We met up with Eldredge Moores (UCD and one of the first geologist to model the Antler Orogeny) in Elko, Nevada on Sept 8th to look at the field evidence for a post-Triassic age for the Roberts thrust with Keith Ketner.  We then headed south to work with the TerraScan geologists in the mountains surrounding Pine Valley (between Carlin and Eureka, Nv.) for a few weeks.  In early October we traveled to Wendover and met up with Dave Mille, Richard Allmendinger, Dick Robison, and Grant Steele to discuss the evidence for a major structural dislocation of lower Paleozoic facies in the region.  We ended the year by looking at Cambrian sections in the northern Death Valley region.

 

Field Research, 1982

January was spent writing reports for our annual visit to Gulf Oil headquarters in mid-February.  We attended the Anaheim, California GSA meeting in mid-April and then visited the Cambrian section near Bear Lake, San Bernardino Mountains.  In late May we met up with Dick Robison and A.J. “Burt” Rowell in Eureka, Nevada and showed them the outer shelf Cambrian facies in the Quinn Canyon and Grant Ranges.  In June, A.J. Rowell and M.N. “Peggy” Rees invited us meet them in Winnemucca and look at the Cambrian sections in the northern Shoshone Range and the Hot Springs Range which played a central role in their research on the upper Cambrian continental margin (Rowell, Rees, and Suczek, 1979).  We then returned to the Wendover area to begin a detailed study of the relatively unknown Cambrian sections in this region.  We spent most of July looking at Cambrian sections in northeastern Utah and in Idaho, as far north as Clayton.  In August, we returned to eastern Nevada and looked at sections from the Cherry Creek Range southward to the Snake Range.  In early September we visited the classic Cambrian section at Eureka, Utah and the Ophir Canyon section near Tooele, Utah.  We returned to the Wendover region in October and spent several days looking at Cambrian sections in the nearby mountain ranges in anticipation of a joint research paper (McCollum and Miller, 1991).  Later that month we returned to Bishop and met up with Jeffery Mount (UCD), a leading sedimentologist who had published several papers on the Lower Cambrian strata in the White-Inyo Mountain region, to look at some of the sections there.

 

Field Research, 1983

Our last annual meeting in Houston, Texas with Gulf Oil Company took place in late March and we visited Dick Robison and Burt Rowell at University of Kansas on our way back to Reno, Nevada.  We both presented talks in May at AAPG/SEPM meeting in Sacramento and attended the Salt Lake City GSA meeting in early June.  We continued our joint project with Dave Miller on the Cambrian System in the Wendover region during the summer months, took a small contract with Amselco (Ely office) to do some faunal ID’s on an Upper Cambrian Dunderberg Shale prospect in the Eureka, Nevada mining district.  In September, Linda took a faculty position in the Geology Department, Eastern Washington University teaching mostly upper division and graduate courses in petroleum geology, micropaleontology, clay mineralogy and shales, and paleoecology.  Mike rented out the Reno home and joined Linda in mid-December.

 

Results of our three year research

 

There were three distinct areas that our Cambrian research touched upon: 1) the structural duplication of the outer Lower Paleozoic shelf based on the juxtaposition of major facies trends along an east to west transect of the miogeocline, 2) production of a series of paleogeographic maps for each of the Cambrian biozones, and 3) publish a modern stratigraphic study of the Cambrian section in any region that needed it.  The first area was the most speculative and we ended up giving a series of talks and poster sessions (L.B. McCollum, 1983, 1986; M.B. McCollum, 1983) before going on to more acceptable topics like the paleographic maps for the Cambrian of the Great Basin (McCollum and McCollum, 1988) and a final attempt at combining both projects with a little help from our friends (McCollum, Robison, and Rees, 1988).  Although there were several regions of the Great Basin where the Cambrian was in need of a modern study, only the Wendover region in northern Nevada and adjacent Utah was published (McCollum and Miller, 1991).

 

REFERENCES CITED

 

Armstrong, R.L., 1968, The Cordilleran Miogeosyncline in Nevada and Utah.  Utah Geological and Mineralogical Survey Bulletin 78, 58 p.

 

Hintze, L.F., 1988, Geologic History of Utah.  Brigham Young University Geology Studies Special Publication 7, 202 p.

 

Levy, M., and Christie-Blick, N., 1989, Pre-Mesozoic palinspastic reconstruction of the eastern Great Basin (western United States).  Science, v. 245, p. 1454-1462.

 

McCollum, L.B., 1983, Continental suspect terranes in the western U.S.  58th annual meeting, Pacific Sections of the American Association of Petroleum Geologists and Society of Economic Paleontologist and Mineralogists, program and abstracts, p. 109.

 

McCollum, L.B., 1986, A stratigraphic comparison of lower Paleozoic rocks between the Esmeraldia and Waucobia continental terranes, California and Nevada.  Geological Society of America Abstracts with Programs, v. 18, no. 2, p. 155.

 

McCollum, L.B., McCollum, M.B., 1988, Cambrian paleogeography of the Great Basin.  Geological Society of America Abstracts with Programs, v. 20, no. 7, p. 121.

 

McCollum, L.B., Miller, D.M., 1991, Cambrian stratigraphy of the Wendover area, Utah and Nevada.  USGS Bulletin 1948, 43 p.

 

McCollum, L.B., Robison, R.A., and Rees, M.N., 1988, Paleobiogeography of the Middle Cambrian outer shelf of the Great Basin.  Geological Society of America Abstracts with Programs, v. 20, no. 3, p. 212.

 

McCollum, M.B., 1983, Comparison of upper Proterozoic and Cambrian rocks with continental suspect terranes in the Western U.S.  58th annual meeting, Pacific Sections of the American Association of Petroleum Geologists and Society of Economic Paleontologist and Mineralogists, program and abstracts, p. 110.

 

Palmer, A.R., 1971, The Cambrian of the Great Basin and adjacent areas, western United States.  In Holland, C.H., ed., Cambrian of the New World.  Wiley-Interscience, p. 1-78.

 

Rowell, A.J., Rees, M.N., and Suczek, C.A., 1979, Margin of the North American continent in Nevada during Late Cambrian time.  American Journal of Science, v. 279, p. 1-18.

 

Snow, J.K., and Wernicke, B.P., 2000, Cenozoic tectonism in the central Basin and Range: Magnitude, rate, and distribution of upper crustal strain.  American Journal of Science, v. 300, p. 659-719.

 

Stewart, J.H., 1980, Geology of Nevada.  Nevada Bureau of Mines and Geology Special Publication 4, 136 p.

 

Stewart, J.H., and Poole, F.G., 1974, Lower Paleozoic and uppermost Precambrian Cordilleran miogeocline, Great Basin, western United States.  In Dickinson, W.R., ed., Tectonics and Sedimentation, SEPM Special Publication 22, p. 28-57.

 

This document was last updated January 5, 2003.

 

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