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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