Marble - Colorado Geological Survey

GEOLOGIC CHARACTERIZATION
INVESTIGATION ACTIVITIES
Literature Review
The earliest written account of the geology of
the Elk Mountain region was produced by the
Hayden Survey in the early 1870s. Reports of
their work in the Aspen area, including a
1:125,000 scale geologic map on a topographic
base, are given in the United States Geological
and Geographical Survey Annual Reports of
1874-1876 (Hayden, 1874; Peale, 1874; Hayden,
1876; Holmes, 1876). The map documents
early impressions of the complex structural
features of the area. This work remained the
only published geologic map of the Elk Mountain
region until those of Bryant in 1969-1971
(Bryant, 1969,1970,1971a). Bryant's studies of
the area have appeared in various publications
and are culminated in Geology of the Aspen 15
Minute Quadrangle, Pitkin and Gunnison
Counties, Colorado, published in 1979 (Bryant,
1966,1971b, 1972a, 1972b, 1979). Bruce
Bryant's personal input was extremely helpful
throughout this evaluation. Numerous other
workers have also written on the various aspects
of the geology of the Elk Range and their
studies were consulted. An extensive bibliography
accompanies this report.
Aerial Photography
Black and white aerial coverage of the Conundrum-Colorado
Highland property at a scale of
1:24,000 was produced by Merrick and Company,
under contract to CGS, during June of
1989. The most recent color aerial photography
coverage was produced by the USFS, flight line
No. 1081, photos 201-203, dated September 24,
1982 at 1:24,000 scale. Stereo images from the
1989 photography were digitized by computer
to produce a topographic base map of the area
at a scale of 1 inch equals 400 feet, with a
contour interval of 10 feet. Ground control for
aerial mapping was provided by CGS.
Aerial photography was utilized throughout
the geologic investigation to verify ground observations
and to assist in field location. Ground
textures of the Conundrum Valley as seen on
the aerial photographs have provided insight
into the structural complexity of this area.
Survey Control
CGS received all survey notes from USFS in
April of 1989. The Forest Service has not conducted
an official survey of the claim block, but
has recovered existing corners where possible.
The 472.46 acre claim block is comprised of:
The California Placer—MS No. 4928^
153.023 acres, patented April 1891
The Edith M. Placer—MS No. 12334,160.0
acres, patented February 1899
The Vera Placer—MS No. 12335, 20 acres,
patented February 1899
The Vermont Placer—MS No. 12393,
139.434 acres, patented February 1899 (see
Plate 3).
The California Placer was surveyed by Lee
Hayes, U.S. Mineral Surveyor, on September
13,1887. The Edith M., Vera, and Vermont
Placers were surveyed by George W. Wyce, U.S.
Deputy Mineral Surveyor, in mid December,
1897. No record of any subsequent boundary
survey for this claim block is in existence. Original
claim corners constructed of rock markers
scribed with claim number and corner designation
have been recovered at various locations
on the property (see Plate 3). CGS has copies of
all original survey notes.
Control for topographic mapping and claim
location was established by CGS in June of
1989. A closed loop traverse of 11,500 feet was
run through panel points and selected claim
corners where available. Horizontal closure
error in the traverse yielded an accuracy ratio
of 1:14,200. This corresponds to a maximum
error of plus or minus 0.814 feet for X and Y
coordinates. Vertical closure error yields an
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