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C. H. Maxwell

Publications and source records attributed to C. H. Maxwell.

11 recordsLinked to original sources
USGS1995

Photogeologic map showing distribution of sinkholes south of Fairplay, Park County, Colorado — A possible geologic hazard

A large group of at least 50, and perhaps significantly more, sinkholes partially surrounds Black Mountain 6-10 mi south Fairplay in South Park, Park County, Colorado. The sinkholes occur in bedrock in the evaporite facies of the Middle Pennsylvania Minturn Formation, and in Quaternary soil, alluvium, and glacial outwash gravels that overlie the evaporite beds. Sinkholes range in size from small depressions a few feet across to large holes several hundred feet across. Measured sinkholes range in size from about 25 ft in diameter and 2 ft deep to about 235 ft in diameter and 25 ft deep. In places, several sinkholes have coalesced to form depressions as much as 750 ft long and 400 ft wide. One large cluster of small craters is about 1,8000 ft long and 600 ft wide. As reported to us by a resident rancher, one small sinkhole collapsed about 10 years ago. The area of sinkholes extends into land now under development for residences, and the sinkholes thus pose a potential hazard that needs to be considered in future development. Also, they might jeopardize existing farmland, structures, ans roads (including U.S. Highway 285), as well as projected roads and airstrips. This report is not a comprehensive evaluation of the distribution and origin of the sinkholes; its intent is to call attention to their presence and to encourage further study. Many by not all of the sinkholes were visited; the geologic map is based mainly on the interpretation of aerial photographs by D.R. Shawe.

Colorado↗
USGS1985

Durangite from the Black Range, New Mexico, and new data on durangite from Durango and Cornwall.

Durangite, associated with cassiterite, hematite, quartz, tridymite, cristobalite and clinopyroxene, occurs in small veinlets within flows, ash-flow tuffs and lithic tuffs in a tin mine near Boiler Peak, New Mexico. It is clear to semi-translucent, pale yellow-orange to medium orange-red with a vitreous lustre, pale yellow streak; H. 5-5.5%; irregular to conchoidal fracture and a good (110) cleavage; elongate along c with (110), (010), (021) and (111) the prominent forms; Dmeas 3.90, Dcalc 3.92 g/cm3; alpha medium yellow orange 1.634(3), beta pale yellow orange 1.663(3), gamma colourless 1.685(3); weak to moderate dispersion r < v. The structural formula is: (Na0.93Li0.07)SIGMA 1.00(Al0.89Fe0.07Mn0.06)SIGMA 1.02As0.99O4(F0.90(OH)0.07)SIGMA 0.97. Indexed XRD powder data are tabulated; a 6.574(1), b 8.505(2), c 7.019(1) A, beta 115.34o; space group C2/c; Z = 4. Additional X-ray and chemical data on durangite from Durango and Cornwall are also included.-L.T.T.

Canadian Mineralogist↗