Circular 146Structural geology of Big Hatchet Peak Quadrangle, Hidalgo County, New Mexico
By R. A. Zeller, Jr. (with commentary by S. Thompson III), 1975, 23 pp., 3 figs., 2 sheet.
Supplement to Zeller's Memoir 16 (1965). In the Big Hatchet Peak quadrangle, field evidence indicates three general episodes of deformation. Prior to the deposition of Lower Cretaceous rocks, a deformation in the Precambrian was followed by epeirogenic movements during the Paleozoic and Mesozoic. Differential subsidence beginning in Desmoinesian time formed the Alamo Hueco Basin; reefs developed on the margin between the basin and shelf. Only epeirogenic movements are indicated in the Lower Cretaceous sequence. The episode of greatest structural deformation in the are occurred later than Early Cretaceous deposition and earlier than Tertiary deposition. This orogeny produced large folds, reverse, thrust, and overthrust faults, and probably some high-angle faults. Thrusting in the Big Hatchet Mountains was generally toward the west and southwest, but that in the Sierra Rica apparently was toward the northeast, similar to the general direction indicated on other areas of the region. The Tertiary-Recent deformation produced the Basin and Range topography. In addition to the normal faults bounding the ranges, broad open folds, two systems of high-angle faults, and minor thrust faults were formed.
This report on the structural geology on the Big Hatchet Peak quadrangle
is a supplement to the memoir on the stratigraphic geology. Much of the
discussion in the introduction to that work is pertinent here and should
be reviewed. An index map shows the location of the Big Hatchet Peak quadrangle
in Hidalgo County, New Mexico, and the chief geographic features of the
region. This oversized 15-min quadrangle covers 296 mi2 of typical basin-and-range
country. The highest point is Big Hatchet Peak at 8,366 ft above sea level,
and the lowest point is at 4,129 ft near Artesian Well in the Hachita Valley.
The average elevation in the Big Hatchet Mountains is about 6,000 ft, and
that of the Sierra Rica is about 5,000 ft. The most prominent ridges and
valleys in the ranges trend northwest and reflect structural control, but
faults show little topographic expression. However, exposures of bedrock
generally are good.
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