Laramide thrust faulting, Klondike Hills, southwestern New Mexico
— LeRoy L. Corbitt, F. L. Nials, and R. J. Varnell

The Klondike Hills (fig. 1) are at the north end of the Cedar Mountains approximately 50 km (30 mi) southwest of Deming. Basin-Range faulting during the Tertiary created the present mountains by uplift along range-marginal faults; internal structures within the Klondike Hills, however, are principally thrust faults of Laramide age.

 

The Klondike Hills are near the northern margin of the Cordilleran foldbelt of southwestern New Mexico (Corbitt and Woodward, 1973). The foldbelt trends west-northwest through the southwestern corner of New Mexico and is mainly characterized by low-angle thrust faults and subordinate closely com-pressed, overturned folds. The southern part of the Klondike Hills consists of a structurally complex thrust plate of Ordovician El Paso-Montoya and Silurian Fusselman carbonates overlying the Mississippian Keating Formation. South of the Klondike Hills, the Cedar Mountains (fig. 1) consist primarily of post-orogenic Tertiary volcanic rocks. However, one small exposure of prevolcanic rocks in the Cedar Mountains exposes Mississippian carbonates which have been thrust over Cretaceous conglomerates (Varnell, 1976).

 

Yielding on the thrusts was northward toward the foreland. The amount of displacement cannot be determined accurately, but may have been several kilometers. North-northeast yielding thrusts are present south and west of the Klondike Hills in the Apache Hills (Peterson, 1976), Sierra Rica Hills and Big Hatchet Mountains (Zeller, 1958), Hatchet Gap (Lasky, 1947), Little Hatchet Mountains (Zeller, 1970) and Brockman Hills (Corbitt and others, 1977); to the north in the Victoria Mountains (Kottlowski, in Griswold, 1961); and to the northeast in the Snake Hills and Florida Mountains (Corbitt, 1971; Corbitt and Woodward, 1973) (fig. 1).

 

Financial support for this report was provided by Eastern New Mexico University.