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J.F. Smith

Publications and source records attributed to J.F. Smith.

4 recordsLinked to original sources
USGS1943

Geology of the Cimarron Range, New Mexico

In north-central New Mexico the rugged Cimarron Range marks the eastern margin of the Southern Rocky Mountains, abruptly rising more than 5000 feet above the adjacent Great Plains. Structurally the range is a northward-plunging anticline with a core of pre-Cambrian crystalline rocks. Faulting along the eastern and western margins of the anticline separates the mountains from the Great Plains and the Moreno Valley. North of Cimarron Canyon the anticline plunges beneath the Tertiary sediments of the Raton Coal Basin. To the south the structure is obscured by the basaltic flows of the Ocaté Mesa. Upturned Paleozoic to Tertiary sedimentary rocks crop out along the eastern and northern margin of the anticlinal uplift. Regional relations are obscured by extensive Tertiary intrusions in the northern portion of the area and by the lava flows to the south. In the valley of Rayado Creek a volcanic plug which fed some of the lava flows has been exposed by erosion. In this region there is evidence for a Mid-Tertiary surface of low relief in the central portion of the mountains, a later lava-capped surface believed to be the equivalent of the Broad Valley Stage, the surface of the Park Plateau, and the Ocate Mesa. Three well-developed gravel-capped Pleistocene pediment surfaces extend steplike from the mountain front into the Great Plains. Both structurally and topographically the Cimarron Range is similar to the Colorado Front Range. An attempt is made to reconstruct the geologic history of the Cimarron Range and to fit it into the broader story of the development of the Southern Rocky Mountains in New Mexico. © 1943 Geological Society of America.

New Mexico↗
USGS1941

Geology of the Moreno Valley, New Mexico

The Moreno Valley, located along the complex eastern boundary between the Sangre de Cristo Mountains and the Great Plains, is structurally a broad, northwardplunging syncline, disrupted by smaller folds and faults. This major synclinal structure is the result of the Laramide disturbance. Deformation, however, has continued possibly into the Quaternary. Intrusions, probably contemporaneous with those of the Spanish Peaks, have deformed the strata in the northern portion of the Moreno Valley. Scully Mountain is a northwestward-plunging anticline produced by a porphyry intrusion. A Mid-Tertiary surface of low relief is now represented by broad mountain flats at elevations near 10,000 feet. The Moreno Valley was initiated as a topographic feature about the close of the Mid-Tertiary. Its subsequent history is in many respects similar to that of the Rio Grande Depression. During the Quaternary a broad valley stage and three lower pediments have been developed. The lowest pediments are cut on deformed valley fill, believed to be Pliocene and here named the Eagle Nest formation. The early drainage of the valley was south and east into the Canadian River. Stream piracy by the Cimarron River diverted drainage to the east through the present Cimarron Canyon into the Canadian River. Drainage south of the point of capture has been reversed for about 14 miles, the present stream draining the southern portion of the Moreno Valley flowing northward to the Cimarron River. © 1941 Geological Society of America.

New Mexico↗