Geology and Coal Deposits of the Raton Coal Field, Colfax County, New Mexico

ABSTRACT: Cretaceous and Tertiary coal-bearing rocks of the Raton coal field underlie about 1,000 square miles in the New Mexico portion of the Raton basin. The Raton basin is a large arcuate north-south-trending structural trough that extends southward from Huerfano Park, Colorado, to Cimarron, New Mexico. High-volatile A- to B-rank bituminous coking coal has been mined in the field since about 1870. Sedimentary rocks exposed in the Raton coal field range in age from Late Cretaceous to Paleocene and, in the central part of the field, have an aggregate thickness of about 6,000 feet. Upper Cretaceous rocks consist of the Pierre Shale, the Trinidad Sandstone, the coal-bearing Vermejo Formation, the lower part of the Raton Formation, and, in the western part of the coal field, also the lower part of the Poison Canyon Formation where it is laterally equivalent to the Raton. Paleocene rocks comprise the upper part of the Raton Formation, which is also coal bearing, and the Poison Canyon Formation, the youngest stratigraphic unit in the area. Coal beds occur throughout the Vermejo and Raton Formations in much of the field. The most extensive and valuable beds, however, are the Raton coal bed near the base of the Vermejo Formation and a group of coal beds in the upper part of the Raton Formation. The Raton coal bed occurs as thick elongate deposits that trend north to northeastward; early mining was concentrated in these deposits along the southeastern margin of the coal field. Several minable coal beds occur in the upper part of the Raton Formation and arc being evaluated now. These beds are less extensive than the Raton coal bed. One of these, the York Canyon bed, is the only bed being mined in 1969 in the Raton coal field. Tertiary intermediate to basic dikes and sills of wide extent are present throughout much of the coal field and have locally intruded and destroyed large amounts of coal. However, projections of field and drilling data indicate that large deposits of coal still remain.