Pre-carboniferous paleotectonics of the San Juan Basin, New Mexico
— G. M. Stevenson and D. L. Baars

This paper summarizes and updates the state of knowledge concerning Cambrian-Devonian rock units in the San Juan Basin of northwest New Mexico and southwest Colorado. Earlier workers mapped all outcropping rock units of the Cambrian and Devonian in the Four Corners region. Since this mapping took place 20 to 25 years ago, little information has been published about the early Paleozoic rock units.

 

Deep wells drilled in the late 1950's and early 1960's penetrated the sequence and provided a regional understanding of the Cambrian and Devonian environments of deposition. Since then, many more deep tests have been drilled and a much more complex paleotectonic history is becoming apparent.

 

Figure 1 is a correlation of all Paleozoic rock units in the northern and southern San Juan Basin. Baars and Stevenson (elsewhere in this volume) discuss the Permian stratigraphy in the San Juan Basin. However, for proprietary reasons, the Mississippian and Pennsylvanian stratigraphic relationships cannot be disclosed at this time. All available mechanical logs and commercial sample logs have been used in constructing the maps and cross section illustrated in this paper. [Editor's note: see papers by Armstrong on the Mississippian and Jentgen on the Pennsylvanian elsewhere in this volume.]