Transposition structures in Precambrian rocks of New Mexico
— Jonathan F. Callender

Precambrian rocks in New Mexico have been the subject of geologic study for almost 100 years. Early reconnaissance work tended to draw together diverse lithologies into relatively simple stratigraphic groups, and to correlate these groups over large areas of the state, particularly in northern New Mexico. Although many workers noted the highly deformed character of Precambrian rocks in New Mexico, with a few notable exceptions (such as Bingler, 1965), little notice was taken of the stratigraphic problems inherent in complexly deformed rocks. Recent detailed structural analysis in northern New Mexico has cast doubt on some early stratigraphic correlations, mainly because certain contacts interpreted as being stratigraphic may be tectonic (Holcombe and Callender, 1982). The major types of tectonic contacts that produce pseudo- stratigraphic relations in complexly deformed rocks are low-angle faults and transposition layering. This brief note discusses the latter Phenomenon, which is common in many Precambrian terrains in New Mexico. Although field evidence for low-angle faults is accumulating, the presence of regional low-angle faults of Precambrian age in New Mexico is hypothetical and will be discussed only briefly here.