Proterozoic geology of the central Sante Fe Range, northern New Mexico
Rodney V. Metcalf


Approximately 15 km2 were mapped in the central Santa Fe Range, between the Pecos-Picuris and Borrego faults. Two major lithologic assemblages are present: (1) a south-dipping block of migmatitic supracrustal rocks which have volcanic and volcaniclastic protoliths; and (2) a suite of deformed calc-alkalic plutonic rocks ranging in composition from granite to quartz diorite. The boundaries separating these two assemblages are, at least in part, tectonic. The supracrustal rocks experienced a syn-kinematic episode of localized partial melting at metamorphic conditions of T = 650 to 730°C and 5.2 to 5.5 kbars. The calc-alkalic plutonic suite can be divided into an early felsic group and a later mafic group. Intrusion, solidification and deformation of the felsic group pre-dated the solidification of migmatite leucosomes. Intrusion of the mafic group may have been contemporaneous with the migmatization event. Whole-rock major and trace-element data for the calcalkalic suite show fractionation trends similar to those seen in Phanerozoic arc-related plutonic rock suites. A younger group of alkali granites and associated epidote veins intruded most of the above mentioned lithologies.


  1. Metcalf, Rodney V., 1990, Proterozoic geology of the central Sante Fe Range, northern New Mexico, in: Tectonic development of the southern Sangre de Cristo Mountains, New Mexico, Bauer, Paul W.; Lucas, Spencer G.; Mawer, Christopher K.; McIntosh, William C., New Mexico Geological Society, Guidebook, 41st Field Conference, pp. 179-187.

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