Proterozoic plutonic rocks of the central Santa Fe Range: Trace element evidence of subduction zone magmatism, north-central New Mexico
Rodney V. Metcalf

Abstract:

Proterozoic plutonic rocks of the central Santa Fe Range exhibit a broad range of high-K calc-alkaline compositions from 51 to 73 weight percent Si02. From oldest to youngest, the suite can be divided into (1) a group of foliated felsic granitoid rocks, primarily granites, (2) a group of mafic granitoid rocks, including hornblende quartz diorite, hornblende biotite tonalite and biotite tonalite, and (3) a group of alkali granites and associated pegmatites. The plutonic rocks intrude a group of migmatitic supracrustal rocks. Field relationships demonstrate that pluton emplacement was broadly synchronous with deformation and upper amphibolite facies metamorphism within the supracrustal rocks. Incompatible trace element data from the plutonic rocks exhibit similarities to modern subduction zone magma systems, i.e, an enrichment in Rb, Ba, K, Sr and Th and a depletion in Nb and Ti. The plutonic rocks of the central Santa Fe Range most likely represent a batholith formed over a subduction zone as part of a Proterozoic continental arc system.


Citation:

  1. Metcalf, Rodney V., 1995, Proterozoic plutonic rocks of the central Santa Fe Range: Trace element evidence of subduction zone magmatism, north-central New Mexico, in: Geology of the Santa Fe Region, Bauer, Paul W.; Kues, Barry S.; Dunbar, Nelia W.; Karlstrom, K. E.; Harrison, Bruce, New Mexico Geological Society, Guidebook, 46th Field Conference, pp. 185-191.

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