Date of Award

5-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Matthew L. Gorring

Committee Member

Joshua Galster

Committee Member

Gregory Pope

Abstract

The Byram Intrusive Suite granite gneisses of the New Jersey Highlands are believed to be similar in chemical composition as well as age to the Storm King hornblende granite gneisses of the Hudson Highlands of New York (Drake et al., 1991, Ratcliffe and Aleinikoff, 2001; Volkert et ah, 2010). The goal of this project is to determine the geochemical continuity between the Byram Intrusive Suite of the NJ Highlands and the Storm King granite gniesses, located near Bear Mountain, NY. Thirtytwo samples of granitic gneisses with similar field relations and textures to the Byram and Storm King granite gneisses were collected in the western Hudson Highlands spanning the region between the New Jersey border and the Hudson River within Sterling Forest and Harriman State Parks, NY. The samples are all coarse-grained, hornblendebearing monzogranites and syenogranites. Whole-rock elemental analysis was obtained via inductively coupled plasma optical emissions spectrometer (ICP-OES) for major elements and inductively coupled plasma mass spectrometer (ICP-MS) for trace elements. The collected samples all have variably mild A-type granite chemical characteristics defined by high FeOt/(FeOt+MgO) (~0.9), K2O/Na2O (1.5-2), high Ba (500-1800 ppm), Nb (20-50 ppm), Y (60-180 ppm), total rare earth elements (REE) (300- 800 ppm) and low MgO (0 .7% ), CaO (<2%), and Sr (80-180 ppm). REE patterns are light rare earth element (LREE)-enriched (La/YbN = 5-15), but have flat middle rare earth element (MREE) and relatively high heavy rare earth element (HREE) concentrations (~20-40x chondrite) with moderately deep negative europium anomalies (Eu/Eu* = 0.14- 0.78). Compared to data from Volkert et al. (2004) and Verrengia (2004), the major and trace element geochemistry of granitic gneisses analyzed for this study are nearly identical to the Byram Intrusive Suite and the Storm King granite gneiss. The lack of europium in the samples points towards the initial crystallization of plagioclase. It is also highly likely that due to the formation of the rocks in an anorogenic setting that the parental magmas of the Byram and Storm King Granites were fractionated into more felsic daughter magmas. All these rocks are interpreted to form a contiguous metaigneous unit across the New Jersey and Hudson Highlands and were formed by a continental lithsopheric thinning/delamination and crustal melting event that occurred after the Elzeverian Orogeny between 1190 and 1170 Ma.

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