Identifying tectonic assembly in high-grade gneiss terranes: Case study in the Adirondack Lowlands, New York.

What: This project will be an integrated structural and metamorphic study that will focus on two high-grade fault zones in the Adirondack portion of the Grenville Province, with a focus on dating deformation, determining shearing conditions within the zone, and identifying discontinuities across the boundaries.

When: July 12 to August 9, 2008

Where: Adirondacks and Colgate University

Who: 9 students. William Peck, Associate Professor, Colgate University; Bruce Selleck, Harold Orville Whitnall Professor of Geology, Colgate University; and Martin Wong, Assistant Professor, Colgate University.

Project Description and Goals

This project will focus on the Carthage Colton Shear zone (CCSZ) and Black Lake shear zone (BLSZ) in the Adirondacks. Two weeks will be spent mapping and collecting samples in the field, after an introductory field trip examining Adirondack geology. The final two weeks of the project will be spent at Colgate preparing samples for analytical work at Colgate and elsewhere. We will make use of SEM, XRF, XRD, stable isotope and fluid inclusion instrumentation at Colgate, tailoring analytical strategies to either be completed before departure or finished at student home institutions.

Student Projects

Possible projects include deformation studies of fault rocks and syntectonic intrusive rocks, metamorphic petrology and carbon isotope thermometry of marbles across the faults, geothermobarometry of pelites in the fault zone, fluid inclusion and stable isotope study of syntectonic high-temperature veins, whole-rock chemistry of aluminous rocks from the BLSZ to determine protoliths of the enigmatic tectonized lithologies. These projects will probably be synthesized into topical papers about the BLSZ and CCSZ discussing metamorphic petrology, intrusion history, and structures.

Field Conditions

We will be housed in cabins in the Adirondacks and dorms at Colgate. The closeness of the field sites to Colgate (2-3 hrs) will allow return trips to the field near the end of the project if preliminary work shows the need to make new measurements or collect additional samples. Field work in this part of the Adirondacks is fairly straightforward; access is good, the locals are friendly, and the localities are close enough to each other that the students will have a good idea of the scope of all the projects.

Course Preparation

Igneous & Metamorphic Petrology or Structural geology, Field camp (or similar field experience) recommended.