| Granites represent probes of the earth's interior and provide information on the compositional, lithologic, and thermal characteristics of the earth, in addition to the processes that occur within the earth. They are especially useful because they occur in a variety of tectonic environments, including regions at destructive plate margins, in regions characterized by crustal extension and rifting, and within ophiolite complexes formed at divergent plate margins. Some even occur within plates, far from plate boundaries. The Northern Appalachians is an orogenic belt that contains many granitic and gabbroic plutons that intruded at various times, and provide a window into a significant part of the earth's crust and mantle.; The focus of this dissertation is the Deblois Pluton Complex (DPC) and the associated sedimentary and metamorphic rocks. The DPC outcrops over 1680 km2 and cross-cuts two major terrane boundaries, the Turtle Head Fault, and the Sennebec Pond Fault. Furthermore, the DPC has been affected by shearing from the Norumbega Fault System. The objective of the research is to constrain the tectonic models for the Acadian-Salinic orogenies in eastern Maine. This study of the DPC involved geological mapping, structural geology, igneous and metamorphic petrology, geochemistry, geographic information system and remote sensing.; The consists of DPC has Mantled Feldspar, Porphyritic, and Medium-grained granites, and a suite of two-mica granites. Feldspar accumulation appears to be the mechanism for formation of the DPC, whereas, the two-mica granites appear to formed through fractionation. The DPC intruded the crust at a shallow depth, 0.5--2.0 kbar. Medium- to high-grade metamorphic assemblages indicating Barrovian metamorphism were discovered and document the first occurrence of Kyanite in south-eastern Maine. Landsat TM and Shuttle Imaging Radar were used to aid mapping in forested areas, and they document a correlation between vegetation, mineral alteration, and outcrop location. Remote sensing methods also help unravel the structural history of the region. |
