3rd geo report RE WRITE 3
Metamorphic and Igneous Rocks of the Hudson Highlands
3rd Field Report
Abstract
The entire region of the Hudson Highlands underwent high-grade metamorphism, and at a series of locations different intrusions occurred during the Grenville Orogeny. Certain evidences to help back up this claim are the presence of gneissic rock and index minerals such as Siliminite and Garnet. Since the mineral composition indicates granulite facies, then its protolithic content is pelitic, meaning shale/mudrock. Also, a series of magmatic intrusions were shown the form of Lamprophyre, Granite, Pegmatite, and Diorite.
Introduction
Located within the Hudson Highlands proto-continents collided giving rise to a major crustal thickening event called the Grenville Orogeny. It is important to study it because, it provides the geologic history of that particular area. In order to study the area, one must be able to identify detailed information about identifying rock types, mineral composition and associating it with its proper metamorphic facies.
Methods
The Hudson Highlands was measured and analyzed along Harriman State Park, October 25th, 2013. Location was determined using Google maps on cellular devices equipped with Global Positioning Systems (GPS). Once location was determined, it was then recorded on the base map of Popolopen Lake Quadrangle. Features such as orientation, facies, fabric relations, and relative abundances of minerals were visually identified and recorded. Grain size and mineral composition were measured at a cm-m scale. Tools to help these features was a ruler, hand lens, Silva Compass, and the “Geology in the Field”, written by Robert R. Compton. Finally, an ACF/ACM diagram was plotted based on mineral composition.
Data:
Metamorphic Rocks:
Garnet Siliminite Gneiss Gneiss rock that is foliated and dark in color with bandings measuring up to 0.2cm, and the light bandings measuring up to 2cm. Minerals located within the dark bandings consists of Biotite (40%)
3rd Field Report
Abstract
The entire region of the Hudson Highlands underwent high-grade metamorphism, and at a series of locations different intrusions occurred during the Grenville Orogeny. Certain evidences to help back up this claim are the presence of gneissic rock and index minerals such as Siliminite and Garnet. Since the mineral composition indicates granulite facies, then its protolithic content is pelitic, meaning shale/mudrock. Also, a series of magmatic intrusions were shown the form of Lamprophyre, Granite, Pegmatite, and Diorite.
Introduction
Located within the Hudson Highlands proto-continents collided giving rise to a major crustal thickening event called the Grenville Orogeny. It is important to study it because, it provides the geologic history of that particular area. In order to study the area, one must be able to identify detailed information about identifying rock types, mineral composition and associating it with its proper metamorphic facies.
Methods
The Hudson Highlands was measured and analyzed along Harriman State Park, October 25th, 2013. Location was determined using Google maps on cellular devices equipped with Global Positioning Systems (GPS). Once location was determined, it was then recorded on the base map of Popolopen Lake Quadrangle. Features such as orientation, facies, fabric relations, and relative abundances of minerals were visually identified and recorded. Grain size and mineral composition were measured at a cm-m scale. Tools to help these features was a ruler, hand lens, Silva Compass, and the “Geology in the Field”, written by Robert R. Compton. Finally, an ACF/ACM diagram was plotted based on mineral composition.
Data:
Metamorphic Rocks:
Garnet Siliminite Gneiss Gneiss rock that is foliated and dark in color with bandings measuring up to 0.2cm, and the light bandings measuring up to 2cm. Minerals located within the dark bandings consists of Biotite (40%)