Igneous Petrology of Cape Granites Essay

In site one there was a high proportion of very unspherical rocks. According to this the hypothesis is right, in site two there is a lot more smother rocks medium sized and in site 3 there are very small pebbles which are very smooth and spherical. The pebbles get smoother and rounder while it goes downstream. Due to us only taking about 10 rocks our result may have been not right as there were some pebbles which were largely over sized. Most of the other load is dissolved by solution such as limestone and chalk

Approximately 17 meters thick, Unit A defines the lowest third of the Juniata Formation. Fragments of marine fossils, including bryozoans, brachiopods, and gastropods, are commonly found in the bottom-most portion of this unit of structureless mudstone and quartz arenite. Quartz grains in the sandstone beds of Unit A are typically immature and fine-grained, though the sandstone packages tend to coarsen upwards. Though typically structureless, intermittent bedding of the sandstone and shale packages is observed in this unit, and some areas display

Next, we can see that the rock displays a subtle porphyritic texture with plagioclase comprising the phenocrysts. The overall texture of the surrounding groundmass is granoblastic equigranular. Under thin section we also see a weakly defined foliation evidenced in the preferential alignment of actinolite grains and to a lesser extent chlorite grains. Undulose extinction is also observed in quartz indicating the rock was subject to deformation. The normalized quartz, alkali-feldspar, and plagioclase (QAP) values of this rock indicate that it is classified as a grano-diorite according to the IUGS QAPF classification system which is consistent with the hand sample interpretation.

Sims et al. (1989) synthesized U-Pb zircon ages for the Pembine-Wausau terrane. Sims concluded that the volcanic rocks were generated from around 1889 to 1860 Ma as island arcs and closed back-arc basins above the south-dipping subduction zone (Niagara fault zone). Granitoid rocks in the terrane, emplaced from around 1870 to 1760 Ma, are mainly granodiorite and tonalite but include gabbro, diorite, and granite. These developed as island arcs above the Eau Pleine shear zone. The Niagara fault zone contains a relict ophiolite, suggesting that the rocks in the Pembine-Wausau terrane probably accumulated on

This study classifies the two granites under one unit named the Kilbride Granite, however, the research, which uses both radiometric dating and composition analysis, identifies them as two compositionally separate units with different ages. On the other hand, it is not wrong to say that the granites were related as they are the two latest forming members of the Eastern Red Hills complex. (Bell and Harris, 1986)

Lyons sandstone can be divided into two distinct types which are the red and grey facies. The red facies are the red- colored sandstone which contains no hydrocarbons and the gray facies are the white to black- colored sandstone which contain hydrocarbon in its matrix (Levandowski,

The latest rocks in this region were formed in Pleistocene time as imperfectly consolidated gravel of river terraces and alluvial deposits of the

Complete this week’s lab by filling in your responses to the questions from Geoscience Laboratory. Select answers are provided for you in red font to assist you with your lab work. Although you are only required to respond to the questions in this worksheet, you are encouraged to answer others from the text on your own.

At Laurel Hill Duke Forest there is a large granodiorite cliff adjacent to a river on one side. This cliff is not smooth and has several parallel fractures instead of one steep slope. Observations of this cliff were taken in order to gather data and find possible explanations for why this cliff is where it is located and why the river adjacent to it follows a V-shaped path. One observation was that the range of the strikes and dips of the fractures facing river were all near parallel ranging from strike of 170-190 degrees and dips ranging from 70-90 degrees. There were other fractures oriented differently on other sides of the outcrop. Also, the surface of the outcrop was highly weathered in some parts where the rock type was not distinguishable without using a rock hammer and had moss growing over it.

It is subdivided, from north to south, into the Wabigoon, Quetico, Wawa, and Minnesota River Valley (MRV) subprovinces (Figure 2, Jirsa et al., 2011). The Wabigoon subprovince is composed of greenschist facies mafic volcanic and volcaniclastic rocks intruded by granitoid batholiths. Algoma-type iron formation and small mafic intrusions are also common in this terrane. Amphibolite to greenschist facies rocks comprise the majority of the Quetico subprovince. In Minnesota, it occurs as a westward thinning belt of relatively homogenous metasediments and interstratified migmatites. The Wawa subprovince is composed of greenschist facies mafic and felsic volcanic rocks, granitoid batholiths and subsidiary Algoma-type iron formation. The MRV is the oldest of the terranes, and is characterized by granulite facies gneissic domes (Jirsa et al., 2011). Although not included as part of this study, a comprehensive overview of the mineral potential of the Vermillion Greenstone (Wawa Terrane in MN) was provided by Peterson

A period of volcanism resulted in igneous intrusions within the Raton Basin-Sierra Grande Uplift Province that was sourced from the upper mantle about 26. 6 billion years ago and is associated with parallel dikes and sills (Higley, 2007). Igneous rocks are common within the Raton Basin and include Tertiary dikes and sills that range in age from 6.7 to 29 5 million years ago (Flores and Bader, 1999). One of the main differences between dikes and sills is that dikes are longer lived magma conduits and sills are features that form when magma is in neutral buoyancy with the surrounding rock (Rooper et al., 2006). These volcanic events are associated with hydrothermal alteration of coal within the basin (Higley, 2007).

This formation is a very fine grain Mississippian limestone. To test to see if this was the Bangor formation we used HCL and because there was a reaction we know its limestone. This formation could also be described as gray in color as well as an average thickness of 700 feet. We see the Bangor until stop eight, where we see a very different vertical bedding. Also different at stop eight is the outcrop no longer reacts with HCL. From this we gathered that we had moved into the Hartselle formation. In the Hartselle Formation, Mississippian aged sandstones are dominant. This particular stop had a large amount of jointing. After the Hartselle, we figured the Pride Mountain Formation would be next, however at stop nine we see the Maury Formation present. This stop focused on the rock located inside the creek. Because we were unable to go into the creek to get the strike and dips, we once again had to do a projected orientation. Also found on this stop were natural sulfur springs, easy to notice with the smell that it gives off. The Maury formation consist of Mississippian- Silurian aged shale. At the next stop, stop 10, we encounter the Ft. Payne formation. Although this area location was thickly vegetated, we were able to conduct the acid test and saw that the HCL reacts in some places but not all. From this we concluded that this was the cherty limestone of the Ft. Payne formation. The following stop, 12, we went up section and arrived at the Maury Formation once again. At the final stop, location 13, we see Ft. Payne Formation. All of the metamorphism and deformation in the southernmost Appalachians can be related to the movement of the thrust sheets and stacks (Higgins,

Many millions of years ago the Sierra Nevada was filled with ocean water until sediments began collecting and formed mountain ranges. Over a large period of time, the mountains began to wear out and became immersed in the ocean once again. Many different particles and materials began to make layers and created the first mountain system. After the Jurassic era, “…new strata were folded and crumpled and invaded by molten granite from below” (Beatty, 1943). A large

All of the volcanic and metasedimentary rocks are metamorphosed, whose grades are extending from greenschist to upper amphibolite, characterized by low-pressure but high-temperature (Isachsen & Bowring, 1994). The influence of basement fracture zone is reflected in the homoclinal and abruptly alternated trends of the volcanic belts, which is more frequently found in the southwestern domain of the province, while north belts show angular patterns (Fyson & Helmstaedt, 1988; Padgham,1992; Padgham & Fyson, 1992). Except for the sharp dips of the volcanics, regional-scale folds, foliations and cleavages over several successions shown in the metasedimentary rocks are studied to understand the deformation and metamorphism (Isachsen & Bowring, 1994). Fyson & Helmstaedt (1988) compare three major types of folds which are ranked by their ages and sizes from oldest, most extensive F0 to minor-sized, cleavage-foliation-associated S3 folds with intermediate type F1 between them and they suggest that the parallel trend and they suggest both foliation and folds are results of syntectonic

It is currently the largest exposed granite in the world weighing approximately one trillion pounds; although, only one third of the mountain can be seen as a majority of the mountain expands below ground as far as North Carolina. The enormous pluton mountain, as scientifically identified by geologist, was formed by a complex folding and faulting that had subsequently created the Blue ridge mountains. Though what remains as a mystery to many geologist is as to how such a massive granite mountain has become exposed. Although there are several theories that have been publicated to explain such a phenomena none are substantial or advocated the most. While the origins of Stone Mountain are elusive, the correlations of this landmarks with american history are intricately