Essay on technical report

Submitted By jojojojo1234
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Technical Report The oldest layer is marble which is a metamorphic rock. Over the course of many years, sediment are deposited to form a layer of sedimentary rock. However, an event such as an igneous intrusion or the presence of a batholith can transform that sedimentary rock into metamorphic rock. Marble is a non foliated metamorphic rock which mean it is created through contact metamorphism on the parts that the igneous intrusion is touching the marble, but rest of layer of the marble is created through regional metamorphism. Because the parent rock of a marble is a limestone, the layer of limestone was first formed on the surface before the heat from the igneous intrusion -- over the course of many year-- has altered the limestone into marble. The evidence that indicates that this layer is marble is its medium grained texture and its reaction to HCl once scratched. Marble has microcrystalline from the transformation. The second oldest layer is the metamorphic rock, quartzite. Quartzite can be formed through both regional and contact metamorphism. This non foliated rock made up of quartz and having sandy texture, existed probably as a sandstone until heat and pressure over many millions of years metamorphosed it into quartzite. This happened in a medium energy environment. Medium energy environment allowed sand sized grains to be deposited so to create a layer of sedimentary rock. Sandstone being the parent rock of quartzite was most likely this layer that formed before contact metamorphism changed this layer quartzite. The contact metamorphism occurred as an igneous intrusion changed the once sedimentary rock into a metamorphic rock. The third oldest rock that came is an 562 million years old igneous rock called diorite. Diorite is an intrusive intermediate rock. Diorite formed in a slow cooling magma underground because it is an intrusive igneous rock which is why this rock has the large crystal. This igneous rock is the igneous intrusion that caused the metamorphism of both the marble and quartzite. After the igneous intrusion came and transformed sandstone into quartzite, more sand was deposited on top of quartzite to form sandstone. We know that this layer is sandstone because it is a clastic sediment grains with midsize grains. The next oldest layer is the layer of shale. Shale is also a sedimentary rock, much like the sandstone, except the grains of a shale is much finer that it is not visible. Just like sandstone, this layer formed as sediments such as clay and maybe a little bit of fossils. Because shale is made up with such small grains we can assume that this area around 354 to 417 years ago had a low energy environment as the layer of shale was forming. The sixth oldest layer is claystone. Like sandstone and shale, claystone is a sedimentary rock. Weathering of sandstone probably caused the breakdown of sand into finer grains causing it to be deposited as shale. The…