Metamorphism RockGneissic Gneissic rock come from the Metamorphism rock. Metamorphism rock change their form. The changes are in the mineralogy, texture, and sometimes the chemical composition of rocks Metamorphism rocks takes place usually in elevate temperatures and pressures. These rocks gradually change until state of equilibrium with the new environment. The Agents of metamorphism include heat, pressure, and chemically active fluids.
Gneissic Gneissic rock is a common and widely distributed type of rock. The rocks with a banded appearance are call gneissic. Foliated gneissic will not usually split as easily as slates and some schist. I found this gneissic rock in Turlock lake . The place can be found along the side of Lake Street in the county of Stanislaus.
Gneissic I identify the rock for its texture, it has little dark biotite flakes, and the light silicate minerals. Given the rock a banded or layered appearance. Gneissic has a foliated texture
Quartz Quartz is a very hard metamorphism rock. The Changes on Metamorphism rocks increased the density, change in size, reorientation of mineral grains The transformation of low temperature minerals into high temperature minerals. Metamorphism rocks can be broadly classified in foliation exhibited and to lesser extend on the chemical composition.
Quartz The quartz is a non foliated texture Fused quartz grains, massive, very hard We can find this type of rock in the water or near to it. The quartz are formed in sandstone. Quartz formed under moderate to high grade and the grains in sandstone fuse together. The quartz ridges are often bare or covered only with very thin layer of soil and a little vegetation.
I identify this rock because it was near the waterin a river that passes through Yosemite NationalPark, and this rock shows grains typical of aquartz. These rocks colors are in a scale fromwhite to gray.
Sedimentary Rocks About 75 percent of the land areas are covered by sediments and sedimentary rocks. Across the ocean floor the earth solid surface, virtually everything is covered by sediment. These rocks are mostly located in mid ocean, water and at some volcanic areas. The particles of the sedimentary rocks by accumulating is call sediment.
Sedimentary Rocks The sediment are formed by weathering and erosion in a source area, and then they are transported to the place of deposition by water, winds mass movement or glaciers. This group of rocks provides geologists with much of the basic information they need to reconstruct the details of Earth history.
Sandstone The name of this rock in which the sand size grain dominate Sandstone is the most abundant sedimentary rock, accounting for approximately 20 percent of the entire group. Sandstone form in a variety of environment and often contain significant clues about their origin. The shapes of the sand can also help decipher the history of sandstone. The sandstone also containing significant amount of feldspar and angular grain of the ferromagnesian minerals.
This sandstone is asedimentary rock ; I foundit in Turlock Lake insidethe cold water
Igneous The igneous rocks are composed or interlocking crystals. Igneous are form in two basic settings Magma and Crystallizes. When magna loses its mobility before reaching the surface it eventually crystallizes to form an igneous rocks. They are also known as plutonic rocks. Igneous rocks are abundant in western portions of the american like volcanic peak cascades and mountains .
Granite Rock This rock is dominated by minerals. The geologist also refers to granite rock as being felsic. Granitic rocks are rich in silica they contain about 70 percent of it.
Granite RockThe granite is an igneous rock. I foundthis sample in the mountains of Yosemite.I identify this rock by its texture.
Mafic Basaltic Rock Basalt is a very dark green to black. This rock is composed primarily of pyroxene and calcium. Basalt is the most common extrusive igneous rock. Many volcanic island and Iceland are composed mainly of Basalt rocks/ I found that this rock is a Basaltic based on the color, texture and the upper layers.
San Andreas Fault I was not able to take an actual picture of the San Andreas fault; I found these pictures in the internet, and they show a clear view of the fault near the San Francisco Bay. A fault is an area where ground pushing in different directions meet. The pressure of the opposing movements eventually becomes too much, resulting in an earthquake. The San Andreas Fault is a large fault running underneath California, including many heavily populated areas. Many geologists predict a devastating earthquake along that fault in California running from San Diego to San Francisco. It is a fault line where major quakes have occurred along. There are plates that rest on top of each other and at the point of the fault there is a lot of pressure. If these tectonic plates move there could possibly be a quake as powerful as the last one to hit Japan or worse. The power in these plates measure in the range of hundreds of a-bombs going off at once - that is the kind of pressure that would be released.
weathering processes Physical and Chemical weathering Physical disintegration and chemical decomposition of rocks, minerals, and immature soils at or near the Earths surface. Physical, chemical, and biological processes induced or modified by wind, water, and climate cause the changes. Weathering is distinguished from erosion in that no transportation of material is involved. A broader application of erosion, however, includes weathering as a component Chemical is the process of chemically altering a rock, but not by heat and pressure metamorphism, simply by chemical constituents changing the rock. This is most famously seen in the case where dilute solutions of hydrochloric acid , runs across limestone, which is calcite, dissolves it, and leaves behind caves, or sink holes, or karst topography, Physical weathering is the breaking down of rock without changing its composition. The filling of cracks with water which then freezes and expands breaking the rock apart is one type of physical (also called mechanical weathering) called ice wedging or frost action. Gravity causing rock to fall and break apart is another example of physical weathering. Plant roots growing in cracks and breaking the rock apart is another example of physical weathering.
Mass wasting and erosionevents erosion is an action causing large bodies of rock to become much smaller. The mechanisms for this are wind/weather, chemical and mechanical. Wind erosion can be seen in deserts where the wind Caries small particles of sand the scrubs larger bodies into weird twisted shapes. Chemical erosion is seen in acid rain and such. This leaches or alters chemicals in the rock causing it to alter or dissolve. Mass erosion is by which soil, regolith, and rock move down slope under the force of gravity. Types of mass wasting include creep, slides, flows, topples, and falls, each with its own characteristic features, and taking place over timescales from seconds to years.
sedimentary environments A sedimentary, or depositional, environment is an area on the Earths surface, such as a lake or stream, where large volumes of sediment accumulate. All environments settings; terrestrial, coastal or marginal marine, and marine, environments, each with their own characteristic environmental factors and ments of deposition belong to one of three sedimentary deposits, make up a sedimentary environment.
practical use of geologythis is a bridge on my townFirebaugh CA, we use verymucho this is the way to goto Fresno.
Resources www.geology.com www.geol.umd.edu/~tholtz/G102/102terr.htm http://science.jrank.org Texbook Tarbuck Lutgens Tasa, An introduction to Physical geology Tenth Edition.