MSED 252 wks1.21

 This week my classmates and I were able to use virtual resources in order to further our understanding on earths physical changes throughout the decades. By using the Smithsonian website (https://www.smithsonianmag.com/science-nature/travel-through-deep-time-interactive-earth-180952886/) I was able to see and read about earths evolvement. Below I have summarized some of the information I learned today.   Haden earth about 4 billion years ago:  At this point in time the earth was extremely hot and had no water. This environment was to harsh for any life form to survive. A large piece of earth was broken off by a collision that created the moon.  Below is an example of what scientists believe earth looked like during this time.  Late Archean to Early Proterozoic about 2 billion years ago:   At this point in time oceans and continents began to form, but there was no oxygen in the atmosphere. Due to the intense radiation from the sun it is unlikely that life was thriving on our planet. Ho

This week I was able to further my understanding on relative dating. I am now able to look at layers of rock and determine which layer is the oldest. Relative dating gives geologists a rough estimate on when events in the past occurred. They do this by using principles developed by scientists such as Nicolaus Steno to determine the relationship between relative age and rocks. Listed below are the principals used to determine relative age. The Law of Superposition:  When observing un-deformed sedimentary rocks the oldest are on the bottom, and the youngest are on the top.  Principle of original horizontality:  Sedimentary rocks are nearly always horizontal when deposited. When they are not this is evidence of a shift in the earth's crust.  Principle of lateral continuity:  Sediments that are laterally continuous. As a result rocks that are similar are separated by a valley or other erosional features.  Principle of crosscutting relationships:  Features such as faults and igneous int

This week my classmates and I took a deeper look into rock identification. To do this we were given a few different rocks and had to put them in different groups according to their characteristics. These groups were igneous, sedimentary and metamorphic rocks. Once we selected a rock to analyze we looked at it closely and tried our best to determine where it would go.  Igneous rock characteristics:  Crystal formation, fine or course grained dependent on rate of cooling, glassy, air pockets, light or dark in color, and are rich in iron and (or) magnesium. The photo below are the rocks I characterized as igneous.      Sedimentary rock characterizations:  Weathered due to environment, rounded, provide historic information, contain other minerals and solid particles, shale, sandstone, conglomerate, and often contain fossils. The photo below are the rocks I classified as sedimentary.    Metamorphic rock characterizations:  Form from pre-existing rock, changes from due to hat and pressure, f

 This week my classmates and I were able to further our understanding on igneous, sedimentary, and metamorphic rocks. After this activity I felt more comfortable in my ability to identify where different rocks fall in the rock cycle, along with what factors identify them.  Lab:   We were given about 40 rocks and minerals to identify as shown in the photo below. With each rock I was able to pick out key characteristics. For example igneous rocks have crystals of various different sizes. This is due to the rate at which the rock cooled. Sedimentary rocks can often be rounded due to weathering and erosion. Metamorphic rocks are often flat as a result of heat and pressure. By using this knowledge and other physical attributes I was able to fill out the chart below, and name some of the rocks provided.