(Author: Fiona Kelly)

There are three basic branches of Geology: Minerals, Fossils, and Rocks. 

• Minerals:  A solid, natural substance, where the atoms are arranged in an orderly, repeating pattern. They are commonly referred to as crystals. Some examples are quartz, emerald, and onyx.  
• Fossil:  Any recognizable evidence of pre-existing life. These can take the form of a body fossil, or a trace. A body fossil is the classic dinosaur found in any natural history museum. It is a bone of a vertebrate. A trace fossil is an imprint left by a plant or animal that has since dying decomposed. Plants and invertebrates leave trace fossils. Fossils can also give the approximate geological time that a specimen lived in, giving key information about the Earth at that time, along with personal information about that specimen.  
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I'm going to describe rocks separately, because within this category are three more sub-categories. 

 

Rocks are a coherent, naturally occurring solid combination of minerals.  

• Igneous Rocks: Formed by freezing or cooling. Plutonic igneous rocks are formed by cooling slowly. Volcanic igneous rocks are formed by cooling quickly.  
• Metamorphic Rocks: Formed deep below the Earth's surface. Pre-existing rocks go through a solid state of change due to extreme temperature and pressure.  
• Sedimentary Rocks: Formed at or near the surface of Earth. Clastic sedimentary rocks are formed by the cementation of loose grains. Chemical sedimentary rocks are formed by the precipitation of mineral from water. Biogenic sedimentary rocks are shells, such as those found on oysters, clams, and mollusks.  

There is a bit of a debate surrounding the scientific definition of a word used to classify rocks. The term facies is a Latin word meaning aspect or appearance. However, this is where the agreement ends. Some scientists use the term to mean a body of rocks with specified characteristic. Others use it to mean sedimentary rocks that share appearances. In the environmental sense, the word is used to mean a type of depositional environment rocks are found in.  

These include but are not limited to: 

• Fluvial: Rivers or streams 
• Terrestrial: On land 
• Erg: Desert 
• Glacier: Ice

Rocks, Rocks, Rocks, and don't forget the Minerals

This meeting I learned the most important thing there is to learn when studying Geology.

Rocks.

Let me tell you, that those were the best two hours I've ever had talking about rocks and minerals. I never really imagined myself learning what was on the surface of the Earth as in depth as I did on Tuesday. To know that these solid objects hold some of the most interesting moments of Earth's history in them is amazing. 

There was a part of the meeting where we looked at this large, heavy trace fossil with an imprint of a footprint. Now, just when I was about to loose interest and jump to the conclusion that it was a mold of a fossil; I was lured back. After I was told that I was holding a real fossil, I couldn't help but feeling as if I just poked the Queen or someone. I was holding part of our history. History that took place before the word history was even made.

I felt kind of special.

Learning different types of rocks makes me want to identify every single rock I see. Of course, that'd be hard to do without odd looks; but I am thankful I have the knowledge to tell the difference between a metamorphic rock from a sedimentary. So far I'm learning many new things that are both interesting and useful to know. I like to know my surroundings and where I am, what's not better than understanding the very foundation I'm standing on today?

Our little Rock Tour

More so than anything, today was mainly a gateway into what we would be doing. We basically started to get a grasp on all the knowledge involved with rocks. We talked about the different kinds of geology. Things like Physical geology, historical geology, paleontology, and archaeology. We talked about the different types of rock. We saw what igneous rocks were, what metamorphic rocks were, and what sedimentary rocks were. We also learned about how minerals are different. Samples of each kind were actually brought in. We got to have a little hands on tour of all kinds of rocks, and minerals. we saw how hard talc was compared to a thing like corundum. We got to see rocks that were from all over the world (courtesy of Matt). We also got to see rocks from different parts of CT. We looked at rocks like obsidian from volcanoes(Igneous rocks), rocks off the bank of rivers and streams(fluvial rocks) rocks like sandstone and limestone(sedimentary rocks), and rocks like marble or graphite(Metamorphic rocks).

Unraveling Earth's History Mystery

Today was interesting because I learned about different types of rocks and minerals. Most importantly, I learned how they formed like that and what they were composed of. We also saw dinosaur tracks imprinted into mud stone. What struck me was how dinosaur footprints embedded into rock for millions of years were discovered by humans thankfully without being disturbed. I guess they were waiting to be found! :)

We learned about sedimentary, volcanic, and metamorphic rocks and how each type is formed in different areas of the Earth. Furthermore, it was cool to see a satellite picture of sand being deposited into the Gulf by the Mississippi River; it was remarkable. Random thought: It's crazy how even though graphite and diamonds are both made from carbon, their atomic structures can create different substances!

Learning about Geologic Time

   The geologic time scale was created to represent Earth's long history. Scientists placed Earth's in order by relative age to create the geologic column. They developed the scale by studying rock layers and index fossils. It's kind of like a sand art bottle. The different colors of sand represent different layers of history. The sand on the bottom is relatively older than the sand that's on top and is considered young. Radioactive dating helps determine the absolute. For example, if you look at the Grand Canyon, you can visualize the multitudes of color change and layers. The oldest layers obviously lay at the bottom and the younger ones stack up way on the top. However, due to erosion, some layers wear off and in some rare phenomenons, the layers can completely flip around. 

   There are four types of time divisions: eon, era, period, and epoch. These are listed from 1st largest to 4th largest. We can say that geologic time began when Earth was formed, and will end when the sun demolishes the solar system.The divisions of the geologic time scale depend on the history of life on the Earth at that moment. Every time period had a different change in its atmosphere and environment which evolved life. It's crazy to see how much the Earth has evolved. 

Brain Dump in Three...Two...One

Earth was formed approximately 4.6 billion years ago. It began with single-celled organisms in the Proterozoic eon. This was in the pre-Cambrian period. Before we get any further, let me explain the divisions of time that we'll be using. Eons are the largest division of time, with Proterozoic, Paleozoic, Mesozoic, and Cenozoic falling under it. Eras are the second largest division, and include two or more periods. Periods are the third largest division, and are what epochs are divided into. Epochs are the fourth largest division, and are subdivisions of periods. A simpler way of remembering that is Eon>Era>Period>Epoch.

Towards the end of the Ediacaran era, we start to see more soft-bodied animals. As we move into the Paleozoic eon, shelly marine animals start to diversify, and we see more invertabrates such as trilobites. (Invertabrates are animals without a backbone or skeletal structure, such as jelly fish and crustaceans.) From these animals evolve the first fish, around the time of the Ordovician period. Around this same time, we see the first insects. Not long after, the first amphibians and the first seeds appear on land, occurring towards the end of the Devonian period. From here on, we start to see some of the more familiar creatures, such as Reptiles and Synapsids.  From these creatures evolved dinosaurs, which then went extinct by the end of the Cretaceous period.

Paleontologists are able to determine the age of all of these creatures, and the timeline that they fall on, by studying the layers of sediment and rock found in the Earth. The bottom-most layers date back the farthest, while the top-most layers are the most recent. Where the fossils fall in those layers determine their age, which is how scientists date them, and place them in the specific periods that they lived in.

What I learned

         Today was a flood of information, that I am still trying funnel through my storm drains. We learned about the geological time scale. We ended up learning about eons, eras, periods, epochs. Things like the Cenozoic, Mesozoic, Paleozoic, and Precambrian Eras. We talked about how geology is a way to find out things about the time before humans. We talked about radioactive dating, and relative age dating. We talked about how these layers of the earth go from oldest to youngest, starting bottom to top. The reason this is important is because of the things in these layers, specifically fossils.

         We learned about how it started with Single cell organisms, then moved on to soft bodied animals, shelled animals, fish/insects, tres, amphibians, so on and so forth. We toured the museum, specifically the Klein Geology Lab. We looked at the Trilobites and compared them to modern day arthropods. We moved on to the ancient fish shown in the museum. We talked about how very primitive organisms moved on land to make amphibians. We talked about dinosaurs possibly evolving into birds. And mammals coming, with humans coming last.

What Juhi learned

Juhi learned things today that both blew her mind and made her question everything around her.

Now, Juhi's going to stop talking in third person because she knows that she'd mess up if she didn't. To start off, when the topics were first introduced I thought that I knew about them and understood the gist of them. Turns out that I was wrong. I didn't know that the major time divisions of Earth are divided by the different life forms that started to exist. There are four major eras called the, Proterozoic, Paleozoic, Mesozoic, and the Cenozoic. Within each era there are different periods that divide them, and within the periods there are subdivisions called epochs. The part that blew my mind was that after an event of a new life form, a new division started. It amazed me how these are the same event that led to our existence. It's hard to believe that this was Earth's history before we came along, and now it's up to us to uncover all of these mysteries that our planet has left us to discover.

The First Day

The most interesting thing that I learned today was, The Major Division Of Time. EON- being the largest division of geologic time. ERA- being the 2nd largest. PERIOD-being the 3rd largest, and EPOCH-4th largest. This is interesting to me because i've never heard about it. Today was the first time I heard about it, Now I'm looking forward to do more research on the The Major Division Of time. Also another  interesting thing was, All the different species of organism that lived millions of years ago for example Trilobites, Trilobites form one of the earliest known groups of arthropods, Trilobites are now extinct. They are now found in Fossils.

What Janae Learned

At the beginning of the day, I was blown away with the topics that were presented to me. I was familiar with the Earth's historical timeline, but was unaware of the depth of it. I had heard of eras and periods but didn't understand how they were different or what they fit into. For example, I now know that the time frame called Cenozoic is an era and that there are periods of times during that era called Tertiary and Quaternary. Also I know now that these eras weren't randomly decided, but they were actually divided by life and events that have taken place in Earth's history. I've been able to realize how the information that I have obtained today will will benefit me. While observing some of the Yale Peabody's Natural History Museums exhibits today, I've been able to make connections between the timeline and concepts that interpret to museum visitors regularly. For example evolution, while looking at Earth's timeline we can identify the extinction of dinosaurs and the evolution of birds. The idea that some dinosaurs might have evolved to birds plays into how I have to interpret the idea of evolution here at the museum. Already I'm very excited about better understanding the Earth's timeline. I believe that this is very useful information and can help me understand other topics or even conversations that I might engage in in the future.

Today was the first day of the Evolutions Geoscience Fellowship at the Peabody Museum of Natural History. 6 new interns met to learn some fundamentals of geologic time with mentor Matthew Ormrod. Here are some of our thoughts from the first day!