Sedimentary Rock

9/28/13

Sedimentary rocks are one of the three main rocks groups including igneous and metamorphic rocks.The Sedimentary rocks are formed in four different ways: by the deposition of the weathered remains of other rocks, by the accumulation and consolidation of other sediments, by the deposition of the results of biogenic activity, and by precipitation from solution. 

Clastic sedimentary rocks are formed by erosion by friction of waves, and by transportation where the sediment is carried along by a current. The rock is then formed by disposition and compacting where the sediment is squashed together to form a rock.

The rocks can also be formed by overburden pressure as particles of sediment are accumulated from air, ice, or water sources carrying the particles.

Chalk, limestone, sandstone, clay, and shale are a few types of common Sedimentary rocks. 

Sedimentary rocks cover 75% of the Earth's surface and around 8% of the total volume of the crust. They form a bedding (also known as "strata") just above igneous rocks which cover 90-95% of the earths crust below the Sedimentary rocks. Metamorphic rocks also make up part of the Earth's crust.

Sedimentary rocks are used for coal, fossil fuels, drinking water, and ores. The rocks are also an asset to  roads, houses, canals, and tunnels. 

Website: http://www.sciencedaily.com/articles/s/sedimentary_rock.htm

Picture 1:http://blessan.files.wordpress.com/2010/03/sedimentary-rocks1.jpg

Picture 2: http://upload.wikimedia.org/wikipedia/commons/thumb/7/75/Helgoland_Lummenfelsen_22067.JPG/500px-Helgoland_Lummenfelsen_22067.JPG

Estuaries

What is an Estuary? 

An Estuary is a partially-enclosed body of water that has an opening 
to the open ocean with streams flowing into it. Estuaries can help create 
fresh water by mixing it with the salt water from the ocean and the fresh 
water from the streams and rivers.

However, an Estuary needs some type of tide to maintain 

a connection between the multiple water sources. If the waters are non-

tital, the rivers will form a delta. 

The world's largest Estuary is the Gulf of St. Lawrence, located 
in eastern Canada.  


"Estuarine environments are among the most productive on earth, creating more organic matter each year than comparably-sized areas of forest, grassland, or agricultural land. The tidal, sheltered waters of estuaries also support unique communities of plants and animals especially adapted for life at the margin of the sea." (EPA.gov)

Estuaries are very diverse; they contain shallow waters,
 fresh and salt marshes, swamps, mud and sand flats, rocky shores, oyster reefs, mangrove forests, river deltas, tidal pools, and seagrasses. 
Estuaries are popular places for recreation and many types of scientific research. 
Migratory birds often seek refuge during long journeys in estuarine environments.

Article 1: http://www.sciencedaily.com/articles/e/estuary.htm

Article 2: http://water.epa.gov/type/oceb/nep/about.cfm

Picture 1: http://ccma.nos.noaa.gov/_images/estuary.jpg

Picture 2: http://b.static.trunity.net/images/209830/500x0/scale/Gulf_of_St._Lawrence.png

Drilling to the Earth's Mantle through Oceanic Crust

Mike Del Priore
9/15/13

Drilling through the Earth's crust

            Deep-water drilling technology is being developed by The Integrated Ocean Drilling Program (IODP) and AGR drilling services. Why? According to Geology.com, "Drilled cores from the mantle could provide scientists with answers to questions about the structure, composition, mineralogy, and in situ physical properties of oceanic crust and the geological nature of the seismic Moho."

            Primarily, such drilling was only used for shallow-water oil and gas recovery. But now that IODP is aided by AGR, they are now able to expand their drilling to lower depths of the ocean. 

          "The 'riserless mud recovery technology' (RMRT), owned by AGR, is expected to operate in hyper-deepwater depths greater than 12,000 feet." (Geology.com). A major benefactor for this project is DeepStar Consortium, an industry that supports deepwater research and technology. 

           Previous to this project, on an IODP expedition, scientists encountered mantle depths while looking into seafloor spreading rates. The drilling reached volcanic rock and a fossil magma chamber deep beneath the ocean floor.

Website:   http://geology.com/press-release/drilling-to-mantle/

Picture:     http://geology.com/press-release/drilling-to-mantle/riserless-mud-recovery-lg.jpg

9/2/13

Mike Del Priore

THE ANTARCTIC ICE SHEET

Did you know that the largest single mass of ice on the planet is the one you see above. The Antarctic Ice Sheet is about 14 million square kilometers (holds 30 million cubic km of ice!). Almost all of the fresh water on the Earth's surface is contained here (90%). 

The picture shown above is the western portion of the ice mass. It extends 2500 m below sea level! However, in the eastern portion, it lays on a land mass. 

If the ice mass was not here, the land would be entirely submerged in the ocean floor. The ice keeps gathering because of all the snowfall it gets; therefore, it grows in the winter but loses ice in the summertime.

According to BBC News, "Scientists found that glaciers on the East Antarctic Ice Sheet (EAIS) advance and retreat in synch with changes in temperature." 
Scientists fear that the sea levels in West Antarctic are receding which will cause the sheet to lose ice and eventually be submerged if it keeps receding.

Website:  http://www.sciencedaily.com/articles/a/antarctic_ice_sheet.htm

BBC News:  http://www.bbc.co.uk/news/science-environment-23868841

Picture:  http://www.iceagenow.com/West_Antarctic_ice_sheet.jpg