Answer To: Wilson Cycle Lab Through numerous reading summary exercises this semester, you have been introduced...
Taskin answered on Jul 27 2021
WILSON CYCLE LAB EXERCISE SOLUTIONS
The Wilson Plate Tectonic Cycle (Dewey and Burke, 1974, Burke and Dewey, 1975) shows frequent opening followed by closing of ocean basin (mainly Atlantic Ocean) which goes through six stages to accomplish the cycle whereby again starting from the initial stage which is Rifting of the Continent followed by Immature to Mature ocean and ending with the Subduction process which ends the cycle, along the same continental boundaries from which its started to split(Wilson et al., 2019). Rifting and Mountain Building processes plays a significant role in the region like these weakened Lithosphere thereby eases the possible deformation in the near future (Audet & Bürgmann 2011; Buiter & Torsvik 2014). J.Tuzo Wilson codify the model of the plate tectonic (Wilson, 1965, Wilson, 1968).
There are six stages which elaborate the Wilson cycle and they are;
1) Embryonic Stage: Upliftment of the crustal plate is dominant in this stage of Wilson Cycle. Rift valleys are characteristic features of this stage. Major rock types linked in the first stage are Tholeitic basalts, Alkali basalts.
Modern examples include: East African Rift (Active) and Gulf of Suez, Egypt (Active).
Fig 1 (a): Google Earth image of East African Rift (EAR). EAR also known as Afro-Arabian Rift Valley as it extends from Jorden (SW Asia) southward and moves through Eastern Africa to Mozambique. EAR is one of the most prominent extensive rifts on Earth’s Surface. Many lakes in the rift are fjordlike and much deeper. The formation of rifts triggered somewhat 30Ma back and still continuing.
Source: Britannica, T. Editors of Encyclopaedia (2017, February 21). East African Rift System. Encyclopedia Britannica. https://www.britannica.com/place/East-African-Rift-System.
Fig 1 (b): USGS Earthquake map (at the earliest 30 Days) of East African Rift. No recent Earthquake activity shown in and around the region of East African Rift. Among the modern example this is one of the region who seems to be dead i.e., no seismic activity in recent time (i.e., within one month).
Source- ESRI, HERE, Gar min © open street map contributor and the GIS user community.
Fig 1 (c): Google Earth image of Gulf of Suez, Egypt. It is a north western flank of the Red Sea in between western portion of Africa and Sinai Peninsula (Eastern parts of Egypt). Suez Canal link Gulf of Suez to Mediterranean Sea which is significant Shipping route. Gulf of Suez is approximately 180-210feet deep which is a shallow depth.
Source: Britannica, T. Editors of Encyclopaedia (2015, January 16). Gulf of Suez. Encyclopedia Britannica. https://www.britannica.com/place/Gulf-of-Suez.
Fig 1 (d): USGS Earthquake map (at the earliest 30 Days) of Gulf of Suez, Egypt. No recent Earthquake activity shown in and around the region of Gulf of Suez, Egypt. Among the modern example this is one of the region who seems to be dead i.e., no seismic activity in recent time (i.e., within one month).
Source- ESRI, HERE, Gar min © open street map contributor and the GIS user community.
2) Young Ocean: Horizontal extension/spreading is dominant in this stage resulting in narrow seaways with central depression and young active spreading ridge. Igneous rock types found here are Tholeitic basalts (inc MORB), Alkali basalts and sediments like Evaporates, Shelf and Basin deposits. Thermal low grade metamorphism is also observed.
Modern examples include: Red Sea and Gulf of Aden.
Fig 2 (a): Google Earth image of Red Sea. Arabian Peninsula and North Africa is divided by Red Sea which lies in a Fault Depression. The trough shaped topography of the sea floor of Red Sea is quite rugged with V-shaped indented forms on the sea floor. Submarine Ridges (Sills) feature also present on the floor of Red Sea.
Source: Schreiber, B. Charlotte and Ryan, . William B.F. (2020, May 15). Red Sea. Encyclopedia Britannica. https://www.britannica.com/place/Red-Sea.
Fig 2 (b): USGS Earthquake map (at the earliest 30 Days) of Red Sea. No recent seismic activity shown in and around these region. Among the modern example this is one of the region who seems to be dead i.e., no seismic activity in recent time (i.e., within one month).
Source- ESRI, HERE, Gar min © open street map contributor and the GIS user community.
Fig 2 (c): Google Earth image of Gulf of Aden. It is a deep water basin which connects the route between Arabian Sea and Red Sea. Sheba Ridge (rough topography) which is a continuation of Indian Ocean Ridge system is the prominent relief feature of this gulf. Sea floor of the Gulf of Aden spreads away from the axis of the Sheba Ridge.
Source: Britannica, T. Editors of Encyclopaedia (2019, March 26). Gulf of Aden. Encyclopedia Britannica. https://www.britannica.com/place/Gulf-of-Aden.
Fig 2 (d): USGS Earthquake map (at the earliest 30 Days) of Gulf of Aden. No recent seismic activity shown in and around the region of Gulf of Aden. Among the modern example this is one of the region who seems to be dead i.e., no seismic activity in recent time (i.e., within one month).
Source- ESRI, HERE, Gar min © open street map contributor and the GIS user community.
3) Mature Stage: In this stage basin subsidence yields large ocean basins with active spreading ridge which means spreading is still plays pivotal role. Igneous rock types include Tholeitic basalt, Alkali basalt with abundant shelf to deep marine sediments deposits. This stage too shows thermal low grade metamorphism.
Modern examples include: Atlantic Ocean and Western Indian Ocean.
Fig 3 (a): Google Earth image of Atlantic Ocean. Atlantic Ocean is S-shaped and narrow in length with an average depth of 3300meters and maximum depth of 8380meters. Mid Atlantic ridge (huge median mountain range) is an spectacular feature of the ocean floor having breadth of 1600km. Seamounts, Abyssa Hills also...