Basin Environment

Author Phoomphavis Boonsrirojna      Editor Poomisant Srimaharaja
What is a basin?
From the dictionary, basin is an open shallow usually a round container used especially for holding liquids. (from www.thefreedictionary.com)

Here we will talk about basin that is a sedimentary basin not the basin that is used in the toilet, so it is a geological basin.
But from this definition it is still hard to understand, so the best way is to show you some pictures of the basins.
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Picture
The Michigan Basin
​So, in this picture you can see that this basin is pulled downward and it has a characteristic that can keep liquid in the bottom of it.
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Why this is important? 
When we start the exploration for petroleum, one of the first places that has a chance to contain oil and gas usually is place that has basin characteristic. This why the type of basins is the thing that is important to know.
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Type of basins
1. Rift-related basins
a) Rift basin: happen when the continental crust is rifting.
Example: East Africa Rift
Picture
Rift basin that create a Rift valley.

b) Passive margin basin: mostly due to long-term accumulation of sediments on the continental shelf.
Example:  East coast of North America
Picture
Passive Margin Basin.
Picture
The Thingvellir fracture zone at Thingvellir National Park in southwestern Iceland.

​2. Subduction-related basins
​a) Trench: one plate subducting(downward) and other one upward.
Example: Western edge of Vancouver Island.

b) Forearc basic: The area between the accretionary wedge and the magmatic arc, largely caused by the negative buoyancy of the subducting plate pulling down on the overlying continental crust.
Example: Georgia Strait


​c) Foreland basin: the weight of a large mountain on the overlying continental crust cause the basin
Example: The sediment filled plain south of the Himalayas
Picture
Because of the gravity, the weight of mountain cause the basin to form.
Picture
Himalayas: One of the most important and beautiful mountains in the world and separating Indain subcontinental from the Tibetan Plateau.

​​d) Strike-slip basin: caused by the slip between two plate, creating down-dropped block.
Example: Various locations on the San Andreas Fault or the Anatolian Fault
​Reference:
https://media1.britannica.com
https://en.wikipedia.org/wiki/Himalayas
https://web.viu.ca