| 1/ The Wilson Cycle describe the four stages of plate tectonics:
(1) Rifting of continents
(2) Continental drift, seafloor spreading & formation of oceanic basin
(3) Closure of ocean basins by subduction of oceanic lithosphere
(4) Continental collision and final closure of oceanic basin
2/ A rifting produced by forces applied at the plate boundaries.
3/ A rifting produced by body force related to thermal thinning of the lithospheric mantle.
4/ Continental rift results in the upwelling and decompression of the asthernosphere. Decompression produces partial melting of the mantle and therefore basaltic magmas.
5/ Deep water post-rift sediments, shallow water syn-rift sediments with reef and coral, volcanic rocks, detrital pre-rift sediments, and the basement.
6/ A basin bounded by normal faults.
7/ Rift basins host oil and gas resources?
8/ When ocean floor is produced. Extension is localised at the Mid-Oceanic Ridge.
9/ Normal faults.
10/ An anticline produced by the flexure of the hanging block above a normal fault.
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11/ Sand.
12/ Pinch-out.
13/ A basin in which normal faults have been reactivated into reverse faults.
14/ They are good traps for hydrocarbon.
15/ Because cooling and therefore strengthening of the lithosphere is faster compare to tectonics thinning. Extension moves to weaker adjacent regions.
16/ The first stage (tectonic subsidence) is related to the stretching of the lithosphere. The second stage (thermal subsidence) is related to the cooling and thermal thickening of the lithosphere. (Remember the base of the lithosphere is an isotherm).
17/ 50-100 Myr.
18/ Pure shear model (proposed by McKenzie), and simple shear model (proposed by Wernicke).
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