geodynamics turcotte ch 3 problem solutions

Basement involved is postulated for the Pirital Thrust which cuts previously emplaced cover structures like the El Furrial structural unit. A careful analysis of both the chronostratigraphy and the internal geometry of the more » foredeep and piggy-back syntectonic deposits are also used to establish the kinematics of each individual structure. The present geometries of the sectons show a major discrepancy between the cover and basement lengths, which could be explained by tectonic inheritance from the Tethyan margin. Crustal scale balanced cross-sections have been here completed from available surface and subsurface data across this major transfer zone which links the oceanic subduction of the Lesser Antilles with the continental subduction of the Andes. The eastern Venezuelan Ranges result from oblique convergence along the South American-Caribbean plate boundary, whose main surface expression is the El Pilar dextral strike-slip fault. The generation of short-lived continental microplates is also advanced as a model for breakup of large continental plates, as sea-floor spreading is established along nascent continental margins. Relative motion between five of these plates is invoked as the evolutionary model, accounting for the observed tectonic physiography as well as the extensional and compressional features of the Cotonou basin and the peri-Niger Delta region. The results support a hypothesis that during the breakup of Africa and South America, the Gulf of Guinea cul-de-sac consisted of several microplates, generated from brittle deformation of continental crust in response to mantle convection stresses from below, as well as torsional stresses from the northward of the South Atlantic rip into the Brasilo-West African region. Seismic stratigraphic and structural analysis more » illustrate tectonic control of clastic and carbonate sedimentation, and the interplay of basinal subsidence with eustatic sea-level changes. Depth-to-basement data from exploratory wells in the basins were evaluated with thermo-mechanical subsidence models, to make geodynamic estimates of lithospheric extension. Data interpretation reveal discordant fracture zones beneath the Niger Delta region, indicating the Gulf of Guinea basins originated as a series of pull-apart basins, that favorable maturation estimates, migration pathways to good source-rocks, and trapping stratigraphic and structural configurations exist for the accumulation of hydrocarbons in several parts of the basin.

The assembled aeromagnetic, reflection-seismic, well-log, and gravity data, eliminate the large, problematic gaps in published geophysical data over the shallow-marine and coastal onshore.

Geodynamics turcotte ch 3 problem solutions