Heat flow and tectonics of the Ligurian Sea basin and margins
Jemsek, John P.
MetadataShow full item record
Heat flow, tectonic subsidence and crustal thickness distributions in the Ligurian Basin are best explained by asymmetric lithospheric thinning mechanisms. Over 150 heat flow measurements are made on several transects between Nice, France and Calvi, Corsica on continental slope and rise settings. Thermal gradient determinations are improved using an optimization technique. Piston core data and surface sediment 3.5 kHz reflectivity patterns help constrain thermal conductivity obtained from over 100 in situ stations. Plio-Quaternary stratigraphy is revised using new seismic reflection profiles: a boundary fault system associated with postrift margin uplift, a Pleistocene-age Var Fan construction, and recent diapirism of Messinian salt are indicated. After assessing local thermal disturbances (mass-wasting, microtopography, and salt refraction), positive heat flow corrections are made for multi-lithologic sedimentation histories and glacial paleotemperatures. Using boundary-layer cooling models, equilibrium heat flow estimates support geologic evidence for Oligocene and early Miocene rifting. Heat flow maxima correlate well with two "oceanic" sub-basins, suggesting that the southeastern trough near Corsica is ~5 Myr younger, consistent with the southeastern progression of volcanism and back arc rifting in the Western Mediterranean. Tectonic subsidence-crustal thickness trends indicate lithospheric stretching, with heat flow supporting asymmetric sub-crustal lithospheric thinning during the conjugate margin formation.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1988
Showing items related by title, author, creator and subject.
Magde, Laura S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-03)The formation of new oceanic crust is the result of a complex geodynamic system in which mantle rises beneath spreading centers and undergoes decompression melting. The melt segregates from the matrix and is focused to ...
Tectonics of the East Pacific rise : studies of faulting characteristics and magnetic and gravity anomalies Lee, Sang-Mook (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1995-02)The global mid-ocean ridge system is one of the most striking geological features on the surface of the Earth. In this system, the East Pacific Rise (EPR) is the fastest spreading ridge and is thus considered as the most ...
The influence of magma supply and eruptive processes on axial morphology, crustal construction and magma chambers Hooft, Emilie E. E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-12)Two-thirds of the surface of the Earth is created at mid-ocean ridges where magmas rise from the mantle and cool to form the oceanic crust. The objective of this Thesis is to examine the influence of magma supply and ...