This is the Home Page of a conference on "Atlantic-Type Divergent Margins". Here, you find, the less falsifiable hypothesis explaining the origin of these continental margins, which are, by far, volcanic in nature and the more significant tentative geological interpretations of auto-trace of the more significant seismic line. All proposed tentative interpretations are personal and engage no one than the author.

If you click on the interlinks (underlined text and bots), you can navigate and you will find a text and the majority of the plates shown during these conference.

This schematic geological cross-section of Angola offshore is representative of the Atlantic-type divergent continental margins. It illustrates the main geological features allowing the understanding of the different petroleum systems present on these margins : (i) Pre-Pangea Sediments (Basement and / or Paleozoic sediments), which are limited by the pre-rifting unconformity (PRU) ; (ii) The Rift-Type Basins, developed during the lengthening of the Pangea super-continent ; (iii) The Breakup Unconformity (BUU), which corresponds to the breakup of the Gondwana lithosphere and highlights the upper limit of the rift-type basins, in which organic rich (organic matter type I) lacustrine shales (parallel internal configuration) are potential source-rocks ; (iv) The BUU Unconformity is fossilized by the SDRs (sub-aerial volcanism) or by the margin infra-salt sediments ("sag basin" of some American geoscientists) ; (v) The SDRs (seaward dipping reflectors), which correspond to sub-aerial lava-flows poured out of the sub-aerial expansion centers and flowing outward in direction of the individualized continents (admittedly they are considered as incapable of generate hydrocarbons) ; (vi) The Angola-Congo salt geographic basin, which is a twin of the Brazilian geographic salt basin, that is to say, has always been individualized and never connected with the Brazilian geographic salt basin; (vii) The Transgressive (backstepping) and Regressive (forestepping) phases of the post-Pangea continental encroachment stratigraphic cycle ; (v) The potential marine source-rocks (organic matter type-II), in association with the interface between the transgressive and regressive phases ; (vi) Potential dispersive source rocks (organic matter type III) within the regressive interval, etc.

click on the underlined text

Atlantic-Type Divergent Margins

by

Carlos Cramez

Send E-mails to carloscramez@gmail.com or to carlos.cramez@bluewin.ch with comments and suggestions to improve these geological notes.
Copyright © 2012 Ccramez, Switzerland
Last updated: July, 2014