Magmatism and Extension: When, Where and Consequences on Margins Structure

Laurent Geoffroy

Most passive margins show evidences of magmatism at one stage of their evolution. However, there are huge differences in the volumes of magma between those margins as well as in the timing of mantle melting regarding the extension which ends up to lithosphere breakup. A subdivision between magma-(very)poor and magma-(very)rich margins is thus correct, but there seems to exist no intermediate members. I present a synthesis of data from the NE-Atlantic margins (and some also from other volcanic passive margins elsewhere), some of them being unpublished, which summarize the most conspicuous aspects of the structure and development of those margins. It is very clear for the author that no published lithospheric model of passive margins structure and evolution fits the basic observations from volcanic passive margins. This evidently has huge consequences on the exploration strategy of these quite distinct passive margins.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013