Bernet_diagenesis

Matthias Bernet, Ph.D.
Laboratoire de Géodynamique des Chaînes Alpines

Maison des Géosciences

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FRANCE                                                                   Email: matthias.bernet “at” ujf-grenoble.fr

Diagenesis of siliciclastic sedimentary rocks

Diagenesis, including the destruction of primary porosity by compaction and precipitation of authigenic phases, and the creation of secondary porosity through dissolution, is of particular interest in determining the aquifer and reservoir qualities of sandstone. Diagenetic process and products are commonly studied in the context of burial in sedimentary basin, and possible subsequent exhumation of sandstone units. Only little consideration has been given to contact diagenesis, in areas where intrusion of basaltic rocks in rift settings has caused only minor or none contact metamorphism, but max have triggered high-temperture (150°-250°C) diagenetic reactions and cementation.

RECENT AND CURRENT RESEARCH PROJECTS INCLUDE:

Diagenetic history of the Triassic Beacon Supergroup in central Victoria Land, Antarctica
Petrographic, mineralogical, and geochemical analysis of samples from 4 different outcrops of the Beacon Supergroup in Victoria Land, Antarctica showed that intrusion of Jurassic dolerite sills caused pervasive Ca-zeolite cementation, even in rock poor in zeolite precursor material (volcanic clasts or plagioclase). However, illite crystallinity, determined from XRD analyses, indicated none to only very low-grade metamorphic conditions in samples in direct contact to the sills. Results have been published in Bernet and Gaupp (2005)

Burial and contact diagenesis of siliciclastic rocks in the Hartford Basin, CT, USA
A suite of samples was collected throughout the southern Hartford Basin in Connecticut, including the Triassic New Haven Arkose, and Jurassic Shuttle Meadow, East Berlin, and Portland Formations. Samples in the New Haven Arkose were taken in direct contact to Jurassic basalt flows and sills and a various distances. The aim is to reconstruct the overall diagenetic history of the siliciclastic rocks in this basin and the thermal overprint caused by the basalt intrusions and flows.

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Matthias Bernet, LGCA, Universite Joseph Fourier, 38041 Grenoble Cedex 9, FRANCE

Last Revised By: Matthias Bernet, February 2008