Project Details
Projekt
Geochemistry of gases in seismogenic depths of the San Andreas Fault Zone
Applicant
Professor Dr. Jörg Erzinger
Subject Area
Mineralogy, Petrology and Geochemistry
Term
from 2007 to 2010
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 37334093
The origin of gases and fluids in seismogenic depths of the San Andreas Fault (SAP), their composition, spatial distribution, temporal variations, migration mechanisms, as well as the link to seismic processes are only in part understood. We propose to perform gas and fluid studies on drill core, drill cutting, and drill mud gas from the SAFOD core drilling campaign in 2007, in order to gain quantitative information on the geochemistry of fluids and gases in seismogenic depths. Own drill-mud gas analysis from the SAFOD main hole (MH) revealed important information on the contribution of mantle-derived fluids to the total fluid inventory of the SAF and the migration of such fluids, and on the origin and distribution of the main non-atmospheric gaseous components on relatively large spatial scale. However, some questions addressed to gases at the SAF remained open: 1) the origin of the huge amounts of H2 in drill-mud gas found during drilling the SAFOD MH and 2) absolute gas concentrations and small-scale distribution of gases and fluids in fault zone rock which would help to understand fluid migration mechanisms at seismogenic depths. Drill-mud gas samples and drilled rock samples have been collected for investigations on isotopes (noble gases, (13C on CO2 and hydrocarbons, H/D on H2 and CH4) as well as mechanochemical gas synthesis. In combination with results from on-site experiments, this information provides better understanding of the behaviour of fluids and gases at seismogenic depths of the SAF.
DFG Programme
Infrastructure Priority Programmes
