Transport and (bio)geochemical processes at cold seeps of the Makran convergent margin

Abstract

The present thesis focuses on pore water transport and geochemical processes including mineral authigenesis at hydrocarbon seeps of the Makran convergent margin, which is characterized by a stable oxygen minimum zone (OMZ) between depths of ~150-1000 m limiting oxygen availability for metazoan respiration. Considering the functioning of the geochemistry at cold seeps, this thesis provides an improved understanding of counteracting pore water transport processes at the sediment/water interface and the activity of related chemosynthetic organisms. It further shows that the combination of calculated ages of authigenic barium enrichments together with nonsteady state pore water modeling can accurately document events of upward SMT migration. Finally, earthquakes fracturing gas hydrate-cemented sediments are identified as a hitherto unknown trigger mechanism for marine hydrocarbon seepage.