Investigating the Link Between Fault Interaction Styles and Paleofluid Flow Using Clumped Carbonate Thermometry of Calcite Veins, Moab Fault, East-Central Utah
Earth and Atmospheric Science, Saint Louis University, Saint Louis, MO, USA
The Moab fault, an exhumed paleo-hydrocarbon reservoir in east-central Utah, places Jurassic sandstones adjacent to Jurassic and Triassic sandstone and shale units. Structural diagenetic features such as deformation bands, joints, and shear joints are present in broad zone of damage along various segments of the fault. Calcite veins formed during different phases of fault formation and linkage as indicated by cross-cutting relations among vein sets. Fluid inclusion and clumped isotope analyses of these veins are consistent with fluid temperatures 67 to 128°C and a range of isotopic values indicating alternating periods of fluid compartmentalization and open flow of waters from both meteoric and deeper formation sources. Different workers agree that host lithology, fault architecture, and the fluid chemical environment greatly influence the hydraulic behavior of faults. The current study proposes to build upon the previous work as the data are sparse and come from only a few localities. The argument we make is that (1) the veins in this study are syntectonic, (2) the fluid source for the veins vary systemically spatially and temporally as individual fault strands began to link-up, and (3) that clumped carbonate thermometry of veins may be used to provide constraints on the fluid source and temperature during the evolution of fault linkage. With these constraints, we hope to provide a hydraulic evolution model for faults zones that can help aid in risk assessment of the sealing and non-sealing potential of faults, particularly in zones of fault overlaps and intersections.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects