3-D and 4-D Definition of Structural Fluid Flow Networks in Devonian Carbonates Using Sulfide Tracers: Emanuel Range of the Lennard Shelf, Canning Basin, Western Australia

Colorado School Of Mines, Golden CO

Investigators

Abstract

EAR-0073763 Hitzman & Nelson Understanding the geometry and nature of fluid flow in the earth's upper crust is critically important to a number of geoscience disciplines related to societal and industrial activities, including petroleum geology, ore deposit geology, hydrogeology, geothermal energy, and seismic hazard analysis. Crustal fluid flow is commonly controlled by structural permeability of fault and fracture networks. Although fault-fracture flow networks have been studied extensively through modeling and 2-D field studies, few 3-D field studies have been undertaken on ancient flow networks. Zn-Pb deposits in the Canning basin of Western Australia provide a unique natural laboratory to investigate crustal fluid flow in 3-D. Metalliferous basinal brines flowed along fault-fracture networks as the basin compacted and dewatered, and deposited metal sulfide minerals when the fluids reached permeable, reactive carbonate formations. The area was unaffected by deformation following mineralization. We propose to build a 3-D model of the paleo-flow network by mapping the distribution of sulfide minerals, deposited along faults and fractures, using superb 2-D surface exposure, 3-D underground exposures, 500+ kilometers of diamond drill core, and extensive seismic reflection, aeromagnetic, and gravity data. Cross-cutting vein relationships and petrographically determined sulfide parageneses will be used to determine the relative timing of mineralizing events, thus extending the model to 4-D (time).