Influence of recent depositional and tectonic controls on marine gas hydrates in Trujillo Basin, Peru Margin

摘要

The development of bottom simulating reflectors (BSRs) and the gas hydrate stability zone (GHSZ) in continental margins is related to recent depositional and tectonic processes. This interrelation is important for understanding the potential resource of gas hydrate deposits. The purpose of this study is to understand the influence of such activity on the marine gas hydrate system of the seaward extension of the Trujillo Basin, Peru Margin. Here, we analyze near-seafloor heat flow probe data, high-resolution multichannel seismic (MCS) profiles, swath bathymetry and ocean floor observation system (OFOS) images. Based on our results, we identify three main physiographical subregions in the study area: (1) an area with turbidites, continuous BSRs and low-to-moderate near-seafloor heat flow (7-33 mW/m~2), (2) an area with sediment waves of turbidity origin, a mix of continuous and patchy BSRs, and moderate near-seafloor heat flow (26-39 mW/m~2), (3) an area with extensional faulting, patchy BSRs and moderate-to-high near-seafloor heat flow (52-110 mW/m~2). We conclude that sediment flow processes are the result of recent depositional controls, and faulting is the result of recent tectonic activity. Near-seafloor heat flow around chemoherms is moderate. Estimates of BSR-derived heat flow show differences to near-seafloor heat flow. This difference points to advection of fluids occurring at the seafloor. Alive Calyptogena and tube worms were observed in these venting zones. Based on our analysis, we conclude that: (1) recent depositional processes control the development of continuous BSRs and may restrict heat transfer through the GHSZ in the form of fluid venting at the seafloor, (2) recent tectonic processes control the development of patchy BSRs and allow heat transfer through the GHSZ along faults, which is manifested as fluid venting at the seafloor.