The effect of sedimentary cover on submarine hydrothermal processes — some simple numerical simulations and applications

Abstract

Conductive and convective thermal numerical models are used to demonstrate the potential effect of sedimentary sequences on the formation and containment of hydrothermal systems in underlying oceanic lithosphere. Blanketing sediments appear to be effective in promoting subseafloor hydrothermal convection (and by inference, replacement style mineral deposits). These results should be relevant not just to near-axis environments but also longer term lower temperature hydrothermal alteration in a range of submarine environments. Moreover, the results emphasize the significance of the stratigraphical transition from volcanic-dominated to epiclastic sediments, which should be amenable to targeting by lithofacies mapping, as well as geophysical and geochemical detection. The concept is applied to several ancient examples, including the Archean Panorama Zn deposit in the Pilbara craton of Western Australia.