Jurnal Internasional Pulsa degassing yang berbeda selama invasi magma di Karoo Basin bertingkat – Wawasan baru dari pemodelan aliran fluida hidrotermal – Galerne – – Geokimia, Geofisika, Geosystems
Placement of magma in organic-rich sedimentary basins is a major driver of past environmental crises. Using a 2D numerical model, we investigated the process of thermal cracking in contact of the cooling aureoles and subsequent transportation and thermogenic methane emissions by hydrothermal fluids. Our model includes Mohr-Coulomb failure criteria for starting hydrofracturing and dynamic porosity / permeability. We investigate the Karoo Basin, taking into account the nature of host-rock material from borehole data, realistic total organic carbon content, and different threshold geometries. Consistent with geological observations, we found that thermal feathers rapidly rose on the edge of the sills in the form of plates, guided along a high permeability pathway which cracked vertically. In contrast, feathers that are less focused and slower appear from the edges and the center of the flat frame. Using the new scale-up method based on the threshold-to-sediment ratio, we found that the degassing of the Karoo Basin occurs in two different phases during the invasion of magma. Fast degassing is triggered by sills placed in the top 1.5 km emitted ~ 1.6 · 3] Thermogenic Gt methane, while thermal feathers originating from deeper sills, carry 12 times greater methane mass, may not reach the surface. We suggest that large amounts of this methane can be mobilized by heat provided by adjacent sills. We conclude that the LIP Karoo may have emitted ~ 22.3 · 10 Thermogenic Gt in half a million years of magmatic activity, with emissions of up to 3 Gt / year. The quantity of methane and the rate of this emission can explain negative negative C Toarcian environmental crisis trip.