Numerical investigation of the effect of volatilization and the supercritical state of pore water on maturation of organic matter in the vicinity of igneous intrusions

摘要: Abstract This study presents a numerical investigation of the effect volatilization and supercritical state pore water on maturation organic matter in host rocks based heat flow models assuming instantaneous finite-time intrusion mechanisms magma. A 15 m thick, well-dated basic sill DSDP 41-368 hole near Cape Verde Rise, eastern Atlantic is selected as an example due to sufficient thermophysical parameters definite burial thermal history shale rocks. Results indicate: (1) The temperature-dependent properties at hydrostatic pressure 414 bar predicted vitrinite reflectance ( R r) less than 0.1% no which mechanism magma assumed can hence be ignored reasonably; (2) consideration reduce r significantly. In case mechanism, maximum deviation caused by pore-water reaches 1.3% location half thickness away from contact (i.e. X / D  = 0.5), above 0.5% occur region 0.3 1.0 form . attains 1.15%  = 0.25, where larger lies between 0.15 0.6 ; (3) If hydrothermal convection allowed for, overlying that underlying same inner aureole igneous intrusions, whereas phenomenon converse outer region. contrast, measured profile shows , totally higher Thus, it not resulted asymmetry current profiles below sill; (4) conduction model matches well with one out geothermometer unreliable water. demonstrates magma, together volatilization, possibly represents natural conditions.