--> Heat Flow Calculated vs Heat Flow Measured in Gulf of Mexico the Oceanic Crust

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Heat Flow Calculated vs Heat Flow Measured in Gulf of Mexico the Oceanic Crust

Abstract

Abstract

Thermal knowledge and tectonic scenario help us to identify source rock maturity state in sedimentary basins. In areas without temperature measurement, paleothermal data can give some idea about the thermal evolution. In absence of thermal or paleothermal information the geophysical data inversion methods can be used to estimate thermal state of sedimentary basins.

The heat flow in the Gulf of Mexico oceanic crust was calculated from magnetic data inversion and the results were compared with heat flow measured and heat flow agree with oceanic crust age.

Analytic inversion method was used to calculate Curie point depth. To set the Curie temperature value, we assessed the range of gabbro's Curie temperature, which is comprised between 530 and 580°C. The gabbro's lithology is actually the main constituent of the oceanic crust in the Gulf of Mexico, as evidenced by seismic velocities that fall into the velocities of this type of ultramafic rocks. With such Curie isotherm values, geometries derived from the various grids are similar, since the only different variable between them is the temperature value. The observed difference is ∼5 mW/m2. In both cases, the calculated heat flow is greater than the heat flows previously reported and calculated from temperature measurements of sea bottom.

Depth of magnetic source bottom obtained can be interpreted as a thermal limit. According to the depth obtained here for the 530°C isotherm, the average value obtained for the heat flow in the oceanic crust of the Gulf of Mexico ranges from 45.0 to 55.0 mW/m2, which is quite similar to previously published average values comprised between 46.3 to 53.0 ±0.8 mW/m2, which were actually derived from the age of the its oceanic crust.

The difference between the calculated heat flow and reported heat flow in the Gulf of Mexico may be due to the measurement instruments or local geological heterogeneities.