Vitrinite reflectance distributions and thermal history of sediments: An end-member sensitivity analysis

Abstract

An end-member analysis was performed using algorithms ofExtended cabfac qmodel on 21 sample distributions of vitrinite reflectance (VR) by depth from the Inigok well in the National Petroleum Reserve of Alaska (NPRA). Eight end members, which account for 99% of the variance, adequately recreate the VR distributions. These eight end members contain stratigraphic information based on systematically increasing or decreasing mixing proportions with depth. Paleoheat flux determined from end members, or from orthogonally filtered sets of end members, is not significantly different from paleoheat flux determined from arithmetic mean values of VR, indicating that the arithmetic mean provides an adequate representation of each VR distribution analyzed in this well. Additionally, use of filtering devices to assess the degree of trustworthiness of signal in VR distributions enables an assessment to be made of the degree of stability of paleoheat flux variation estimates.