The case for vestiges of Early Solar System biota in carbonaceous chondrites: petroleum geochemical snapshots and possible future petroleum prospects on Mars Expedition

摘要

This research documents the analysis and interpretation of selected Carbonaceous Chondrites (CC) including Murchison, Allende, NWA 3003, Dhofar 735, Orgueil, Tagish Lake and Vigarano using organic petrology, scanning electron microscopy, and petroleum geochemistry. The kerogen microstructures and bitumen within CCs closely resemble remnant 2.5 Ga terrestrial microbial-like structures and their biodegraded components and solid bitumen. In both instances, organoclasts are associated with framboidal iron sulfides or oxides and clay-like minerals. The organic-rich kerogens within three CCs (especially Murchison) might have served as petroleum source rocks for the early generation of hydrocarbons. The maturity varies between 0.7% (Orgueil) and 1.24% (Murchison), to 5.1 % Ro (Vigarano) with predicted maturation temperatures of 100° to 475°C. Geochemical analysis of selected CCs (Murchison, Orgueil, and Tagish Lake) reveal the organic richness and the presence of low molecular weight n-alkanes (C_(10) to C_(20)), complex cyclo-and isoalkanes, nonhydrocarbons, elemental sulfur with abundant aromatic compounds, most of them similar to bacterial and algal derived petroleum products. Apart from the concept of panspermia, the data highlights that three CCs sustained a formation temperature (<200°C) capable of supporting bacterial growth in a cooler early Solar System environment. In effect, the information encoded within these extraterrestrial sediments represents a cosmic analogue to terrestrial geopolymers and bitumen that may include some crude oil biomarkers. Therefore, the authors propose a model of a "universal unconventional petroleum system", which implies a prospect of oil and gas within the Martian environment and elsewhere within the Solar System.