The role of early Archean Terrestrial Environments in Weathering, Sediment Transport, and the Colonization of Land

点击翻译按钮获取中文摘要

Archean terrestrial strata preserve a unique and potentially valuable record which allows to constrain the history of interaction between geo-, bio and atmosphere: It includes conditions of paleosol formation, intensity and type of weathering and processes of sediment generation and maturation. The oldest preserved (microbial) traces of early life on land bear on fundamental geo-bio-interactions such as mechanism and degree of nutrient delivery, strategies of radiation avoidance, and atmospheric composition. Eolian strata may convey unique environmental parameters such as local wind strength and atmospheric density, with implications for aridity and circulatory systems. Lastly, terrestrial evaporites relate to temperature, evaporation and groundwater movement. Although Archean terrestrial depositional systems are rare and generally poorly preserved for a number of reasons, their potential value warrants their detailed investigation. I suggest the topical investigation of the Early Archean (3.22 Ga) Moodies Group, South Africa from which the world’s oldest purportedly eolian strata have been reported. Our preliminary surveys have documented microbial mats, evaporite concretions, and a sedimentary breccia unit but to-date been unsuccessful in confirming eolian strata. Geological mapping, section measuring, textural studies, evaporite analysis and sandstone petrography will constrain the terrestrial settings, improve our understanding of Archean terrestrial processes and constrain related SPP research projects. Insights may even extend to conditions on Mars where aqueous environments were (and are) far more tenuous.