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

太古代陆相地层保存了独特的、具有潜在价值的记录，它可以约束地质、生物和大气之间相互作用的历史：它包括古土壤形成的条件、风化的强度和类型以及沉积物生成和成熟的过程。陆地上保存最古老的早期生命（微生物）痕迹与基本的地球-生物相互作用有关，如养分输送的机制和程度、辐射避免策略和大气成分。风成地层可能传达独特的环境参数，如当地风力强度和大气密度，对干旱和循环系统有影响。最后，陆地蒸发岩与温度、蒸发和地下水运动有关。虽然太古宙陆相沉积体系很少见，而且由于一些原因通常保存较差，但它们的潜在价值值得对其进行详细的研究。我建议对南非的早太古宙（3.22 Ga）穆迪集团进行专题调查，据称那里有世界上最古老的风成地层。我们的初步调查已经记录了微生物席、蒸发岩结核和沉积角砾岩单元，但迄今为止尚未成功确认风成地层。地质填图、剖面测量、结构研究、蒸发岩分析和砂岩岩石学将限制陆地环境，提高我们对太古宙陆地过程的认识，并限制相关的SPP研究项目。洞察甚至可以扩展到火星上的条件，那里的水环境过去和现在都要脆弱得多。

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.