Exploration of Mars focuses on the detection of potential biosignatures as well as a thorough understanding of 3.7–3.0 Ga Hesperian paleoenvironments and their possible habitability. On Earth, Eo-Archean and Paleoarchean sedimentary rock assemblages are commonly fluvial conglomerates, sandstones, mudstones, carbonates, cherts and banded iron formation all of which may be metamorphosed at low-to high-grade conditions. Similar lithologies are described from Martian successions as well. During the 4.0 to 3.6 Ga Eoarchean Era, Earth had cooled down sufficiently to allow the development of increasing volumes of proto-continental crust, but not enough for large-scale plate tectonics. The igneous Archean lithology preserved from this time interval is characterized by typical tonalite-trondhjemite-granodiorite (TTG) suites and ultramafic to felsic volcanic igneous rocks. In the Paleoarchean (3.6-3.2 Ga), crustal growth by TTG formation continued and the proto crust thickened and stabilized by intracrustal granitoid magmatism. The early Earth’s atmosphere was primarily anoxic (CO2-and CH4-rich) although very low levels of O2 may have been present. Some of the oldest indicators of life are 12C-enriched isotope ratios and C–H–N–(P) elemental associations found in marine meta-sedimentary rocks of the ca.3.7 Ga Isua Greenstone Belt, Greenland. While these rocks are of amphibolite metamorphic facies, the ca. 3.5 Ga and somewhat younger Paleoarchean rock units on the Pilbara craton of Western Australia and the Barberton Greenstone Belt, South Africa, include sedimentary rocks that did not experienced any significant petrological changes. In contrast, early silicification has led to the preservation of rare, carbonaceous micro fossils of prokaryotes and microbial mats. Macroscopic expressions of such microbial mats are microbialites such as stromatolites in carbonate and chert as well as microbially induced sedimentary structures (MISS) in siliciclastic-evaporite deposits. The surprisingly high diversity of fossils show that Paleoarchean Earth may have teeming with life. Data suggest a close resemblance of these biota to modern ones. Geochemical analyses using a wide spectrum of methods reveal that the early Archean microbial communities included Bacteria and Archaea colonizing terrestrial and marine environments, as well as living in hydrothermal systems. The physical and biological changes of early Earth are discussed by the ICS Subcommission for Precryogenian Stratigraphy in order to formally establish the Eoarchean/Paleoarchean boundary. While on Earth Hadean rocks are absent, the Martian stratigraphy of same ages appears to be more complete and therefore may constitute a future archive of information on life’s evolutionary pathway and planetary histories.