『Abstract
　This paper presents a speculative scenario for the evolution of the earth's surface environment and biological community 3.5-2.4 Ga based on the geologic record and its interpretation. Available geologic evidence suggests that the earth's climate before 3.2 Ga was hot, probably 50-73℃、as a result of a　CO2 and CH4 greenhouse. The early biological community was probably dominated by anoxygenic photosynthetic thermophiles. Cyanobacteria, if they evolved before 3.1 Ga, would have struggled to survive at such high temperatures. As a result, the atmosphere contained extremely low levels of O2 and ��³³S shows wide departures from 0 indicating mass independent fractionation of S isotopes in the upper atmosphere. This hot early climate collapsed 3.1-3.0 Ga due to growth of large new blocks of continental crust (cratons), the weathering of which resulted in the depletion of atmospheric CO2 and eventual drawdown of CH4 due to formation and rainout of methane aerosols. Cooling may have culminated in glaciation about 3.0-2.9 Ga. This climatic catastrophe and attendant changes in atmospheric composition drove a major biological revolution 3.0-2.7 Ga characterized by the emergence of new low-temperature taxa, including cyanobacteria, and their spread throughout surface environments at the expense of extreme thermophiles, including methanogens. During a period of general tectonic stability, and the formation of associated three-dimensional stromatolites, and a mild oxygenation of the atmosphere and attendant reduction in mass independent fractionation. As the cratons that had formed 3.1-3.0 Ga were eroded down and gradually covered by sediments, tectonic recycling and a burst of new greenstone-belt volcanism began to increase atmospheric CO2 after 2.75 Ga and by 2.7 Ga surface temperatures had returned to ＞60℃. Cyanobacteria were again suppressed, O2 production waned, and atmospheric mass independent fractionation is again indicated by extreme variations in ��³³S. These conditions persisted, perhaps intermittently, until about 2.5-2.4 Ga, when weathering and erosion of vast new blocks of continental crust formed about 2.65-2.6 Ga caused the second, and probably last collapse of a ＞60℃ surface climate. Broad tectonic, climatic, and biological events 3.5-2.9 Ga are remarkably parallel to those of the Late archean and Paleoproterozoic 2.75-2.2 Ga and Neoproterozoic 1.0-0.50 Ga. These 〜500-myr long cycles of greenstone volcanism and crustal generation; climatic and atmospheric instability; and biological innovation reflect the long-term interaction of the tectonic, atmospheric, climatic, and biological components of the earth's surface system. They suggest that the evolution of the earth's interior, expressed through its control on the formation of large blocks of continental crust, has influenced atmospheric composition and climate which in turn have provided a fundamental control on the timing and directions of biological evolution throughout earth history.

Keywords: Archean; Continental crust; Atmosphere evolution; Stromatolites; Climate evolution; Evolution of life; Barberton; Greenstone』

1. Introduction
2. Archean environment and life 3.5-3.0 Ga
　2.1. Continental crust before 3.0 Ga
　　2.1.1. Barberton granite-greenstone terrain (BGGT)
　　2.1.2. Pilbara Craton
　　2.1.3. Crustal development before 3.0 Ga
　2.2. Atmospheric evolution and climate before 3.0 Ga
　2.3. Life before 3.1 Ga
3. Archean environment and life 3.0-2.7 Ga
　3.1. Continental crust 3.0-2.7 Ga
　3.2. Atmospheric evolution and climate 3.0-2.7 Ga
　3.3. Life 3.0-2.7 Ga
4. Archean environment and life 2.7-2.4 Ga
　4.1. Continental crust 2.7-2.4 Ga
　4.2. Atmospheric evolution and climate 2.7-2.4 Ga
　4.3. Life 2.7-2.5 Ga
5. Discussion
　5.1. Archean evolutionary scenario
　5.2. CO2 versus CH4 as the principal greenhouse gas
　5.3. Hot spring analog
6. Later Precambrian events
7. Conclusions
Acknowledgments
References