Knowra Paleoarchean Paleoarchean The earliest era of the Archean Eon, spanning approximately 3.6 to 3.2 billion years ago. Its rocks preserve evidence of early crust, oceans, and life.
Isua Greenstone Belt : A belt of ancient metamorphosed volcanic and sedimentary rocks in southwestern Greenland, with rocks dating to about 3.8 billion years ago. Its older rocks frame the Paleoarchean record and preserve evidence debated as signs of early life.
Plate tectonics : The system of moving lithospheric plates that reshapes Earth’s surface and recycles crust. Whether modern-style plate motion operated during the Paleoarchean remains central to reconstructing its crust.
Archean : A geologic eon spanning roughly 4.0 to 2.5 billion years ago, when Earth’s earliest preserved crust and life developed. The Paleoarchean is the first era within this broader eon.
Origin of life : The set of scientific questions about how the first living systems arose from nonliving chemistry. The Paleoarchean may postdate life’s emergence, but its rocks do not settle when or how it began.
Barberton Greenstone Belt : A South African sequence of Archean volcanic and sedimentary rocks, including some of Earth’s best-preserved ancient crust. Its rocks record Paleoarchean volcanism, shallow-water environments, and possible microbial structures.
Greenstone belt : A sequence of metamorphosed volcanic and sedimentary rocks, commonly preserved within ancient continental crust. These belts preserve much of the Paleoarchean record of volcanism, oceans, and early sedimentation.
Geologic time scale : The chronological framework that divides Earth’s history into eons, eras, periods, and smaller units. Its formal boundaries place the Paleoarchean between the Eoarchean and Mesoarchean.
Early life : The earliest biological organisms and ecosystems inferred from geological and chemical evidence. Possible Paleoarchean biosignatures are crucial but difficult to distinguish from nonbiological structures.
Pilbara Craton : An ancient block of continental crust in Western Australia that preserves rocks from the Archean Eon. Its Paleoarchean formations preserve evidence of early crust and hydrothermal environments.
Komatiite : An ultramafic volcanic rock formed from exceptionally hot, magnesium-rich magma. Paleoarchean komatiites indicate mantle temperatures and melting conditions unlike most modern volcanism.
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