Hadean Earth and primordial continents: The cradle of prebiotic life

摘要: Abstract The Hadean history of Earth is shrouded in mystery and it considered that the planet was born dry with no water or atmosphere. Earth-Moon system had many features common during birth stage. Solidification magma ocean at 4.53 Ga generated primordial continents komatiite. We speculate upper crust composed fractionated gabbros middle felsic by anorthosite ca. 21 km depth boundary, underlain meta-anorthosite (grossular + kyanite + quartz) down to 50–60 km depth. thickness mafic KREEP basalt lower crust, separating from underlying mantle not well-constrained might have been up 100–200 km depending on degree fractionation gravitational stability versus surrounding density. must final residue enriched several critical elements including Ca, Mg, Fe, Mn, P, K, Cl which were exposed surface Earth. Around 190 million years after solidification ocean, “ABEL bombardment” delivered volatiles H 2 O, CO , N as well silicate components through addition icy asteroids. This event continued for 200 Myr subordinate bombardments until 3.9 Ga, preparing prebiotic chemical evolution cradle first life. Due vigorous convection arising high potential temperatures, disintegrated dragged deep mantle, marking onset plate tectonics.