Origin of the Earth: A proposal of new model called ABEL

摘要

The Earth was born as a dry planet without atmosphere and ocean components at 4.56?Ga, with subsequent secondary accretion of bio-elements, such as carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) which peaked at 4.37–4.20?Ga. This two-step formation model of the Earth we refer to as the advent of bio-elements model (ABEL Model) and the event of the advent of bio-elements (water component) as ABEL Bombardment. It is clear that the solid Earth originated from enstatite chondrite-like dry material based on the similarity in oxygen isotopic composition and among other isotopes. On the other hand, Earth's water derives primarily from carbonaceous chondrite material based on the hydrogen isotopic ratio. We present our ABEL model to explain this enigma between solid Earth and water, as well as secondary accretion of oxidizing bio-elements, which became a precursor to initiate metabolism to emerge life on a highly reductive planet. If ABEL Bombardment had not occurred, life never would have emerged on the Earth. Therefore, ABEL Bombardment is one of the most important events for this planet to evolve into a habitable planet. The chronology of ABEL Bombardment is informed through previous researches of the late heavy bombardment and the late veneer model. ABEL Bombardment is considered to have occurred during 4.37–4.20?Ga, which is the concept to redefine the standard late heavy bombardment and the late veneer models. Also, ABEL Bombardment is the trigger of the transition from stagnant lid tectonics to plate tectonics on this planet because of the injection of volatiles into the initial dry Earth. Graphical abstract Display Omitted Highlights ? The Earth formed by two steps, named the ABEL (advent of bio-elements) model. ? The Earth was born as a completely dry planet at 4.53?Ga without water components. ? By ABEL Bombardment during 4.37-4.20?Ga, water components were accreted on the dry Earth. ? Secondary accretion of oxidizing bio-elements became a precursor to initiate metabolism. ? ABEL Bombardment initiated plate tectonics after stagnant lid tectonics.