13 Results Found

The Hadean was an enigmatic period in the Earth’s history when ocean formation and the emergence of life may have occurred. However, minimal geological evidence is left from this period. To understand the primordial ocean’s composition, we focused on...

The assumption that there was a “water problem” at the emergence of life—that the Hadean Ocean was simply too wet and salty for life to have emerged in it—is here subjected to geological and experimental reality checks. The “warm little pond” that wo...

Abiotic fixation of atmospheric dinitrogen to ammonia is important in prebiotic chemistry and biological evolution in the Hadean and Archean oceans. Though it is widely accepted that nitrate (NO₃⁻) was generated in the early atmospheres, the stable p...

Korenaga and coworkers presented evidence to suggest that the Earth’s mantle was dry and water filled the ocean to twice its present volume 4.3 billion years ago. Carbon dioxide was constantly exhaled during the mafic to ultramafic volcanic act...

Life cannot emerge on a planet or moon without the appropriate electrochemical disequilibria and the minerals that mediate energy-dissipative processes. Here, it is argued that four minerals, olivine ([Mg>Fe]₂SiO₄), bridgmanite ([Mg,Fe]SiO₃), serp...

The presence of exposed land on the early Earth is a prerequisite for a certain type of prebiotic chemical evolution in which the oscillating activity of water, driven by short-term, day–night, and seasonal cycles, facilitates the synthesis of proto-...

Fixed nitrogen species generated by the early Earth’s atmosphere are thought to be critical to the emergence of life and the sustenance of early metabolisms. A previous study estimated nitrogen fixation in the Hadean Earth’s N₂/CO₂-domina...

The RNA world hypothesis suggests that chemical networks consisting of functional RNA molecules could have constructed a primitive life-like system leading a first living system. The chemical evolution scenario of RNA molecules should be consistent w...

We have recently criticised the natural pH gradient hypothesis which purports to explain how the difference in pH between fluid issuing from ancient alkali vents and the more acidic Hadean ocean could have driven molecular machines that catalyse reac...

Since the pioneering experimental work performed by Urey and Miller around 70 years ago, several experimental works have been developed for approaching the question of the origin of life based on very few well-constructed hypotheses. In recent years,...

Life most likely started during the Hadean Eon; however, the environmental conditions which contributed to the complexity of its chemistry are poorly known. A better understanding of various environmental conditions, including global (heliospheric) a...

We present a systematic study of Pb isotope ages obtained from sources of the late Phanerozoic volcanic rocks from unstable Asia and also volcanic rocks and kimberlites from stable regions of the Siberian and Indian paleocontinents. In the mantle sou...

Zircon U–Pb dating and Hf isotopic analyses are performed on clastic rocks, sedimentary tuff of the Dongchuan Group (DCG), and a diabase, which is an intrusive body from the base of DCG in the SW Yangtze Block. The results provide new constrain...