scholarly journals Green Rust: The Simple Organizing ‘Seed’ of All Life?

Life ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 35 ◽  
Author(s):  
Michael Russell

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 activity associated with magmatic plumes that produced the thick, dense, and relatively stable oceanic crust. In that setting, two distinct and major types of sub-marine hydrothermal vents were active: ~400 °C acidic springs, whose effluents bore vast quantities of iron into the ocean, and ~120 °C, highly alkaline, and reduced vents exhaling from the cooler, serpentinizing crust some distance from the heads of the plumes. When encountering the alkaline effluents, the iron from the plume head vents precipitated out, forming mounds likely surrounded by voluminous exhalative deposits similar to the banded iron formations known from the Archean. These mounds and the surrounding sediments, comprised micro or nano-crysts of the variable valence FeII/FeIII oxyhydroxide known as green rust. The precipitation of green rust, along with subsidiary iron sulfides and minor concentrations of nickel, cobalt, and molybdenum in the environment at the alkaline springs, may have established both the key bio-syntonic disequilibria and the means to properly make use of them—the elements needed to effect the essential inanimate-to-animate transitions that launched life. Specifically, in the submarine alkaline vent model for the emergence of life, it is first suggested that the redox-flexible green rust micro- and nano-crysts spontaneously precipitated to form barriers to the complete mixing of carbonic ocean and alkaline hydrothermal fluids. These barriers created and maintained steep ionic disequilibria. Second, the hydrous interlayers of green rust acted as engines that were powered by those ionic disequilibria and drove essential endergonic reactions. There, aided by sulfides and trace elements acting as catalytic promoters and electron transfer agents, nitrate could be reduced to ammonia and carbon dioxide to formate, while methane may have been oxidized to methyl and formyl groups. Acetate and higher carboxylic acids could then have been produced from these C1 molecules and aminated to amino acids, and thence oligomerized to offer peptide nests to phosphate and iron sulfides, and secreted to form primitive amyloid-bounded structures, leading conceivably to protocells.

Author(s):  
Michael J Russell

Korenaga and coworkers present evidence to suggest that 4.3 billion years ago the Earth’s mantle was dry and water filled the ocean to twice its present volume.[2] CO2 was constantly exhaled during the mafic to ultramafic volcanic activity associated with magmatic plumes that produced the thick, dense and relatively stable oceanic crust. In that setting two distinct major types of sub-marine hydrothermal vents were active: ~400 °C acidic springs whose effluents bore vast quantities of iron into the ocean, and ~120 °C, highly alkaline and reduced vents exhaling from the cooler, serpentinizing crust at some distance from the heads of the plumes. When encountering the alkaline effluents, the iron from the plume head vents precipitated out forming mounds likely surrounded by voluminous exhalative deposits similar to the banded iron formations known from the Archean. These mounds and the surrounding sediments likely comprising nanocrysts of the variable valence FeII/FeIII oxyhydroxide, green rust. The precipitation of green rust, along with subsidiary iron sulfides and minor concentrations of Ni, Co and Mo in the environment at the alkaline springs may have established both the key bio-syntonic disequilibria, and the means to properly make use of them – those needed to drive the essential inanimate-to-animate transitions that launched life. In the submarine alkaline vent model for the emergence of life specifically it is first suggested that the redox-flexible green rust microcrysts spontaneously formed precipitated barriers to the complete mixing of carbonic ocean and alkaline hydrothermal fluids, barriers that created and maintained steep ionic disequilibria; and second, that the hydrous interlayers of green rust acted as 'engines' that were powered by those ionic disequilibria and drove essential endergonic reactions. There, aided by sulfides and trace elements acting as catalytic promoters and electron transfer agents, nitrate could be reduced to ammonia and carbon dioxide to formate, while methane may have been oxidized to methyl and formyl groups. Acetate and higher carboxylic acids could then have been produced from these C1 molecules and aminated to amino acids, and thence oligomerized to offer peptide nests to phosphate and iron sulfides and secreted to form primitive amyloid-bounded structures, leading conceivably to protocells.


Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 249
Author(s):  
Marie-Paule Bassez

The expression “follow the water” is used to recognize inside the universe, life as it exists on Earth. It is shown here that the expression “follow the high subcritical water” can be used to recognize the components of life that formed prior to the emergence of life. It is also shown that this particular water leaves signatures inside rocks that are produced during high subcritical water–rock interactions. These signatures are ferric minerals, which are currently explained by the presence of microorganisms. The consideration of water in the high subcritical domain may lead to postpone the date of the existence of FeII-oxidizing and O2-producing microorganisms, and consequently the date of the appearance of oxygen in the atmosphere. Alkaline water at pH ~9.5 to 14 and in the specific domain of temperature ~300–350 °C, pressure ~10–25 MPa, and density ~700–600 kg/m3, allows us to understand the formation of silica and ferric minerals, and the synformation of components of life in anoxic geological terrains such as the banded iron formations on early Earth and extraterrestrial objects such as Enceladus. The high subcritical water lets appear the continuity between rocks and life, which is conceptualized by the word “geobiotropy”.


Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 94
Author(s):  
Xiaoxue Tong ◽  
Kaarel Mänd ◽  
Yuhao Li ◽  
Lianchang Zhang ◽  
Zidong Peng ◽  
...  

Banded iron formations (BIFs) are enigmatic chemical sedimentary rocks that chronicle the geochemical and microbial cycling of iron and carbon in the Precambrian. However, the formation pathways of Fe carbonate, namely siderite, remain disputed. Here, we provide photomicrographs, Fe, C and O isotope of siderite, and organic C isotope of the whole rock from the ~2.52 Ga Dagushan BIF in the Anshan area, China, to discuss the origin of siderite. There are small magnetite grains that occur as inclusions within siderite, suggesting a diagenetic origin of the siderite. Moreover, the siderites have a wide range of iron isotope compositions (δ56FeSd) from −0.180‰ to +0.463‰, and a relatively negative C isotope composition (δ13CSd = −6.20‰ to −1.57‰). These results are compatible with the reduction of an Fe(III)-oxyhydroxide precursor to dissolved Fe(II) through microbial dissimilatory iron reduction (DIR) during early diagenesis. Partial reduction of the precursor and possible mixing with seawater Fe(II) could explain the presence of siderite with negative δ56Fe, while sustained reaction of residual Fe(III)-oxyhydroxide could have produced siderite with positive δ56Fe values. Bicarbonate derived from both DIR and seawater may have provided a C source for siderite formation. Our results suggest that microbial respiration played an important role in the formation of siderite in the late Archean Dagushan BIF.


2016 ◽  
Vol 7 (6) ◽  
pp. 927-936 ◽  
Author(s):  
Mahima Singh ◽  
Jayant Singhal ◽  
K. Arun Prasad ◽  
V.J. Rajesh ◽  
Dwijesh Ray ◽  
...  

1983 ◽  
Vol 18 (S2) ◽  
Author(s):  
J.C. Duchesne ◽  
A. Rouhart ◽  
C. Schoumacher ◽  
H. Dillen

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