Mechanisms of microtunneling in rock substrates: distinguishing endolithic biosignatures from abiotic microtunnels

  title={Mechanisms of microtunneling in rock substrates: distinguishing endolithic biosignatures from abiotic microtunnels},
  author={Nicola McLoughlin and Hubert Staudigel and Harald Furnes and Benjamin Eickmann and Magnus Ivarsson},
Rock‐dwelling, endolithic micro‐organisms can create tubular microcavities (TMCs) by the dissolution of rock substrates. Microtunnels can also conceivably be formed by abiotic processes, and collectively, these structures are here termed tubular microcavities. A textural record of life in subseafloor environments is provided by biological TMCs, and it is imperative to distinguish these from abiological tunnels. To this end, the morphologies and petrographic context of tunnels formed by chemical… 

Dubiofossils from a Mars‐analogue subsurface palaeoenvironment: The limits of biogenicity criteria

It is argued that abiotic processes driven by serpentinization could account for the same set of lifelike features, and a chemical garden experiment is reported that supports this view.

Microscale Biosignatures and Abiotic Mineral Authigenesis in Little Hot Creek, California

The results reveal that even when mineral precipitation is largely abiogenic, the potential to preserve biosignatures in hot spring settings is high and may provide insight into the biogenicity of ancient Earth and extraterrestrial rocks.

A Hierarchical System for Evaluating the Biogenicity of Metavolcanic- and Ultramafic-Hosted Microalteration Textures in the Search for Extraterrestrial Life.

A hierarchical scheme is proposed to provide a framework for identifying robust biosignatures of microbial life in the altered oceanic crust on Earth, and in extraterrestrial altered mafic-ultramafic rocks, particularly on Mars.

Deconstructing Earth’s oldest ichnofossil record from the Pilbara Craton, West Australia: Implications for seeking life in the Archean subseafloor

The findings reveal that the Euro Basalt microtextures are not comparable to microbial ichnofossils from the recent oceanic crust, and the evidence for life in these Archean lavas is questioned, suggesting metamorphic reactions could be commonplace in Archean pillow lavas and need to be excluded when seeking traces of life in the subseafloor on the early Earth.

University of Southern Denmark Intricate tunnels in garnets from soils and river sediments in Thailand-Possible endolithic

Garnets from disparate geographical environments and origins such as oxidized soils and river sediments in Thailand host intricate systems of microsized tunnels that significantly decrease the

Sulfur isotope evidence for a Paleoarchean subseafloor biosphere, Barberton, South Africa

The Archean sub-seafloor has been proposed as an environment for the emergence of life, with septate clusters of titanite microtextures in pillow lava rims argued to be the earliest traces of

Comparing biosignatures in aged basalt glass from North Pond, Mid-Atlantic Ridge and the Louisville Seamount Trail, off New Zealand

It is proposed that diverse biosignatures in oceanic crust may form during different stages of crustal evolution.

Authigenic Mineral Texture in Submarine 1979 Basalt Drill Core, Surtsey Volcano, Iceland

Micrometer‐scale maps of authigenic microstructures in submarine basaltic tuff from a 1979 Surtsey volcano, Iceland, drill core acquired 15 years after eruptions terminated describe the initial



On biogenicity criteria for endolithic microborings on early Earth and beyond.

The current understanding of the controls upon the distribution of euendolithic microborings are reviewed and three lines of approach are proposed for testing their biogenicity: first, a geological setting that demonstrates a syngenetic origin for the eu endolithicmicroborings; second, microboring morphologies and distributions that are suggestive of biogenic behavior and distinct from ambient inclusion trails; and third, elemental and isotopic evidence suggestive of biological processing.

Use of NanoSIMS in the search for early life on Earth: ambient inclusion trails in a c. 3400 Ma sandstone

Ambient inclusion trails (AIT) are enigmatic microtubular structures created by the migration of mineral crystals through a lithified substrate. The decomposition of organic material has been

Microbial activity in the alteration of glass from pillow lavas from hole 896a

Within the altered parts of the glass rim of pillow lavas of Hole 896A, at depths at least 432 m below seafloor (237 m below the top of volcanic basement), microbes have been identified. This is

Tuff life: Bioalteration in volcaniclastic rocks from the Ontong Java Plateau

We report microscopic textural, geochemical, isotopic, and biomolecular evidence for microbial alteration of glass shards in a 337.7 m thick sequence of poorly sorted vitric and lithic tuffs

Oceanic Pillow Lavas and Hyaloclastites as Habitats for Microbial Life Through Time – A Review

This chapter summarizes research undertaken over the past 15 years upon the microbial alteration of originally glassy basaltic rocks from submarine environments. We report textural, chemical and

Fossil preservation in the Neoproterozoic Doushantuo phosphorite Lagerstatte, South China.

The same processes that gave rise to Phanerozoic phosphatized Lagerstatten--phosphatic encrustation, and impregnation, probably mediated by microbial activity--effected soft-tissue preservation in the Doushantuo Lagerstatte.