Publikationsdatum:
2023-11-20
Beschreibung:
Late Devonian (Frasnian) pillow basalts from the Frankenwald and Thüringer Wald within the Saxothuringian zone in Germany were found to contain abundant putative biogenic filaments, indicating that the volcanic rocks once harbored microbial life. The mineralized filaments are found in calcite-filled amygdules (former vesicles), where they started to form on internal surfaces of vesicles after seawater ingress. The filaments postdate an early fibrous carbonate cement but predate later equant calcite spar, revealing syngenetic formation. A biogenic origin of filaments is indicated by their size and morphology resembling modern microorganisms, their independence of crystal faces and cleavage plans, complex branching patterns, and internal segmentation. The filamentous microorganisms represent cryptoendoliths that lived in structural cavities of the basalt. They became preserved upon microbial clay authigenesis similar to the encrustation of modern prokaryotes in iron-rich environments. Filaments consist of clay minerals with the endmember composition berthierine-chamosite and illite-glauconite. Based on the discovery of fossilized filamentous microorganisms in Late Devonian pillow basalts of the Saxothurigian zone that are similar to filaments previously found in Middle Devonian pillow basalts of the Rhenohercynian zone, it is apparent that cryptoendolithic life was more widespread than previously recognized. Structural cavities within seafloor basalt may thus represent a common, perhaps universal niche for life in the oceanic crust.
Schlagwort(e):
Aluminium oxide; Calcium oxide; Calculated; Center for Marine Environmental Sciences; Chromium(III) oxide; Electron microprobe JEOL JXA 8900R; Facies name/code; Frankenwald, northern Bavaria, Germany; FW-05-b; Geological sample; GEOS; Iron oxide, FeO; Magnesium oxide; Manganese oxide; MARUM; Potassium oxide; Sample ID; Silicon dioxide; Sum; TH-be-08-09C; Thuringian Forest, Germany; Titanium dioxide
Materialart:
Dataset
Format:
text/tab-separated-values, 1488 data points
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