Increased biomass and carbon burial 2 billion years ago triggered mountain building

The geological record following the c. 2.3 billion years old Great Oxidation Event includes evidence for anomalously high burial of organic carbon and the emergence of widespread mountain building. Both carbon burial and orogeny occurred globally over the period 2.1 to 1.8 billion years ago. Prolifi...

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Bibliographic Details
Published in:Communications earth & environment 2021-11, Vol.2 (1), p.1-9, Article 238
Main Authors: Parnell, John, Brolly, Connor
Format: Article
Language:English
Subjects:
Biomass
Biosphere
Carbon
Compressive strength
Cyanobacteria
Deformation
Earth crust
Isotopes
Lithosphere
Metamorphism
Mountains
Organic carbon
Orogeny
Oxidation
Sedimentation
Sedimentation & deposition
Sediments
Shale
Shearing
Thickening
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Summary:The geological record following the c. 2.3 billion years old Great Oxidation Event includes evidence for anomalously high burial of organic carbon and the emergence of widespread mountain building. Both carbon burial and orogeny occurred globally over the period 2.1 to 1.8 billion years ago. Prolific cyanobacteria were preserved as peak black shale sedimentation and abundant graphite. In numerous orogens, the exceptionally carbonaceous sediments were strongly deformed by thrusting, folding, and shearing. Here an assessment of the timing of Palaeoproterozoic carbon burial and peak deformation/metamorphism in 20 orogens shows that orogeny consistently occurred less than 200 million years after sedimentation, in a time frame comparable to that of orogens through the Phanerozoic. This implies that the high carbon burial played a critical role in reducing frictional strength and lubricating compressive deformation, which allowed crustal thickening to build Palaeoproterozoic mountain belts. Further, this episode left a legacy of weakening and deformation in 2 billion year-old crust which has supported subsequent orogenies up to the building of the Himalayas today. The link between Palaeoproterozoic biomass and long-term deformation of the Earth’s crust demonstrates the integral relationship between biosphere and lithosphere.
ISSN:2662-4435
2662-4435
DOI:10.1038/s43247-021-00313-5