On the enigmatic mid-Proterozoic: Single-lid versus plate tectonics

Roberts, Nick M.W.; Salminen, Johanna; Johansson, Åke; Mitchell, Ross N.; Palin, Richard M.; Condie, Kent C.; Spencer, Christopher J.. 2022 On the enigmatic mid-Proterozoic: Single-lid versus plate tectonics. Earth and Planetary Science Letters, 594, 117749. 10.1016/j.epsl.2022.117749

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Official URL: http://dx.doi.org/10.1016/j.epsl.2022.117749

Abstract/Summary

The mid-Proterozoic (ca. 1850–850 Ma) is a peculiar period of Earth history in many respects: ophiolites and passive margins of this age are rare, whereas anorthosite and A-type granite suites are abundant; metamorphic rocks typically record high thermobaric (temperature/pressure) ratios, whereas ultrahigh pressure (UHP) rocks are rare; and the abundance of economic mineral deposits features rare porphyry Cu-Au and abundant Ni-Cu and Fe-oxide Cu-Ag (IOCG) deposit types. These collective observations have been used to propose that a stagnant-lid, or single-lid, tectonic regime operated at this time, between periods of plate tectonics in the Paleoproterozoic and Neoproterozoic. In our reappraisal of the mid-Proterozoic geological record, we not only assess the viability of the single-lid hypothesis for each line of evidence, but also that of the plate tectonic alternative. We find that evidence for the single-lid hypothesis is equivocal in all cases, whereas for plate tectonics the evidence is equivocal or supporting. We therefore find no reason to abandon a plate tectonic model for the mid-Proterozoic time period. Instead, we propose that the peculiarities of this enigmatic interval can be reconciled through the combination of two processes working in tandem: secular mantle cooling and the exceptionally long tenure and incomplete breakup of Earth's first supercontinent, where both of these phenomena had a dramatic effect on lithospheric behaviour and its resulting imprint in the geological record.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.epsl.2022.117749
ISSN:	0012821X
Date made live:	07 Sep 2022 14:16 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533159

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.epsl.2022.117749

ISSN:

0012821X

Date made live:

07 Sep 2022 14:16 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/533159