TY  - JOUR
A1  - Nicoli, Gautier
A1  - Ferrero, Silvio
T1  - Nanorocks, volatiles and plate tectonics
JF  - Geoscience frontiers
N2  - The global geological volatile cycle (H, C, N) plays an important role in the long term self-regulation of the Earth system. However, the complex interaction between its deep, solid Earth components (i.e. crust and mantle), Earth's fluid envelopes (i.e. atmosphere and hydrosphere) and plate tectonic processes is a subject of ongoing debate. In this study we want to draw attention to how the presence of primary melt (MI) and fluid (FI) inclusions in high-grade metamorphic minerals could help constrain the crustal component of the volatile cycle. To that end, we review the distribution of MI and FI throughout Earth's history, from ca. 3.0 Ga ago up to the present day. We argue that the lower crust might constitute an important, long-term, volatile storage unit, capable to influence the composition of the surface envelopes through the mean of weathering, crustal thickening, partial melting and crustal assimilation during volcanic activity. Combined with thermodynamic modelling, our compilation indicates that periods of well-established plate tectonic regimes at <0.85 Ga and 1.7-2.1 Ga, might be more prone to the reworking of supracrustal lithologies and the storage of volatiles in the lower crust. Such hypothesis has implication beyond the scope of metamorphic petrology as it potentially links geodynamic mechanisms to habitable surface conditions. MI and FI in metamorphic crustal rocks then represent an invaluable archive to assess and quantify the co-joint evolution of plate tectonics and Earth's external processes. (C) 2021 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
KW  - Nanorocks
KW  - Plate tectonics
KW  - Volatiles
KW  - Lower crust
Y1  - 2021
U6  - https://doi.org/10.1016/j.gsf.2021.101188
SN  - 1674-9871
VL  - 12
IS  - 5
PB  - Amsterdam [u.a.]
CY  - Elsevier
ER  - 
TY  - JOUR
A1  - Merdith, Andrew S.
A1  - Williams, Simon E.
A1  - Brune, Sascha
A1  - Collins, Alan S.
A1  - Müller, R. Dietmar
T1  - Rift and plate boundary evolution across two supercontinent cycles
JF  - Global and planetary change
N2  - The extent of continental rifts and subduction zones through deep geological time provides insights into the mechanisms behind supercontinent cycles and the long term evolution of the mantle. However, previous compilations have stopped short of mapping the locations of rifts and subduction zones continuously since the Neoproterozoic and within a self-consistent plate kinematic framework. Using recently published plate models with continuously closing boundaries for the Neoproterozoic and Phanerozoic, we estimate how rift and peri-continental subduction length vary from 1 Ga to present and test hypotheses pertaining to the supercontinent cycle and supercontinent breakup. We extract measures of continental perimeter-to-area ratio as a proxy for the existence of a supercontinent, where during times of supercontinent existence the perimeter-to-area ratio should be low, and during assembly and dispersal it should be high. The amalgamation of Gondwana is clearly represented by changes in the length of peri-continental subduction and the breakup of Rodinia and Pangea by changes in rift lengths. The assembly of Pangea is not clearly defined using plate boundary lengths, likely because its formation resulted from the collision of only two large continents. Instead the assembly of Gondwana (ca. 520 Ma) marks the most prominent change in arc length and perimeter-to-area ratio during the last billion years suggesting that Gondwana during the Early Palaeozoic could explicitly be considered part of a Phanerozoic supercontinent. Consequently, the traditional understanding of the supercontinent cycle, in terms of supercontinent existence for short periods of time before dispersal and re-accretion, may be inadequate to fully describe the cycle. Instead, either a two-stage supercontinent cycle could be a more appropriate concept, or alternatively the time period of 1 to 0 Ga has to be considered as being dominated by supercontinent existence, with brief periods of dispersal and amalgamation.
KW  - Supercontinent cycle
KW  - Rodinia
KW  - Gondwana
KW  - Supercontinent breakup
KW  - Plate tectonics
Y1  - 2018
U6  - https://doi.org/10.1016/j.gloplacha.2018.11.006
SN  - 0921-8181
SN  - 1872-6364
VL  - 173
SP  - 1
EP  - 14
PB  - Elsevier
CY  - Amsterdam
ER  -