Abstract Details
(2020) Is Paleoproterozoic Atmospheric Oxygenation Linked to the Emergence of Continents Above Sea-Level? Evidence from Sulfur and Oxygen Isotopic Signatures in Archean to Proterozoic Sediment-Derived Granitoids
Liebmann J, Spencer CJ, Bucholz CE, Kirkland CL, Martin L, Xia X-P & Kitchen N
https://doi.org/10.46427/gold2020.1554
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09d: Room 3, Thursday 25th June 22:12 - 22:15
Janne Liebmann
View all 2 abstracts at Goldschmidt2020
View abstracts at 7 conferences in series
Christopher J. Spencer View all 4 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Claire E. Bucholz View all 2 abstracts at Goldschmidt2020
Christopher L Kirkland View all 3 abstracts at Goldschmidt2020
Laure Martin View all 2 abstracts at Goldschmidt2020
Xiao-Ping Xia View abstracts at 5 conferences in series
Nami Kitchen View abstracts at 9 conferences in series
Christopher J. Spencer View all 4 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Claire E. Bucholz View all 2 abstracts at Goldschmidt2020
Christopher L Kirkland View all 3 abstracts at Goldschmidt2020
Laure Martin View all 2 abstracts at Goldschmidt2020
Xiao-Ping Xia View abstracts at 5 conferences in series
Nami Kitchen View abstracts at 9 conferences in series
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Submitted by Janne Liebmann on Thursday 25th June 03:45
Hi Jingjun, thanks for your question. The figure you are referring to shows the environment of emplacement (subaerial vs. submarine) of continental LIPs. We argue for a ~2.4 Ga emergence of continents, because at this time the fraction of subaerially erupted continental LIPs increases from ~10% to ~70%. In contrast, the vast majority of continental LIP events around 2.7 Ga show evidence for submarine eruption. We interpret the increase in subaerial continental LIP volcanism to be related to an increase in subaerial continental area (i.e. the subaerial emergence of continents). A 2.4 Ga emergence of continents is further supported by a change in oxygen isotope composition of shales, which has been linked to the onset of a modern hydrological cycle (Bindeman et al., 2018, Nature), a change in average oxygen isotope ratio of detrital zircon (Spencer et al., 2019, GCA), and an increase in seawater 87Sr/86Sr ratio (Flament et al., 2013 , Precambrian Research) all of which have been reasonably linked to subaerially exposed continents. Note that the figure showing the proportion of subaerial continental LIPs only includes LIP events for which the environment of eruption could be determined (based on characteristics of associated extrusive rocks and/or sediments). However, as for many of these Precambrian LIP events only dyke swarms are preserved, a definitive categorization was not possible in some cases. Events that could not be classified are not shown in this figure. I hope this answers your question!
Hi Jingjun, thanks for your question. The figure you are referring to shows the environment of emplacement (subaerial vs. submarine) of continental LIPs. We argue for a ~2.4 Ga emergence of continents, because at this time the fraction of subaerially erupted continental LIPs increases from ~10% to ~70%. In contrast, the vast majority of continental LIP events around 2.7 Ga show evidence for submarine eruption. We interpret the increase in subaerial continental LIP volcanism to be related to an increase in subaerial continental area (i.e. the subaerial emergence of continents). A 2.4 Ga emergence of continents is further supported by a change in oxygen isotope composition of shales, which has been linked to the onset of a modern hydrological cycle (Bindeman et al., 2018, Nature), a change in average oxygen isotope ratio of detrital zircon (Spencer et al., 2019, GCA), and an increase in seawater 87Sr/86Sr ratio (Flament et al., 2013 , Precambrian Research) all of which have been reasonably linked to subaerially exposed continents. Note that the figure showing the proportion of subaerial continental LIPs only includes LIP events for which the environment of eruption could be determined (based on characteristics of associated extrusive rocks and/or sediments). However, as for many of these Precambrian LIP events only dyke swarms are preserved, a definitive categorization was not possible in some cases. Events that could not be classified are not shown in this figure. I hope this answers your question!
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