The modern configuration of the South East Asian Islands (SEAI) evolved over the last fifteen million years, as a result of subduction, arc magmatism, and arc-continent collisions, contributing to both increased land area and high topography. The presence of the additional land area has been postulated to enhance convective rainfall, facilitating both increased silicate weathering and the development of the modern-day Walker circulation. Using an Earth System Model in conjunction with a climate-silicate weathering model, we argue instead for a significant role of SEAI topography for both effects. This dataset archives model output used in this investigation, including simulations using the Community Earth System Model version 1.2, and the climate-silicate weathering model GEOCLIM. All data are in Netcdf format, and were generated either by the Community Earth System Model 1.2 (Hurrell et al. 2013) or the climate-silicate weathering model GEOCLIM (Park et al. 2020). Model output is organized into 4 tar files: 1) B1850C5.tar Contains model output for the fully coupled CESM1.2 runs, for 2D fields and for 3D pressure vertical velocity (W) between 10S-10N. Monthly mean data for years 41-110 of the simulations. Naming convention is No SEAI topography: B1850C5_noSEAItopo_y41-110.nc and B1850C5_noSEAItopo_W_y41-110.nc 50% SEAI topography: B1850C5_0.5SEAItopo_y41-110.nc and B1850C5_0.5SEAItopo_W_y41-110.nc 100% SEAI topography: B1850C5_y41-110.nc and B1850C5_W_y41-110.nc 150% SEAO topogaphy: B1850C5_1.5SEAItopo_y41-110.nc and B1850C5_1.5SEAItopo_W_y41-110.nc 2) E1850C5.tar Contains model output for the slab ocean CESM1.2 runs, for 2D fields and for 3D pressure vertical velocity (W) between 10S-10N. Monthly mean data for years 21-50 of the simulations. Naming convention is No SEAI topography: E1850C5_noSEAItopo_y21-50.nc and E1850C5_noSEAItopo_W_y21-50.nc 50% SEAI topography: E1850C5_0.5SEAItopo_y21-50.nc and E1850C5_0.5SEAItopo_W_y21-50.nc 100% SEAI topography: E1850C5_y21-50.nc and E1850C5_W_y21-50.nc 150% SEAO topogaphy: E1850C5_1.5SEAItopo_y21-50.nc and E1850C5_1.5SEAItopo_W_y21-50.nc 3) GEOCLIM.tar Contains model output from the climate-silicate weathering model GEOCLIM. Data is provided for all 573 parameter combinations. All values are climatological annual means. All files contain these variables: GMST: global mean surface temperature (in K) atm_CO2_level: atmospheric pCO2 (in ppm) degassing: globally-integrated CO2 flux (in mol/yr) The files ending with 1xCO2.nc also contain these spatial fields: lithology fraction: fraction of land covered by a lithology class erosion: Regolith erosion rate (m/yr) weathering: Ca-Mg weathering rate (mol/m^2/yr) E1850C5_1xCO2.nc - GEOCLIM output using the Modern SEAI simulation as input, and for CO2 fixed to 286.7ppm. E1850C5_noSEAI_1xCO2.nc - GEOCLIM output using the no SEAI simulation as input, and for CO2 fixed to 286.7ppm. E1850C5_noSEAItopo_1xCO2.nc - GEOCLIM output using the flat SEAI simulation as input, and for CO2 fixed to 286.7ppm. E1850C5_noSEAI_equil.nc - GEOCLIM output using the no SEAI simulation as input, and CO2 adjusted so that system is in carbon flux equilibrium. E1850C5_noSEAItopo_flatSEAIslope_equil.nc - GEOCLIM output using the flat SEAI simulation as input, and CO2 adjusted so that system is in carbon flux equilibrium. 4) Surface.tar Contains land fraction and surface geopotential fields for the modern SEAI (Landfrac.nc) and no SEAI (Landfrac_noSEAI.nc) simulations References Hurrell, J.W., Holland, M.M., Gent, P.R., Ghan, S., Kay, J.E., Kushner, P.J., Lamarque, J.F., Large, W.G., Lawrence, D., Lindsay, K. and Lipscomb, W.H., 2013. The community earth system model: a framework for collaborative research. Bulletin of the American Meteorological Society, 94(9), pp.1339-1360. Park, Y., Maffre, P., Goddéris, Y., Macdonald, F.A., Anttila, E.S. and Swanson-Hysell, N.L., 2020. Emergence of the Southeast Asian islands as a driver for Neogene cooling. Proceedings of the National Academy of Sciences, 117(41), pp.25319-25326.
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Carbonation and decarbonation reactions: Implications for planetary habitability
Abstract The geologic carbon cycle plays a fundamental role in controlling Earth's climate and habitability. For billions of years, stabilizing feedbacks inherent in the cycle have maintained a surface environment that could sustain life. Carbonation/decarbonation reactions are the primary mechanisms for transferring carbon between the solid Earth and the ocean–atmosphere system. These processes can be broadly represented by the reaction: CaSiO3 (wollastonite) + CO2 (gas) ↔ CaCO3 (calcite) + SiO2 (quartz). This class of reactions is therefore critical to Earth's past and future habitability. Here, we summarize their significance as part of the Deep Carbon Obsevatory's “Earth in Five Reactions” project. In the forward direction, carbonation reactions like the one above describe silicate weathering and carbonate formation on Earth's surface. Recent work aims to resolve the balance between silicate weathering in terrestrial and marine settings both in the modern Earth system and through Earth's history. Rocks may also undergo carbonation reactions at high temperatures in the ultramafic mantle wedge of a subduction zone or during retrograde regional metamorphism. In the reverse direction, the reaction above represents various prograde metamorphic decarbonation processes that can occur in continental collisions, rift zones, subduction zones, and in aureoles around magmatic systems. We summarize the fluxes and uncertainties of major carbonation/decarbonation reactions and review the key feedback mechanisms that are likely to have stabilized atmospheric CO2 levels. Future work on planetary habitability and Earth's past and future climate will rely on an enhanced understanding of the long-term carbon cycle.
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- Award ID(s):
- 1650329
- NSF-PAR ID:
- 10128839
- Date Published:
- Journal Name:
- American Mineralogist
- Volume:
- 104
- Issue:
- 10
- ISSN:
- 0003-004X
- Page Range / eLocation ID:
- 1369 to 1380
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Volatile elements (water, carbon, nitrogen, sulfur, halogens, and noble gases) played an essential role in the secular evolution of the solid Earth and emergence of life. Here we provide an overview of Earth's volatile inventories and describe the mechanisms by which volatiles are conveyed between Earth's surface and mantle reservoirs, via subduction and volcanism. Using literature data, we compute volatile concentration and flux estimates for Earth's major volatile reservoirs and provide an internally balanced assessment of modern global volatile recycling. Using a nitrogen isotope box model, we show that recycling of N (and possibly C and S) likely began before 2 Ga and that ingassing fluxes have remained roughly constant since this time. In contrast, our model indicates recycling of H 2 O(and most likely noble gases) was less efficient in the past. This suggests a decoupling of major volatile species during subduction through time, which we attribute to the evolving thermal regime of subduction zones and the different stabilities of the carrier phases hosting each volatile. ▪ This review provides an overview of Earth's volatile inventory and the mechanisms by which volatiles are transferred between Earth reservoirs via subduction. ▪ The review frames the current thinking regarding how Earth acquired its original volatile inventory and subsequently evolved through subduction processes and volcanism.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.2138/am-2019-6884
