1
|
Giuliani A, Drysdale RN, Woodhead JD, Planavsky NJ, Phillips D, Hergt J, Griffin WL, Oesch S, Dalton H, Davies GR. Perturbation of the deep-Earth carbon cycle in response to the Cambrian Explosion. SCIENCE ADVANCES 2022; 8:eabj1325. [PMID: 35245120 PMCID: PMC8896790 DOI: 10.1126/sciadv.abj1325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 01/11/2022] [Indexed: 05/26/2023]
Abstract
Earth's carbon cycle is strongly influenced by subduction of sedimentary material into the mantle. The composition of the sedimentary subduction flux has changed considerably over Earth's history, but the impact of these changes on the mantle carbon cycle is unclear. Here, we show that the carbon isotopes of kimberlite magmas record a fundamental change in their deep-mantle source compositions during the Phanerozoic Eon. The 13C/12C of kimberlites before ~250 Ma preserves typical mantle values, whereas younger kimberlites exhibit lower and more variable ratios-a switch coincident with a recognized surge in kimberlite magmatism. We attribute these changes to increased deep subduction of organic carbon with low 13C/12C following the Cambrian Explosion when organic carbon deposition in marine sediments increased significantly. These observations demonstrate that biogeochemical processes at Earth's surface have a profound influence on the deep mantle, revealing an integral link between the deep and shallow carbon cycles.
Collapse
Affiliation(s)
- Andrea Giuliani
- Institute of Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, Clausiusstrasse 25, Zurich 8092, Switzerland
| | - Russell N. Drysdale
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Jon D. Woodhead
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Noah J. Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
| | - David Phillips
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Janet Hergt
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - William L. Griffin
- Australian Research Council Centre of Excellence for Core to Crust Fluid Systems (CCFS) and GEMOC, Department of Earth and Environmental Sciences, Macquarie University, North Ryde, 2109 New South Wales, Australia
| | - Senan Oesch
- Institute of Geochemistry and Petrology, Department of Earth Sciences, ETH Zurich, Clausiusstrasse 25, Zurich 8092, Switzerland
| | - Hayden Dalton
- School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Gareth R. Davies
- Department of Earth Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands
| |
Collapse
|
2
|
Palin RM, Roberts NMW. Metamorphism at convergent plate margins: Preface. GEOSCIENCE FRONTIERS 2022; 13:101288. [PMID: 38620920 PMCID: PMC8412981 DOI: 10.1016/j.gsf.2021.101288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 08/15/2021] [Indexed: 04/17/2024]
Affiliation(s)
- Richard M Palin
- Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, United Kingdom
| | - Nick M W Roberts
- Geochronology and Tracers Facility, British Geological Survey, Environmental Science Centre, Nottingham, United Kingdom
| |
Collapse
|
3
|
Hydrothermal 15N15N abundances constrain the origins of mantle nitrogen. Nature 2020; 580:367-371. [DOI: 10.1038/s41586-020-2173-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 02/04/2020] [Indexed: 11/08/2022]
|
4
|
C- and N-bearing Species in Reduced Fluids in the Simplified C–O–H–N System and in Natural Pelite at Upper Mantle P–T Conditions. MINERALS 2019. [DOI: 10.3390/min9110712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
C- and N-bearing species in reduced fluids weree studied experimentally in C–O–H–N and muscovite–C–O–H–N systems and in natural carbonate-bearing samples at mantle P–T parameters. The experiments reproduced three types of reactions leading to formation of hydrocarbons (HCs) at 3.8–7.8 GPa and 800–1400 C and at hydrogen fugacity (fH2) buffered by the Fe–FeO (IW) + H2O or Mo–MoO2 (MMO) + H2O equilibria: (i) Thermal destruction of organic matter during its subduction into the mantle (with an example of docosane), (ii) hydrogenation of graphite upon interaction with H2‑enriched fluids, and (iii) hydrogenation of carbonates and products of their reduction in metamorphic clayey rocks. The obtained quenched fluids analyzed after the runs by gas chromatography-mass spectrometry (GC–MS) and electronic ionization mass-spectrometry (HR–MS) contain CH4 and C2H6 as main carbon species. The concentrations of C2-C4 alkanes in the fluids increase as the pressure and temperature increase from 3.8 to 7.8 GPa and from 800 to 1400 C, respectively. The fluid equilibrated with the muscovite–garnet–omphacite–kyanite–rutile ± coesite assemblage consists of 50–80 rel.% H2O and 15–40 rel.% alkanes (C1 > C2 > C3 > C4). Main N-bearing species are ammonia (NH3) in the C–O–H–N and muscovite–C–O–H–N systems or methanimine (CH3N) in the fluid derived from the samples of natural pelitic rocks. Nitrogen comes either from air or melamine (C3H6N6) in model systems or from NH4+ in the runs with natural samples. The formula CH3N in the quenched fluid of the C–O–H–N system is confirmed by HR–MS. The impossibility of CH3N incorporation into K-bearing silicates because of a big CH3NH+ cation may limit the solubility of N in silicates at low fO2 and hence may substantially influence the mantle cycle of nitrogen. Thus, subduction of slabs containing carbonates, organic matter, and N-bearing minerals into strongly reduced mantle may induce the formation of fluids enriched in H2O, light alkanes, NH3, and CH3N. The presence of these species must be critical for the deep cycles of carbon, nitrogen, and hydrogen.
Collapse
|
5
|
Self-consistent Energetic Particle Acceleration by Contracting and Reconnecting Small-scale Flux Ropes: The Governing Equations. ACTA ACUST UNITED AC 2018. [DOI: 10.3847/1538-4357/aad8b3] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
6
|
Bebout G, Banerjee N, Izawa M, Kobayashi K, Lazzeri K, Ranieri L, Nakamura E. Nitrogen Concentrations and Isotopic Compositions of Seafloor-Altered Terrestrial Basaltic Glass: Implications for Astrobiology. ASTROBIOLOGY 2018; 18:330-342. [PMID: 29106312 PMCID: PMC5867513 DOI: 10.1089/ast.2017.1708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 10/03/2017] [Indexed: 05/24/2023]
Abstract
Observed enrichments of N (and the δ15N of this N) in volcanic glasses altered on Earth's modern and ancient seafloor are relevant in considerations of modern global N subduction fluxes and ancient life on Earth, and similarly altered glasses on Mars and other extraterrestrial bodies could serve as valuable tracers of biogeochemical processes. Palagonitized glasses and whole-rock samples of volcanic rocks on the modern seafloor (ODP Site 1256D) contain 3-18 ppm N with δ15Nair values of up to +4.5‰. Variably altered glasses from Mesozoic ophiolites (Troodos, Cyprus; Stonyford volcanics, USA) contain 2-53 ppm N with δ15N of -6.3 to +7‰. All of the more altered glasses have N concentrations higher than those of fresh volcanic glass (for MORB, <2 ppm N), reflecting significant N enrichment, and most of the altered glasses have δ15N considerably higher than that of their unaltered glass equivalents (for MORB, -5 ± 2‰). Circulation of hydrothermal fluids, in part induced by nearby spreading-center magmatism, could have leached NH4+ from sediments then fixed this NH4+ in altering volcanic glasses. Glasses from each site contain possible textural evidence for microbial activity in the form of microtubules, but any role of microbes in producing the N enrichments and elevated δ15N remains uncertain. Petrographic analysis, and imaging and chemical analyses by scanning electron microscopy and scanning transmission electron microscopy, indicate the presence of phyllosilicates (smectite, illite) in both the palagonitized cracks and the microtubules. These phyllosilicates (particularly illite), and possibly also zeolites, are the likely hosts for N in these glasses. Key Words: Nitrogen-Nitrogen isotope-Palagonite-Volcanic glass-Mars. Astrobiology 18, 330-342.
Collapse
Affiliation(s)
- G.E. Bebout
- Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania, USA
- Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University, Misasa, Japan
| | - N.R. Banerjee
- Department of Earth Sciences, Western University, London, Canada
| | - M.R.M. Izawa
- Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University, Misasa, Japan
- Department of Earth Sciences, Western University, London, Canada
| | - K. Kobayashi
- Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University, Misasa, Japan
| | - K. Lazzeri
- Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania, USA
| | - L.A. Ranieri
- Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania, USA
| | - E. Nakamura
- Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University, Misasa, Japan
| |
Collapse
|
7
|
Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2005. Photochem Photobiol Sci 2006. [DOI: 10.1039/b515670j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|