{"id":325,"date":"2019-11-01T02:53:22","date_gmt":"2019-11-01T02:53:22","guid":{"rendered":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/?p=325"},"modified":"2020-05-27T18:36:28","modified_gmt":"2020-05-27T18:36:28","slug":"the-carbon-cycle-in-the-mantle","status":"publish","type":"post","link":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/2019\/11\/01\/the-carbon-cycle-in-the-mantle\/","title":{"rendered":"The carbon cycle in the mantle"},"content":{"rendered":"\n<p><\/p>\n\n\n\n<p>Though the total carbon content of the mantle is largely unknown, the isotopic signatures of its sources and sinks suggests much about how the mantle operates. Together, geochemical and mineralogical analyses of a new diamond, a compendium of studies of the magnitude of carbon fluxes into and out of the mantle, and a simple geophysical model suggest that the mantle acts as two interacting reservoirs of carbon: (1) subducting slabs (the reservoir for depleted carbon) descend deep into (2) the bulk mantle (the enriched-carbon reservoir) to possibly as deep as the core-mantle boundary. These reservoirs mix to a small degree; that degree is a function of the isotopic composition of the bulk mantle (\u03b413C from -8 to -3.5 parts per thousand) and the residence time of carbon in the mantle (1-10 Gyr). The residence time is a function of the net flux out of the mantle, which is itself a sum of seafloor spreading rates, oceanic sediment deposition rates, calcium carbonate precipitation rates, and arc volcanism fluxes. This paper summarizes many studies of these fluxes to estimate those above quantities relevant to mantle convection. <\/p>\n\n\n\n<div class=\"wp-block-file\"><a href=\"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-content\/uploads\/sites\/104\/2019\/11\/CCinMantle.pdf\">CarbonCycleMantle_Poinar2012.pdf<\/a><a href=\"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-content\/uploads\/sites\/104\/2019\/11\/CCinMantle.pdf\" class=\"wp-block-file__button\" download>Download<\/a><\/div>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"866\" height=\"483\" src=\"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-content\/uploads\/sites\/104\/2019\/11\/sleep_diagram_slabgraveyard.png\" alt=\"\" class=\"wp-image-327\" srcset=\"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-content\/uploads\/sites\/104\/2019\/11\/sleep_diagram_slabgraveyard.png 866w, https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-content\/uploads\/sites\/104\/2019\/11\/sleep_diagram_slabgraveyard-300x167.png 300w, https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-content\/uploads\/sites\/104\/2019\/11\/sleep_diagram_slabgraveyard-768x428.png 768w\" sizes=\"auto, (max-width: 866px) 100vw, 866px\" \/><figcaption> <br> The isotopic fractionation of carbon by biological processes also has wide-reaching implications. Geological evidence shows that the fractionation has been quite constant over the age of the Earth, yet the mismatch between the \u03b413C of the bulk mantle and of subducting sediment suggest that subducting slabs descend to a largely separate reservoir. The \u03b413C of diamonds suggest that this reservoir is deeper than the transition zone, and may even be at the core-mantle boundary. Thus, analysis centered on the relatively inaccessible carbon content of the mantle could provide evidence for full- rather than layered-mantle convection, one of the largest questions in geophysics. <\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"http:\/\/3.bp.blogspot.com\/-O1WyABCOzI8\/Tfvz7_MV7LI\/AAAAAAAAEYA\/MYshChHvyEo\/s1600\/Forest+trail.jpg\" alt=\"\" \/><figcaption> We know from the amount of accumulated carbon on the Earth\u2019s surface that the net flux of carbon <span style=\"text-decoration: underline\">out<\/span> of the mantle over the age of the earth has been of order 10^8 to 10^9 kg\/yr. <br>Photo by Meacham Wood, tartanscot.blogspot.com<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Though the total carbon content of the mantle is largely unknown, the isotopic signatures of its sources and sinks suggests much about how the mantle operates. Together, geochemical and mineralogical &hellip; <a href=\"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/2019\/11\/01\/the-carbon-cycle-in-the-mantle\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">The carbon cycle in the mantle<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":301,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-325","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/posts\/325","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/users\/301"}],"replies":[{"embeddable":true,"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/comments?post=325"}],"version-history":[{"count":2,"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/posts\/325\/revisions"}],"predecessor-version":[{"id":480,"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/posts\/325\/revisions\/480"}],"wp:attachment":[{"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/media?parent=325"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/categories?post=325"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ubwp.buffalo.edu\/glaciermodelinglab\/wp-json\/wp\/v2\/tags?post=325"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}