本文選題：錳礦 + 大塘坡組��； 參考：《科學(xué)通報(bào)》2017年Z2期

【摘要】：2010年發(fā)現(xiàn)的貴州道坨錳礦是一個(gè)超大型的海相沉積礦床,其含礦地層為南華系大塘坡組一段黑色頁(yè)巖.對(duì)道坨錳礦大塘坡組一段含錳黑色頁(yè)巖測(cè)定的Re-Os同位素等時(shí)線年齡為660.6±7.5 Ma,該年齡與前人測(cè)定的大塘坡組黑色頁(yè)巖底部凝灰?guī)r夾層中鋯石U-Pb年齡在誤差范圍內(nèi)一致,進(jìn)一步限定了"大塘坡"式錳礦的成礦時(shí)代和Sturtian冰期的結(jié)束年齡,且可與全球Sturtian冰期結(jié)束的Re-Os同位素年齡進(jìn)行對(duì)比.由Re-Os等時(shí)線年齡得到的~(187)Os/~(188)Os初始比值為0.781,結(jié)合前人的研究成果,說(shuō)明在Sturtian冰期后伴隨著大氣氧含量的快速升高及陸地冰川的融化,冰川融水?dāng)y帶著陸源物質(zhì)進(jìn)入到含Mn~(2+)的裂谷盆地,使得盆地表層水體含氧量迅速增加,生物大量繁殖,Mn~(2+)被氧化為MnO_2而沉淀,之后在盆地底部還原環(huán)境中伴隨著有機(jī)質(zhì)的埋藏及成巖作用而最終形成菱錳礦.
[Abstract]:The Daotuo manganese deposit, which was discovered in 2010, is a very large marine sedimentary deposit. The ore-bearing strata are the black shale of the Datangpo formation of the South China series.The Re-Os isotopic isochron age of the first section of the Datangpo formation is 660.6 鹵7.5Ma. this age is consistent with the zircon U-Pb age in the tuff intercalation at the bottom of the Datangpo formation.The metallogenic age of the Datangpo type manganese deposit and the end age of the Sturtian glacial age are further limited, and can be compared with the Re-Os isotopic age at the end of the global Sturtian glacial age.The initial ratio of Re-Os isochron dating is 0.781. Combined with previous studies, it is shown that the rapid increase of atmospheric oxygen content and the melting of terrestrial glaciers are associated with the Sturtian glacial age.Glacial meltwater carries land-based materials into the rift basin containing Mn~(2, which makes the oxygen content in the surface water of the basin increase rapidly, and a large number of living organisms are oxidized to MnO_2 and precipitated.After that, magnesite was formed in the reductive environment at the bottom of the basin with the burial and diagenesis of organic matter.
【作者單位】： 中國(guó)地質(zhì)科學(xué)院礦產(chǎn)資源研究所;國(guó)土資源部成礦作用與資源評(píng)價(jià)重點(diǎn)實(shí)驗(yàn)室;貴州大學(xué)資源與環(huán)境工程學(xué)院;國(guó)家地質(zhì)實(shí)驗(yàn)測(cè)試中心;貴州省地質(zhì)礦產(chǎn)勘查開發(fā)局一0三地質(zhì)大隊(duì);
【基金】：國(guó)家自然科學(xué)基金(41472089) 中國(guó)地質(zhì)調(diào)查局地質(zhì)調(diào)查項(xiàng)目(DD20160346)資助
【分類號(hào)】：P597;P618.32

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本文編號(hào)：1765127