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Correlation of the stratigraphic cover of the Pilbara and Kaapvaal cratons recording the lead up to Paleoproterozoic Icehouse and the GOE
Earth-Science Reviews ( IF 10.8 ) Pub Date : 2020-12-01 , DOI: 10.1016/j.earscirev.2020.103389
Andrey Bekker , Bryan Krapež , Juha A. Karhu

Abstract The Turee Creek Basin of the Pilbara Craton is critical for timing onset of the early Paleoproterozoic Icehouse and the GOE. We establish correlation to the Koegas/Postmasburg Supersequence of the Kaapvaal Craton based on a common compressional basin, with the Pilbara succession deposited near the orogen and the Kaapvaal succession near the flexural arch. Whereas Turee Creek cyclicity was controlled by tectonic subsidence, glacioeustatic influence is discernible in the Koegas/Postmasburg Supersequence. Key features of the Turee Creek Basin are: the mid-Kungarra Formation glaciogenic Meteorite Bore Member; unconformity-bound sequences above the Kungarra Formation; and the basaltic Bubbawalyee Formation conformably above Quartzite 3. On the Kaapvaal Craton, the equivalent glaciogenic unit (Makganyene Formation), overlying the sedimentary Koegas Subgroup and underlying the basaltic Ongeluk Formation, is unconformity-bound. We correlate the sub-Ongeluk unconformity with the sub-Quartzite 3 unconformity, and propose tectonostratigraphic equivalence of the Ongeluk and Bubbawalyee formations. There are no equivalents of the post-Ongeluk, Hotazel and Mooidraai formations above the Bubbawalyee Formation on the Pilbara Craton, which is significant because the Hotazel Formation provides the earliest evidence for the GOE. Consequently, rather than spanning the GOE, the Turee Creek Basin provides a chemostratigraphy during its eve. All carbonate sediments deposited before and after the first global glaciation (Meteorite Bore/Makganyene) yield carbon isotope values close to 0‰, establishing that the first carbon isotope excursion occurred long after closure of the Turee Creek-Koegas/Postmasburg basin and onset of the GOE. It therefore appears that the carbon cycle responded to, rather than triggered, the GOE.

中文翻译:

Pilbara 和 Kaapvaal 克拉通的地层覆盖记录到古元古代冰库和 GOE 的相关性

摘要 Pilbara Craton 的Turee Creek 盆地对于早期古元古代冰库和GOE 的开始时间至关重要。我们建立了与 Kaapvaal Craton 的 Koegas/Postmasburg 超层序的关联,基于一个共同的挤压盆地,Pilbara 层序沉积在造山带附近,Kaapvaal 层序沉积在弯曲拱附近。尽管 Turee Creek 的周期性受构造沉降控制,但在 Koegas/Postmasburg Supersequence 中可以辨别出冰川静力的影响。Turee Creek 盆地的主要特征是: 中昆加拉组冰川成因陨石孔段;昆加拉组上方不整合面层序;和玄武岩 Bubbawalyee 组在石英岩 3 之上。在 Kaapvaal 克拉通上,等效的冰川形成单元(Makganyene 组),上覆沉积的 Koegas 亚群和下伏玄武质 Ongeluk 组,受不整合面约束。我们将亚 Ongeluk 不整合面与亚石英岩 3 不整合面相关联,并提出 Ongeluk 和 Bubbawalyee 地层的构造地层学等价性。在皮尔巴拉克拉通的 Bubbawalyee 组之上没有 Ongeluk、Hotazel​​ 和 Mooidraai 后的地层,这很重要,因为 Hotazel​​ 组为 GOE 提供了最早的证据。因此,Turee Creek 盆地在其前夕提供了化学地层学,而不是跨越 GOE。在第一次全球冰川作用(陨石孔/Makganyene)之前和之后沉积的所有碳酸盐沉积物产生的碳同位素值接近 0‰,确定第一次碳同位素漂移发生在Turee Creek-Koegas/Postmasburg盆地关闭和GOE开始之后很久。因此,碳循环似乎是响应 GOE 而不是触发 GOE。
更新日期:2020-12-01
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