کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6436762 | 1637608 | 2013 | 14 صفحه PDF | دانلود رایگان |
- A new correlation scheme for early Paleoproterozoic glaciations is proposed.
- The second of three glacial epochs is framed by the disappearance of MIF (Î33S).
- The same glaciation was arguably a snowball Earth.
- The new scheme simplifies early Paleoproterozoic Earth history.
- It reconciles apparent asynchrony between MIF disappearance in North America and South Africa.
Existing correlation schemes between early Paleoproterozoic successions divorce the low-latitude Makganyene glaciation in southern Africa from the Great Oxidation (GO), as recorded by the disappearance of mass-independent fractionation of S-isotopes (MIF-S) in sedimentary sulfide and sulfate minerals. They also suggest a younger age for the GO in southern Africa (~Â 2.3Â Ga) compared with North America (~Â 2.4Â Ga), which is physically implausible. A new correlation scheme is proposed in which the Makganyene glaciation is temporally linked to the GO and to the second of three Huronian glaciations in North America, the one with postglacial cap-carbonate. In the new scheme, only three glacial epochs are needed globally, all three are represented in southern Africa, and the second was a circa 2.40Â Ga snowball Earth coincident with the GO.
Journal: Chemical Geology - Volume 362, 20 December 2013, Pages 143-156