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Chemostratigraphic correlation of carbonate successions in the Gariep and Saldania Belts, Namibia and South Africa
Author(s) -
Fölling P. G.,
Frimmel H. E.
Publication year - 2002
Publication title -
basin research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.522
H-Index - 83
eISSN - 1365-2117
pISSN - 0950-091X
DOI - 10.1046/j.1365-2117.2002.00167.x
Subject(s) - diamictite , geology , carbonate , paleontology , group (periodic table) , glacial period , geochemistry , sedimentary rock , clastic rock , chemistry , organic chemistry
Inter‐ and intrabasinal correlation of Neoproterozoic carbonate successions and associated glaciogenic deposits from the Pan‐African Gariep Belt and the Kango inlier in the Saldania Belt (Namibia and South Africa) is proposed on the basis of new δ 13 C Carb and 87 Sr/ 86 Sr I data. Highly positive δ 13 C Carb values (as much as + 8.65‰) and low 87 Sr/ 86 Sr I ratios (0.7071–0.7077) were obtained on carbonate successions of the Hilda Subgroup between an older and a younger diamictite in the Port Nolloth Group (Gariep Belt). These results are in agreement with data elsewhere that suggest deposition between the global ∼ 750 Ma Sturtian and ∼ 580 Ma Marinoan glaciations. Considerably lower, positive δ 13 C Carb values (up to + 1.01‰) and higher 87 Sr/ 86 Sr I ratios (0.7082–0.7085) mark the carbonates (Bloeddrif Member, Holgat Formation) on top of the Numees Formation diamictite and support a correlation of this diamictite with the Marinoan glaciation. In the southern extension of the Gariep Belt, correlation of the Widouw Formation limestone (Gifberg Group) with the Bloeddrif Member carbonates is proposed based on similar isotopic characteristics. In the Kango inlier of the Saldania Belt, two carbonate‐bearing members exist in the Matjies River Formation. The lower one of these two (Nooitgedacht Member) compares well with the Hilda Subgroup, whereas the upper one (Kombuis Member) shows strong similarities to the Bloeddrif Member carbonates. This implies that all younger stratigraphic units of the Kango inlier are not correlatives of the Port Nolloth Group, as previously assumed, but syn‐ to post‐orogenic with respect to the 540–580 Ma Pan‐African orogeny.