Hartwig E. Frimmel

New Pb-Pb Single Zircon Age Constraints on the Timing of Neoproterozoic Glaciation and Continental Break-up in Namibia

Dating of single zircons from low-grade metamorphosed rhyolites in the Rosh Pinah Formation of the Gariep Belt in southwestern Namibia, using the Pb evaporation technique, yielded a primary crystallization age of

Early Cambrian ocean anoxia in South China

741 \pm 6 Ma

Organic-walled microfossils and biostratigraphy of the upper Port Nolloth Group (Namibia): implications for latest Neoproterozoic glaciations

. Both the stratigraphic position and the geochemistry of the volcanic rocks indicate an early continental rift environment. The new data not only provide an age for the massive Zn-Pb-Cu sulfide mineralization associated with these volcanic rocks, but they also set a maximum age limit for Neoproterozoic continental break-up in southern Namibia. This age is statistically indistinguishable from a recently reported age of

Late Vendian Closure of the Adamastor Ocean: Timing of Tectonic Inversion and Syn-orogenic Sedimentation in the Gariep Basin

748 \pm 3 Ma

Basin-internal derivation of hydrocarbons in the Witwatersrand Basin, South Africa: evidence from bulk and molecular δ13C data

for stratigraphically equivalent volcanic rocks in the northern rift of the Damara Belt, suggesting that the onset of the formation of the N-S-trending Adamastor ocean and of the NE-trending Khomas ocean in central and northern Namibia occurred at the same time. The volcanic unit directly overlies, in both rift grabens, a diamictite horizon with glaciogenic features. Our new results further constrain the age of this glacial epoch, which may be correlated with the Sturtian glaciation, to around 750 Ma.

Chapter 8 Tectonic Events and Palaeogeographic Evolution of Southwestern Gondwana in the Neoproterozoic and Cambrian

New U‐Pb zircon ages and geochemical data for felsic intrusive and extrusive rocks from the Richtersveld Igneous Complex (RIC) and related rocks in the westernmost part of the 1.03–1.06‐Ga Namaqua‐Natal metamorphic belt, South Africa, indicate that this complex is not related to post‐Namaqua orogenic collapse but is the product of mantle‐derived alkaline magmatism in an extensional stress field that led to the breakup of a Neoproterozoic supercontinent. The oldest age obtained for the crystallization of granitic to syenitic melts is \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape