The oldest evidence of eukaryotes in the fossil record comes from a recurrent assemblage of morphologically differentiated late Paleoproterozoic to early Mesoproterozoic microfossils. Although widely distributed, the principal constituents of this Tappania-DictyosphaeraValeria assemblage have not hitherto been recognized on Laurentia. We have recovered all three taxa from a shallow-water shale ...

Based on structural, petrographic and geochronological work (SHRIMP zircon, monazite and rutile), the Mesoproterozoic Albany–Fraser Orogeny is divided into two discrete thermo-tectonic stages, between c. 1345 and 1260 Ma (Stage I) and c. 1214 and 1140 Ma (Stage II). The existence of a two-stage history is confirmed by the discovery of 1321924 Ma detrital zircons and 1154915 Ma metamorphic rutil...

Establishing an accurate timescale for the history of life is crucial to understand evolutionary processes. For this purpose, relaxed molecular clock models implemented in a Bayesian MCMC framework are generally used. However, these methods are time consuming. RelTime, a non-Bayesian method implementing a fast, ad hoc, algorithm for relative dating, was developed to overcome the computational i...

Iron ox ide cop per gold (IOCG) de pos its are rec og nized world-wide and in clude a num ber of world-class, high-ton nage, low-grade Cu-Au de pos its that are typ i cally hosted in in tru sive-hy dro ther mal brec cias and in clude the Mesoproterozoic Olym pic Dam (Aus tra lia) and IgarapeBahia Alemao (Brazil) de pos its (Hitzman et al., 1992). In the Ca na dian Cor dil lera, nu mer ous Mesop...

The authors show that the Mesoproterozoic (1.6-1.0 bn year before present) was no “boring billion” but a “bustling billion” - not only with Stromatolites and their apex in the Calymmian and Ectasian but also with the presence of multicellular organisms. To make it visible a graphical reconstruction was created. For a long time, it was assumed that there existed no noteworthy biosphere on Earth ...

Compressed organic-walled microfossils attributable to five filamentous taxa, and ten coccoidal eight, (taxa originally spheroidal forms and two originally ellipsoidal, colonial forms), all having long time-ranges in the Proterozoic, have been identified in fine-grained siliciclastic sediments in cores from four bore holes cutting subsurface equivalents of the Mesoproterozoic Conselheiro Mata G...

Abstract The Twakputs Gneiss is a garnetiferous, K-feldspar megacrystic, biotite granite-granodiorite orthogneiss. It represents major unit in the Kakamas Domain of Mesoproterozoic Namaqua-Natal Metamorphic Province extending about 250 km between Riemvasmaak South Africa and Grünau southern Namibia. occurs as foliation-parallel, sheet-like bodies tightly infolded together with granulite-facies ...

Micro-scale analytical techniques permit correlation of chemistry with morphology of individual Proterozoic acritarchs (organic-walled microfossils), and thus provide new approaches for elucidating their biological affinities. A combination of micro-Fourier transform infrared (FTIR) spectroscopy and laser micro-Raman spectroscopy was used to investigate the organic structure and composition of ...

The Copper Harbor Conglomerate is a Mesoproterozoic (1.09 Ga) freshwater sedimentary sequence that outcrops in the Upper Peninsula of Michigan. The formation was deposited during infilling of the failed Midcontinent Rift and contains fluvial, lacustrine, and alluvial fan facies. This study describes and analyzes the formation of small domal structures preserved in fluvial sandstone facies withi...

The Itapuranga alkali granite and Uruana quartz syenite are large K-rich EW-elongated intrusions, in the central part of the Neoproterozoic Brasília Belt, central Brazil. They are associated with Pireneus lineaments, which cut the regional NNW-SSE structures of the southern part of the belt. SHRIMP and conventional U-Pb data for the Itapuranga and Uruana intrusions indicate crystallization ages...