Neoproterozoic

Results-Arsenic Preliminary results for As in the <63-pm fraction indicate C-horizon soil concentrations range from a low of 2.2 ppm to a high of 345 ppm with a mean of 22.3 ppm (Fig. 1). The highest As sample site is located within the Late Neoproterozoic/Cambrain Meguma... 

Fig.4. Schematic reconstruction of the Late Neoproterozoic-Early Palaeozoic tectonic evolution of the Tyrone Central Inlier. TCI, Tyrone Central Inlier TPG, Tyrone Plutonic Group TVG, Tyrone Volcanic Group OT, Omagh Thrust CBC, Clew Bay Complex LD, Longford-Down terrane LNA, Lough Nafooey Arc (from Chew et al. 2008).

Neoproterozoic to Early Paleozoic rocks of the Annidale area are interpreted to mark the southeastern margin of Ganderia in the New Brunswick segment of the northern Appalachians (Johnson et al. 2009). The area is underlain by Late Cambrian to Early Ordovician rocks of the Annidale Group and Late Neoproterozoic to Early Cambrian rocks of the Belleisle Bay Group, which are juxtaposed along a major tectonic boundary marked by the Taylor Brook Fault (Fig. 1). 

Lawson Brook Fm 3 Carpenter Brook Fm Late Neoproterozoic to Early Cambrian... 

Hoffman JH, Hodges RR, McElroy MB, Donahue TM, Kolpin M (1979) Composition and structure of the Venus atmosphere results from Pioneer Venus. Science 205 49-52 Hoffman PE, Kaufman AJ, Halverson GP, Schrag DP (1998) Neoproterozoic snowball earth. Science 281 1342-1346... 

Greenwood PF, Arouri KR, Logan GA, Summons RE, Abundance and geochemical signihcance of Cj dialkylalkanes and highly branched alkanes in diverse Meso- and Neoproterozoic sediments, Org Geochem 35 331-346, 2004. 

O Brien, S.J., Dube, B. and O Driscoll C.F. (1999) High-Sulphidation, Epithermal-Style Hydrothermal Systems in Late Neoproterozoic Avalonian rocks on the Burin Peninsula, Newfoundland Implications for Gold Exploration Report 99-1, Current Research Newfoundland Department of Mines and Energy Geological Survey, pp. 275-96. 

In our simulations, we assumed that seawater compositions during the Neoproterozoic era would have been similar to present-day seawater, except for high Fe(II) concentrations. We arbitrarily assigned our hypothethical ocean a Fe(II) concentration of 0.01065 m, the same concentration as Ca to maintain a charge balance, we removed an equivalent amount of Na (from 0.48610 to 0.46480m) (Fig. 5.6). 

We assumed fixed 02(g) partial pressures of 0.00 and 0.02 bars for snowball Earth and hothouse Earth, respectively. A low model value is necessary for snowball Earth because otherwise ferrous iron is oxidized to ferric iron, whose solubility is too low to account for banded iron formations. It is in the late Neoproterozoic era that atmospheric O2 rose to modern values (Holland, 2004). According to Canfield and Teske (1996), between 1.05 and 0.64 Ga ago, O2 levels were 5-18% of the modern value (0.2 bars). For hothouse Earth, we choose a level of 10% of the modern value. For our simulations, it is immaterial whether we used 0.002, 0.02, or 0.2 bars of O2 pressure. All are sufficient to completely oxidize ferrous to ferric iron. 

Bodiselitsch B, Koeberl C, Master S, Reimold WU (2005) Estimating duration and intensity of Neoproterozoic snowball glaciations from Ir anomalies. Science 308 239-242... 

Cockell CS (1999) Life on Venus. Plant Space Sci 47 1487-1501 Cometta S, Sonnleitner B, Sidler W, Fiechter A (1982) Population distribution of aerobic extremely thermophilic microorganisms in an Icelandic natural hot spring. Eur J Appl Microbiol Biotechnol 16 151-156 Condon DJ, Prave AR, Benn DI (2002) Neoproterozoic glacial-rainout intervals Observations and implications. Geology 30 35-38... 

Huber C, Wachtershauser G (2006) a-hydroxy and a-amino acids under possible Hadean, volcanic origin-of-life conditions. Science 314 630-632 Huber H, Stetter KO (1998) Hyperthermophiles and their possible potential in biotechnology. J Biotechnol 64 39-52 Hurtgen MT, Arthur MA, Halverson GP (2005) Neoproterozoic sulfur isotopes, the evolution of microbial sulfur species, and the burial efficiency of sulfide as sedimentary pyrite. Geology 33 41-44 Husain V, Winkler O (2007) Semiclassical states for quantum cosmology. Phys Rev D 75 024014... 

Huterer D, Starkman GD, Trodden M (2002) Is the universe inflating Dark energy and the future of the universe. Phys Rev D 66 043511 Hyde WT, Crowley TJ, Baum SK, Peltier WR (2000) Neoproterozoic snowball Earth simulations with a coupled climate/ice-sheet model. Nature... 

Jiang G, Kennedy MJ, Christie-Blick N (2003) Stable isotopic evidence for methane seeps in Neoproterozoic postglacial cap carbonates. Nature 426 822-826... 

Sankaran AV (2003) Neoproterozoic snowball earth and the cap carbonate controversy. Curr Sci 84 871-873... 

MukhopadhyayA,Ni L, Weiner H (2004) A co-translational model to explain the in vivo import of proteins into HeLa cell mitochondria. Biochem J 382 385-92 Mus MM, Moczydlowska M (2000) Internal morphology and taphonomic history of the Neoproterozoic vase-shaped microfossils from the VisingsO Group, Sweden. Norsk Geol Tidsskr 80 213-228... 

Porter SM, Meisterfeld R, Knoll AH (2003) Vase-shaped microfossils from the Neoproterozoic Chuar Group, Grand Canyon a classification guided by modern testate amoebae. J Paleont 77 409-429... 

Miller B. V., Samson S. D., and D Lemos R. S. (1999) Time span of plutonism, fabric development, and cooling in a Neoproterozoic magmatic arc segment U—Pb age constraints from syn-tectonic plutons, Sark, Channel Islands, UK. Tectonophysics 312, 79-95. 

Watt G. R. and Thrane K. (2001) Early Neoproterozoic events in East Greenland. Precamb. Res. 110(1-4), 165-184. 

Parkinson C. D., MotoM A., Onishi C. T., and Maruyama S. (2001) Ultrahigh-pressure pyrope-kyanite granulites and associated eclogites in Neoproterozoic nappes of Southeast Brazil. In Fluid/Slab/Mantle Interactions and Ultrahigh-P Minerals (eds. Y. Ogasawara, S. Maruyama, and J. G. Liou). Waseda University, Tokyo, pp. 87 -90. 

Shen Y. (2002) C-isotope variations and paleoceanographic changes during the late Neoproterozoic on the Yangtze Platform, China. Precamb. Res. 113, 121-133. 

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