Stratigraphic Studies of the Ordovician and Devonian Formations Throughout the Northwest Plains Area

As yet the knowledge of Ordovician and Devonian physiography in this vast northwest region remains almost a complete secret. Very little, in any, work has been done along this line with the exception of those areas where the various formations outcrop.

Permability and Porosity of Devonian Dolomites in Northwestern Montana

The purpose of this investigation is to record data per­taining to porosity and permeability derived from physical tests performed on Devonian dolomites occurring in northwestern Montana, and to subsequently summarize the results obtained as an aid in determining the possibility of those dolomites being suitable reservoir rocks for oil and gas accumulation.

Microstructural and geochemical investigation of North American lower-middle Paleozoic trilobites and recent arthropods

Trilobites ¥tere collected from Ordovician and Devonian formations of Ontario} New York} Ohio} Oklahoma} and Indiana. Diversity was generally low} but 19..?telllS and Ph..~tY>ps ¥tere the most abundant species from the Ordovician and Devonian} respectively. Recent marine arthropods ¥tere collected from the Atlantic shore of the middle Florida Keys} and from the Pacific and lagoonal waters at Cape Beale} B. C. Fresh-water arthropods were collected along the shore of the Severn River in northcentral Ontario. Cuticles ¥tere analyzed for major} minor and trace elements, 180 and 13C isotopes, as ¥tell as examined by scanning electron micr?scope to identify original and diagenetic fabrics. Examination of trilobite cuticles by scanning electron microscope revealed several microstructures consistent with those observed in Recent arthropods. Microstructures} such as setae and tegumental gland duct openings} in like sized Lim/IllS and Isoteline trilobites may indicate common ancestral origins for these organisms, or simply parallel cuticle evolutions. The dendritic microstructure, originally' thought to be a diagenetic indicator, was found in Recent specimens and therefore its presence in trilobites may be suggestive of the delicate nature of diagenesis in trilobites. The absence of other primary microstructures in trilobites may indicate alteration, taxonomic control} or that there is some inherent feature of S EM examination which may' not allow detection of some features} while others are apparently visit·le onl~1 under SH.·1. The region of the cuticle sampled for examination is also a major influence in detecting pristine microstructures, as not all areas of trilobite and Recent arthropod cuticles will have microstructures identifiable in a SEM study. Subtleties in the process of alteration, however} ma~·· leave pristine microstructures in cuticles that are partial~/ silicified or do 10m itized, and degree and type of alteration may vary stratigraphically and longitudinally within a unit. The presence of fused matrices, angular calcite rhombs, and pyrite in the cuticle are thought to be indicative of altered cuticles, although pyritization may not affect the entire cuticle. t-~atural processes in Recent arthropods, such as molting, lead to variations in cuticle chemistries, and are thought to reflect the area of concentration of the elements during calcification. The level of sodium in Recent arthropods was found to be higher than that in trilobites, but highly mobile when sUbjected to the actions of VY'€'athering. Less saline water produced lovy'€'r magnesium and higher calcium values in Recent specimens .. and metal variations in pristine Ordovician trilobite cuticle appears to follow the constraints outlined for Recent arthropods, of regulation due to the chemislry of the surrounding medium. In diagenetic analysis, sodium, strontium and magnesium proved most beneficial in separating altered from least altered trilobites. Using this criterion, specimens from shale show the least amount of geochemical alteration, and have an original mineralogy of 1.7 - 2.4 mole % MgC03 (8000 t(> 9500 ppm magnesium) for both /s>..?/e/11S lJA'i.riff!11S and PseIAit'11J17ites I..itmirpin..itl/~ and 2.8 - 3.3 mole % MgC03 (5000 to 7000 ppm magnesium) for Ph.i{).?PS This is Slightly lower than the mineralogy of Recent marine arthropods (4.43 - 12.1 mole % MgC03), and slightly higher than that of fresh-water crayfish (0.96 - 1.82 mole % MgC03). Geochemically pristine trilobites were also found to possess primary microstructures. Stable isotope values and trends support the assertion that marine-meteoriclburial fluids were responsible for the alteration observed in a number of the trilobite specimens. The results of this stUdy suggest that fossil material has to be evaluated separately along taxonomic and lithological lines to arrive at sensible diagenetic and e nvironmenta I interpretations.

The fossil plants of the Devonian and Upper Silurian formations of Canada,

Pt. 2 has title: The fossil plants of the Erian (Devonian) and Upper Silurian formations of Canada ... Montreal, Gazette Printing Company, 1882.

SYSTEMATICS, TAPHONOMY, and PALEOECOLOGY of HOMALONOTID TRILOBITES (PHACOPIDA) FROM THE PONTA GROSSA FORMATION (DEVONIAN), PARANA BASIN, BRAZIL

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Layer-cake, anoxia, and other myths: A new look at the Devonian-Mississippian Bakken Formation Reservoir, Williston Basin, North Dakota

The Upper Devonian-Mississippian Bakken Formation in the Williston Basin is one of the most prolific onshore petroleum systems in the continental U.S., consisting of a middle carbonate-siliciclastic member sandwiched between two organic-rich units, the Lower and Upper Bakken shales. Dr. Egenhoff discusses the formation’s surprising departures from standard stratigraphy models and depositional models which contribute to its unique characteristics.

Alluvial-eolian interaction in a Cambrian rift margin: the Pedra das Torrinhas and Pedra Pintada formations (Guaritas Group, RS)

This work presents a study of selected outcrops from the Pedra das Torrinhas Formation of the Guaritas Group (Cambrian, Camaquã Basin), near the basin bordering Encantadas Fault Zone. The studied succession includes alluvial fan deposits that pass laterally into eolian deposits. Sedimentary facies and architectural element analysis were performed, followed by sedimentary petrography and microscopic porosity analysis, aiming to characterize the porosity of the deposits and its spatial distribution. The main objective was to contribute to a better understanding of the porosity spatial distribution in depositional systems characterized by the interaction between alluvial and eolian processes, with special reference to deposits formed prior to the development of terrestrial plants. Porosity values are related to depositional processes, with higher porosities associated to eolian dune deposits (mean of 8.4%), and lower porosity related to interdunes (mean of 3.4%) and alluvial fans (mean of 4.3%). Architectural elements analysis revealed the spatial relationships of these deposits, a response to the interplay of the eolian and alluvial processes. The integration of porosity data reveals that the interaction of alluvial and eolian processes results in heterogeneous distribution of porosity at the facies association scale. Eolian reworking of alluvial facies increases porosity whereas sheet-flood and other alluvial processes in the interdune areas reduce porosity.

Comparative study of the biochemical changes and volatile compound formations during the production of novel whey-based kefir beverages and traditional milk kefir

Cheese whey (CW) and deproteinised cheese whey (DCW) were investigated for their suitability as novel substrates for the production of kefir-like beverages. Lactose consumption, ethanol production, as well as organic acids and volatile compounds formation, were determined during CW and DCW fermentation by kefir grains and compared with values obtained during the production of traditional milk kefir. The results showed that kefir grains were able to utilise lactose from CW and DCW and produce similar amounts of ethanol (7.8-8.3 g/l), lactic acid (5.0 g/l) and acetic acid (0.7 g/l) to those obtained during milk fermentation. In addition, the concentration of higher alcohols (2-methyl-1-butanol, 3-methyl-1-butanol, 1-hexanol, 2-methyl-1-propanol, and 1-propanol), ester (ethyl acetate) and aldehyde (acetaldehyde) in cheese whey-based kefir and milk kefir beverages were also produced in similar amounts. Cheese whey and deproteinised cheese whey may therefore serve as substrates for the production of kefir-like beverages similar to milk kefir. (C) 2010 Elsevier Ltd. All rights reserved.

Pterygotid euryterid chelicera from the lower devonian of Victoria

A single eurypterid (Arthropoda: Chelicerata) chelicera, assigned to Acutiramus sp. cf. A. bohemicus, is described from the Wilson Creek Shale, Turtons Creek inlier, north of Foster, Victoria, Australia. The specimen comprises the proximal portion of both rami. This pterygotid chelicera supports an Early Devonian (?Lochkovian) age for the stratum at this locality, by comparison with occurrences of A. bohemicus from the Czech Republic and closely related species in northern Gondwana.

A Devonian (Givetian) fore-reef slope sequence at Liangshuijing and implication for Devonian platform-to-depression development in Guilin, South China

Three Bahama-like carbonate plaforms-the Guilin, Yangshuo and Yanshan-occurred in Guilin and the surrounding regions during Middle and Late Devonian, which, at a broad scale, are part of an extensive carbonate platform (Xiangzhou carbonate platform) facies in South China. The intraplatform depression facies, a unique characteristic of the Chinese Devonian depositional sequence, separates Bahama-like (platform-to-depression) carbonate subplatfonns. Intraplatform depressions resulted from syndepositional faulting that cut the basement of carbonate subplatforms and affected further platform development. The Liangshuijing section, located between the Guilin platform in the north and the Yangshuo platform in the south, is representative of the fore-reef slope facies neighboring an intraplatform. depression. The South edge of the fore-reef slope lies adjacent to the Yangshuo reef carbonate platform, and the north edge graded into the Yangdi pelagic depression facies. A detailed sedimentary and microfacies analysis work done in this study at the Liangshuijing section shows a distinct vertical facies change from back-reef, restricted platform, hemipelagic, to fore-reefslope facies, differing from either shallow-water benthic facies or typical pelagic facies. Various benthic and pelagic lithofacies and their associations have been recognized in the Liangshuijing section, including dolomitic rudstone, gastropod wackestone, Amphipora floatstone, tentaculitoid wackestone, stromatolite and oncoid limestone, Amphipora grainstone, grain flows, laminated limestone, flat-pebble and brachiopod floatstone, and carbonate turbidites. Eight types of sedimentary cycles composed of two or three lithofacies have been distinguished, which are able to indicate environment changes. Stromatolites, oncoids, grain flows, carbonate turbidites, and tentaculitoid limestones characterize the slope and intraplatform depression lithofacies. Analysis of the vertical sedimentary cycles in the Liangshuijinag section and the lateral stratigraphic equivalents suggest the differing facies patterns occurred at the middle Varcus Zone (Givetian) of Middle Devonian, coeval with the development of fore-reef slope facies in the Guilin area in response to syndeposifional faulting.