Devonian

Estimates of oil shale deposits by continent are given in Table 1 (2). Characteristics of many of the world s best known oil shales are summarized in Table 2 (3,4). Oil shale deposits in the United States occur over a wide area (Table 3). The most extensive deposits, covering ca 647,000 km (250,000 mi ), are the Devonian-Mississippian shales of the eastern United States (5). The richest U.S. oil shales are in the Green River formation of Colorado, Utah, and Wyoming. Typical mineral and organic analyses for Green River oil shale are given in Table 4. 

Devonian 400 Myr Continents collide at end of period. Asteroid probably collides with Earth. Diversification of bony and cartilaginous fishes trilobites diversify origin of ammonoids, amphibians, insects first forests. Mass extinction at end of period (ca. 75% of species disappear)... 

FIGURE 15.7 Secondary changes in the total group composition of soluble organic matter as a result of simulated water washing extracts of the Miocene lignite and shale (both of the Bechatow open cast mine, Poland), the Upper Devonian shale (the Holy Cross Mountains, Poland), and the Upper Carboniferous bituminous coal (the Upper Silesia Coal Basin, Poland). 

Wandless GA (1993) Instrumental neutron activation analysis of Devonian Ohio Shale SDO-i. 

In Kane JS (ed.) U.S. Geological Survey Bulletin 2046. The USGS Reference Sample Devonian Ohio Shale SDO-i pp D1-D5. 

The Eh of connate waters (water entrapped in the interstices of sediment at the time of deposition) ranges from 0 to -200 mV. For example, formation water from two monitoring wells in the lower limestone of the Florida aquifer near Pensacola ranged from +23 to -32 mV,67 and formation fluids from a Devonian limestone in Illinois used for injection at a depth of about 3200 ft had an Eh of -154 mV.16... 

Nurse I d like to mention a sort of half-relevant observation in coelocanths, the fish that are living fossils. When people looked at pre-Devonian fossils of these fish from 300 million years old, the cell size in sections of the fossilized bone was as much as 10 times smaller than the modern fish. The idea was that the fish have accumulated more DNA and the cells have got bigger, but the form of the fish has remained the same. 

If the asteroid-impact theory is correct, the extinctions should be repetitive and the Ir anomaly should be observed in other geological stratigraphic levels corresponding to known extinctions. About five other massive extinctions (besides the one at the end of the Cretaceous Period) have been noted [25]. These come at the end of the Cambrian ( 500 MY ago), the Ordovician (M35 MY age), the Devonian ( 345 MY ago), the Permian ( 230 MY ago) and the Triassic ( 195 MY ago) Periods. 

Velsicol Chemical Corporation maintained two injection wells at its plant near Marshall, Illinois, to dispose of caustic wastes from pesticide production as well as contaminated surface runoff. In September 1965, the company began to inject the wastes into Devonian dolomites of the Grand Tower Formation at a depth of about 2600 feet. The wells accepted about 6 million gallons of waste monthly. 

Mattes, B. W. and E. W. Mountjoy, 1980, Burial dolomitization of the Upper Devonian Miette Buildup, Jasper National Park, Alberta. In D.H. Zenger, J. B. Dunham and R. L. Effington (eds.), Concepts and Models of Dolomitization. SEPM Special Publication 28, 259-297. 

Nelson, J., Paradis, S., Christensen, J. Gabites, J. 2002. Canadian Cordilleran Mississippi Valley-type deposits A case for Devonian-Mississippian back-arc hydrothermal origin. Economic Geology, 97, 1013-1036. 

Paradis, S., Turner, W.A., Coniglio, M., Wilson, N. Nelson, J.L. 2006. Stable and radiogenic isotopic signatures of mineralized Devonian carbonates of the Northern Rocky Mountains and the Western Canada Sedimentary Basin. In Hannigan, P.K. (ed) Potential for carbonate-hosted lead-zinc Mississippi Valley-type mineralization in northern Alberta and southern Northwest Territories Geoscience Contributions,... 

Radon in soil gas is present everywhere throughout the province in all geologic terrains. Soil gas Rn concentrations range from a low of 0.1 kBq/m3 to a high of 207.0 kBq/m3 with a mean of 25.3 kBq/m3 (Fig. 3). The highest Rn soil gas concentrations are also associated with Middle-to-Late Devonian leucomonzogranite of the South... 

The identification of elevated U in the C-horizon soil and elevated Rn in the soil gas associated with the Middle-to-Late Devonian leucomonzogranite of the South Mountain Batholith are examples of the type of information generated by the... 

The Guadiana Basin occupies a total area of 66,850 km2 in Spain and Portugal, 8,350 km2 of which comprises the Iberian Pyrite Belt (IPB) one of the world s largest concentrations of base metal sulphide deposits (Leistel et al., 1997 Ribeiro et al., 1990). Three plant species (Cistus ladanifer, Lavandula luisieri and Thymus vulgaris) were utilized in this study. The soils in which these plants were sampled are developed over varied geological formations. The oldest formation (PQ Group, Upper Devonian) consists of a thick sequence of arenites and shales... 

Near term options include primarily the unconventional natural gas resources (Western tight gas sands, Eastern Devonian gas shales, geopressured aquifers, and methane from coal deposits). Mid-term options include coal gasification (peat... 

Devonian black shale Mid-Proterozoic black shales ... 

As seen in Figure 6, mean 8 Mo in these ancient sediments is significantly offset from that of modem seawater and from mean 8 Mo of recent euxinic sediments. The offset is in the direction of less fractionation of Mo isotopes in the oceans (closer to the likely 5 MOjj ), as would be expected if removal of Mo to euxinic sediments expanded at the expense of removal to oxic (and suboxic) sediments. The result is consistent with the hypothesis of expanded ocean anoxia, and consequent increase in the areal extent of euxinic depositional settings, during this time. A similar, albeit smaller, offset is seen in repeated measurements of a Devonian black shale sample (USGS SDO-1 Fig. 6). This shift could he interpreted as consistent with somewhat expanded euxinic deposition during this time—an interpretation consistent with other evidence of expanded Paleozoic ocean anoxia in inland hasins. While further work is needed, these initial results are promising. 

Sageman BB, Murphy AE, Weme JP, Straeten CAV, Hollander DJ, Lyons TW (2003) A tale of shales the relative roles of production, decomposition, and dilution in the accumulation of organic-rich strata, Middle-Upper Devonian, Appalachian basin. Chem Geol 195 229-273 Sarmiento JL, Toggweiler JR (1984) Anew model for the role of the oceans in determining atmospheric pCOj. Nature 308 621-624... 

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