Depositional settings

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. 

The submarine depositional setting inferred for most Early Devonian volcanic rocks in part explains the highly variable alkali contents. Specifically, many have generally low Na20 (< 3 wt.%) and high... 

In terms of total watershed C stock, recent empirical and modeling studies conclude that erosion—and the balance between its effects on productivity and decomposition in eroding and depositional sites—tends to lead to an increase in stock, even if there are local decreases in the eroding sites themselves (Stallard, 1998 Smith et al., 2005 Berhe et al., 2007). The rate at which C accumulates in a watershed due to erosion and deposition depends on the strength of erosion and management of productivity, as well as on the types of depositional settings involved (Berhe et al., 2007 van Oost et al., 2007). 

Predict the probable variations in the proximate and ultimate makeup and BTU levels for coals which formed in similar vegetational and depositional settings to those of the peats studied in this project. 

Fig. 10.4 Experimental set-ups for different plasma (electro)chemical experiments (a) DC set-up of Klemenc, (b) set-up for the recovery of metal from slags, (c) vapor-phase electrolytic deposition set-up of Ogumi et al.

In a landmark study of soils on depositional settings, Jenny (1962) examined soils on the... 

Bestland E. A., Retallack G. J., Rice A. E., and Mindszenty A. (1996) Late Eocene detrital laterites in central Oregon mass balance geochemistry, depositional setting and landscape evolution. Geol. Soc. Am. Bull. 108, 285-302. 

The most direct field evidence that the extent of sedimentary organic matter preservation is affected by exposure to bottom-water oxygen comes from oxidation fronts in deepsea turbidites of various ages and depositional settings (Wilson et al., 1985 Weaver and Rothwell, 1987). One of these deposits in which the timing of the exposure to oxic and anoxic conditions is well documented, is the relict f-turbidite from the Madeira abyssal plain (MAP) —700 km offshore... 

Martin D. McB. (1999) Depositional setting and implications of Paleoproterozoic glaciomarine sedimentation in the Hamersley Province, Western Australia. GSA Bull. Ill, 189-203. 

Winter B. L. and Knauth L. P. (1992) Stable isotope geochemistry of cherts and carbonates from the 2.0 Ga Gunflint Iron Formation implications for the depositional setting, and the effects of diagenesis and metamorphism. Precamb. Res. 59, 283-313. 

Table 3 Studies on sedimentary-sulfur geochemistry for selected depositional settings. 

ReviU A. T., VoUcman J. K., O Leary T., Summons R. E., Boreham C. J., Banks M. R., and Denwer K. (1994) Depositional setting, hydrocarbon biomarkers and thermal maturity of tasmanite oil shales from Tasmania, Australia. Geochim. Cosmochim. Acta 58, 3803-3822. 

Sediments were also subsampled from each of the four stratigraphic layers of the sequence. In order to examine the relationship of cave sediments to modern, nearby depositional settings, samples were also collected from a nearby sinkhole pond with hand operated coring device and from the high terrace and flood plain soils with a shovel (Fig. 1). 

Fig. 6.8. Schematic of sonoelectrochemical deposition set-up and the sonic and electrochemical waveforms.

Fedo, C. M., Myers, J. S. Appel, P. W. U. 2001. Depositional setting and palaeogeographic implications of earth s oldest supracrustal rocks, the >3.7Ga Isua Greenstone Belt, west Greenland. Sedimentary Geology, 141/142, 61-77. 

The Middle Devonian Marcellus Formation consists of black bituminous shale and minor argillaceous limestone lying conformably on the Dundee Formation limestones. Its depositional setting resembles that of the Whitby Formation and the Marcellus... 

The climatic conditions and episodic flooding that characterized the depositional setting of the Lunde enhanced the infiltration of suspended clay particles and the formation of coatings around framework grains in the sandstones. Clay minerals formed by weathering processes in the hinterlaixl under arid to semi-arid climatic conditions would be expected to... 

Schwartz, D.E (1988) Characterizing the lithology, petrophysical properties and depositional setting of the Belridge Diatomite, South Belridge field, Kern County, California. In Studies of the Geology of the San Joaquin Basin (Ed. Graham, S.A.). Soc. Econ. Paleont. Miner. Pacific Sec. Publ., 60, 281 -301. 

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