Devonian rocks

In the southern TCZ only Early Devonian rocks are exposed, and all of them are assigned to the Tobique Group. The Tobique and Dalhousie groups are in part coeval and are similar in terms of rock types. The depositional environment for the Tobique Group is, for the most part, thought to be outer shelf or slope based on sedimentary bed forms and ichnofauna and the presence of abundant pillow lava and hyaloclastite in mafic volcanic units. In... 

Table II. Bituminous Substances in Devonian Rocks from Huntingdon County, Pa. (7)...

Table IV. Carbohydrate Components of Middle and Upper Devonian Rocks of Central Pennsylvania0...

Dr. Swain Very little hydrocarbon material was present in the distilled acid extracts, but dried distillates showed small amounts of aromatic hydrocarbons that had distilled over in Soxhlet flasks. Much larger quantities of residual hydrocarbons were extracted with benzene from Devonian rocks of this area in an earlier study (7). 

A few studies reported considerable intracrystalline isotopic variations within millimetre-sized saddle dolomite crystals. For example, a 1.4%o variation in 6 0 and a 0.7%o variation in 5 C were found in isotopically zoned saddle dolomite crystals from Cretaceous carbonates of south Texas (Woronick Land, 1985). In another study, a 5.2%o decrease in 6 0 (-6 to -11.2%o) and a systematic increase in fluid inclusion homogenization temperature (127-146°C) were reported for a single saddle dolomite crystal in Devonian rocks of Canada (Kaufman et al., 1990). Further, Spangen-berg et al. (1995) reported preliminary stable isotope results for intracrystalline heterogeneities in white sparry dolomite (largely equivalent to saddle dolomite) in samples from a Peruvian MVT... 

Ores of antimony sometimes occur m the Devonian rocks of Rhenish Prussia between Wintrop and Meutrop, four miles from Arnsberg, where are found bands of bituminous limestone from 6 inches to 18 inches in thickness, interstratified between clay slates and siliceous shales. Stil)uite penetrates all these strata, which are overlain by Millstone Grit. Tt is-also noticed that the stibnite accumulates more plentifully towards the middle part of the various beds, but gradually thins out near the bedding planes of deposition. Sometimes fragments of the country are included in the more massive portions. (D.)... 

Slow, continuous sedimentation during the period beginning in the Permian resulted in minimal variation in isotherm depths and in the depths of isolines (Fig. 6.17) in the Mereksen area. Our calculations of temperature and organic matter maturity in Ordovician, Silurian, and Devonian rocks at the close of the Carboniferous (approximately 288 Ma) are shown in Table 6.7. These calculations show that at the beginning of the Permian, organic matter in Ordovician and Silurian shales was in the lower part of the oil window (Fig. 6.17). 

The counting rates of the Beacon rocks appear to depend on the concentration of organic matter they contain. For example, the average gamma-ray counting rate of Devonian rocks of the Beacon... 

Billings, E. (1859) On some new genera and species of Brachiopoda, from the Silurian and Devonian rocks of Canada. Canadian Naturalist and Geologist, 4,131-135. 

Drapeau, G. and Boucot, A.J. (1969) Siluro-Devonian rocks of Lake Memphremagog. Quebec Department of Natural Resources, Geological Exploration Service, Special Paper 1,44pp. 

A series of tectonic collisions between the eastern margin of North America and other land masses during the Devonian and Carboniferous to Permian periods (approximately 400 and 300 million years ago, respectively) deformed the sequence of Silurian and Devonian rocks in the Rosendale region and uplifted the ancient Appalachian Mountains. Today, the deeply eroded western flank of the ancient Appalachian... 

FIG. 7—Simplified stratigraphic column of the Ordovician, Silurian, and Devonian rock units exposed in the Rosendale natural cement region. Dolostone from the Rosendale and Whiteport members of the Upper Silurian Rondout Formation was used in the production of natural cement. The Glasco Member of the Rondout Formation was not suitable for natural cement production. Stratigraphic thicknesses after Waines and Hoar [13] (please refer to discussion therein for information regarding geologic units not mentioned within this text). 

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