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The Pennsylvanian Fire Clay tonstein of the Appalachian basin - its distribution, biostratigraphy, and mineralogy: discussion

Article Abstract:

The 1994 compendium by Rice et al. repeated obsolete hypotheses regarding the Fire Clay tonstein by omitting a few key references. Recent works by Webster et al., Congdon et al. and Lyons et al. show that silica-melt inclusions are more important than what Rice et al. posit in their paper. Webster et al. showed that Appalachian tonsteins range in composition; Congdon et al., that tonsteins can be differentiated by silica-melt; and Lyons et al., that distinctions can also be made between North American and European tonsteins. Through silica-melt, accurate sourcing of Fire Clay tonstein is possible.

Observations, North America, Silica, Vitreous, Vitreous silica, Volcanic ash, tuff, etc., Volcanic rocks, Mineralogy, Determinative, Determinative mineralogy

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Paleozoic and Mesozoic rocks of Stikinia exposed in northwestern British Columbia: implications for correlations in the northern Cordillera: discussion and reply

Article Abstract:

Efforts to describe the stratigraphic relationships of rocks in British Columbia, particularly in northern Cordillera, reflects the unending pursuit of earth scientists to reinterpret terrane and assemblage relationships. Although these researches provide new insights on the causes of surface deformations, they have undermined the value of terrane analysis. By adopting inconsistent methods for performing terrane analysis, researchers have over emphasized rock differences at the expense of their similarities.

Evaluation, Geological research, British Columbia

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Fringe cracks: key structures for the interpretation of the progressive Alleghanian deformation of the Appalachian plateau

Article Abstract:

The fringe cracks evident in the vertical joints of Devonian clastic sedimentary rocks of the Finger Lakes, NY-area, establishes the development of Alleghanian deformation that occurred in the Appalachian plateau. The character of the fringe cracks and its relation to the parent joints indicates the occurrence of deformation and the behavior of twist hackles, whether abrupt or gradual. The systematic behavior of the fringe cracks could be used as a method to identify the tectonic history of the area.

Geology, Structural, Structural geology, Rocks, Sedimentary, Sedimentary rocks, Finger Lakes (New York)

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