No description available.

No description available.

No description available.

No description available.

Paleozoic rocks of Vancouver Island are exposed in three major belts: the China Creek-Saltspring, the Home Lake-Cameron River, and the Buttle Lake-Big Interior belts. Stratigraphic sequences in these three belts are grossly similar, though differing in detail. The Paleozoic rocks of each belt are correlated with the Sicker Group, originally defined in the southern part of the China Creek-Saltspring belt. Within the Sicker Group, two major lithological units are recognized, and are referred to as the Lower and Upper Divisions of the group. The base of the Sicker Group has not been seen. The upper contact of the group appears to be anpaunconformity, above which Upper Triassic volcanic and sedimentary rocks of the Vancouver Group occur. The Lower Division consists mainly of volcanic rocks and non-calcareous clastic rocks. In the Upper Division, limestones and thin-bedded cherty sediments predominate. The major unit within the Upper Division of the Buttle Lake-Big Interior belt is a limestone formation (named herein) of 1000 to 1100 feet maximum thickness. Thin-bedded, fine-grained non-calcareous rocks of unknown age, tentatively included within the Sicker Group Upper Division, conformably overlie the limestone at certain localities. A rich fauna of brachiopods, bryozoans, molluscs, corals and foraminifers has been found in the Upper Division. A meagre flora of algae and fragments of vascular plants is present in a locally-developed basal sandstone of the Upper Division. At least 42 genera, represented by 52 species, have been recognized in the Upper Division fauna; many fossils remain to be identified. Four of the brachiopod species are regarded as new. Faunas similar to that of the Upper Division of the Sicker Group have been listed or described from other northern Cordilleran regions. Correlation is thus suggested with the Permian Coyote Butte Formation of central Oregon, the Black Mountain Formation of northwestern Washington, part of the Cache Creek Group of mainland British Columbia, and parts of the Permo-Carboniferous successions of Alaska and Yukon Territory. Permian faunas of the Arctic Archipelago, Greenland, Spitsbergen and northwestern Russia contain many genera and some species in common with the fauna of the Sicker Group. Species of Hor-ridonia, Spiriferella and Kochiproductus are particularly significant in this regard, linking the Sicker Group fauna with the "Arctic Permian" and "Russian" boreal faunas. Despite the strong boreal affinities of the Vancouver Island fauna, however, relationships also with western Pacific equatorial faunas are suggested by certain brachio-pods and many of the bryozoans. The faunal relationships thus established, and the presence of certain diagnostic brachiopods and tentatively identified fusulinids, indicate the age of the Upper Division of the Sicker Group to be Early Permian (Wolfcampian-Leonardian). The evident mixing in the Permian fauna of Vancouver Island of elements of boreal and equatorial faunas prohibits conclusive bio-geographic analysis at the present stage of investigation. The present evidence of faunal distributions is also inconclusive with respect to the assessment of theories of continental drift and polar wandering. Lower Division rocks represent deposits of a moderately deep gulf or basin on the continental borderland, formed during a period marked by tectonic and volcanic activity. Diminishing crustal unrest culminated in the shoaling waters and carbonate deposits characteristic of the Upper Division. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Ordos basin rests upon the North China Block and is one of the largest sedimentary basins in north China, with more than 15 km of Phanerozoic strata. Published estimates suggest that over 2000 m of carbonates and lesser amounts of siliciclastics were deposited on the North China Carbonate Platform (NCCP) from the Lower Can1brian through the Middle Ordovician. However, lower Paleozoic facies successions and deposystems of northwestern Ordos basin remain poorly represented in western literature. This paper constrains depositional environments, lithologies, facies relationships and sea-level history of the northwestern part of the North China block (NCB) in an effort to further document the Early Paleozoic geologic history of western Ordos basin. New stratigraphic data come largely from measured sections in the Zhuozi Shan and Helan Shan in northwest Ordos basin. Strata in the mountains of northwestern Ordos are divided into eleven lithofacies assemblages, distinguished by lithology, stacking patterns and sedimentary structures. Lithofacies assemblages in northwest Ordos are grouped into four lithostratigraphic units that make up the composite type section. Unit A is dominantly composed of shale and mudrock lithofacies, Unit B is dominantly composed of thin-bedded lime mudstone and banded and bioturbated lime mudstone to wackestone, Unit C is dominantly composed of quartz sandstone and dolostone and Unit D is dominantly composed of fossiliferous packstone. These four units were observed in all lower Paleozoic sections of the Helan Shan and Zhuozi Shan. Deposition of Middle Cambrian through lowermost Lower Ordovician strata in northwest Ordos basin occurred on a storm-influenced, mixed siliciclastic and carbonate, shallow-water ramp. Lateral trends in quartz sandstone, paleokarsts, thrombolites and section thickness suggest that accommodation space increased to the south. The depositional architecture changed in the Middle Ordovician to a carbonate shelf environment. The sea-level history of northwestern Ordos shows transgression through the Late Can1brian, regression in the Early Ordovician, followed by a Middle Ordovician transgression, corresponding with North American sea level signatures. Lower Paleozoic sections in northwestern Ordos basin are broadly similar to those previously described in western literature. However, based upon stratigraphic data, shoreline trends of the NCCP model are proved inapplicable to northwestern Ordos. There is no evidence for lower Paleozoic tectonics such as aulacogen-controlled subsidence and platform tilting as described by previous workers. The sea-level history interpreted for northwest Ordos basin is more similar to North American curves than to the North China Carbonate Platform model, suggesting a eustatic control on lithofacies stacking patterns in northwest Ordos basin.

No description available.

No description available.

No description available.

Reprocessing of line PR3 proprietary seismic reflection data (24-fold) has delineated Grenvillian, Paleozoic and Mesozoic structures within the Appalachian foreland, Blue Ridge, and Piedmont of the central Appalachians. The eastern portion of PR3 can be correlated along strike with the western portion of line 1-64, reprocessed earlier at Virginia Tech. The 1-64 seismic reflection data (12-fold) images the crust from the eastern Valley and Ridge, Blue Ridge, Piedmont and Atlantic Coastal Plain provinces. Automatic line drawing displays were produced from both data sets for the purpose of interpreting and comparing subsurface structures. Within the Piedmont, large reflective structures imaged on both lines PR3 and 1-64 are interpreted to be nappes that might be comprised of deformed Catoctin, Evington Group and possibly younger metamorphosed rocks. A concealed extension of the Green Springs mafic mass intrudes a nappe imaged along the PR3 profile. The Blue Ridge-Piedmont allochthon was transported in a northwest direction along the Blue Ridge thrust, which ramped upward beneath the Piedmont province approximately 12 km east of the surface exposure of the Mountain Run Fault. Along line PR3, the Blue Ridge thrust maintains an undulating geometry, and the maximum thickness of the Blue Ridge allochthon is interpreted to be approximately 4.5 km. The Blue Ridge metamorphic allochthon is generally acoustically transparent and overlies parautochthonous Lower Paleozoic shelf strata. The maximum thickness of these strata is approximate1y 8 km. Shelf strata are interpreted to extend as far east as 5 km east of the surface exposure of the Mountain Run Fault, the northeastward extension of the Brevard Fault Zone, where they are truncated by the Blue Ridge thrust at a depth of 10.5 km (3.5 s). Various folds and blind thrusts are imaged beneath the Appalachian foreland; however, the foreland does not appear to have experienced the same degree of deformation as observed in the eastern provinces. A basement uplift approximately 45 km wide is imaged beneath the Valley and Ridge province and is interpreted as having formed prior to Upper Cambrian time. Further west, reflections itnaged beneath the Glady Fork anticline in the Appalachian Plateau are interpreted as a positive flower structure associated with wrench fault tectonics. Relatively few deep crustal reflections are inlaged along line PR3. The majority of reflections that does exist at these depths is observed beneath the Piedmont and eastern Blue Ridge. The high reflectivity associated with the Grenvillian basement in these areas suggests that this crust was deformed during compression related to the Paleozoic orogenies and extension related to Late Proterozoic and Mesozoic rifting. / Master of Science