Physical Sciences and Mathematics Commons^™

Paleoclimatic Implications Of Oxygen Isotope And Sedimentological Study Of Late Miocene And Early Pliocene Sediments From The South Atlantic, Western Indian Ocean, And The Gulf Of Aden, Kathryn M. Scanlon

Geology Theses and Dissertations

Previous work by many authors has implied that the Antarctic ice sheet underwent a major expansion in the latest Miocene. It was intended in the present study to use the oxygen isotope event, which could be expected to accompany this glacial expansion, as a stratigraphic marker to aid in the correlation of several DSDP Sites. Samples were taken at approximately 100,000 year intervals throughout the latest Miocene and early Pliocene sections at Sites 237 and 249 in the western Indian Ocean, Site 360 in the South Atlantic and Site 231 in the Gulf of Aden. Oxygen isotope analyses were done …

The Development Of Foliations In Low, Medium And High Grade Metamorphic Tectonites, William J. Gregg

Geology Theses and Dissertations

Studies of foliation and associated microstructures are presented from a variety of rock types and localities in the metamorphic terrains of the northeastern United States.
At Islesboro, Maine cleavage is well developed in lower greenschist grade siltstones and interbedded pelites of lower Paleozoic age. Cleavage in the siltstone units consists of two types of discrete mica films: short film segments and lengthened mica film. Thick secondary mica-rich layers are also exhibited in some siltstones. The short film segments appear to be basic elements through which cleavage development progresses by a linkage process that is poorly understood. The linkage of these …

Geology Of The Badger Bay-Seal Bay Area, North-Central Newfoundland, K. Douglas Nelson

Geology Theses and Dissertations

Coastline in the Badger Bay-Seal Bay area of north-central Newfoundland exposes the thickest and least disrupted section of Ordovician rocks in Newfoundland's Central Volcanic Belt. The following conformable stratigraphic sequence is observed: 1) >5 km. of variegated mafic and silicic submarine volcanics and volcaniclastics of lower Ordovician age; 2) a thin (<.5 km.) sequence consisting of thin bedded red and green argillites, manganiferous cherts, bioturbated cherts and black sulferous graptolite-bearing argillites of Caradocian age; 3) >1.2 km. of quartz-rich sandstones of upper Ordovician age. Correlative sequences occur to the east in the Fortune Harbour Peninsula area and on New World Island. Together they record Early Ordovician island arc volcanism, Medial Ordovician cessation of volcanism and subsidence, and Medial through Late Ordovician uplift and …

Stratigraphy And Petrology Of The Nooksack Group In The Glacier Creek-Skyline Divide Area, North Cascades, Washington, Jon Niels Sondergaard

WWU Graduate School Collection

The 6-7 kilometer thick Upper Jurassic-Lower Cretaceous Nooksack Group is divided informally into four units on the basis of lithology. The basal unit consists of tuffaceous sandstone and keratophyric tuff with minor intercalations of argillite and intermediate crystalline volcanic rocks. The lower unit is composed of interbedded black argillite and volcaniclastic sandstone. The middle unit consists of thick-bedded volcaniclastic sandstone and coarse, sedimentary breccia with minor argillite. The upper unit is comprised of interbedded black argillite and volcaniclastic sandstone.

Lithologies and sedimentary structures within these units suggest: (1) the lower and upper units represent depositional lobe deposits of a middle …