Physical Sciences and Mathematics Commons^™

Evaluating The Deep-Sea Coral Acanella From Hawaii As A Paleoceanographic Archive, Geraldine Hourigan Lantier

Geology Theses and Dissertations

Deep-sea corals have emerged as potential proxies of changing paleoceanographic properties. The utility of deep-sea corals for the purpose of interpreting paleoclimatic reconstructions is still in the discovery phase. However, long life spans, a relatively stable habitat, and unique growth geometry provide support to the growing body of research that has identified deep-sea corals as indicators of past climate and ocean properties. Two colonies of Acanella were collected from the permanent thermocline at depths between 414 and 437 m in the Makapuu Coral Bed, Oahu, HI in 1997 by submersible. Here I present results from a pilot study of the …

Thermochronological Evidence For Neogene Incision Of The Rio Pativilca Canyon, Northern Peru, Matthew James Montario

Geology Theses and Dissertations

The Peruvian Andes have attained modern elevations of ~4000 m. Many peaks along the drainage divide are in excess of 5500 m with ~2-3 km of vertical relief, and canyons cut into the western edge have up to 3.5 km relief. The Rio Pativilica Canyon is cut into a folded Mesozoic marine sequence intruded by granitic rocks of the Coastal Batholith, which are overlain by Tertiary volcanics: this canyon has relief in excess of ~3 km. Based on geomorphological evidence, two episodes of valley incision cut the Puna erosional surface: 1) The Vallé stage, which is characterized by broad valleys …

Mapping Of A Detachment Fault In Kythera Island And Study Of The Related Structural Shear Sense Indicators, Antonios Marsellos

Geology Theses and Dissertations

Kythera Island is located on the prominent submarine horst between Crete and the Peloponnese in the southwestern part of the Aegean. The structure of Kythera is characterized by a pile of tectonic slices derived from different paleogeographic zones. The upper unmetamorphosed units comprise pelagic limestones and cherts of Pindos zone emplaced by thrusting in the Eocene on top of Tripolis zone neritic limestones. These units are separated from the lower metamorphosed unit of Phyllite-Quartzite (PQU) exposed in the northern part of Kythera by an extensional detachment fault of Late Miocene age. The lower tectonic unit of PQU was affected by …

Complexity Of Devonian K-Bentonites In The Appalachian Foreland Basin: Geochemical And Physical Evidence Supporting Multi-Layered K-Bentonite Horizons, Lucas Benedict

Geology Theses and Dissertations

Detailed analysis of Lower to Middle Devonian K-bentonites in the Appalachian Basin reveals physical and geochemical characteristics within supposed single eruptive event deposits that indicate a more complex depositional history is recorded in many of these volcanic beds. Variations in bedding showing multiple coarse and fine-grained layers within a K-bentonite layer can be seen in some Devonian K-bentonite beds. Microscopic irregularities show variations in the orientation of volcanic grains, and subtle phenocryst layers within a K-bentonite suggest changes in depositional environment where changing water and wave regimes rework and redeposit material on the sea floor. The presence of fossil layers …

Analysis Of Glasses Present In Quartz And Apatite Phenocrysts From Ordovician K-Bentonites In The Mohawk Valley, Ny, Stefanie Dannenmann

Geology Theses and Dissertations

More than 20 bentonites occur in the Middle Ordovician black shales of the Utica Formation that outcrop along tributaries to the Mohawk River in New York State. Pristine melt inclusions within quartz and apatite phenocrysts are commonly found in at least 40% of the bentonites. Constraints on magmatic processes can be obtained by examining the major-, minor- and trace-element variations among different melt inclusions in quartz and apatite phenocrysts from individual bentonites. The melt inclusions in apatite range in composition from rhyodacitic to rhyolitic, while those in quartz are high-silica rhyolites. Most bentonites within the Middle Ordovician sequence in New …

Pre-Thrust Normal Faults And Post-Tectonic Micas In The Taconic Range Of West-Central Vermont, Nicholas W. Hayman

Geology Theses and Dissertations

New geologic maps show that the Champlain Thrust System traces continuously between Shoreham and Benson, Vermont. The Champlain Thrust System consists of at least three internally imbricated thrust slices in continental shelf facies quartzites and carbonates. From north to south there is a structurally controlled thinning of the Champlain Thrust System, and a climbing in stratigraphic level by the thrusts. Within the Champlain Thrust System are a set of across-strike structures which create offsets in the thrusts and the surrounding lithic map unit boundaries. These structures function as lateral ramps in the thrust system geometry and bound thrust duplexes. Often …

Correlation Of The Tioga Bentonites Using Rhyolitic Melt Inclusions Found In Quartz Phenocrysts As Geochemical Fingerprints, John W. Waechter

Geology Theses and Dissertations

The Tioga bentonites were first noted by Fettke in 1931 from well cuttings in the Tioga gas fields of Tioga County, Pennsylvania. They have been used by many investigators (Oliver, 1954, 1956; Dennison, 1963; Dennison and Textoris, 1967, 1978; Epstein, 1986; Smith and Way, 1983; Way et al., 1986) as a time-plane to correlate stratigraphic units from eastern Pennsylvania to Illinois and from southern Ontario to Virginia. The Tioga bentonites are recognized as seven major volcanic ash layers labeled Tioga-A - Tioga-G as well as several minor layers labeled Tioga-A1 - Tioga-A3 (Way et al., 1986). They occur within the …

The Origin Of Metalliferous Argillites In The Shoal Arm Formation Of North-Central Newfoundland, Volker Brüchert

Geology Theses and Dissertations

The Middle Ordovician Shoal Arm Formation, which is located in the central volcanic belt of north-central Newfoundland, is a tripartite assemblage of hematitic argillites, grey cherts, and black shales directly underlying a flysch sequence. The hematitic argillites are enriched in Fe, Mn, Ni, Pb, and Co. Factor analysis and principal component analysis indicate the presence of a hydrothermal component, presumably derived from hydrothermal activity in the coeval Lawrence Head volcanics. Unusual, (?) calcareous Mn-Fe-oxide nodules are present in the top parts of turbidites in the hematitic argillites. Electron microprobe analysis of a color transition from a red to a green …

Slickenside Petrography: Slip-Sense Indicators And Classification, Young-Joon Lee

Geology Theses and Dissertations

Petrographic study has been carried out on slickenside thin sections, to find out reliable microstructures for determining the slip-sense of faults, and to classify slickensides morphologically. Thin sections are made cut parallel to the striation and perpendicular to the slip plane. Many useful slip-sense indicators are found in thin section even though such indicators may be absent in hand specimens. They are (1) off-set or bending of once-continuous bodies such as veins, layers, grains or twin lamellae, (2) crystal fibers growing nearly parallel to the slip direction, (3) extensional fractures aligned oblique to the slip plane, (4) S-C geometries in …

Origin, Sedimentary Geochemistry, And Correlation Of Middle And Late Ordovician K-Bentonites: Constraints From Melt Inclusions And Zircon Morphology, Carsten Schirnick

Geology Theses and Dissertations

The present study of Paleozoic K-bentonites demonstrates that the geochemistry of melt inclusions and the morphology of zircons can be studied by inexpensive and simple-to-use methods, which rely on phenocrysts. Constraints are obtained that lead to (a) the origin of these altered volcanic ashes, (b) the geochemistry of ash-to-K-bentonite-alteration, and (c) the reliable correlation of extensively altered volcanic ashes (i.e. K-bentonites).
Silicic melt inclusions (i.e. non-devitrified) have been found in quartz and zircon phenocrysts contained within Ordovician and Devonian K-bentonites from New York State, the Upper Mississippi Valley, and Pennsylvania. Origin, source, and tectonic setting of the volcanism that produced …

Granitic Pegmatites In The Southeastern Adirondacks: Their Use As Indicators Of Temperature, Pressure, And Fluid Conditions During A Late Stage Of The Grenville Orogeny, John P. Mihalich

Geology Theses and Dissertations

Granitic pegmatites associated with the Grenville orogeny intrude a mid-Proterozoic, upper amphibolite to near granulite facies terrane in the southeastern Adirondack Mountains of New York State. The inferred anatectic, fluid-saturated, and minimum melt characteristics of the pegmatites suggest that they can be used as analogs of the "granite" or "haplogranite" system, and as indicators of crustal temperature, pressure, and fluid conditions during a late stage of the Grenville orogeny. Bulk chemical compositions of seven simple, undeformed pegmatites in the southeastern Adirondacks indicate that they are generally depleted in silica and sodium, and enriched in potassium, relative to experimental data on …

Sedimentology And Tectonic Significance Of The Nutzotin Mountains Sequence, Alaska, Jane Kozinski

Geology Theses and Dissertations

The Nutzotin Mountains Sequence, a Mesozoic flysch sequence in the eastern Alaska Range, was studied along the southern border and in the central portions of the outcrop belt. Three lithologic associations are recognized in the Bonanza Creek section (southern margin) that together indicate a coarsening-upward trend, suggestive of a prograding fan system. These associations are (from bottom to top): 1) debris flow conglomerates overlain by 500 m of intercalated mudstone and base-missing turbiditic siltstone, and mass movement features such as slump folds and slump horizons, 2) 195 m of thicker, coarser turbidites intercalated with mudstones; turbidites are graded but lack …

A Numerical Approach For Determining The Variable Ascent Velocity Of A Granitoid Diapir, Keith I. Mahon

Geology Theses and Dissertations

A mathematical model for granitoid diapirism has been developed that accounts for the time dependent thermal and rheological conditions encountered by the intruding body. This model is derived by the simultaneous solution of the partial differential equations of energy, continuity, and momentum utilizing scaling analysis. The underlying assumption is that deformation of the surrounding country rock is confined to a relatively thin layer with a temperature dependent Newtonian viscosity. When the country rock is modeled as a power-law fluid, the effective viscosity is dependent upon temperature and shear strain rate.
This model allows for realistic temperature gradients within the crust …

Geology Of The Frozen Ocean Lake - New Bay Pond Area, North-Central Newfoundland, Timothy M. Kusky

Geology Theses and Dissertations

Rocks of the Frozen Ocean Group outcrop in the Frozen Ocean Lake-New Bay Pond Area, Newfoundland, and are here divided into four formations. The Lewis Lake Formation forms the base of the Frozen Ocean Group, and is composed predominantly of mafic volcanic flows; this is conformably overlain by the Blue Star Formation which is entirely sedimentary in nature. The Blue Star Formation is in turn conformably overlain.by the Bursey Point Formation, which is a mixed volcanic and sedimentary unit. The top of the Frozen Ocean Group is marked by the Lynx Pond Formation, a mixed silicic- and mafic-volcanic formation, with …

Structural Analysis Of Deformed Carboniferous Strata, Mispec Beach, Southern New Brunswick, Lauren Magin Bradley

Geology Theses and Dissertations

Mispec Beach, New Brunswick is a coastal exposure of deformed Carboniferous sedimentary rocks. Late Paleozoic deformation in the region is thought to have occured in a restraining bend in the Cobiquid - Chedabucto fault.
Within this exposure, two main generations of deformation are recognized. The first deformation is associated with slaty cleavage development, pebble elongation, and the formation of quartz veins. The second generation structure is a moderately developed crenulation cleavage. The diversity of structures present at this outcrop allows for a qualitative determination of the principal axes of stress and strain associated with the first generation structures.

The Geology Of Ophiolitic And Adjoining Rocks Of Chagnon Mountain, Southern Quebec, Janet M. Harris

Geology Theses and Dissertations

Chagnon Mountain is located near the southern end of the Baie Verte-Brompton Line in the Eastern Townships of southern Quebec. The lithologic units in the area of study, from west to east and going up structure, are: gabbro, quartz-diorite, diabase, volcanics, the St. Daniel Formation and the Peasley Pond Conglomerate of the Glenbrooke Group. All these rocks have been metamorphosed to the greenschist facies. Contacts between the plutonic rocks are irregular and gradational indicating only one parent magma. Diabase dikes are present in the diabase unit and in the volcanics indicating the dikes acted as feeders to the volcanics. Geochemical …

Some Aspects Of Deformation Fabrics Along The Highland/Lowland Boundary, Northwest Adirondacks, New York State, Peter C. Hall

Geology Theses and Dissertations

The Geology of the Whippoorwill Corners Area, NW Adirondacks, NYS
In the northwestern Adirondack Mountains of New York State lies a 110 km long, 0-5 km wide topographic and lithologic boundary which divides the Adirondack Highlands from the Northwest Lowlands. Structurally this boundary is apparently a highly strained zone of intensely foliated and lineated rocks. Within the zone mineral grains are highly recrystallized and of fine grain size with respect to rocks outside the zone, quartz becomes undulose, and mineral assemblages frequently exhibit retrograde characteristics. Despite the apparent high strain no demonstrable offset may be seen across the zone. Furthermore, …

Chatham Fault Zone, Old Chatham-East Chatham, New York: Mesostructures And Microstructures: Their Spatial And Age Relationships, Jorge Mora M.

Geology Theses and Dissertations

Detailed studies in rocks of Mettawee (Late Precambrian? to Early Cambrian) and Walloomsac (Middle Ordovician) slates between Old Chatham and East Chatham, New York, have shown that these rocks were intensely deformed during the Taconic orogeny and a later deformation event(?). Two generations of structures are clearly recognized in the area. The first generation (G1) includes tight west-verging folds whose axial plane foliation is the regional foliation slaty cleavage (S1). These structures are considered synchronous with the regional metamorphism of the Taconic orogeny and correlative with those structures belonging to the D2 deformation event proposed by Ratcliffe (1979) and Rowley …

Provenance Study Of The Middle Ordovician Sandstones Of New York And Western Vermont, Stephen A. Tanski

Geology Theses and Dissertations

Medial Ordovician rocks exposed in westernmost New England and eastern New York State include thick sequences of marine sandstones which are part of a belt extending from Newfoundland to Tennessee. A petrographic study was made of 237 samples distributed across the entire outcrop belt (approx. 250 km. north-south along strike and 190 km. east-west across strike).
Two distinct types of sandstone are recognized, the oldest, and most widespread, is a deep water lithic wacke deposited by turbidity currents and found interbedded with shale (flysch). The younger sandstone is found only in the southeastern part of the study area and is …

Geology Of The Fondo Negro Region, Dominican Republic, J. Calvin Cooper

Geology Theses and Dissertations

Detailed geologic mapping of the Fondo Negro-Sierra de Martin Garcia region of the Southwestern Dominican Republic establishes that this area is part of a broad and diffuse Northern Caribbean plate boundary zone (PBZ). Faulting in the study area is predominantly left lateral strike-slip, with secondary compression (thrusting) causing both substantial, and rapid, uplift of the region. Folding associated with the wrench faulting affects rocks of all ages in the field area from Paleocene limestones to Quaternary alluvial fans.
New stratigraphic designations are proposed for mappable litho-units in the area, and these are correlated with Hispaniola stratigraphy in general based on …

Geology Of The Plutonic And Hypabyssal Rocks Of The Betts Cove Ophiolite Complex, Newfoundland, Bruce D. Idleman

Geology Theses and Dissertations

The Betts Cove ophiolite complex lies within the Dunnage Zone island arc terrain of central Newfoundland. It forms the base of the lower Ordovician Snooks Arm Group, which consists of mafic igneous rocks of the ophiolite and a thick sequence of volcanic and volcaniclastic rocks which conformably overlies it. The Snooks Arm Group is unconformably overlain by sub-aerial sediments and volcanics of the presumed Silurian Cape St. John Group.
The base o£ the ophiolite complex consists predominantly of ultramafic rocks. These are interlayered on a variety of scales, and show mesoscopic igneous structures which suggest that they were produced by …

Some Chemical And Mineralogical Aspects Of Plutonic Rocks From The North Arm Mountain Massif, Bay Of Islands Ophiolite, Newfoundland, Jerry W. Sullivan

Geology Theses and Dissertations

Whole-rock major and trace element compositions of one basalt, one diabase, and 21 rocks from the magmatic-plutonic units of the North Arm Mountain massif, Bay of Islands ophiolite, Newfoundland, were determined. Mineral compositions of a subset of the plutonic rocks were also determined.
The major and trace element compositions of the basalt and diabase are similar to abyssal tholeiites, and this is consistent with the REE data of Malpas (1978) and Suen, et. al. (1979) that suggest the lavas and dikes formed from a depleted or slightly enriched abyssal tholeiitic magma. The alkaline nature of the magma proposed by several …

Structural Studies Of The Ordovician Flysch And Melange In Albany County, New York, Frederick W. Vollmer

Geology Theses and Dissertations

The middle Ordovician rocks of the Albany 15 minute quadrangle comprise interbedded graywacke and shale, and in the east, coarse cobble or olistostromic deposits. The detrital composition, westward fining and regional westward transgression of these deposits indicate that these were sediments shed off the westward thrusting Taconic Allochthon. Primary sedimentary structures show that these rocks were deposited by turbidity currents flowing into a longitudinal trough, probably formed in response to increased load during overthrusting. Although strongly dependent on lithology, deformation intensity generally increases from west to east; from essentially undeformed bedded flysch through asymmetrically folded and thrust beds to highly …

Petrography, Mineral Chemistry And Microstructures Of Gabbros From The Mid-Cayman Rise Spreading Center, Frieda L. Malcolm

Geology Theses and Dissertations

The suite of gabbroic rocks collected by the DSRV ALVIN in 1976 and 1977 from the walls of the Mid-Cayman Rise spreading center were studied in detail to provide the best available data on plutonic rocks sampled directly from the ocean floor. The rock types studied include variably deformed and altered gabbros, orthopyroxene gabbros, olivine gabbros and troctolites, and a few amphibolites. Mineral chemical analyses suggest that the various rock types are representative of a fractionation trend from magnesian troctolites through olivine and clinopyroxene gabbros to iron-enriched orthopyroxene gabbros. Within many individual samples, the primary mineral phases are apparently chemically …

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 Lucea Inlier, Western Jamaica, Jack Grippi

Geology Theses and Dissertations

The Lucea Inlier exposes a Santonian to Campanian 4 km + thick sequence of shale-siltstone, resedimented volcaniclastics, lenses of shallow-water limestone, micritic limestone, pebbly mudstone and sandy pebble to boulder conglomerate. Clastics were deposited by a variety of gravity flow mechanisms. Petrographically sandstones are lithic or feldspathic arenites and contain only very small amounts of detrital quartz. Structurally the inlier is characterized by simple, open, east-west trending folds. A spaced, vertical axial-planar cleavage is developed in shales and fine siltstones. Two major east-west trending left-lateral fault zones, the Fat Hog Quarter and Maryland faults, cut the inlier into three blocks, …

Long-Distance Turbidite Correlations In The Horseshoe Abyssal Plain, William H. Hoyt

Geology Theses and Dissertations

Few studies on modern abyssal plain turbidites have attempted to assess the lateral extent of individual units and few have therefore been able to provide any information on the evolution of turbidity deposits across long abyssal plain distances. In the 4755 m-deep Horseshoe Abyssal Plain, ten distinct lithologic units (six of these Iberian Peninsula-derived turbidites) were delineated in nine piston cores on the basis of stratigraphic position, thickness (range of 20 cm to greater than 500 cm), color, sediment type, sedimentary structures, x-ray mineralogy, and the ubiquitous presence of units in all abyssal plain and supplying canyon piston cores. In …

Structural Studies In The Moretown And Cram Hill Units Near Ludlow, Vermont, William J. Gregg

Geology Theses and Dissertations

The geology of the eastern limb of the Green Mountain Anticlinorium consists of a series of Paleozoic metasedimentary rocks with lithologic boundaries arranged in a remarkably straight trend approximately parallel to the axis of the Green Mountains. Published reports of the area, consisting largely of reconnaissance mapping, have treated this complex series of polyphase deformed rocks as an essentially upright autocthonous sedimentary sequence. Boundaries between rock units have, for the most part, been assumed to be primary in origin, as have various structural elements within the rock units. More recent work in selected areas within the Ludlow Quadrangle has revealed …

A Study Of Some Petrologic And Structural Aspects Of The East Dover Ultramafic Bodies, South Central Vermont, Mark Allen Hoffman

Geology Theses and Dissertations

INTRODUCTION (pp.1-4)

Mineralogical, textural and chemical changes of ultramafic rocks in response to regional deformation and metamorphism are, at best, imperfectly known (Miyashiro, 1973, p. 30). In Vermont, which has an extremely prominent and well-exposed belt of ultramafics (fig. 1), investigation of these rocks has largely been directed toward such processes as serpentinization, steatitization, and the formation of metasomatic zones at the contacts with country rocks. With few exceptions, there is a lack of detailed descriptions of regional metamorphic textures, mineralogy, and structures developed in the Vermont ultramafic rocks. It is the main purpose of this thesis to describe the …