The research reported in this thesis focuses on Late Cretaceous and Cenozoic fossil brachiopods of Western Australia. Although the work is primarily taxonomic, it also includes biodiversity, distribution and some aspects of ecology of the brachiopods described.The most recent information on the anatomy, physiology and ecology of brachiopods is summarised at the beginning of the thesis.Identification of brachiopods is determined primarily on internal morphological features as brachiopods tend to be homomorphic, many species looking externally the same. The morphological features used in the identification of the brachiopods described within the thesis are defined.The fossil material studied has come from four sedimentary basins in Western Australia. The Carnarvon Basin contains Late Cretaceous and Cenozoic fossil material. The Perth Basin also has Late Cretaceous and late Cenozoic brachiopods The Bremer and Eucla Basin have Cenozoic deposits. The stratigraphy of the deposits containing the brachiopods is described.Until this study commenced, eight species had been described from Western Australia. This thesis describes fifty eight species including thirty new species, one new family and two new genera.In preparing descriptions of the new species it become evident that many of the species from the Southern Hemisphere were quite different to those found in the Northern Hemisphere. Their closest affiliation was with genera and species described from the Antarctic Peninsula. Four genera and one species from the Late Cretaceous deposits of Western Australia are common to the Late Cretaceous deposits of the Antarctic Peninsula. In the examination of the Tertiary material from the Carnarvon Basin, it also became clear that there was a strong correlation with Tertiary material from the Antarctic Peninsula. At least four genera are common to both deposits. Six brachiopod ++ / genera from the Middle Miocene deposits of the South Shetland Islands Antarctica are common to New Zealand. Nine genera, identified from the La Meseta Formation, Seymour Island, Antarctic Peninsula, are also common to New Zealand. These genera are also found in Australia. This evidence has led to the proposal that in the Late Cretaceous there was a common shelf environment from the Antarctic Peninsula to the north-west coast of Western Australia. In this area, which formed the high latitude southern circum-Indo-Atlantic faunal province, brachiopods evolved different genera and species than those in the northern hemisphere. Many then dispersed into northern areas of the Indian, Atlantic and finally Pacific Oceans.When the material from the Middle to Late Eocene of the Bremer and Eucla Basin was examined, five genera were found to be common to the Early Tertiary of the Carnarvon Basin. When comparing the species from the south-western basins and those from the south- east it was evident that similar species occur in the Middle to Late Eocene of the Bremer, Eucla, St Vincent and Murray Basins. There are some fifteen species in common. Many of these species then occur in the Late Oligocene south-eastern basins near Victoria and Tasmania as the gap between the Australia mainland and Tasmania began to open. One species that occurs in the Late Eocene of Western Australia is also described from the Late Oligocene of New Zealand.In considering the distribution of the Cenozoic brachiopods, genera first appear in the north-west of Western Australia and they then appear in chronological order in the south-western basins and south-eastern basins of South Australia, then the south-eastern basins of Victoria and Tasmania and then New Zealand. By the Late Eocene, there was a shallow marine connection between the Bight and the Tasman Sea. By the Late Oligocene this had widened and ++ / Australia was finally totally separated from Antarctica.The Proto-Leeuwin Current was responsible for the distribution of the brachiopods from the north-west of Western Australia to the southern coast. Possible mechanisms for the distribution of genera to New Zealand include rafting and an extended larval stage.It has been suggested that brachiopods in Australia are distributed according to the substrate on which they settle rather than any other factor. Using the information on the distribution of brachiopods in Western Australia throughout the Cenozoic this hypothesis is examined. It is suggested that avoidance of light in the photic zone and food availability with competition with bivalves are more important factors than substrate conditions.

Central southern Fiordland, New Zealand, is underlain extensively by metasediments and associated metavolcanics. These are mapped in three lithostratigraphic units, from west to east Edgecumbe Group, Cameron Group and Cumbrae Supergroup. Lower Cameron Group units lithocorrelate with Central Fiordland Belt lithological associations and with those of Fraser Complex, Westland. Eastern Fiordland Belt metavolcanics and lacustrine metasediments are tectonostratigraphically unrelated to Cameron Group, from which they are separated by the Grebe Fault. They instead have affiliations with the Loch Burn Formation, Largs Volcanics, Drumduan Group and Paterson Group. These units (collectively, "Cumbrae Supergroup") represent remnants of a Triassic-Jurassic calc-alkaline arc. Six deformational episodes are identified in central southern Fiordland. The earliest, D₁, is obliterated by D₂ and M₂ metamorphism. D₃ is restricted to the Southwest Fiordland Block. D₄ occupied a brief interval of M₃ time. D₄ of the Central and Western Fiordland Belts corresponds to earliest deformation in Eastern Fiordland Belt metavolcanics. The Grebe Fault is a left-lateral reverse D₄ fault; now vertical, it previously dipped eastward. The Dusky Fault, a reactivated D₅ left-lateral transfer structure, accommodated the dip-slip component of displacement at low-angle normal faults during mid-Cretaceous extension. Open folds represent D₆. Post-glacial scarps mark the post-D₆ Kilcoy and Vincent Faults. Their merged northward continuation is intersected by the tailrace tunnel of the Manapouri Hydroelectric Power Station. Southwest Fiordland Block pelites were metamorphosed at 665 �C, c. 3 kbar during M₂. Early M₃ is of contact metamorphic aspect. Late M₃ is distinctively polybaric: Central Fiordland Belt kyanite-garnet pelites recrystallised at c. 8.5 kbar after metamorphism in the sillimanite field at c. 3.5 kbar. Western Fiordland Orthogneiss 12 kbar granulite assemblages formed during late M₃. South of the Dusky Fault, late M₃ is almost asymptomatic. The M₃ field gradient is continuous across the Grebe Fault: in the Eastern Fiordland Belt, late M₃ staurolite and garnet supersede chloritoid in lacustrine (meta-)sapropel-silts. The Grebe Fault is an important tectonostratigraphic break; it may separate New Zealand�s Western and Eastern Provinces. Its relationship to any "Median Tectonic Zone" is unclear, as no such zone has been found in southeastern Fiordland. Cumbrae Supergroup rocks within the "Median Tectonic Zone" represent the arc that nourished the Eastern Province�s Barretts Formation, Murihiku Supergroup and Stephens Subgroup. The Cumbrae arc was �obducted� westwards during Early Cretaceous continent-arc collision. This event simultaneously halted Eastern Province volcanogenic sedimentation and tectonically buried Fiordland, imposing late M₃ pressure increments. Drumduan Group lawsonite is coeval. Cretaceous collision induced glaciation. Late Cretaceous climatic deterioration and extensional tectonism caused icecap development. The Otago "Peneplain" is a Late Cretaceous subglacial floor. Accumulation of voluminous perennial Cretaceous ice on Earth has hitherto not been inferred. Facultative psychrophily in New Zealand�s ancient endemics and their preference for dark conditions reflect passage through a hitherto-unsuspected evolutionary bottleneck: prolonged winter darkness and harsh climate of near-polar Late Cretaceous New Zealand exerted extraordinary evolutive pressures on ancestral forms after biotic links with Gondwana were severed. New Zealand�s ancient endemics are the evolutionary derivatives of a Late Cretaceous near-polar fauna.

Many scientific studies have been conducted on the Cretaceous-Paleogene boundary (KTB) in the Gulf coast region and, in particular, the Brazos River section in Falls County, Texas. Despite this, there remains much to be learned about the KTB and its depositional environment. Study of the KTB has been multidisciplinary, primarily in the fields of sedimentology and paleontology. Some researchers in these disciplines have questioned the consensus view of the placement of the KTB and subsequent interpretation of the timing of depositional events and mass extinction events. Geophysical methods have potential to provide additional understanding of the physical properties of the KTB. To date, study of the KTB has relied on point data and borehole information to create cross sections of the complex. Seismic refraction surveys can provide spatially continuous information on susburface horizons located adjacent to the KTB. In this study, seismic first-arrival traveltimes are processed with a tomographic modeling program to map the top of the hummocky cross-bedded sandstone (HCS), which is a key indicator of the deposition environment at the time of KTB boundary complex placement. The survey area is located at Cottonmouth Creek, a tributary of the Brazos River. Three seismic lines were surveyed, one across Cottonmouth Creek, and two parallel to the creek on either side. The data from the two parallel lines were processed using the 2-D seismic refraction tomography algorithm of Zelt and Smith. The reconstructed depth to the HCS in the survey area is approximately 6 m, with layer seismic velocities of 364, 1800, and 2200 m/s, respectively. Seismic tomography successfully mapped the HCS layer and reveals approximately 1 m amplitude undulations vertically and undulations on the order of several m horizontally. These variations are consistent with exposed surfaces of the HCS in the creek bed. Seismic refraction has been utilized successfully herein to map a key buried indicator, namely the top of the HCS layer, associated with the KTB complex. A detailed 3-D seismic refraction survey at this site is recommended to generate a high-resolution 2-D terrain map of the top of the HCS layer.

Many of the world's oil fields and aquifers are found in carbonate strata. Some of these formations contain vugs or cavities several centimeters in size. Flow of fluids through such rocks depends strongly upon the spatial distribution and connectivity of the vugs. Enhanced oil recovery processes such as enriched gas drives and groundwater remediation efforts like soil venting operations depend on the amount of hydrodynamic dispersion of such rocks. Selecting a representative scale to measure permeability and dispersivity in such rocks can be crucial because the connected vug lengths can be longer than typical core diameters. Large touching vug (centimeter-scale), Cretaceous carbonate rocks from an exposed rudist (caprinid) reef buildup at the Pipe Creek Outcrop in Central Texas were studied at three different scales. Single-phase airflow and gas-tracer experiments were conducted on 2.5 in. diameter by 5 in. long cores (core-scale) and 5- to 10-ft-radius well tests (field-scale). Zhang et al. (2005) studied a 10 in. diameter by 14 in. high sample (bench-scale). Vertical permeability in the bench-scale varied from 100 darcies to 10 md and in the core-scale averaged 2.5 darcies. The field-scale permeability was estimated to be 500 md from steady state airflow and pressure transient tests. In the bench and core scales a connected path of vugs dominates flow and tracer concentration breakthrough profile. Tracer transport showed immediate breakthrough times and a long tail in the tracer concentrations characterized by multiple plateaus in concentrations. Neither flow nor tracer transport can be explained at these scales by the standard continuum equations (Darcy’s law or 1D convection dispersion equation). However, interpreting field-scale measurements with standard continuum equations suggested that a strongly connected path of vugs did not extend past a few feet. In particular, the tracer experiment in the field scale can be modeled accurately using an equivalent homogeneous porous medium with a dispersivity of 0.5 ft. In our measurements, permeability decreased with scale, while vug connectivity and multi-scale effects associated with vug connectivity decreased with increasing scale. We concluded that approximately 5 ft could be considered the representative scale for the large-touching-vug carbonate rocks at the Pipe Creek Outcrop. The major contribution of this research is the introduction of an integrated, multi-scale, experimental approach to understanding fluid flow in carbonate rocks with interconnected networks of vugs too large to be adequately characterized in core samples alone. / text

Lower Cretaceous strata in central Texas are divisible into genetically related rock bodies. The Lower Trinity Group contains a lower terrigenous near shore deposit (Hosston Formation) which interfingers with an overlying shallow water, offshore limestone-dolomite sequence (Sligo limestone); this Group may contain a barrier reef section downdip. The Middle Trinity Group, a sequence of grey to black shale and limestone, does not intercalate with either the underlying or overlying rock bodies. Updip, near the Texas craton hingeline, it is separated from the overlying rocks by a disconformity. Downdip the Stuart City reef, a rudistid limestone, exists continuously between the top of the Middle Trinity Group and the upper part of the Georgetown formation of the Washita Division. Back reef deposits are separable into Upper Trinity Group, Fredericksburg Group and part of the Washita Division. The Upper Trinity Group consists of the basal Hensel sand (mostly updip outside the area of study) which intercalates going downdip with the usually dolomitic Glen Rose limestone. The middle part of the lower Glen Rose contains a reefal limestone section which is restricted to the area near and over the San Marcos arch and near the Stuart City reef. The upper Glen Rose is a sequence of dominantly evenly-bedded, dolomitic, foraminiferal limestone. The Fredericksburg Group includes the East Texas basin lagoon deposits of the Walnut and Comanche Peak formations and the rudistid limestone deposits of the lower Edwards. The lower Edwards intercalates with the lower units of the Walnut over the San Marcos arch and with successively higher units toward the East Texas basin; lower Edwards and Comanche Peak produce a similar pattern. The basal unit of the Washita Division is a widespread black shale (Kiamichi) and shaley limestone (middle (Kiamichi) Edwards) which is absent by onlap around the Belton high (proposed new term). The dolomitic, rudist limestone of the upper Edwards interfingers with the lower beds in the Georgetown limestone north of the San Marcos arch. The remainder of the Georgetown and the overlying Del Rio clay are laterally continuous throughout the area of study. The Buda limestone pinches out near the edge of the Texas craton and thickens going southeast and downdip.

No description available.

Intermediate igneous rocks exposed in the Badger Pass area and 3.5 km away in the McDowell Springs area of Beaverhead County, Montana, previously mapped as Cretaceous intrusive (Ki), and Cretaceous undifferentiated volcanics (Kvu) respectively, exhibit little geochemical variation. Trace element, and lead isotope analyses provide strong evidence allowing for a single source. REE patterns, obtained through ID-ICP-MS, are essentially identical. Mineral/melt Eu analyses reveal that Eu behaved predominantly as a divalent cation, refuting an earlier study asserting that trivalent Eu dominated. Data suggest rocks were formed under low oxygen activity conditions, not oxidizing conditions as previously reported. Geochemical data combined with field mapping allow us to establish the temporal relationship between late Cretaceous thrusting, intrusion, and volcanism in this locale. Folding, faulting and thrusting were significantly, if not entirely, completed prior to the commencement of volcanism. Volcanism included contemporaneous thrust plate intrusion, foreland extrusion, and hypabyssal foreland intrusion.

Four new lepidosaurs from the Early Cretaceous deposits of the Tlayua Quarry, Central Mexico are described, establishing their phylogenetic relationships using cladistic methodology. These lepidosaurs have unique characters never present in related forms suggesting that they have evolved in isolated environments far from immediate ancestors, indicating the insular nature of the quarry. The sphenodontid Pamizinsaurus tlayuaensis is covered with unique rows of small rounded osteoderms that could have protected it against predation in open environments. Ankylosphenodon pachyostoseus has unusual teeth ankylosed deep into the dentary with probable continuous growth, which combined with propalinal action of a deep lower jaw suggest herbivory. Unique pachyostotic ribs and vertebrae, delay in the ossification of the epiphyses, and zygapophyses horizontally oriented to stiffen the vertebral column could be related to aquatic behavior. The unique morphology of Pamizinsaurus and Ankylosphenodon argue against the concept of low morphological diversification of sphenodontians. / The lizard Huehuecuetzpalli mixtecus shows most iguanian features, but still retains a divided premaxilla, amphicoelous vertebrae, thoracolumbar intercentra, and the second distal tarsal, supporting a phylogenetic position as sister-group of squamates. Although late in the fossil record, Huehuecuetzpalli provides important information on early transformation of characters in lizard evolution. Tepexisaurus tepexii is an early scincomorph relatively more primitive to all known scincoids. The lack of osteoderms indicates that Tepexisaurus and some paramacellodids are not scincoids, suggesting that the Paramacellodidae is not monophyletic. The relative primitive morphology of Tepexisaurus in Albian deposits can be correlated with the late presence of sphenodontians and the relictual nature of Huehuecuetzpalli in Tlayua. This suggests that TIayua was a refuge for archaic terrestrial forms. / Character transformation at the origin of the Squamata was explored through a phylogenetic analysis including basal lepidosauromorphs, the best known early squamates, and extant squamate "families". Results using a rigorously reviewed data set, show that many characters suggested to be squamate autapomorphies are certainly along a lineage basal to the Squamata, which includes Marmoretta, Tamaulipasaurus, the Ardeosauridae (redefined to include Bavarisaurus), and Huehuecuetzpalli. The name Squamatoidea to group all taxa basal to Squamata + squamates is suggested. The Total Branch Support index obtained falls between values of other published phylogenies. The low values seem to be affected by the inclusion of several fossil taxa with incomplete information and the redistribution of a limited number of characters in a greater number of branches.

Underground coal fires commonly metamorphose or melt surrounding rocks at temperatures exceeding 1000°C. Numerous “baked” sandstone clinker deposits occur in the Cretaceous sedimentary rocks exposed in the San Rafael Swell, UT. This study examines clinker in three main localities: 1) East Carbon, UT, 2) Helper, UT, and 3) Emery, UT. The extent of pyrometamorphism in these areas is variably developed, but reached high enough temperature in Helper, UT to initiate melting and the production of paralavas. These paralavas were examined compositionally and mineralogically to determine melting conditions, peak temperatures, and mobility of different metals as a result of pyrometamorphism. X-ray diffraction and petrographic analysis showed that paralavas in the Helper locality contain the high temperature SiO2 polymorphs tridymite and cristobalite which alone indicate temperatures exceeding 875°C in several samples. Paralavas containing diopside+tridymite and cordierite+mullite+cristobalite provide more restrictive estimates of temperature as they form cotectic and eutectic assemblages in the SiO2-Mgo-CaO and SiO2-MgO-Al2O3, respectively. The assemblages indicate minimum temperatures of melting and metamorphism of 1330–1465ºC. The high temperatures of the paralavas generate increased metal mobility, potentially signifying a hazard if leached out into the environment

The collection and analysis of a large number of belemnites and oysters with excellent biostratigraphic and diagenetic control has resulted in a highly detailed determination of the seawater Sr-isotope curve through the Jurassic and Early Cretaceous. The new data confirm the broad trends established by previous work, but the much sharper resolution of the new data allows the application of Sr-isotope stratigraphy with an optimal stratigraphic resolution of ± 1 to 4 ammonite subzones (± 0.5 to 2 Ma). The data show a general decline from the Hettangian (Early Jurassic) to a minimum in the Callovian and Oxfordian (Middle/Late Jurassic). This is followed by an increase through the Kimmeridgian (Late Jurassic) to a plateau reached in the Barremian (Early Cretaceous). In addition, there are major negative excursions in the Pliensbachian/Toarcian (Early Jurassic) and Aptian/Albian (Early Cretaceous). Stable isotope data collected from belemnites and oysters have resulted in the most extensive Jurassic δ¹³C and δ¹⁸O database to date. While both the carbon and oxygen data appear to give reasonable marine signals, the scatter in the data suggests that future research must document possible biological fractionation effects and develop better indicators for the diagenetic alteration of 613C and 6i 8O. The final chapter documents an unexpected correlation between sudden shifts in the Sr-isotope curve, the occurrence of positive 513C excursions, and the eruption of flood basalts. In the Jurassic and Cretaceous there is a correlation in time between sudden downward shifts in the Sr-isotope curve (Pliensbachian, Aptian, Cenomanian/Turonian), the occurance of positive 613C excursions, and the eruption of flood basalts. Each of these major downward shifts in the Sr-isotope curve is followed by a sudden upward shift, which although associated with a positive 613C excursion is not associated with an episode of flood basalt volcanism. In the Cenozoic the Sr-isotope curve no longer displays downward shifts, but the correlation continues between the occurrence of flood basalts and positive 513C excursions. Several lines of evidence suggest that the eruption of flood basalts is associated with pulses of hydrothermal activity, and that this hydrothermal activity brings about the conditions necessary for the genesis of carbon-burial events.