A grande maioria dos cinodontes não-mamalianos possui seu esqueleto póscraniano completo, porém muitos se encontram apenas parcialmente descritos. A maior parte do conhecimento acerca deste grupo e de suas relações filogenéticas com os mamíferos baseia-se na anatomia sincraniana e dentária, uma vez que a abundância de material desta natureza é relativamente maior do que a de restos pós-cranianos. O afloramento Schoenstatt localiza-se na periferia do Município de Santa Cruz do Sul (BR 471), Rio Grande do Sul, Brasil, ao lado da rodovia RST 287, sendo atribuído à Zona de Associação de Santacruzodon. Neste afloramento, é registrada uma fauna meso-triássica na qual predominam os cinodontes nãomamalianos, dos quais já foram registrados pelo menos 100 espécimes. Com base em material craniano e dentário, já foram reportados nesta localidade os traversodontídeos Santacruzodon hopsoni, cf. Massetognathus e Menadon besairei, enquanto que o material pós-craniano ainda não foi estudado. Esta dissertação objetiva descrever a morfologia do material pós-craniano pertencente à família Traversodontidae, coletado no afloramento Schoenstatt e depositados na Seção de Paleontologia do MCN-FZBRS, estudando comparativamente espécies das demais Zonas de Associação do Triássico do RS e de outras formações triássicas gonduâicas. Todos os restos pós-cranianos aqui descritos, foram separados em dois morfótipos distintos, sendo proposto para o morfotipo I, Menadon besairei e para o morfotipo II, Santacruzodon hopsoni. Para esta classificação, foram utilizados critérios anatômico-morfológicos específicos de cada osso, bem como o tamanho dos ossos e associação destes com material sincraniano e dentário. Após a análise morfológica, pode-se observar uma mescla de caracteres ditos “reptilianos” e outros “mamalianos” para os espécimes estudados, o que corrobora com os estudos anteriores sobre anatomia pós-craniana de cinodontes não-mamalianos, sendo observado que o morfótipo I, possui uma maior quantidade de caracteres primitivos em relação ao morfótipo II, mais derivado e similar à condição mamaliforme dos mamíferos mais primitivos. / Most of the non-mammalian cynodonts have its postcranial skeleton complete however in most cases partially described. The most of the knowledge about this group and their phylogenetic relationships with mammals is based on sincranian and dental anatomy, since the abundance of such material is relatively higher than the post-cranial remains. The Schoenstatt outcrop is located on the city of Santa Cruz do Su (BR 471)l, Rio Grande do Sul, Brazil, side of Highway RST 287, being assigned of the Santacruzodon Assemblege Zone. In this outcrop, is predominant one meso- Triassic fauna typified by non-mammalian cynodonts, of which there have been recorded at least 100 specimens. Based on cranial and dental material, have already been reported for this localition the traversodontids Santacruzodon hopsoni, Massetognathus and Menadon besairei, Whereas postcranial material has not been studied. This work aims to perform the morphological description of the postcranial material of the traversodontids collected in Schoenstatt outcrop and deposited in Paleontologycal Collection of the Fundação Zoobotânica do Rio Grande do Sul studying comparatively the other species of the others Assemblege Zones of Triassic of the RS and others Triassic Gondwana formations. All postcranial materials described herein, are separated into two distinct morphotypes, being proposed for the morphotype I, Menadon besairei and for the morphotype II, Santacruzodon hopsoni. For this classification, specific anatomical and morphological criteria of each bone were used, well as bone size, and association of these with sincranian and dental materials. After morphological analysis, we can observe a blend of "reptilian" and other mammals characters for the studied specimens, which corroborates previous studies on postcranial anatomy of non-mammalian cynodonts, been observed that the morphotype I, has a greater number of primitive characters relative to morphotype II, more derivative and similar to mamaliforme condition of primitive mammals.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-02-16T14:09:38Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 1.UNIVERSIDADE FEDERAL DE PERNAMBUCO - PDF.pdf: 2290380 bytes, checksum: 779f1a4fa95fe4cc4bf311af3f117d25 (MD5) / Made available in DSpace on 2017-02-16T14:09:38Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) 1.UNIVERSIDADE FEDERAL DE PERNAMBUCO - PDF.pdf: 2290380 bytes, checksum: 779f1a4fa95fe4cc4bf311af3f117d25 (MD5) Previous issue date: 2016-03-04 / CAPES / Apresentamos uma descrição detalhada da morfologia e osteohistologia de pequenos ossos de Arcosauromorpha encontrados da Zona de Associação de Hyperodapedon, referente à Sequência Santa Maria II, Supersequência Santa Maria, Triássico Superior do Rio Grande do Sul, Brasil. O material é composto por ossos de tamanho reduzido, com dimensões menores do que 57mm, encontrados associados in situ. O espécime é composto por um úmero e um metatarsal III direitos, extremidade proximal de uma falange ungueal, um arco neural quase completo de uma vértebra pré-sacral e um centro vertebral pré-sacral. Comparações morfológicas entre UFSM11326 e outros organismos do Triássico mostraram se tratar de um dinossauriano, com possível associação ao grupo Sauropodomorpha. São elas: morfologia da crista deltopeitoral do úmero apresentando prolongamento do cume na crista deltoide; eixo de torção das porções proximal e distal do úmero; morfologia do metatarsal III, apresentando ângulo de torção entre as extremidades proximal e distal superior a 60° e presença do ombro medial; posições da diapófise, parapófise e das infracavidades diapofisiais restantes no arco neural. Este grupo de arcossauros já foi registrado anteriormente em estratos triássicos da Supersequência Santa Maria. As análises do fechamento das suturas do arco neural indicaram um indivíduo jovem, com suturas abertas em forma de zíper. As sessões finas da diáfise do úmero e do metatarsal III, corroboram este estado ontogenético, indicando se tratar de um espécime em fase inicial de desenvolvimento. Exibiu um complexo ósseo fibrolamelar (comum em espécimes dinossaurianos), composto por ósteons primários, sem ocorrência de marcas de crescimento (LAGs ou annuli), áreas extensas de reabsorção ou a presença de lamelas circunferenciais externas (external fundamental system = EFS). Este padrão evidencia uma estratégia de crescimento rápido, sustentado por elevadas taxas metabólicas, superiores a dos répteis modernos, e comparáveis com aquelas já encontradas para este grupo de arcossauros. Definimos portanto que UFSM11326 corresponde a um Sauropodomorpha jovem, sem a conclusão de seu crescimento assintótico, com elevados níveis de deposição óssea e consequente crescimento acelerado até o momento de sua morte. / Here we present a detailed description of the morphology and osteohistology of small bones of Arcosauromorpha found at the Hyperodapedon Association Zone, referring to the Santa Maria II Sequence, Santa Maria Supersequence, Upper Triassic of Rio Grande do Sul States, Brazil. The material consists of small sized bone (dimensions smaller than 57mm) found associated in situ. The specimen consists of a right humerus and metatarsal III, proximal extremity of an ungueal phalanx, an almost complete neural arch of a pre-sacral vertebra, and a pre-sacral vertebral center. Morphological comparisons between UFSM11326 and other organisms from Triassic revealed that it is a dinosaurian, possibly related to Sauropodomorpha group. The similarities include the morphology of the deltopectoral humerus crest that has an extension of the deltoid crest; twist axis from proximal and distal portions of the humerus; morphology of metatarsal III with torsion angle between the proximal and distal extremities greater than 60° and medial shoulder; positions of the infracavities of the apophysis, parapophysis and diapophysal remaining at neural arch. This archosaurs group has already been registered previously in Triassic strata of the Santa Maria Supersequence. The analyses of the closure of the sutures of the neural arch indicate it to be a young individual with open sutures zipper-shaped. The final sessions of the humeral diaphysis and metarsal III corroborate this ontogenetic state, showing it to be a specimen at an early stage of development. A fibrolamellar bone complex that is common in dinosaurian specimens is present, composed of primary osteons, without occurrence of growth marks (LAGs or annuli), extensive reabsorption areas or external circumferential lamellas (external fundamental system = EFS). This pattern shows a rapid growth strategy, supported by high metabolic rates that are greater than in modern reptiles and comparable with those already found to this archosaurs group. We conclude that UFSM11326 corresponds to a young Sauropodomorpha without completing its asymptotic growth and with high levels of bone deposition and subsequent rapid growth until the moment of his death.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-11T11:17:51Z No. of bitstreams: 1 marciaraquelpegorarodemacedo.pdf: 5847098 bytes, checksum: 6cf16b9ed061b6daffde11584b9e8e4e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-11T13:25:30Z (GMT) No. of bitstreams: 1 marciaraquelpegorarodemacedo.pdf: 5847098 bytes, checksum: 6cf16b9ed061b6daffde11584b9e8e4e (MD5) / Made available in DSpace on 2017-05-11T13:25:30Z (GMT). No. of bitstreams: 1 marciaraquelpegorarodemacedo.pdf: 5847098 bytes, checksum: 6cf16b9ed061b6daffde11584b9e8e4e (MD5) Previous issue date: 2008-02-26 / A paleontologia do Rio Grande do Sul é conhecida principalmente pelos estudos de materiais triássicos que começaram no século passado, com as expedições de Von Huene e Price nas décadas de 20 e 40, por exemplo. Desde então novos afloramentos são constantemente descobertos e nestes, destaca-se uma variada paleofauna. Nesta paleofauna, os arcossauros, rincossauros, cinodontes, dicinodontes e procolofonídeos são os grupos mais representativos e mais estudados, com enfoque principalmente na sua morfologia, sistemática e evolução. Entretanto, pouca atenção é dada aos aspectos paleoecológicos destes grupos. Assim, este trabalho visa descrever a tafonomia e caracterizar a paleoecologia de três sítios fossilíferos do Triássico Médio do Rio Grande do Sul – Cortado, Linha Várzea e Picada do Gama. A partir da integração de dados obtidos do material coletado até o momento pode se chegar a algumas conclusões específicas sobre cada assembléia, bem como sobre a representatividade paleoecológica destas para o período temporal que compreende a Cenozona de Therapsida. A quantificação e caracterização tafonômica dos elementos ósseos e coprólitos tiveram um importante papel para a diagnose das assembléias estudadas, visto que representaram tanto a paleofauna quanto às características paleoambientais da época. Inferiu-se que a mortandade ocorrente nos sítios estudados foi natural (doença ou predação) e as assembléias formaram-se por eventos de sedimentação gradual, permitindo: a preservação de diferentes estágios ontogenéticos e de icnofósseis característicos de diferentes grupos e condições ambientais, bem como a preservação de características aleoclimatológicas do local. O Sítio Cortado e Linha Várzea representam assembléias autóctones, enquanto o Sítio Picada do Gama apresenta assembléia para-autóctone com alguns elementos bem preservados autóctones. Os Sítios Linha Várzea e Cortado são característicos de planícies de inundação e o Sítio Picada da Gama é característico de depósito de canal. Os padrões de fragmentação e o alto nível de desarticulação dos fósseis indicam período prolongado de exposição ao intemperismo e alterações eodiagenéticas. As proporções de herbívoros e carnívoros presentes em todos afloramentos indicam que os padrões de controle trófico de cadeias alimentares já apresentavam modelos complexos bem estabelecidos baseados em grandes biomassas de herbívoros sustentando carnívoros de topo. Na Cenozona de Therapsida, a base das cadeias alimentares se dava pela presença de dicinodontes como consumidores primários (herbívoros) e arcossauros no topo (carnívoros). Os cinodontes, apesar de apresentarem especializações alimentares, não foram atribuídos a nenhuma posição na cadeia, pois de acordo com a disponibilidade de alimentos, esses animais seriam menos seletivos, e, dependendo da época do ano, poderiam se comportar como oportunistas, ocupando diversas posições dentro das cadeias alimentares. / The paleontology of the Rio Grande do Sul state, southern Brazil, is known mainly by the studies of Triassic materials that had initiated in the beginning of the 20th century with the expeditions of Von Huene and Price in the decades of 20 and 40, respectively. Since then, new outcrops constantly are discovered, some of them with a rich paleofauna. In this paleofauna, the archosaurs, rhynchosaurs, cynodonts, dicynodonts and procolophonids are the most representative and more studied groups, mainly in its morphology, systematic and evolution. However, little attention is given to the paleoecological aspects of these groups. Thus, this work aims to describe the taphonomy and the paleoecology of three outcrops of the Middle Triassic of the RS – Cortado, Linha Várzea and Picada do Gama. By integrating the material collected until the moment, some specific conclusions for each assembly can be achieved, as well as on the paleoecological representation of these for the time period that contains the Therapsida Cenozone. The quantification and taphonomical characterization of the bones and coprolites had an important role for diagnosing the studied outcrops, as they record both paleofaunistic and paleoenvironmental features. The mortality of the studied outcrops was natural (disease or predation) and the assemblies had formed through time, allowing the preservation of: different ontogenetical stages; ichnofossils of different groups and environmental conditions; and paleoclimatological features of the place. The Cortado and Linha Várzea outcrops represent autochthonous assemblages while the Picada do Gama outcrop presents a para-autochthonous assemblage, with some well preserved autochthonous elements. The Cortado and Linha Várzea outcrops are characteristic of distal flooding plains and the Picada do Gama outcrop records both channel deposits and proximal flooding plain facies. The pattern of fossil fragmentation and the high level of disarticulation indicate a prolonged period of exposition to weathering and superficial eodiagenetic alterations. The rate of herbivorous and carnivores in all outcrops indicate that the patterns of trophic control of the food chains already showed complex models, established in great biomasses of herbivorous supporting carnivorous on top. In the Therapsida Cenozone, the food chains bases are represented by first-level consumer dicynodonts (herbivorous) and archosaurs in the top (carnivorous). Cynodonts, although presenting food specializations, had not been attributed to any position in the chain, as these animals would be less selective, and depending on the time of the year, they could behave as opportunists, occupying diverse positions inside of the food chains.

The Glacier Creek volcanogenic massive sulfide (VMS) deposit is hosted within Late Triassic, oceanic back-arc or intra-arc, rift-related, bimodal volcanic rocks (Hyd or Tats Group) of the allochthonous Alexander terrane known as the Alexander Triassic Metallogenic Belt (ATMB). The deposit presently consists of four tabular massive sulfide lenses with a resource of 4.75 Mt. at 1.84% Cu, 4.57% Zn, 0.15% Pb, 0.28 g/t Au and 29.07 g/t Ag. A deposit-scale thrust fault offsets stratigraphy along the axial surface of a deposit-scale anticline. The massive sulfide lenses are barite-rich and are divided into 6 main ore-types based on mineral assemblages. There is a large range of sphalerite compositions, with low-Fe sphalerite dominant throughout the lenses and high-Fe sphalerite at the top and bottom of the lenses in pyrrhotite-rich zones. Lenses contain anomalous Sb, Hg and Tl. Gangue minerals include barite, quartz, barian-muscovite, calcite, albite, highly subordinate chlorite and locally hyalophane and celsian. Overlying massive sulfide is a tuffaceous hydrothermal sediment with anomalous REE patterns and local hyalophane. The general footwall to all four lenses is a thick unit of coherent to volcaniclastic feldspar-phyric basalt containing extensive lateral alteration. Four alteration facies are recognized based on mineral assemblages. Mass balance calculations for the footwall indicate general gains of S, Fe, Si and K with coincident loss of Ca, Na and Mg, along with trace element gains of Tl, Sb, Hg, Ba, Zn, Cu, As and loss of Sr with increased alteration intensity. Short wavelength infrared (SWIR) spectroscopy shows a general decrease in Na, K and Al content of muscovite and increase of Fe+Mg and Ba content towards ore. Integrated petrographic, mineral, chemical and sulfur-isotope data suggest a transition during deposit formation, from high-temperature, acidic, reduced hydrothermal fluids mixing with oxidized, SO4-rich seawater, to later cooler, low fO2-fS2 conditions of formation and a lack of SO4 in seawater.

Upper Triassic and Jurassic rocks in the central Graham Island area comprise shale, siltstone, sandstone, and conglomerate of the Kunga, Maude, and Yakoun Groups. Volcanic rocks are common in the Middle Jurassic Yakoun Group. The oldest unit exposed within the study area is the Lower Jurassic Sandilands Formation of the Kunga Group, a more than 250 metre thick sequence of interbedded organic-rich shale, tuff, siltstone, and sandstone. The Lower Jurassic Maude Group conformably overlies the Kunga Group and is divisible into four formations. The Ghost Creek Formation is an organic-rich black fissile shale, and is overlain by calcareous sandstone of the Fannin Formation. The Whiteaves Formation consists of fissile calcareous grey shale that grades upwards into fossil-rich medium- to coarse-grained, sandstone of the Phantom Creek Formation. The base of the Middle Jurassic Yakoun Group is marked by an angular unconformity. The unit is more than 1500 metres thick and is divided into four lithofacies. The lowermost shale and tuff lithofacies is a sequence of interbedded shale, tuff, siltstone, and sandstone, with shale dominating. The sandstone lithofacies overlies and partly interfingers with the shale and tuff lithofacies and comprises medium- to thickly-bedded lithic arenite interlayered with thinly-bedded shale. The conglomerate lithofacies exists within the sandstone lithofacies and consists mostly of thickly-bedded pebble and cobble conglomerate. The volcanic lithofacies interfingers with, and overlies the sedimentary rocks of the Yakoun Group, and includes lava flows, pyroclastic rock deposits, and lahars. The Kunga and Maude Groups record several relative changes in sea level. They formed in a progressively deepening basin. In Pliensbachian time, the basin shallowed and deposition, represented by the upper Fannin Formation of the Maude Group, was near-shore. Toarcian time is marked by an abrupt transgression. The upper part of the Whiteaves Formation and the Phantom Creek Formation of the Maude Group indicate a subsequent regression. The sedimentary rocks of the Yakoun Group were deposited in local shallow marine basins. Volcanic rocks are most abundant in the eastern parts of the map area, and indicate that an igneous source is located in that direction. All rock units in the map area are deformed by major northwest-trending faults and folds, reflecting at least four northeast-southwest oriented deformational events. The angular unconformity at the base of the Yakoun Group restricts one compressional phase to mid-Jurassic time. Abundant southwest-verging folds suggest development of northeast-dipping thrust faults during this compressional event. Northeast-trending normal faults cut through the thrust faults, postdating them and indicating a period of extension. Rocks of the Sandilands Formation are observed thrust on top of the Yakoun Group, thus indicating a second compressional event. Several small-scale strike-slip faults cut through all described rock units and overlying Tertiary sections, suggesting a late Tertiary deformational event. The Middle Jurassic compressional event may be a result of collision of Wrangellia with North America, or could have been caused by changes in relative plate motion between the North American and Pacific plates during the break-up of Pangaea. Lithologic similarities between the Jurassic and older units of Wrangellia on the Queen Charlotte Islands and coeval rocks of the Alexander terrane in southeastern Alaska suggest that there are no clear differences between the two, and that they were contiguous since Upper Paleozoic time. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Ammonoids were collected from the Chainman Formation (Mississippian) of southeastern Nevada and southwestern Utah, the Phosphoria Formation (Permian) of southeastern Idaho and westernmost Wyoming, and the Thaynes Formation (Triassic) of northeastern Nevada and southeastern Idaho. The collections are interpreted to represent unwinnowed, untransported death assemblages of ammonoids which were subject to chemical conditions of the nekto-benthic environment. Associated lithologies were sampled and geochemically analyzed for content of phosphate and organic matter. Ammonoid fossil collections, combined with ammonoids ilustrated in the literature, were subjected to the graphical W and D analysis of Raup (1967). The basic parameteres involved in the description of shell-coiling geometry are whorl expansion rate, W, and the distance of the generating curve from the axis of coiling of the shell, D. Values of W determined range from 1.32 to 3.96, which correspond to slight and rapid increases in whorl height during coiling. Values of D determined range from 0.02 to 0.55, which correspond to extremes of involute and evolute coiling· geometries, respectively. Body chamber length corresponds with shell coiling geometry. Values determined in this study range from 10° to 540°. Corresponding W values are 3.96 and 1.50, whereas corresponding D values are 0.02 and 0.40, respectively. Average body chamber length in analyzed ammonoids is observed to decrease from 297° to 209° from Mississippian to Triassic time. Increase in apertural area accompanied this trend, and a possible consequence was that a greater range of prey sizes was afforded ammonoids with shorter body chambers. Life-orientation, described as the angle between the apertural plane and the gravitational vector, is calculated entirely on shell form and other geometrical considerations. Recent observations concerning Nautilus, combined with fossil evidence of epizoan encrustation suggest that ammonoids had an ability to control orientation, which is not observed from preservable morphology. From Mississippian to Triassic time, no trends in reconstructed life-orientation can be substantiated, based solely on Wand D values. Rotational stability during directed locomotion is important for conservation of the energy budget of this nektonic carnivorous organ­ ism. This property is calculated by the distance between the center of buoyancy and the center of gravity of the ammonoid. Values deter­ mined range from .04 (very unstable) to .16 (very stable). Corres­ ponding W values are 1.50 and 4.00 where corresponding D values are 0.20 and 0.02, respectively. A trend toward increasing average rota­tional stability (.07 to .10) is noted for amrnonoids from Mississippian to Triassic time. Efficiency in the utilization of calcium carbonate is the ratio of internal volume of the shell to volume of shell material. Values determined range from 5.80 to 7.25. Corresponding W values are 4.00 and 1.50, corresponding D values are 0.02 and 0.54, respectively. Abundant ammonoids found in black, phosphatic limestones rich in organic matter have an average efficiency value of 6.2. Abundant ammonoids from corresponding light-colored crystalline carbonates have an average efficiency value of 6.02, and indicate no correlation between effi­ciency and abundance. Size-frequency distributions are utilized in recognition of oppor­tunistic species of ammonoids. High numerical abundance, high mortality rate of juveniles, small size and conservation of calcium carbonate typifies the paleo-opportunistic species Cravenoceras, Psuedogastrio­ceras and Ophiceras. Biovolume-relative abundance distributions are useful in discerning the carrying capacity of the habitat both in number of individuals and species diversity. A large area under the biovolume-relative abun­dance profile indicates diversification under optimum environmental conditions; a small area under the profile indicates colonization of a stressful habitat. The Chainman, Phosphoria and Thaynes (Columbites Zone) Formations have ammonoid assemblages which show small areas under the biovolume-relative abundance profile, characteristic of anoxic environmental stress. The Permian stratigraphic units correlative with the Phosphoria Formation have ammonoid assemblages which show large areas under the profile and the associated lithologies, i.e., light­ gray,crystalline carbonates, suggest environments which could support a diversified ammonoid fauna, including large-sized species. Ontogenetic variation produces changes in the body chamber length, life orientation, rotational stability, and utilization of calcium carbonate of the analyzed genera of ammonoids. These ontogenetic variations usually resulted in the development of more involute shell-coiling geometries. Corresponding size-frequency distributions suggest increased mortality rates during ontogeny for some genera (Paracravenoceras, Medlicottia) which show decreasing efficiency in the utilization of calcium carbonate. (182 pages)

The ~2 km-thick Late Triassic Sugarloaf Arkose is the basal unit of the half-graben Deerfield basin, Massachusetts. Valley-river, piedmont-river, and alluvial-fan depositional facies within the arkose are defined by paleocurrent data and style of sedimentation. The valley rivers flowed from northeast to southwest, and the facies is present from the bottom to the top of the formation. Piedmont rivers built a megafan eastward into the basin, beginning about in the middle of the arkose. The local alluvial fan built from east to west in the upper-third of the formation. The petrology of the medium sand and conglomerate was used to delineate the source areas for each facies. The medium sand in the valley rivers is mostly granite and granite gneiss fragments, coarsely-polycrystalline quartz grains, and twinned plagioclase. This assemblage is a mixture of granite from continental basement uplift, granite gneiss from a dissected magmatic arc, and phyllites and schist from a recycled collision orogen. The medium sand in the piedmont-river facies lacks granite fragments, and untwinned plagioclase is more abundant than twinned: the provenance is continental basement uplift and recycled collision orogen. The alluvial-fan provenance is similar to the valley rivers, combining recycled collision orogen and dissected magmatic arc. Unlike the valley rivers, granite gneiss and untwinned plagioclase in the alluvial fan are dominant over granite and twinned plagioclase. Quartz provenance in the three facies was granite, trending to granite gneiss in the piedmont-river and alluvial-fan facies. In all facies, plagioclase feldspar is more common than K-feldspar in the medium sand. The conglomerate pebbles, however, are dominated by K-feldspar, most likely due to erosion of pegmatites in the source terrane. Gray quartzite, white and translucent varieties of quartz, and pink granitoid pebbles are also common. The post-depositional diagenesis of the Sugarloaf Arkose affects provenance determination. Diagenetic events include: hematite grain coats, mechanical compaction, albitization of feldspars, albite and quartz overgrowths, authigenic hematite cement, carbonate cement, and illite replacement of feldspars. Within the dry-dominated monsoonal paleoclimate, each facies formed in response to tectonism. The initial appearance of each facies is used to determine the timing of tectonic events. The valley rivers flowed from the northeast in an early NNE-SSW-trending ‘sag’ basin, associated with minor normal faulting. The initial appearance of the east-flowing piedmont rivers about half way up the section implies an early, down to the west, basin-bounding normal fault, which formed perpendicular to N70E-S70E extension. This fault propagated, and, on reaching the northeast corner of the basin, the alluvial fan built to the west off the fault scarp. The Amherst block is a relay ramp between basin-bounding faults in the Deerfield and Hartford basins. Linkage of the two basin-bounding faults through the Amherst block created an integrated basin linking the Triassic strata in the early Hartford and Deerfield basins, and may have caused the unconformity present at the top of the arkose.

No description available.

No description available.

Logging of cores of the Upper Permian and Lower Triassic Khuff Formation, Ghawar, Saudi Arabia, has allowed a high resolution sequence stratigraphic framework to be generated. The lithofacies of this huge, arid epeiric ramp succession include: subaqueous -and supratidal anhydrite, tidal flat laminites, lagoonal mudstone, ooid-peloid grainstone, and subtidal off-shoal open marine mudstone. Third order sequences include the Late Permian upper Khuff C, the Early Triassic Khuff B and the Khuff A sequences, which corrrelate with global cycles. Seven high frequency sequences (HFSs) make up the Changhsingian upper Khuff C. These HFSs are ~400 k.y. duration and probably driven by long term eccentricity. The Early Triassic Khuff B and A sequences are made up of 4 HFSs each, which appear to be ~100 to 200 k.y. duration and not easily tied to eccentricity forcing. The HFSs are in turn composed of parasequences, which appear to be 10 to 20 k.y. average durations, suggesting precessional and half precessional forcing. However, many thin locally developed cycles may be autocycles or subprecessional cycles. Sequence stratigraphic cross sections and facies maps document progradation directions on the platform, reflecting the subtle interplay between the Ghawar structure and regional paleoslopes. Anhydrites are rare in the Permian Upper Khuff C except near the base of the studied interval. Anhydrites are well developed in the Triassic Khuff B and Khuff A where some form transgressive deposits while others are highstand deposits of high frequency sequences. The Permian-Triassic boundary (PTB) on the Arabian Platform marks a significant relative sea-level drop, that exposed from the outcrop belt to somewhere east of Ghawar. This contrasts with transgressive PTB settings elsewhere. Across the PTB the mass extinction is marked by a major decrease in biotic groups. The extinction was followed by development of subtidal thrombolites and increased microbial calcification due to decreased bioskeletonization. The dominant reservoirs in the Permian Upper Khuff C occur in oolite in the uppermost high frequency sequence. In the Triassic Khuff B and A the reservoir facies are commonly non-dolomitized oolitic facies associated with open lagoon carbonates distant from evaporitic tidal flats. Within dolomitized units, best reservoirs are associated with oomoldic porosity, but oolite units proximal to evaporitic tidal flats have porosity plugged by anhydrite. Carbon and oxgyen isotope profiles up to 150 m long were obtained from cored wells of the Khuff Formation, Ghawar Field, Saudi Arabia, across the Permian-Triassic boundary. Major global excursions are at the Changhsingian-Wuchiapingian boundary and the Permian-Triassic boundary, but several smaller excursions also appear to correlate with excursions elsewhere. The presence of the negative C-isotope excursions globally in both δ¹³Ccarbonate and δ¹³C organic as well as in deeper water sections lacking emergence surfaces, strongly supports the idea of these excursions being global phenomena related global C cycling. Over 75% of the negative carbon isotope excursions in Ghawar occur beneath emergence surfaces, including the two major excursions at the Wuchiapingian and Changhsingian stage boundaries. The δ¹³C profiles beneath the boundaries resemble those iii associated with early diagenesis associated with isotopically light soil gas. The δ¹⁸O profiles beneath the surfaces are variable, perhaps reflecting variable effects of evaporation on the meteoric input, mixing or overprinting by burial diagenesis. This suggests that the C-isotope excursions on the Arabian Platform, although global in origin, appear to have been modified by early diagenesis. U depletion across the boundary is compatible with the postulated origins of the PTB event with bottom waters becoming stagnant and reducing, as a result of warming induced by volcanogenic CO₂ released by Siberian trap volcanism, methane release from thermal metamorphism of coals and destabilization of clathrates in the deep sea due to ocean warming. The global extent of the C-isotope and U excursions provides a high resolution correlation tool for Late Permian and Early Triassic successions. / Ph. D.