Os sambaquis do litoral sul brasileiro são marcos paisagísticos, com valor histórico e científico. Constituem-se, predominantemente, de conchas de moluscos e sedimentos com marcante presença de matéria orgânica, empilhados em conformações estratigráficas variadas. Neste trabalho, elegeram-se como objetos de estudo três sambaquis da costa centro-sul de Santa Catarina, com dois tipos de conformações distintas: de um lado, os sambaquis Carniça III e Encantadas III, e, de outro, o Jabuticabeira II, maior e estratigraficamente mais complexo. A proposta é auxiliar na reconstrução dos hábitos e costumes dos povos que viveram nesta área litorânea durante grande parte do Holoceno pré-descobrimento, e inferir suas relações com a evolução do ambiente geológico que os cercava. Para isso, foca-se em duas metas ou objetivos maiores: a aplicação de análise de fácies e de arquitetura deposicional nos sambaquis selecionados; e a investigação do uso de sedimentos paleolagunares como seu material construtivo. Para buscar estes objetivos, utilizou-se uma abordagem multi-analítica, que compreendeu: análise de fácies; determinação dos teores de matéria orgânica e carbonatos mais fosfatos; caracterização da fração grossa por lupa; granulometria; mineralogia de grãos pesados; estudo petrográfico e micromorfológico em seção delgada; microscopia eletrônica de varredura; e geoquímica e isotopia de carbono e nitrogênio. A estratigrafia dos sambaquis Carniça III e Encantada III é composta por um núcleo arenoso sobreposto por camada preta orgânica rica em conchas e artefatos antrópicos (terra preta, codificada como fácies LA). Em contraste, o sambaqui Jabuticabeira II caracteriza-se pela intercalação entre camadas conchíferas e lâminas pretas contendo sepultamentos (fácies funerária, codificada como Lc), capeada por camada de terra preta, rica em artefatos e sepultamentos. Por meio da análise de fácies, foi possível distinguir neste sambaqui três associações, da base para o topo: cascalho-lamosa, areno-lamosa e cascalho-arenosa. A sucessão vertical destas associações reflete o assoreamento progressivo do sistema lagunar e configura assim a relação do sambaqui com o ambiente deposicional do entorno. As associações de fácies, de qualquer hierarquia, são delimitadas pelas lâminas da fácies Lc. As análises do material construtivo utilizado nos sambaquis indicaram proveniência a partir das feições deposicionais mais próximas aos sítios, representadas por fundo, margem e brejo lagunar, nos casos dos sambaquis Jabuticabeira II e Encantada III, e por cordões litorâneos lagunares e dunas eólicas superimpostas, no caso do sítio Carniça III. Os parâmetros granulométricos e os índices de minerais pesados revelaram controle sobretudo geográfico em sua distribuição. A análise de componentes fosfáticos aliados aos sinais isotópicos do carbono e nitrogênio indicam grande processamento antrópico no material constituinte das lâminas funerárias e da terra preta do sambaqui Jabuticabeira II, com características de matéria orgânica putrefata, provável refugo do processamento cotidiano dos sambaquieiros. Já para o Carniça III e Encantada III, este processamento teria sido muito menor. / The sambaquis (also known as shell mounds or shell middens) in the Brazilian southern coast are landscape references and bear historical and scientific value. They are predominantly constituted of mollusk shells and sediments and also hold a sound presence of organic matter, piled up in different stratigraphic configurations. In this work, three sambaquis in the central-southern coast of the Santa Catarina state have been chosen as objects of study. They present two distinct configuration types: on one hand, the Carniça III and the Encantadas III, and, on the other hand, the Jabuticabeira II, which is larger and stratigraphically more complex. The proposal is to assist on the reconstruction of habits and traditions of the people who lived in this coastal area during a great part of the Holocene period (before the Portuguese navigators arrived in Brazil in 1500), and to infer their relations with the evolution of the surrounding geological environment. Two main goals have been set for this purpose: the application of facies analysis and depositional architecture in the selected sambaquis; and the investigation of the use of sediments from paleo-lagoons as their construction material. In order to achieve these goals, a multi-analytical approach has been used comprising: facies analysis; quantity evaluation of organic matter and carbonates associated with phosphates; characterization of the thick fraction in stereomicroscope; granulometry; heavy grains mineralogy; petrographic and micromorphological study of the thin section; scanning electron microscopy (SEM); and both carbon and nitrogen geochemistry and isotopy. The stratigraphy of the Carniça III and Encantada III sambaquis is composed of a sandy nucleus covered with a black organic layer full of shells and anthropic artifacts (black soil, represented as LA facies). In contrast, the Jabuticabeira II sambaqui is characterized by an assorted sequence of shell layers and thin black layers containing burial remains (funerary facies, represented as Lc) covered by black soil, and full of artifacts and burials. According to the facies analysis results, three associations have been found in this sambaqui, from bottom to top: muddy-gravel, muddy-sand and sandy-gravel. The vertical sequence of these associations reflects the progressive aggradation of the lagoon system and it establishes, thus, the relation between the sambaqui and the surrounding depositional environment. The facies associations, in any hierarchy, are limited by the thin layers in the Lc facies. The analysis of the construction materials used in the sambaquis has set their provenance in the nearest depositional features to the sites, represented by the lagoon bottom, margin and swamp for the Jabuticabeira II and Encantada III sambaquis, and by coastal lagoon barriers and superimposed wind dunes for the Carniça III site. The granulometric parameters and the heavy minerals indexes have showed control, mainly geographic, in their distribution. The analysis of phosphate components associated with the carbon and nitrogen isotopic signals shows great anthropic processing in the material which constitutes the funerary and the black soil layers found in the Jabuticabeira II sambaqui, with putrid organic matter characteristics, a probable waste from the day-by-day processing of the people who built the sambaquis. On the contrary, this kind of processing is supposed to have been much lower in the Carniça III and the Encantada III sambaquis.

The Arctic is climatically sensitive to global change and therefore climate records from this region are of key importance. Little, however, is known of the state of the Arctic in the traditionally “greenhouse” period of the Cretaceous. Climate conditions are often assumed to have been warm-temperate as evidenced by the presence of conifers and dinosaur trackways on Svalbard and other Arctic localities. However, isotopic evidence for cooling episodes, sequence stratigraphic evidence for interpreted glacio-eustatic sea-level falls, and the presence of more enigmatic deposits such as dropstones and glendonites has led to a re-evaluation of the question of climatic dynamism during the Cretaceous. This project evaluates the climatic and environmental character of Arctic Svalbard during the Early Cretaceous (palaeo-latitude of c. 65 °N), via a multiproxy sedimentological, geochemical, sequence- and chemo- stratigraphic study of Berriasian–Albian strata from the Central Basin of Svalbard. The “outsized clasts” recorded on Spitsbergen do not show evidence that they were rafted by glacial ice (e.g. surface striations), although could have been rafted by seasonal sea-ice. The results show that regionally widespread cold water conditions were the most likely control on ikaite formation and glendonite preservation. This counters recent studies that suggest a methane-seep driver for Mesozoic glendonites, and supports the global extent of Valanginian to Hauterivian and Late Aptian global cooling. Surface temperatures during cool episodes of < 14 °C, as implied by the presence of glendonites at the seafloor, are consistent with Polar (90 °N) temperatures being below freezing (even given reduced pole-to-equator temperature gradients). This study therefore supports the hypothesis that small polar ice-caps developed during the Valanginian – Hauterivian and Late Aptian cooling events.

A significant amount of palynological work has been done on southern African coal seams in the Ecca Group, but as yet there is little consensus on how these areas relate to each other. This study investigated the palynology of a coal seam from Mmamantswe (Mmamabula area), Botswana, approximately 70 km north-east of Gaborone. A total of 124 samples were taken from two borehole cores and subjected to acid preparation, oxidation and acetolysis. Coal samples were found to be barren of palynomorphs. Fifty carbonaceous mudstones and siltstone samples yielded twenty-two productive samples. A thermal alteration index of 3.0-3.5 was assigned for the sediments. Palynomorph diversity was high, with 64 genera and 90 species present, dominated by trilete and alete spores. This indicates a parent flora of mostly lower order lycopods, sphenophytes and ferns. Non-taeniate bisaccate and monosaccate pollens were scarce, and striates extremely rare (only two species), suggesting an autochthonous origin for the coal swamp. The Mmamantswe core was sub-divided into five microfloral assemblage zones. A transition from monosaccate dominance in the lower part of the core, to equal numbers of monosaccates and non-taeniate bisaccates in the upper part of the core, was seen. As the Mmamantswe palynoflora possesses elements of both the Late Carboniferous glacial floras and the mid-Permian coal floras, it is thought to represent a cross-over assemblage dating to soon after the Permo-Carboniferous boundary (Sakmarian and Early Artinskian). The Mmamantswe assemblage can be correlated with Assemblage Zones II and III of Falcon (1975a); Biozones B and C of MacRae (1988); and Zones 1, 2 and 3 of Anderson (1977) but does not fit well into any existing biozonation. The Mmamantswe palynoflora was most similar to that of Milorgfjella, Dronning Maud Land, Antarctica (Larrson et al. 1990) and the No. 2 Seam, Witbank, South Africa (Falcon 1989). Taphonomic controls on palynomorph preservation suggest that future studies should also attempt to focus on Permian sediments not containing coal, as microfloral assemblages from coal seams tend to be autochthonous, and subject to local climatic influences. Accordingly they are not as useful for inter-basinal correlation across Gondwana.

The southeast part of the Portland Basin has been previously described by other investigators. However, little detailed information existed on the depositional relationships between the units, the various sedimentary fades, or the origin of many of the units.

The estuarine to fluvial sediments of the mid-Cretaceous (Late Albian/Early Cenomanian) Dakota Formation of Jefferson Co., Nebraska (NE) and Washington Co., Kansas (KS) were deposited in a marginal marine setting along the eastern margin of the Cretaceous Western Interior Seaway. Three depositional facies based on various lithic content are recognized in the study area: Facies 1: Fluvial Channel Facies, Facies 2: Paleosol/Interfluve Facies, and Facies 3: Bay Head Delta/Estuarine Facies. The facies interpretation helped confirm that the Dakota Formation was deposited in a marginal marine setting in which low-gradient fluvial systems supplied a wave-dominated, estuary system. Petrographic analysis of the Fluvial Channel Facies concluded that the sandstones can be classified as quartz-rich lithic arkose. These findings differ slightly from previous studies on Cenomanian Dakota Formation strata in Thurston Co., NE. Palynostratigraphic, subsurface, and sedimentologic evidence helped to delineate a more accurate sequence stratigraphic framework for the Dakota Formation in the study area. Three large-scale, unconformity-bounded, sequences (D0, D1, and D2) are recognized, within which deposits of the transgressive and falling stage systems tracts are preserved in the Dakota Formation in the study area. While no physical deposits exist for the falling stage and lowstand systems tracts, evidence for their past occurrence can be observed by the erosional nature of the sequence boundaries. Detailed analysis of the systems tracts framework allows delineation of a generalized sea-level curve for the Dakota Formation in the study area. Analysis of the sequence stratigraphic framework revealed a Late Albian/Early Cenomanian sea-level fall that subsequently created valley incisions of over 25 m into the Late Albian D1 sequence. A careful literature review combined with sequence stratigraphic evidence suggests that a geologically fast-acting eustatic sea-level mechanism lowered worldwide sea-levels by more than 25 m from Late Albian into Early Cenomanian time. A reevaluation of the mid-Cretaceous "greenhouse" world suggests that a glacioeustatic component to the observed sea-level changes may have occurred. A Southern Hemispheric polar ice sheet with limited extent and volume compared to "icehouse" continental ice sheets, along with global alpine glaciers fed by wet climate cycles are hypothesized to account for sea-level fluctuations that resulted in valley incision and subsequent filling in the study area.

Our current understanding of thrust fault kinematics predicts that thrust faults nucleate on low angle, weak surfaces before they propagate upward and forms a higher angle ramp. While this classic kinematic and geometric model serves well in some settings, it does not fully consider the observations of footwall deformation beneath some thrust faults. We examine an alternative end-member model of thrust fault formation called “ramp-first” fault formation. This model hypothesizes that in mechanically layered rocks, thrust ramps nucleate in the structurally strong units, and that faults can propagate both upward and downward into weaker units forming folds at both fault tips. To explore this model, we integrate traditional structural geology field methods, two dimensional cross section reconstructions, and finite element modeling. Field data and retro-deformable cross sections suggest that thrust faults at the Ketobe Knob, in Utah nucleated in strong layers and propagated upward and downward creating folds in weak layers. These findings support the hypothesis that thrust faults and associated folds at the Ketobe Knob developed in accordance with the ramp-first kinematic model.We can apply this understanding of the mechanics behind thrust fault nucleation and propagation in mechanically layered stratigraphy to a wide range of geological disciplines like structural geology and tectonics, seismology, and petroleum geology. By incorporating our knowledge of lithology into fault models, geologists are more likely to correctly interpret structures with limited data sets.

General Statement A detailed study of the southwestern part of the Randolph quadrangle was undertaken in view of the fact that Richardson (1941) mapped a large area of undifferentiated Ordovician rock. Therefore, the purposes of this investigation are: (1) to prepare a more detailed geologic map of the south­western part of the Randolph quadrangle (Plate 1), (2) to describe the struc­ture, stratigraphy, and geologic history of the area, and (3) to relate the geology to adjacent areas. The elevation of the area mapped ranges from approximately 8, 910 to 6, 700 feet above sea level with the major part of the area above 8, 000 feet. This area forms part of the eastern ridge of the Bear River Range (Williams, 1948, p. 1, 125-1, 126). The southern boundary of the area extends east from the southwest corner of the Randolph quadrangle for a distance of about 4 miles. The eastern boundary extends northward about 11 miles and is parallel to the mountain front. The northern boundary is less well defined and is taken as the ridge separating Curtis Creek from the next canyon to the north. The western boundary extends south approximately 10 miles to the southwest corner of the Randolph quadrangle. The southwestern part of the Randolph quadrangle (Figure 1) covers approximately 56 square miles and lies approximately 60 per cent in Cache County and 40 per cent in Rich County. The major part of the area lies within the Cache National Forest. The area mapped is generally accessible from mid-June to mid- September. A road is maintained along the length of the area by the U. S. Forest Service and is passable by automobile except during heavy rain- storms in the summer months. Field Work The field work was done during the summer of 1963. Formation con- tacts, attitudes, and faults were mapped in the field on aerial photographs of the approximate scale 1:20, 000. This information, concerning the south- western part of the Randolph quadrangle, was transferred to a base map constructed from the topographic map of the U. S. Geological Survey of the same area (1912 edition). The base map was enlarged to the scale 1:24, 000. Stratigraphic sections were measured with a 50-foot steel tape. A Brunton compass was used to measure attitudes and slope angles. Sample rock types were collected from each unit and compared with the rock-color chart (Goddard, 1951) to obtain standard color names. Fossils were collected and identified in the laboratory by the author. Previous Investigations The earlier geologic reports from the general area of the Randolph quadrangle are found in the Hayden Survey and the survey of the Fortieth Parallel supervised by King. Hayden (1871, p. 150-156), Peale (1877, p. 573-609), Hague (1877, p. 393-442), and Emmons (1877, p. 326-393) all commented upon the general area. Walcott (1908) studied the Cambrian rocks of the Bear River Range and defined eight formations. Veatch (1907) studied the area adjacent to the Randolph quadrangle in Wyoming. In the Randolph quadrangle, Richardson (1913) divided the Ordovician rocks into three formations, identified the Silurian rocks as a formation, defined one Mississippian formation, and later (1941) published a geologic map of the quadrangle. Mansfield's (1927) study of southeastern Idaho provided valu­able information concerning regional structure and stratigraphy. Williams (1948) mapped the Logan quadrangle which is adjacent to the area on the west. Specific studies (Ross, 1949, 1951; Maxey, 1941, 1958) have given more detailed information concerning Cambrian and Ordovician rocks of the area. A recent publication by Armstrong and Cressman (1963) is important in dating the uplift and thrust faulting in the ancestral Bear River Range. The Geologic Map of Utah (Stokes, 1961) followed the interpretaion of Richardson (1941), for the southwestern part of the Randolph quadrangle, except in the designation of the Wasatch formation which is shown as Knight conglomerate.

Middle-Upper Eocene successions were studied in the Fayum Depression in order to establish depositional and paleoenvironmental models that link the ichnological and sedimentologic data to relative sea-level changes in a sequence stratigraphic framework. Five facies associations (FA1- FA5) are identified. The facies depositional models show overall progradation from quiescent open-marine bay (FA1-2: Gehannam and Birket Qarun formations) to lagoon/distributary channel/estuary sedimentary environments (FA3-5: Qasr El-Sagha Formation). The facies successions and their stratigraphic evolution are controlled by a regional, second-order cycle associated with the northward regression of the Tethys, which is overprinted by subordinate third- and higher-order cycles. Whale-bearing FA1 and FA2 are subdivided into five sedimentary facies. Seventeen ichnospecies belonging to thirteen ichnogenera, as well as rhizoliths are observed within these facies. Facies Association 1 accumulated in a low-energy fullymarine bay, whereas FA 2 represents a bay margin / supratidal paleoenvironments. Clastic point-sources are dominantly hypopycnal although eolian sand may represent an important source locally. The quiescent marine bay is a typical environment and biome for the Eocene whales. Preservation of these fossil whales must occur in association with rapid sedimentation rates, but sufficiently that bioturbation eradicates the physical sedimentary structures. Unusual, large-sized sedimentary structures are examined along the parasequence-bounding surfaces of the Birket Qarun Sandstone. Ichnological data, petrography and stable-isotope analysis are integrated to propose a bio-sedimentologic/diagenetic model, interpreting the origin of these structures as concretion growths around ichnofossils. The marine pore-water carbon was influenced by organic carbon and mixing of meteoric groundwater under eodiagenetic conditions. These conditions led to the precipitation of pervasive authigenic calcite-dominated cement in and around the burrows. More than twenty-five Glossifungites Ichnofaciesdemarcated discontinuities are examined in the study area. These surfaces are grouped into those of autocyclic and those of allocyclic origin. Occurrences of the allocyclically significant Glossifungites Ichnofacies can be classified into sequence-bounding, systems tract-bounding and parasequence-bounding surfaces. Sequence-bounding Glossifungites Ichnofacies-demarcated surfaces divide the studied successions into four third-order sequences. Systems tract-bounding and parasequence-bounding Glossifungites Ichnofacies-demarcated surfaces display higher-order cycles, overprinting the third-order cycles.

Sequence stratigraphy relates changes in vertical and lateral facies distribution to relative changes in sea level. These relative changes in carbonates effect early diagenesis, types of pores, cementation and dissolution patterns. As a result, in carbonates, relative changes in sea level significantly impact the lithology, porosity, diagenesis, bed and bounding surfaces which are all factors that control fracture patterns. This study explores these relationships by integrating stratigraphy with fracture analysis and petrophysical properties. A special focus is given to the relationship between mechanical boundaries and sequence stratigraphic boundaries in three different settings: 1) Mississippian strata in Sheep Mountain Anticline, Wyoming, 2) Mississippian limestones in St. Louis, Missouri, and 3) Pennsylvanian limestones intermixed with clastics in the Paradox Basin, Utah. The analysis of these sections demonstrate that a fracture hierarchy exists in relation to the sequence stratigraphic hierarchy. The majority of fractures (80%) terminate at genetic unit boundaries or the internal flooding surface that separates the transgressive from regressive hemicycle. Fractures (20%) that do not terminate at genetic unit boundaries or their internal flooding surface terminate at lower order sequence stratigraphic boundaries or their internal flooding surfaces. Secondly, the fracture spacing relates well to bed thickness in mechanical units no greater than 0.5m in thickness but with increasing bed thickness a scatter from the linear trend is observed. In the Paradox Basin the influence of strain on fracture density is illustrated by two sections measured in different strain regimes. The folded strata at Raplee Anticline has higher fracture densities than the flat-lying beds at the Honaker Trail. Cemented low porosity rocks in the Paradox Basin do not show a correlation between fracture pattern and porosity. However velocity and rock stiffness moduli's display a slight correlation to fracture spacing. Furthermore, bed thickness is found to be only one factor in determining fracture density but with increasing strain, internal bedforms and rock petrophysical heterogeneities influence fracture density patterns. This study illustrates how integrating sedimentologic and sequence stratigraphic interpretations with data on structural kinematics can lead to refined predictive understanding of fracture attributes.

The Cuu Long and Nam Con Basins, offshore Vietnam, contain sediment dispersal systems, from up-dip fluvial environments to down-dip deep-water slope and basinal environments that operated along the southern continental margin of Vietnam during Pliocene to Recent time. The available data enabled sediment thickness patterns, sequence-stratigraphic relationships, and channel types (fluvial to deep-water channels) within the lower Pliocene to Recent stratigraphic succession in the Cuu Long and Nam Con Son basins of offshore Vietnam to be analyzed. At least nine sequences and their accompanying systems tracts exist in the Pliocene to Recent section. Shelf-edge development in the study area is limited to the Eastern Nam Con Son Sub-Basin. Overall south to southeastward migration of the shelf edge complex during Pliocene to Recent time indicates that the Paleo-Mekong River System was the dominant sediment source for the area.