The area evolved from a Jurassic rifting stage to a Cretaceous sag and a Tertiary foredeep stage. The sedimentary record is subdivided into four tectonostratigraphic units: Jurassic rift deposits, late-Jurassic-Cretaceous sag deposits, latest Cretaceous-Eocene foredeep-transition deposits, and late Eocene-Pliocene foredeep deposits. The rifts are filled with continental volcanics and pyroclastics. The sag deposits form a backstepping marine wedge, which contains the Springhill Formation (main reservoir) and is covered by a muddy and marly aggradational interval deposited in neritic waters of an epeiric sea (main petroleum source and seal). The latest Cretaceous to Eocene is a forestepping-backstepping wedge of glauconitic sandstones and claystones and carbonate buildups of shallow marine origin. The foredeep deepens during the late-Eocene to Oligocene. It is infilled during the Oligocene-late Miocene by a forestepping wedge that prograded from the west and southwest. The age of the foredeep suggests that the southern Andean Orocline formed during the Paleocene-late Eocene interval.

The western Paradise Range of central Nevada exposes complexly deformed rocks comprising three imbricate nappes of the Pamlico allochthon, which is a part of the regionally extensive Luning-Fencemaker fold-thrust belt of mid-Jurassic to Early Cretaceous age. Mapping and structural analysis reveal a complex deformation history involving dynamothermal metamorphism, out-of-sequence thrusting, and transition from ductile to brittle conditions during progressive deformation. The deformation reflects a spectrum of ductile-to-brittle conditions: from a tectonic thickening stage involving large recumbent folds culminating in ductile conditions during greenschist-amphibolite dynamothermal metamorphism and the development of mylonites; to a progressive ductile-to-brittle transition resulting in the developments of kink bands, polyphase buckle folds and thrust emplacement at relatively shallow structural levels. Fold-thrust relations suggest the development of an out-of-sequence duplex with thrusts cutting the hanging-wall of older and lower thrusts. Four episodes of shortening are recognized on the basis of fold-thrust relations. Deformation commenced in the mid-Jurassic and was completed before intrusion of Late Cretaceous granitoid plutons. The first phase of deformation involves the local inversion of large tracts of Late Triassic and Early Jurassic carbonates, clastics, and volcanic rocks of the Pamlico assemblage in recumbent folds with ultimate tectonic burial to depths of 10-20 km. Ductile structures, consisting of penetrative fabrics, mylonitic shear zones, and major recumbent folds were generated at depth During progressive southeast transport, the ductily deformed rocks were carried to shallower structural levels by thrusts that truncate earlier structures. Buckle folds associated with the thrusts indicate a protracted history of motion parallel to the transport recorded in the ductile structures contained within nappes. Following emplacement the three nappes exposed in the western Paradise Range were folded in tight to open upright folds. The final phase of folds documents a shift in the regional shortening axis from northwest-southeast to southwest-northeast.

Various stages of mid-Jurassic salt deformation resulted in post-salt extensional and contractional systems on the continental slope offshore Louisiana. Pre-mid-Cretaceous salt deformation resulted in salt massifs, small allochthonous salt bodies, pseudo-clinoforms and turtle structures. During a significant period of sediment starvation between mid-Cretaceous and mid-Oligocene time, previously formed salt and related structures remained stable. Following the reactivation of salt structures from mid-Oligocene to early-Miocene, rapid sedimentation during middle Miocene resulted in the development of large diapiric salt walls and stocks fed from the pre-mid-Cretaceous salt massifs. The rising diapiric salt structures displaced the downslope section of the rapidly deposited overburden seaward to form the Mississippi Fan Fold Belt focused near the frictional boundary along the basinward limit of the mother salt. The shortening in the fold belt ceased when the allochthonous salt began to spread near sea floor within sediments during Late Miocene. Since late Miocene, up-dip from the fold belt, large scale primary allochthonous salt sheets continued to form and spread down-slope. As massive salt withdrew from the mother salt, large primary withdrawal basins, regional, counter-regional growth fault systems, tension faults, primary and secondary welds and turtle structures formed. With increased sediment loads, the primary allochthonous salt was deformed. Consequently, supra allochthonous structures such as the secondary allochthonous salt, secondary and tertiary withdrawal basins, tertiary, quaternary and quintic welds and large extensional growth faults and occasionally contractional faults developed.

The interplay of sediment supply, accommodation space, and the rate of sea-level rise and fall, determine the thickness and overall extent of offshore deposits along the central Texas shelf. Analysis of near-shore sediment cores suggests that transgressive and highstand shorelines prograded during the Holocene. The preservation of these deposits may be likely given the geometry and distribution of older, offshore shorelines. The Stage 5d and Stage 3 highstand shorelines prograded during an overall sea-level fall. High sediment supply from longshore transport preserved thick, aerially extensive shoreline deposits. Fluvial incision varied significantly during lowstand Stage 2. As the rate of base-level fall increased from Stage 3 to 2, low sediment supply rivers incised narrow, shallow channels with no deltaic deposition, whearas sediment bypass and deeper incision prevailed for the high sediment supply rivers.

The Paleocene Guasare Formation of La Concepcion Field (Maracaibo Basin, Venezuela) consists of thin carbonates that were deposited in a dynamic near-shore marine setting greatly influenced by terrestrial siliclastics and muds. In seismic data, the Guasare Fm. shows uniform thickness and subparallel reflectors. Facies trends were not evident from the 3D seismic data set. Amplitude maps revealed one structurally-related anomaly. The regional setting of the Paleocene was clarified showing that Late Cretaceous foresets indicated a source from the Andean active margin to the west. These clinoforms were overlain by the Paleocene Guasare Formation and its western partial equivalent, the Marcelina Fm., a siliciclastic and coal sequence. Only the overlying Eocene Misoa Formation indicates a northeasterly clastic input and eastward thickening associated with the emplacement of the Lara nappes of the Caribbean active margin. This study is based on 3D seismic data, some well logs, and well cuttings. Cores were unavailable.

Sediments incorporated into accretionary prisms experience significant changes in physical properties, grain fabric, and diagenesis. The record of such changes is preserved in sediment microstructures. Scanning electron microscopy (SEM) analyses were carried out on sediments collected from within and seaward of the Nankai accretionary prism to document microstructural changes with depth, lithology, and discrete deformation during the earliest stages of tectonic deformation. Clay mineral preferred orientations (CPOs) increased with depth due to burial, inclined CPOs were evident adjacent to discrete deformation structures and within the accretionary prism, reflecting the influence of sub-horizontal tectonic stress with accretion. Mineralogical and microstructural contrasts across the decollement and the seaward proto-decollement suggest strength differences that may help to localize the fault at this location.

A 2D high-resolution seismic grid was combined with cores to develop a stratigraphic model of the East Texas shelf and slope, which showed that fluvial deltaic systems do not significantly impact upper slope stratigraphic sequences until very late during a eustatic fall. Rather, prograding delta lobes on the shelf correlate to a condensed section on the slope that continued until the deposition of a shelf-edge delta during OI Stage 3. Soon after, the Brazos system shifted away from the study area and a thick, shale-dominated healing phase wedge developed. These wedge sediments originated from a shelf-edge delta to the east and were transported westward along the upper slope revealing that significant sediment volumes moved not only downdip, but also laterally, into and out of the expected area of influence. During the transgression, the Brazos, Colorado, and Rio Grande fluvial systems each constructed a succession of deposits beginning with a fluvial-dominated delta (12--9 ka), followed by a wave-dominated delta (9--5 ka), and then retreated from the shelf. This unique succession correlates to climate changes occurring in their upper drainage basins. A separation in climate conditions between central Texas and northwestern Texas developed from 14--8 ka. Central Texas became arid, while northwest Texas experienced wet/dry fluctuations. Climate studies from other southwestern states indicate an intensification of the Arizona Monsoon was the cause, driven by a solar insolation maxima. Before this interval, climate and eustatic forcing functioned in tandem. Between 12--9 ka however, the two mechanisms diverged, with the insolation maximum occurring well before the sea level high. This divergence allowed the fluvial response to climate to be deconvolved from the response to eustacy. The Modern Brazos Delta continues to reflect a strong climate influence. The delta plain is composed of preserved ridge/trough pairs that correlate to climate fluctuations. Each rige/trough pair corresponds to a La Nina induced drought that is broken by an El Nino induced flood. Other strong El Nino events not represented on the delta plain belong to a dominantly wet period in Texas so that, without the proceeding drought, sediment was not available to initiate ridge development.

Studies of fault gouge and its role in shear zone deformation are the key to understanding the mechanics of earthquakes and fault zone evolution. With the advantage of exploring the micromechanical process of gouge deformation in "real time", the combination of the Distinct Element Method (DEM) and linear elastic contact bonds provides an opportunity to deform complex, heterogeneous granular assemblages that approximate natural shear zones in a more realistic way, and to study gouge deformation processes that are responsible for unstable sliding of fault zones. Granular assemblages of multiple shaped grains were sheared over a range of normal stresses, sigman, in order to examine the influences of sigman gouge grain shape, grain comminution, and associated dynamic changes in grain characteristics on the frictional behavior of granular shear zones. The results show an inverse power law relationship between sigman and maximum sliding friction, where both its coefficient and exponent are dependent on gouge angularity. Enhanced grain rolling alone does not explain the low frictional strengths of simulated granular assemblages. Shear zone strength is dependent on the competition between strength reduction by fracturing and strength variation by changes in grain characteristics that are related to the partitioning of different deformation mechanisms. DEM experiments were also conducted to simulate the growth of fault gouge zones, for the purposes of studying the processes of gouge zone evolution, and its dependence on sigman and uniaxial compressive strength, sigmaucs. The simulated fault gouge zones exhibit two distinct stages of evolution, i.e., fast growth and slow growth, distinguished by a switch in deformation mechanism from dominantly wear of the fault blocks to dominantly shearing of existing fault gouge. During the fast growth stage, the rates of gouge thickening and bond breakage decrease exponentially and are proportional to sigman and inversely proportional to sigmaucs the rates become relatively constant and the dependency reverses during the slow growth stage. Gouge properties show complex correlations and dependences on shear displacement, sigman and sigma ucs, demonstrating the important effects of depth, mechanical properties of fault rocks, and gouge properties on the evolution and stability of natural faults.

New geochemical data from the Villa de Cura indicate that it is a subducted (and exhumed) island-arc terrane. The majority of the basalts are primitive island-arc tholeiites (44.8--51.5 wt% SiO2, 6.7--22.8 wt% MgO). REE and immobile trace element data from the Villa de Cura exhibit island-arc signatures, including (1) flat to LREE enriched REE patterns with La/Yb ratios of 1.23--6.03, and (2) enrichment of LILE relative to HFSE with a strongly negative Nb anomaly (La/Nb = 1.56--7.90). Thus, the Villa de Cura is similar to other Albian-Aptian age island arc tholeiites documented throughout the Caribbean. A model for formation and initial subduction of the Villa de Cura is presented. Correlation of the Villa de Cura with other allochthonous basalts in the Caribbean will help to constrain developing paleotectonic models of Caribbean.

The continental shelf offshore Nova Scotia is within a passive margin setting and is an excellent area to study the sequence stratigraphy of late Cretaceous and Tertiary sediments. Hydrocarbon exploration offshore Nova Scotia over the past twenty years has produced a substantial amount of well log data. This study integrates the well log data with seismic and biostratigraphic data to create a sequence stratigraphic framework of late Cretaceouse to middle Miocene strata. Sigma Exploration of Calgary has donated access to a large grid of 2D seismic data, covering the outer modern shelf. To help constrain the ages of the sequences, a biostratigraphic analysis of the well Marmora C-34 was performed. Twelve sequences from Campanian to middle Miocene are resolved by integrating the data. Global correlation of results suggest that eustasy is the primary factor in the formation of sequences within the Scotian Basin between lower Eocene and middle Miocene sediments.