Geologic context of geodetic data across a Basin and Range normal fault, Crescent Valley, Nevada

Geodetic strain and late Quaternary faulting in the Basin and Range province is distributed over a region much wider than historic seismicity, which is localized near the margins of the province. In the relatively aseismic interior, both the magnitude and direction of geodetic strain may be inconsistent with the Holocene faulting record. We document the best example of such a disagreement across the NE striking, ~55° NW dipping Crescent normal fault, where a NW oriented, 70 km geodetic baseline records contemporary shortening of ~2 mm/yr orthogonal to the fault trace. In contrast, our geomorphic, paleoseismic, and geochronologic analyses of the Crescent fault suggest that a large extensional rupture occurred during the late Holocene epoch. An excavation across the fault at Fourmile Canyon reveals that the most recent event occurred at 2.8 ± 0.1 ka, with net vertical tectonic displacement of 4.6 ± 0.4 m at this location, corresponding to the release of ~3 m of accumulated NW-SE extension. Measured alluvial scarp profiles suggest a minimum rupture length of 30 km along the range front for the event, implying a moment magnitude M_w of at least 6.6. No prior event occurred between ~2.8 ka and ~6.4 ± 0.1 ka, the ^(14)C calender age of strata near the base of the exposed section. Assuming typical slip rates for Basin and Range faults (~0.3 mm/yr), these results imply that up to one third, or ~1 m, of the extensional strain released in the previous earthquake could have reaccumulated across the fault since ~2.8 ka. However, the contemporary shortening implies that the fault is unloading due to a transient process, whose duration is limited to between 6 years (geodetic recording time) and 2.8 ka (the age of the most recent event). These results emphasize the importance of providing accurate geologic data on the timescale of the earthquake cycle in order to evaluate geodetic measurements

Examining the Mediating Role of Sexual Communication Discrepancies

Past literature has revealed that sexual communication behaviors are important to one’s relationship, as such behaviors predict both relational and sexual satisfaction (Davis et al., 2006; Jones et al., 2018; Mallory, 2022). Furthermore, recent studies have revealed that sexual communication discrepancies (SCD) may play a similar role in predicting relational and sexual health outcomes (Machette, 2022a; Machette & Montgomery-Vestecka, 2023a, 2023b). Similarly, past work on attachment theory, sexual communication, and sexual self-disclosure suggests that individual characteristics, such as one’s attachment, may predict several communication behaviors, including SCD (Coffelt & Hess, 2014; Lopez Portillo, 2020; Machette & Drouin, 2023). Therefore, this dissertation proposed that individual characteristics (i.e., one’s attachment style) would predict sexual communication behaviors (i.e., SCD and sexual self-disclosure) which, in turn, were hypothesized to predict relational and sexual health outcomes (i.e., relational and sexual satisfaction). Additionally, this dissertation hypothesized that SCD would mediate the relationship between attachment styles and satisfaction. It also examined the potential mediating role of sexual self-disclosure within the same relationships, comparing sexual self-disclosure to SCD as potential mediators. Results revealed that avoidant attachment negatively predicted the sexual relationship maintenance and sexual experimentation sub-dimensions of SCD. Results also confirmed past studies that have found both the avoidant and anxious attachment style predicted relational and sexual satisfaction. Moreover, the analyses revealed that sexual relationship maintenance, sexual experimentation, and safe sex positively predicted relational satisfaction, whereas sexual issues negatively predicted relational satisfaction. In addition, sexual relationship maintenance and sexual experimentation positively predicted sexual satisfaction, whereas safe sex negatively predicted sexual satisfaction. Furthermore, results revealed that the relationship between the anxious attachment style and relational satisfaction was partially mediated by the sexual relationship maintenance and sexual experimentation sub-dimensions of SCD. The same two sub-dimensions of SCD partially mediated the relationship between the anxious attachment style and sexual satisfaction. Additionally, sexual relationship maintenance, sexual experimentation, and sexual self-disclosure partially mediated the relationship between the avoidant attachment style and sexual satisfaction. Finally, results revealed that the anxious and the avoidant attachment styles’ relationship with sexual satisfaction was partially mediated by sexual self-disclosure. Taken together, this study took an initial step toward modeling the relationships between antecedents, sexual communication behaviors, and predicted outcomes, suggesting future research could be conducted to model further such relationships and articulate a theory of sexual communication

Map and Data for Quaternary Faults in West Texas and Adjacent Parts of Mexico

The "World Map of Major Active Faults" Project is compiling a series of digital maps for the United States and other countries that show the locations, ages, and activity rates of major earthquake-related features such as faults and fault-related folds; the companion database includes published information on these seismogenic features. This effort is sponsored by International Lithosphere Program (ILP) Project 11-2 and funded by the Earthquake Hazards Reduction Program (EHRP) through the U.S. Geological Survey. The maps and accompanying databases represent a key contribution to the new Global Seismic Hazards Assessment Program (ILP Project II-0) for the International Decade for Natural Disaster Reduction. This compilation, which describes surface faulting in West Texas and adjacent parts of Mexico, is the first of many similar State and regional compilations that are planned for the project. This compilation is presented as a traditional map product and printed catalog of data; however both should be available in digital form in the future. The database provides referenced data on a variety of geographic, geologic, and paleoseismologic parameters. The fault data were compiled by the senior authors (Edward W. Collins and Jay A. Raney, Texas Bureau of Economic Geology) as part of ongoing studies of active faulting in the West Texas area and adjacent parts of Mexico. The U.S. Geological Survey authors are responsible for organizing and integrating State and regional products under the national project, including the coordination and oversight of contributions from individuals and groups (Michael N. Machette, Project Chief), database design and management (Kathleen M. Haller), and digitization and manipulation of map data (Richard L. Dart).Bureau of Economic Geolog

Cosmogenic ^(10)Be and ^(36)Cl geochronology of offset alluvial fans along the northern Death Valley fault zone: Implications for transient strain in the eastern California shear zone

The northern Death Valley fault zone (NDVFZ) has long been recognized as a major right-lateral strike-slip fault in the eastern California shear zone (ECSZ). However, its geologic slip rate has been difficult to determine. Using high-resolution digital topographic imagery and terrestrial cosmogenic nuclide dating, we present the first geochronologically determined slip rate for the NDVFZ. Our study focuses on the Red Wall Canyon alluvial fan, which exposes clean dextral offsets of seven channels. Analysis of airborne laser swath mapping data indicates ∼297 ± 9 m of right-lateral displacement on the fault system since the late Pleistocene. In situ terrestrial cosmogenic ^(10)Be and ^(36)Cl geochronology was used to date the Red Wall Canyon fan and a second, correlative fan also cut by the fault. Beryllium 10 dates from large cobbles and boulders provide a maximum age of 70 +22/−20 ka for the offset landforms. The minimum age of the alluvial fan deposits based on ^(36)Cl depth profiles is 63 ± 8 ka. Combining the offset measurement with the cosmogenic ^(10)Be date yields a geologic fault slip rate of 4.2 +1.9/−1.1 mm yr^(−1), whereas the ^(36)Cl data indicate 4.7 +0.9/−0.6 mm yr^(−1) of slip. Summing these slip rates with known rates on the Owens Valley, Hunter Mountain, and Stateline faults at similar latitudes suggests a total geologic slip rate across the northern ECSZ of ∼8.5 to 10 mm yr^(−1). This rate is commensurate with the overall geodetic rate and implies that the apparent discrepancy between geologic and geodetic data observed in the Mojave section of the ECSZ does not extend north of the Garlock fault. Although the overall geodetic rates are similar, the best estimates based on geology predict higher strain rates in the eastern part of the ECSZ than to the west, whereas the observed geodetic strain is relatively constant

Active megadetachment beneath the western United States

Geodetic data, interpreted in light of seismic imaging, seismicity, xenolith studies, and the late Quaternary geologic history of the northern Great Basin, suggest that a subcontinental-scale extensional detachment is localized near the Moho. To first order, seismic yielding in the upper crust at any given latitude in this region occurs via an M7 earthquake every 100 years. Here we develop the hypothesis that since 1996, the region has undergone a cycle of strain accumulation and release similar to “slow slip events” observed on subduction megathrusts, but yielding occurred on a subhorizontal surface 5–10 times larger in the slip direction, and at temperatures >800°C. Net slip was variable, ranging from 5 to 10 mm over most of the region. Strain energy with moment magnitude equivalent to an M7 earthquake was released along this “megadetachment,” primarily between 2000.0 and 2005.5. Slip initiated in late 1998 to mid-1999 in northeastern Nevada and is best expressed in late 2003 during a magma injection event at Moho depth beneath the Sierra Nevada, accompanied by more rapid eastward relative displacement across the entire region. The event ended in the east at 2004.0 and in the remainder of the network at about 2005.5. Strain energy thus appears to have been transmitted from the Cordilleran interior toward the plate boundary, from high gravitational potential to low, via yielding on the megadetachment. The size and kinematic function of the proposed structure, in light of various proxies for lithospheric thickness, imply that the subcrustal lithosphere beneath Nevada is a strong, thin plate, even though it resides in a high heat flow tectonic regime. A strong lowermost crust and upper mantle is consistent with patterns of postseismic relaxation in the southern Great Basin, deformation microstructures and low water content in dunite xenoliths in young lavas in central Nevada, and high-temperature microstructures in analog surface exposures of deformed lower crust. Large-scale decoupling between crust and upper mantle is consistent with the broad distribution of strain in the upper crust versus the more localized distribution in the subcrustal lithosphere, as inferred by such proxies as low P wave velocity and mafic magmatism

Multi-storey calcrete profiles developed during the initial stages of the configuration of the Ebro Basins exorrheic fluvial network

Multi-storey calcrete profiles developed in the Quaternary on strath terraces of the Cinca and Alcanadre rivers, tributaries of the Ebro River inNE Spain. Two calcrete profiles (Tor 1 and Tor 2) near the village of El Tormillo show horizons with an arrangement that differs from that of commonly described calcrete profiles. Significant lateral changes occur in these profiles within a distance of less than 200 m, reflecting their pedofacies relationship. The Tor 1 profile on terraceQt1 (the highest and oldest) consists of six horizons (frombottomto top): 1) coarse fluvial gravels; 2) mudstones with carbonate nodules; 3) a chalky horizon; 4) laminar horizons, including one peloidal horizon; 5) amulti-storey horizon formed of at least six minor sequences, each ofwhich includes a lower detrital layer, a pisolithic horizon, and a thin discontinuous laminar horizon (these sequences indicate several cycles of brecciation and/or reworking); and 6) a topmost laminar and brecciated horizon also including reworked pisoliths. Some200 mto the north of Tor 1, horizon 5 undergoes a lateral change to channel fill-deposits. The infill of the channels shows a fining-upwards sequence ranging fromclasts of about 10 cmin diameter to red siltswith sparse pebbles. All the clasts come fromthe underlying calcrete horizons. Laminar horizons are interbeddedwith the clastic channel deposits. The youngest calcrete profiles developed on terraceQt3 of the Cinca River and on the Qp4 and Qp6mantled pediment levels. All showrelatively simple profiles composedmostly of lower horizons of coated gravels, with thin laminar horizons at the top. Most of the horizons, especially the laminar ones, show biogenic features such as alveolar septal structures, calcified filaments, biofilms, spherulites, micropores and needle-like calcite crystals. These features indicate the important role of vegetation in the formation of all the above profiles. The interbedding of clastic sediments and pisolithic horizons within the Tor 2 profile indicates several stages of stabilisation during profile formation. These sequences are an indication of the sedimentation, soil formation and reworking processes operating on the soil surface. The alternation of these processes is interpreted as the result of climate–vegetation changes. The channel-fills of Tor 2 indicate erosion and reworking of the hard laminar calcrete horizon. Both Tor 1 and Tor 2 are multi-storey profiles reflecting the complex sedimentation–erosion–pedogenesis relationships at the final stages of the development of its corresponding fluvial terrace. The study of these calcretes shows that these supposedly abandoned terraces continue to be active even though the fluvial network is entrenched. Both the pedofacies relationships and the complexity shown by Tor 1 and Tor 2 reflect the complex and unstable geomorphic setting inwhich these profiles developed. After the establishment of the exorrheic network, less complex calcrete profiles were produced in the lower terraces

Exhumation of the central Wasatch Mountains, Utah: 2. Thermokinematic model of exhumation, erosion, and thermochronometer interpretation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95279/1/jgrb13381.pd

Soil-landscape and climatic relationships in the middle Miocene of the Madrid Basin

The Miocene alluvial-lacustrine sequences of the Madrid Basin, Spain, formed in highly varied landscapes. The presence of various types of palaeosols allows assessment of the effects of local and external factors onsedimentation, pedogenesis and geomorphological development. In the northern, more arid, tectonicallyactive arca, soils were weakly developed in aggrading alluvial fans, dominated by mass flows. reflecting high sedimentation rates. In more distal parts of the fans and in playa lakes calcretes and dolocretes developed: the former were associated with Mg-poor fan sediments whitc: the latter formed on Mg-rich lake clays exposed during minar lake lowstands. The nonh-east part of the basin had a less arid climate. Alluvial fans in this area were dominated by stream Aood deposits, sourced by carbonate terrains. Floodplain and freshwater lakc deposits formed in distal areas. The high local supply of calcium carbonate may have contributed to the preferential developmenl on calcretes on the fans. Both the fan and floodplain palaeosols exhibit pedofacies relationships and more mature soils developed in settings more distant from the sediment sources. Palaeosols also developed on pond and lake margin carbonates, and led to the formation of palustrine limestones. The spatial distributions and stratigraphies of palaeosols in the Madrid Basin alluvial fans suggest that soil formation was controlled by local factors. These palaeosols differ from those seen in Quatemary fans. Which are characterized by climatically induced periods of stability and instability

Pedogenic carbonates as a proxy for palaeo-CO2 in the Palaeozoic atmosphere

According to a model by Cerling (1991, 1999), the carbon isotope composition of calcretes should depend on the soil type and the CO2-concentration in the atmosphere. We have tested Cerling’s model by investigating 14 Palaeozoic sections with soil profiles. A large number of carbonate types of different genetic origin exist in the localities examined. Comparing the Palaeozoic samples with recent and subrecent calcretes, it can be demonstrated that anhedral, cryptocrystalline (<10 μm) and subhedral microcrystalline (10 - 40 μm) carbonates are clearly of pedogenic origin. Crystals of larger size with a poikilotopic texture are of groundwater or burial diagenetic origin. Macro- and micromorphological features, typical of recent calcretes, occur in several soil profiles, but thin section microscopy reveals a strong diagenetic overprint of most pedogenic carbonates. Time equivalent sections with comparable soil types (protosols, calcisols and vertisols) show large variations in carbon isotope composition. On the other hand, different carbonate generations at one site do not differ much. Therefore Palaeozoic calcretes appear to be unsuitable for a deduction of the Palaeozoic CO2-concentration.German Research Foundation (DFG)researc