Several years ago, a new genus and species of peccary, “Muknalia minima”, was described from the Pleistocene of Mexico. We previously examined that specimen and concluded that it was synonymous with the extant collared peccary, Pecari tajacu, but that taxonomic revision is rejected by the authors of the original study (this volume). Here, we provide further analysis of “Muknalia” and expand on previous evidence from both morphology and taphonomy that support synonymy with P. tajacu. We argue that morphological features, both in terms of size and shape, that were used to diagnose “Muknalia” all fall within the range of variation of the extant P. tajacu, or are a consequence of taphonomic modification, including human handling.

The Kattegat sea region between Denmark and Sweden is identified as a region both economically and environmentally sensitive. Statistics indicate that over two thousand vessels per day navigate in the region. Navigation route optimization for the region is vital for efficient transportation. Optimized routes allow a vessel to carry the maximum amount of goods per course leading to efficient fuel consumption, which can greatly benefit in an economical and environmental aspect. Such optimization requires a highly accurate and reliable vertical reference surface for efficient transportation. In the Baltic Sea and Kattegat, a geoid is now used as such a surface. For geoid modelling, homogenous and reliable gravity measurements are required over a larger area surrounding the computation point. The Kattegat region consists of gravity data mainly from the Swedish Fyrbyggaren marine campaign 2019, Kattegat airborne campaign 2018 and several older datasets from the Nordic Geodetic Commission (NKG) database. These gravity data over Kattegat region have been measured using different instruments in various time epochs that inherit them with uncertainties depending on the platform type, instrument sensor type, filter type, corrections applied, processing software and many other parameters. In this study, the data uncertainty of gravity measurements from various sensors in the Kattegat region was studied through statistical and graphical evaluations. It was found out that the data from Kattegat airborne campaign 2018 deviate systematically with from the more reliable Fyrbyggaren marine campaign 2019 and other marine datasets. The airborne campaign was therefore tentatively corrected by the estimated shift +1.46 mGal before further analysis was made of the other datasets. It is found that NKG publication numbers 29, 42, 44, 610, 611 and 616 from the NKG gravity database have a standard uncertainty of around 2-3 mGal. Which is within the range of allowable uncertainty for future applications. These datasets may thus positively contribute to NKG database along with data from the Swedish Fyrbyggaren marine campaign 2019 and the shifted Kattegat airborne campaign 2018. These datasets should be used to model the geoid over the region in the future.

Fragments of a charred wooden bowl were recovered from Aztalan during excavations by the State Historical Society of Wisconsin (SHSW) in 1964. Recent advances in analytical methods facilitated a multidimensional study of these fragments. Radiocarbon-dated to cal AD 994–1154 and found in association with Late Woodland, Mississippian, and hybrid forms of ceramics, the bowl augments our understanding of perishable technologies in these cultural contexts. 3-D models of the fragments allow for a virtual reconstruction of a portion of the bowl, which was carved from a solid piece of ash. Strontium isotope analysis of the wood indicates that the bowl was manufactured from wood locally available to the people at Aztalan.

A genetic algorithm from literature is adapted to design piezoelectric sonar sensors using results from physics simulations to optimize for a uniform voltage response over a wide range of frequencies. The adapted genetic algorithm produces valid sensor designs, and algorithm improvements are proposed. The best case general methods for bathymetric mapping with a sonar sensor is determined by sweeping various point selection algorithms, interpolation algorithms, and algorithm parameters. A set of methods are proposed based on how many sample points are used and what error metric is preferred. Additional algorithms are suggested for future improvements.

Legio is the base of the Roman II Triana and the VI Ferrata Legion, occupied from the early 2nd century to the early 4th century CE. It is the first of its kind to be excavated in the Eastern Roman Empire. Today the site sprawls beneath 30 hectares of pasture with slopes up to 15 degrees. Rapid, dense ground penetrating radar (GPR) survey with an antenna array would be ideal, but so far logistically impractical. The survey has proceeded since 2013 with a single 400 MHz antenna using parallel transects 0.5m apart for 5.85 ha to date. Like most Roman bases, Legio includes an extensive network of buildings and streets enclosed by rectangular fortifications. Unlike most Roman bases, however, it was constructed on a hillside with architectural components built by a combination of bedrock incision and above-ground construction. In addition, much of the site’s stonework has been robbed. These aspects demand topographic correction and interpretation using reflection profiles, depth slices, and 3D models. This paper presents data processing and results for the principia (central headquarters). Previous investigations were conducted at Legio and surrounding area by Tel Aviv University from 1998 to 2010. GPR and excavations since 2013 have been conducted as part of the Jezreel Valley Regional Project (JVRP)in association with the W.F. Albright Institute of Archaeological Research.

The purpose of this study was to develop a better understanding of factors that contribute to persistence in distance learning, and to provide program administrators with research-based recommendations on ways to improve retention rates and academic performance in an online graduate program for educators in the geosciences. This study used both quantitative and qualitative analysis to answer 5 research questions. The quantitative component of the study assessed whether student characteristics which could be identified and quantified through a premission screening correlated to persistence and academic success in the program. Data were collected through a voluntary survey administered during the program orientation. The qualitative component of the study consisted of interviews which were conducted to gain more concrete insights into the perceptions and practices of 2 student groups. The first group of interviewees was granted provisional admission with an undergraduate GPA under 2.75. Each went on to graduate with a cumulative GPA above 3.40. The students in the second group were put on academic probation for earning a course grade below a C early in the program and then went on to graduate. The results showed that there was not a statistically significant difference in the cumulative undergraduate GPA of those who persisted in the program versus those who withdrew or who were dismissed from the program. However, there was a significant difference in the undergraduate grades earned specifically in science courses. An unanticipated finding was that students who had not met with departmental faculty or program alumni were more than twice as likely to leave the program not in good academic standing. It appears that personal interaction is necessary for students to understand what is necessary be successful in the program. As such, administrators should consider incorporating more pre-program advising. It is evident that even students with a history of undergraduate academic success had misconceptions regarding the time commitment necessary to be academically successful. In addition, being a nontraditional student with a need to balance work, personal obligations, and extenuating circumstances was often a more important factor in performance and persistence than the online format of the program.

Robust interpretations of rock thermal histories are critical for resolving the timing and rates of geologic processes, especially as low-temperature thermochronology has become a common tool for investigating the evolution of landscapes and mountain belts and the feedbacks between geodynamic processes. Most interpretations of thermochronologic cooling ages, however, attribute rock cooling entirely to rock exhumation - a common but tenuous assumption in many settings where thermochronology is used to investigate links between tectonics, climate, and landscape evolution, because these places often have history of magmatism. Exploring the complexities - and advantages - of interpreting low-temperature thermochronologic data in magmatic terranes is the principal theme of this work. Using simple analytical approximations as well as the finite-element code Pecube, we characterize the cooling age patterns inside and around plutons emplaced at upper and middle crustal levels and identify the advective and conductive scaling relationships that govern these patterns. We find that the resetting aureole width, the difference between reset and unreset cooling ages in country rocks, and the lag time between pluton crystallization age and pluton cooling age all scale with exhumation rate because this rate sets the advective timescale of cooling. Cooling age-elevation relationships in these steadily exhuming models have changes in slope that would masquerade as changes in exhumation or erosion rates in real datasets, if the thermal effects of the plutons were not accounted for. This is the case both in the country rocks immediately next to upper crustal plutons and, surprisingly, in the country rocks kilometers above mid-crustal plutons with no surface expression. Together with a lag-time analysis useful for the practical question of when it is appropriate to interpret a cooling age as an exhumation rate in crystalline rocks, this work improves our framework for evaluating the effects of magmatism on thermochronologic datasets. We also demonstrate the importance of considering the magmatic history of a region in field studies of the Colorado Plateau, where interpreting apatite (U-Th)/He data requires diagnosing significant inter- and intra-sample age variability. Prior to considering the thermal history of the region, we develop a new model for a common source of this age variability: excess He implantation from U and Th (i.e., eU) hosted in secondary grain boundary phases (GBPs), which can make very low eU apatites hundreds of percent 'too old'. Samples significantly affected by He implantation are not useful for thermal history interpretations, but this model does provide a diagnostic tool for discriminating these samples from those with useful age trends. Once the effects of GBPs have been accounted for, the remaining data from two different thermochronologic archives in the central Colorado Plateau provide a new perspective on the Cenozoic history of the region, which has a multiphase - and enigmatic - history of magmatism and erosion. We find that sandstones in the thermal aureoles around the Henry, La Sal, and Abajo mountains intrusive complexes were usefully primed by magmatic heating in the Oligocene to document the subsequent late Cenozoic history of the region more clearly than any other thermochronologic archive on the Plateau. These data document a stable Miocene landscape (erosion rates<30 m/Ma) that rapidly exhumed ~1.5-2 km in the Plio-Pleistocene (~250-700 m/Ma no earlier than 5 Ma) in the Henry and Abajo mountains, and strongly suggest most of this erosion occurred in the last 3-2 Ma. The integration of the Colorado River ca. 6 Ma, which dropped regional base-level, is the principal driver of this erosion. It is likely, however, that a component of the rapid Pleistocene rock cooling is unique to the high mountains of the Colorado Plateau and reflects an increase in spring snow-melt discharge during glacial periods. Although apatite thermochronology results far from the Oligocene intrusive complexes cannot resolve this detailed Plio-Pleistocene history, they do constrain the onset of late Cenozoic erosion to no earlier than ~6 Ma. Moreover, apatite cooling ages from these rocks also document Oligocene cooling (ca. 25 Ma) that is contemporaneous with the emplacement of the laccoliths and the waning of the vigorous magmatic flare-up that swept through the southwestern USA ca. 40-25 Ma. Although the cooling ages are consistent with ~1 km of exhumation in the late Oligocene and early Miocene, as previous workers have suggested in the eastern Grand Canyon region, we demonstrate that a transient change in the geothermal gradient (peaking at ~50˚C/Ma in the late Oligocene) driven by moderate mid-crustal magmatism can produce identical age patterns. Therefore, we re-interpret the mid-Cenozoic erosion event on the Colorado Plateau as primarily a change in the crustal thermal field, rather than an erosional event. This requires a more significant Laramide-age unroofing in parts of the central Plateau and perhaps a re-evaluation of the interpretations of Oligocene canyon cutting in the Grand Canyon region

The rapid development of space geodesy over the last two decades has had a profound effect on geologic studies by allowing measurements of crustal motion with sub-millimeter per year precision. The focus of this work is to better understand microplate kinematics, intraplate deformation and sea level rise in Europe by use of Global Positioning System (GPS) measurements of crustal deformation. This is accomplished in three separate studies. The first study focuses on crustal motion and sea level rise along the eastern margin of Adria. We use data from tide gauge and continuous GPS (CGPS) stations. We develop a new method to separate common-mode relative sea level from spatially variable signals. From tide gauge data, we find uniform relative sea level rise along the coast that is 2-4 times lower than the estimates for global average sea level rise. In constrast, vertical motion of coastal rocks determined by CGPS varies appreciably from an average of -1.7 ± 0.4 mm/yr in the southern Adria to 0.0 ± 0.4 mm/yr in northern Adria. The most enigmnatical result of this study is that the combination of tide gauge and CGPS data shows that absolute sea level varies in such a way that relative sea level remains constant. The second study focuses on diffuse intraplate deformation of western Eurasia measured by CGPS. We find that our preferred model involves four subplates, separated by the Pyrenees, Rhine Graben, and Trans European Suture Zone, and yields residual velocities indistinguishable from random samples. We interpret the intraplate dormation as the surface manifestation of downwelling mantle lithosphere. The final component of this work is a study of the Northern and Southern Adria microplates' internal stability and tectonic motion. Results show that both Adria microplates are kinematically distinct from one another and from the slowly converging Eurasia and Nubia plates, with implications for the dynamics of the Nubia-Eurasia plate boundary zone. We also find that internal strain within the Adria microplates is statistically insignificant. We estimate appreciable fault slip rates around the periphery of Adria, with implications for slip rates and seismic hazards associated with circum-Adria fault zones.

The American Cordillera, a major mountain belt spanning>15000 km along the western margins of North and South America, formed as a result of crustal shortening and magmatism during ocean-continent convergence. These mountains were the loci of addition and redistribution of continental crust. The contributions presented here address the style, timing, and kinematics of underthrusting of continental crust in the retroarc of the central Andes as well as the rapid burial and metamorphism of forearc rocks that contributed to magmatism in the Canadian Cordillera. This work involved geological mapping and structural analysis coupled with geo- and thermochronological analysis. In the central Andes, results confirm a southward transition in structural style and magnitude of Cenozoic shortening that coincides with the disappearance of a thick Paleozoic basin that accommodated major Cenozoic shortening. U-Pb and (U-Th)/He results also demonstrate that thrust belt kinematics in northwestern Argentina were greatly influenced by pre-orogenic heterogeneities in Cretaceous rift architecture. Results from western Canada reveal that rapid underthrusting of forearc rocks occurred during Late Cretaceous time, likely associated with an episode of shallow subduction. This event did not result in basement-involved foreland uplifts thought to be a signature of shallow subduction in the western United States and central Argentina. Taken together, this work has the major implication that variations in the pre-orogenic upper crustal architecture strongly influence the behavior of the continental lithosphere during orogenesis, a result that challenges geodynamic models that largely neglect upper plate heterogeneities.

A primary goal of paleoclimatology is to extend the instrumental record to capture a wider range of natural variability, documenting the climate system's response to past changes that have no analog in the historical record. Sediment archives of the recent geologic past, both marine and lacustrine, offer the opportunity to study how climate responds to a range of forcings and changing boundary conditions on timescales ranging from years to millennia. In this dissertation I use lacustrine and marine sediment to investigate changes late Quaternary climate, with particular focus on the Last Interglacial period (LIG). First, I use multiple approaches to reconstruct long-term changes in the West African Monsoon by investigating centennial-scale hydrologic variability recorded in Lake Bosumtwi sediments over the past 530,000 years. Over this interval, hydrology in the region is driven by a complex interplay of orbital forcing and glacial-interglacial boundary conditions. Lake level was generally much lower between 50 and 300 ka, likely due to the redistribution of rainfall from the tropics to the subtropics, driven by eccentricity's amplification of precession. Consequently, the Holocene highstand at the lake was both larger and longer lived than the maximum highstand during the LIG.Annual layers were continuously deposited through the LIG in Lake Bosumtwi, and I also present a new, 12,100 year-long, varve record spanning the interval from 128.6 to 116.5 ka. Over the course of the LIG, lake level generally tracks sea surface temperatures (SST) in Gulf of Guinea, including an abrupt drop in lake level that lasted about 500 years ca. 118 ka, coincident with cool SSTs in the North Atlantic and severe aridity in Europe. I find that the despite the generally drier conditions, hydrology varied on similar timescales as the late Holocene, with pronounced multidecadal to centennial-scale variability with non-stationary periodicities. I also investigate the contribution of ocean thermal expansion to sea level rise during the LIG, using a synthesis of paleoceanographic data and a climate model simulation. Globally, LIG SSTs were similar to, or slightly cooler than late Holocene SSTs, with the exception of the North Atlantic, which was several degrees warmer. Consequently, thermal expansion was likely a minor component of sea level rise during the interval, explaining between -0.3 and 0.4 m. of the 6 to 8 m highstand. Lastly, I tested the potential of Raman spectroscopy as a new, non-destructive technique to rapidly measure oxygen isotopic ratios in carbonates at extremely high resolution. Analyses on a suite a synthetic calcites indicate that ¹⁸O/¹⁶O ratios can be measured directly from the Raman spectra and have a 1:1 correspondence with traditional mass-spectrometry measurements. At present, the technique does not have the precision necessary to record natural variability, although there is considerable potential for improving the precision of the technique.