Graduation date: 1968

The diet of Pleistocene cave bears (Ursus spelaeus, U. deningeri) is debated extensively. Traditionally, cave bears were thought to be herbivorous, but more recent studies have proposed that they were more omnivorous. To test this, their skull morphology and that of their confamilials were analysed using 3D geometric morphometrics. The eight extant Ursidae occupy various dietary niches, which are expected to affect the functional morphology of the skull; the resulting dietary morphospace is used to determine the position of cave bears. Landmarks for 3D digitisation were chosen to reflect functional morphology. Extant and extinct Ursidae were digitised with a Microscribe G2. Generalised Procrustes superimposition was performed on the raw coordinates and allometry removed by regressing these onto the log (ln) centroid size pooled per species. Principal component analyses (PCA) and two-block partial least squares analyses (2B-PLS) were conducted on the regression residuals, and (multivariate) analyses of (co)variance ((M)AN(C)OVA) and discriminant function analyses (DFA) performed on the PC scores. PCA and 2B-PLS differentiate between known dietary niches in extant Ursidae. (M)AN(C)OVA and DFA results suggest that cave bears were herbivorous. Differences in the results between the temporalis and the masseter are seen primarily in the position in morphospace of the extant spectacled bear (Tremarctos ornatus), probably due to the influence of its premasseteric fossa on the morphology of the masseteric fossa. Additionally, ANOVAs suggest that there was intraspecific variation within U. spelaeus contradicting lineages proposed on the basis of mitochondrial DNA. This variation may be attributable to environmental factors, such as timberline altitude, influencing the cave bears’ diet.

Fluvial morphosedimentary records surrounding the Orjen massif, western Montenegro, have been studied to investigate the response of Mediterranean river systems to Pleistocene glaciation. A range of depositional contexts, across 12 sites, have been analysed, including: terraced alluvial valley fills, poljes and alluvial fans. These sites include both ice marginal contexts and more distal locations. It can be argued that these settings are broadly representative of the depositional environments found within glaciated upland catchments across the Mediterranean, and especially those in limestone landscapes. The timing of fluvial activity has been constrained using detailed stratigraphical analysis, 35 U-series dates, calcite micromorphology, and soil profile analysis. The fluvial record is fragmentary but is in good agreement with the Pleistocene glacial history of the Orjen massif, developed by Hughes et al. (2010).Two main phases of Pleistocene fluvial sedimentation have been identified in the morphosedimentary record. The most extensive phase of fluvial aggradation is correlated to MIS 12 (Kotorska-Sušica Member) and is characterised by the infilling of large depocentres beyond the maximum MIS 12 ice margins. These deposits dominate the fluvial record. The next recorded phase of fluvial deposition is correlated to MIS 6 (Krivošije Member) and contains only limited evidence of fluvial activity. No morphosedimentary evidence for fluvial deposition in MIS 5d-2 has yet been observed in the study area. An analysis of published studies shows that the Pleistocene glacial and fluvial archives are highly fragmentary across the Mediterranean basin. The limestone karst terrain of Mount Orjen has exerted an important influence on sediment delivery and the meltwater pathways draining the Orjen ice cap over successive glacial cycles. Evidence suggests that, since MIS 12, sediment supply to the fluvial system has declined in accord with the decreasing magnitude of glaciation and subterranean karst flows havebecome increasingly dominant over surface flows. As ice volume and extent decreased in the cold stages following MIS 12, the Pleistocene glacial and surface fluvial systems became progressively decoupled. Two types of surface meltwater routes operated during MIS 12: Type 1 – steep sided limestone bedrock gorges; and Type 2 - alluvial channels draining directly from the ice margin. These contrasting pathways are associated with distinctive sedimentological signatures both at the macro-scale and within the fine (<63µm) matrix fraction This study provides one of the first attempts to directly correlate Pleistocene glacial and fluvial records – and to consider the process interactions – in a range of depositional contexts at the landscape scale.

A stalagmite was collected in the Salón de la Permencia of the Majaguas Cave, that is a part of the Majaguas-Cantera Cave System in Cuba. The use of this stalagmite as a natural climate archive is advantageous not only because stalagmites can record continuous episodes of growth that are thousands of years in duration but also because they are easily and reliably dated, using U/Th dating methods. With this method, the stalagmite was reliably dated to 100 ka and was still active when removed from the cave for analysis. The stable isotopes of oxygen and carbon from this stalagmite from Western Cuba presents information of significant influencing factors on Caribbean precipitation records, and past climatic events during the Pleistocene. Due to the lack of high- resolution records for Western Cuba, this study verifies and adds to our knowledge of past climate variability for the Cuban region and the Caribbean as a whole. The δ18O data in MCS-01 shows a pattern that is very similar to the D-O and Heinrich events clearly recorded in the NGRIP ice core, especially at ~82ka and between 78-70ka. This study provides a continuous precipitation record for the area during the Pleistocene, allowing a greater understanding of the climate drivers that have had an impact on past precipitation patterns in this region.

We report 95 vertebrate taxa (13 fishes, 11 reptiles, 63 birds, 8 mammals) from late Pleistocene bone deposits in Sawmill Sink, Abaco, The Bahamas. The >5,000 fossils were recovered by scuba divers on ledges at depths of 27-35 m below sea level. Of the 95 species, 39 (41%) no longer occur on Abaco (4 reptiles, 31 birds, 4 mammals).We estimate that 17 of the 39 losses (all of them birds) are linked to changes during the Pleistocene-Holocene Transition (PHT) (∼15-9 ka) in climate (becoming more warm and moist), habitat (expansion of broadleaf forest at the expense of pinewoodland), sea level (rising from -80 m to nearly modern levels), and island area (receding from ∼17,000 km2 to 1,214 km2). The remaining 22 losses likely are related to the presence of humans on Abaco for the past 1,000 y. Thus, the late Holocene arrival of people probably depleted more populations than the dramatic physical and biological changes associated with the PHT.

Few Pleistocene paleontological faunas are published in detail for most of Central America. Probably the richest locality of vertebrates in Central America is at Tomayate, El Salvador, and dates to the early-middle Pleistocene. Literature about late Pleistocene vertebrate species from Guatemala is especially scarce. The purpose of the present paper is to introduce the late Pleistocene mammalian remains from Chivacabé, in the western highlands of Guatemala. The Chivacabé fauna radiocarbon dates to between 15,700 and 12,920 calendar years ago. The specimens recovered from excavations between 1977 and1992 are probably only a small portion of the entire fauna likely to exist under 4 to 5 m of redeposited tephra and valley alluvium. Recovered specimens include at least one individual of Glyptotherium sp., three individuals of Cuvieronius cf. C. hyodon, one individual of Equus sp., and two individuals of Odocoileus cf. O. virginianus. One specimen that originally was thought to represent a deer antler is in fact a hyoid bone of Cuvieronius. Previous reports of 'peccary' and Eremotherium from Chivacabé are not supported by archived fossils. No faunal specimens exhibit supposed human modification marks purported by previous investigators; all aberrations observed on the bones and teeth can be explained by other taphonomic processes. The Chivacabé fauna represents one of the very few late Pleistocene faunas from Guatemala described thus far. A preliminary list of late Pleistocene localities known in Guatemala suggests that detailed studies of these faunas are warranted.

Thesis advisor: Amy E. Frappier / A ~7,000 year stable isotope record from a Central American stalagmite is presented as a record of rainfall and consequently Intertropical Convergence Zone (ITCZ) tropical rain belt strength over the late Pleistocene to mid-Holocene. The "amount effect" explains the well-documented inverse relationship between rainfall amount and stable oxygen isotope values observed in tropical monsoon regions and consequently in stalagmite calcite from those regions. ITCZ rainfall influences much of the Central American tropical region and here a ~7,000 year stable isotope record from stalagmite ATM1 harvested from Actún Tunichil Muknal Cave in Belize is presented as a record of ITCZ influenced rainfall during the late Pleistocene to mid-Holocene (5,561 ± 2,488 BP - 12,605 ± 284 BP). Three major oxygen isotope excursions occur within the record. These excursions correspond to the global cold Younger Dryas and 8.2 ka events and a relatively undocumented wet period around 6,300 bp. The Younger Dryas manifests as a relatively moist period in central Belize while the 8.2 ka event manifests as a relatively dry period. The reason for the opposite responses to cooling elsewhere in the globe is posited to be due to orbital forcings. The 6,300 bp relatively wet period appears to be synoptic in scale and two possible triggers for the isotope excursion are presented: eustatic sea level rise causing lagoonal constriction, warming of water off the coast of Belize, and thus increased evaporation and precipitation over the study region; and hurricane clusters, evidenced in the region in the succeeding 1,000 years, in which the location of the Azores High funnels hurricanes to make landfall near the central Belize region. ATM1 provides evidence for tropical leads and/or lags to global climate events and bolsters the idea that high and low latitude climate relationships are complexly interlinked. / Thesis (MS) — Boston College, 2010. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Geology and Geophysics.

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Thesis advisor: Jeremy Shakun / The mechanisms of abrupt climate change during the last glacial period are not yet fully understood. The objective of this research is to use oxygen isotope and magnesium/calcium ratios from foraminifera in a marine sediment core <200 km southeast of New York City (Ocean Drilling Program 174 Site 1073A) to test the hypothesis that changes in freshwater run-off patterns during intermediate extensions of the Laurentide Ice Sheet caused abrupt climate change by disrupting the Atlantic thermohaline circulation. The combination of foraminiferal δ18O and Mg/Ca yields salinity as an isolated variable, which is used as a proxy for Hudson River discharge through ~42,000-28,000 years ago. This thesis reviews the literature on abrupt climate change and compares the Hudson River paleodischarge record to established records of abrupt climate events observed in Greenland ice cores. It concludes that a higher resolution of data points is required to evaluate the impact of Hudson River discharge on abrupt climate change. / Thesis (BS) — Boston College, 2015. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Earth and Environmental Sciences.

Two discreet methods of geometric morphometrics were applied to evaluate the taxonomic utility of each in classifying the craniomandibular region of several Mustela species. Use of both linear measurements and 2-dimensional landmarks proved successful in discriminating between extant M. nigripes (black-footed ferret) and Neovison vison (American mink), in addition to the extant North American weasel species (M. erminea, M. frenata, M. nivalis). Methods were then used to classify Late Pleistocene Mustela spp. fossils collected from Snake Creek Burial Cave (SCBC) of eastern Nevada. Data acquired for unknown predicted group memberships varied markedly among methods and specimens. Nevertheless, results support the presence of M. nigripes and all 3 weasel taxa among the SCBC paleofauna.