No description available.

No description available.

The water vole is common in Middle and Late Pleistocene temperate Palaearctic faunas. It is widely used in biostratigraphy because of tem- poral trends in the size, shape and structure of the first lower molar (M1). However, geographic variation in the evolutionary development of the M1 has restricted the precision and accuracy of age-estimations. This thesis explores morphological variation in the M1 of fossil and extant populations of the lineage Mimomys savini–Arvicola, and uses the phenotype and the genotype to develop evolutionary hypotheses. Geometric and traditional morphometric methods are used to quantify tooth shape and enamel thickness from over 4000 digital photographs of M1s taken from specimens originating from 146 modern and fossil groups across the western Palaearctic. M1s are photographed to ob- tain a true cross-section, giving a more accurate description of molar shape. Morphological variation is explored in terms of sample-size, taphonomy, and ontogeny. Sample sizes of less than 10 are likely to provide inaccurate summary statistics of morphometric variables but depositional type appears to have no systematic effect on within-group variation. Change in the morphology of M1s through ontogeny is an im- portant source of morphological variation, explaining up to 29% of mo- lar shape within-specimens and up to 95% of enamel thickness within enamel layers of specimens. Removal of ontogenetic variation from mo- lar shape improves congruence between morphological and molecular data, indicating age-corrected variables should be used when assessing evolutionary patterns. Temporal and spatial patterns in the enamel thickness quotient (SDQ), based on age-corrected enamel thicknesses, mirror those from published data but differ in some details. Method- ological differences mean absolute SDQ values cannot be compared. Qualitative patterns include a large decrease in SDQ across MIS 12 and a steep east–west morphocline during the late Middle Pleistocene.

No description available.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Pavlostathis, Spyros G.; Committee Member: Huang, Ching-Hua; Committee Member: Hughes, Joseph B.; Committee Member: Sobecky, Patricia A.; Committee Member: Spain, Jim C.

Orientador: Antonio Roberto Saad / Banca: Jairo Roberto Jimenez Rueda / Banca: José Eduardo Zaine / Banca: Antonio Manoel dos Santos Oliveira / Banca: Maira Barberi / v. 1. Texto - v. 2 Anexos e encartes / Resumo: O propósito desta tese foi o de estudar o alto curso do rio Meia Ponte através da integração dos processos de sedimentação quaternária, da caracterização paleoambiental e da interação antrópica, nesta que é a área mais densamente povoada do Estado de Goiás, visando a contribuir com o conhecimento técnico-científico da região. São apresentadas algumas propostas visando ao uso planejado dos recursos naturais da bacia hidrográfica do rio Meia Ponte, principalmente a criação de Áreas de Preservação Ambiental e estabelecimento de um programa de monitoramento hidrossedimentológico nas estações já existentes. / Abstract: The purpose of this thesis was of studying Meia Ponte river's high course through the integration of the processes of quaternary sedimentation of the palaeoenvironmental characterization, and of the anthropic interaction in that that is the area more densely populated of Goiás state, seeking to contribute with the technician-scientific knowledge of the area. Some proposed are presented seeking the planned use of the natural resources of the hidrographic basin of the Meia Ponte river, mainly creation of Environmental Preservation Areas and the establishment of a program of hydrosedimentalogical monitoring in the stations already existent. / Doutor

Tephrochronologies for three marine core sequences from the Adriatic Sea have been constructed. Two of the sequences, PRAD 1-2 and RF93-77, are located in the central Adriatic and the third, SA03-03, lies in the southern Adriatic. Isotopic and biostratigraphic records are available for all three sequences, features of which have been used as isochronous markers in the region. This project aimed to establish whether tephra layers provide (a) secure, independent isochronous tie-lines and (b) a robust methodology for testing correlations based on other methods. A total of 54 tephra layers have been identified within these sequences, of which only 8 are visible layers, the remainder being classified as cryptotephras. Geochemical characterisation of the ash layers has been undertaken using electron microprobe analysis and laser-ablation trace element methods. Geochemical correlation to the detailed tephra record from Lago Grande di Monticchio was performed using chemical element biplots and discriminant function analysis. Bayesian-based age models were generated for the three Adriatic records using available chronological information that are independent of assumptions of synchroneity between proxy marker events. These models allowed comparisons with tephra and palaeoenvironmental data from Lago Grande di Monticchio and other Mediterranean sites. The results support some assumptions of synchronous regional changes, but not others. The key outcomes are (a) the recognition of additional (non-visible) distal ash layers that enhance the potential for correlating marine and terrestrial records in the central Mediterranean; (b) volcanic ash records preserved in Lago Grande di Monticchio and in some localities proximal to volcanic sources appear to be incomplete; and (c) isotopic records in Adriatic sediment sequences reflect regional forcing factors more than local conditions.

Despite considerable active research in the realm of Quaternary studies in Scotland, some parts of the Scottish Highlands remain largely uninvestigated in terms of both glacial and environmental history. For many areas of Scotland the glacial history has been examined: researchers have ascertained aspects of the nature of the Late Devensian (Weichselian) ice sheet that covered most of Scotland and subsequent readvances, chiefly the Loch Lomond Readvance. In a 1979 review of the Loch Lomond Readvance in the British Isles, Sissons published a map of the glacial limits relating to this latest period of glacial activity in Scotland (Figure 1.1). Since then this map has been only slightly modified with certain limits having been established in the western Grampians. For the area further north, little accurate information has been added to this picture. One of the most noticeable omissions in relation to the Loch Lomond Readvance is in the area between Glen Carron and Glen Shiel in southern Ross-shire. Published research regarding the earlier Late Devensian ice sheet is also sparse. Information regarding other aspects of the Quaternary such as those detailed in other parts of the Scottish Highlands are similarly lacking for this area. There are no published accounts of the vegetation history of the area nor of Late Quaternary sea-level changes. This study seeks to fill in some of these gaps with specific reference to the Late Devensian glaciation and aims to relate the patterns of glaciation with other contemporaneous environmental changes through to the establishing of interglacial conditions in the early Flandrian period. Recent studies have demonstrated that aspects of the Late Quaternary environment can usefully be related and this study attempts to follow a similar procedure.

Thesis (M.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The Merrimack Embayment in the western Gulf of Maine is the site of three late-Quaternary paleodeltas. Each delta was deposited by the Merrimack River as its mouth migrated from west to east across the continental shelf during the post-glacial transgression and regression of the sea, In the Merrimack River Valley, a raised, glaciomarine ice-contact delta 33m above present sea level represents deposition of sediments by glacial meltwater at the transgressive marine limit about 13,000 yrs BP. An adjacent delta, preserved at 16m above present sea level, represents the deposition of sediments eroded from the 33m glaciomarine delta during the early stages of marine regression sometime after 13,000 yrs BP. A drowned delta, formed when sea-level was about 50m below present sea-level, is located offshore of the Merrimack River and represents deposition of sediments eroded from the 16m delta and from glacial deposits in the Merrimack Valley during the post-glacial maximum marine regression about 10,500 yrs BP. Major controls on the locations of the deltas include eastward shoreline translation induced by crustal rebound and relative sea-level lowering, and bedrock induced channel entrenchment. The orientation of the deltas and other paleoshoreline features, generally elongate to the south, indicates that a southerly alongshore current was a significant factor in the control of nearshore erosion and deposition. A similar configuration in the present Plum Island and linear sand ridges in the shallow, nearshore zone suggests that the alongshore current has influenced sediment distribution since the retreat of late-Wisconsinan ice from the area. / 2031-01-01

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