Thesis (Ph. D.)--Lehigh University, 2005. / Includes vita. Includes bibliographical references (leaves 121-147).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1973. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 103-113).

No description available.

No description available.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2002. / Bibliography: leaves 98-101. Also available online.

Thesis (M.S.)--University of Wisconsin--Madison, 1999. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-77).

In order to reconstruct a long-time tropical terrestrial record of Asian monsoon in South China, the organic carbon in a 120 m lacustrine sediments from Maar Lake Tianyang was analyzed. Results in TOC, C/N and δ13C value show two lines of variations: (1) from a deep lake environment below 42 m to a shallow lake environment of the upper 42 m, (2) environmental changes between glacial and interglacial conditions throughout the lacustrine sediment sequence. In the shallow lake stage, δ13C values change according to glacial and interglacial periods, comparable with other proxies such as pollen, TOC and magnetic susceptibility. However, variations of these proxies including δ13C values are suppressed in the deep lake sequence, a result of the exceptionally high in-situ aquatic (diatom) productivity within this tropical lake. To differentiate the internal productivity and terrigenous high plant input for the deep lake sequence, a three-end-member model (diatom, C3 and C4 land plants) was developed. The result helps extract further information from the deep lake sequence that reveals both the autochthonous productivity caused by lake-level and terrestrial changes by external forcing mechanisms. The n-alkanes indexes from 115 selected samples show distinctive distributions of various chain-length homologues. Most n-alkane indexes (e.g. Paq, CPI and ACL) show more frequent fluctuations than organic carbon records, implying other environmental alterations within the glacial and interglacial periods. Most n-alkanes indexes show a clear relationship with the palaeoclimate history, but further comparison of individual compound concentrations to other environmental indexes (pollen and δ13C values) suggests that n-C29 is a better index of tree concentration while n-C31 has alternative source from flowering trees instead of grasses. Unique appearance of hopanes in the deep lake sediments suggests high activity of methanotrophic bacteria in chemocline. The examination of GDGT concentration from 130 samples indicates pH, temperature and evolution of archaea and bacteria communities. Complications in the interpretation and correction of GDGT results are also discussed and several alternative corrections for palaeo-temperature reconstruction are provided for further investigations. According to both n-alkane and GDGT results, the sediment sequence contains mainly three different stages: the aquatic mixing community (Crenarchaeota and methanotrophic bacteria) from the bottom to 78m; the aquatic methanotrophic community (Euryarchaeota and methanotrophic bacteria); the terrestrial aerobic community (aerobic bacteria). / published_or_final_version / Earth Sciences / Doctoral / Doctor of Philosophy

The East Kirkton Limestone outcrops in the Bathgate Hills area of central Scotland. The deposit is Visean (Lower Carboniferous) in age and is the site of a tropical freshwater lake set within a richly vegetated volcanic terrain. The succession consists of an unusual sequence of laminated, spherulitic and massive limestone beds, interbedded with thin mudstones, siltstones and abundant volcaniclastic horizons. This study investigates the palaeoenvironment of the East Kirkton lake, and for the first time presents convincing evidence for the presence of hot springs at East Kirkton. Two distinct mounds of massive limestone are located at the north end of the East Kirkton quarry and are interpreted as hot spring vent deposits. Calcite samples from the Lower Mound have light δ¹⁸O_PDB values consistent with precipitation at elevated temperatures ranging from 45°C to ˜80°C, whereas samples from the laminated lake sediments have heavier δ¹⁸O_PDB values, consistent with precipitation at lower temperatures. The East Kirkton Limestone is unique because it contains a variety of unusual radial fibrous calcite (RFC) precipitates, including mm-sized spherules, oncoids, and laminated botryoidal accretions. These are found within the laminated limestone and also within the Lower Mound of massive limestone, and many of them contained filamentous and cellular microbial remains and are within the definition of microbial carbonates. This study provides good evidence for a microbial involvement in the formation of the East Kirkton laminated accretions. A study of modern stromatolites from Lake Tasek Dayang Bunting, Malaysia highlights close similarities with the East Kirkton accretions in terms of morphology and microstructure. Both have a nodular growth morphology and laminated interior consisting of layers of radial fibrous carbonate botryoids interspersed with organic-rich micritic laminae. The modern stromatolites are covered by a microbial community comprising filamentous bacteria and cyanophytes, plus diatoms and associated mucilage, and microbes are thought to have played an essential role in the morphogenesis of both the modern and ancient examples.

Thesis (doctoral)--Wageningen University and the Academic Board of the UNESCO-IHE Institute for Water Education, 2006. / "Propositions" ([1] leaf) inserted. Vita. Includes bibliographical references.