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Late Pleistocene Glaciations And Paleoclimate Of Turkey, Mehmet Akif Sarikaya, Atilla Çi̇ner

Bulletin of the Mineral Research and Exploration

Glaciers respond quickly to climatic changes and thus they are considered to be very accurate indicators of changes in atmospheric conditions. Similarly, the extent of past glaciers gives valuable insights into paleoclimatic changes. For this purpose, we reviewed the paleo-glaciated mountains where cosmogenic surface exposure dating was applied inTurkey. We also evaluated the paleoclimatic results obtained from these studies to provide a regional overview. Twenty-seven mountains in Turkey are high enough to support Quaternary valley glaciers or ice caps. The timing of glaciations was reported mainly by cosmogenic dating of moraines. We re-evaluated the dated sites and recalculated some of …

A High-Resolution Paleoenvironmental And Paleoclimatic History Of Extreme Events On The Laminated Sediment Record From Basin Pond, Fayette, Maine, U.S.A., Daniel R. Miller

Masters Theses

Future impacts from climate change can be better understood by placing modern climate trends into perspective through extension of the short instrumental records of climate variability. This is especially true for extreme climatic events, such as extreme precipitation and wildfires, as the period of instrumental records provides only a few examples and these have likely have been influenced by anthropogenic warming. Multi-parameter records showing the past range of climate variability can be obtained from lakes. Lakes are particularly good recorders of climate variability because sediment from the surrounding environment accumulates in lakes, making them sensitive recorders of climate variability and …

Examining The Mid- Brunhes Event In The Terrestrial Arctic: An Organic Geochemical Record From Lake El’Gygytgyn, Russia, Mary Helen Habicht

Masters Theses

The characteristic glacial and interglacial cycles of the Pleistocene underwent a climatic transition at ~430 ka known as the Mid- Brunhes Event (MBE). Many studies, particularly from the Southern Hemisphere have noted that after this transition, the amplitude of the climatic cycles increased. Despite the indication of an MBE signal in many globally distributed paleoclimate records, the geographic extent of the climatic transition remains unknown and its presence in northern hemisphere and terrestrial records is debated. Lake El’gygytgyn is located in the far- east Russian Arctic and provides the longest, most continuous record of Arctic climate (3.6 Ma). This study …

Development And Validation Of A Physically Based Ela Model And Its Application To The Younger Dryas Event In The Graubünden Alps, Switzerland, Durban Gregg Keeler

Theses and Dissertations

The rapid rate of global warming currently underway highlights the need for a deeper understanding of abrupt climate change. The Younger Dryas is a Late-Glacial climate event of widespread and unusually rapid change whose study can help us address this need for increased understanding. Reconstructions from the glacial record offer important contributions to our understanding of the Younger Dryas due to (among other things) the direct physical response of glaciers to even minor perturbations in climate. Because the glacier equilibrium line altitude (ELA) provides a more explicit comparison of climate than properties such as glacier length or area, ELA methods …

Reconstructing Late Holocene Hydrographic Variability Of The Gulf Of Maine, Nina Millicent Whitney

Electronic Theses and Dissertations

I present an annually resolved reconstruction of seawater temperatures in the

western North Atlantic from 1695-1915. This paleoclimate record was constructed

using oxygen isotopes measured in precisely dated Arctica islandica shells collected

off of Seguin Island in the western Gulf of Maine. The temperature reconstruction

was derived from this oxygen isotope time series using a modern d¹⁸O_w-salinity

mixing line developed for coastal waters in the Gulf of Maine from water samples

collected over the last decade. The d¹⁸O_w and salinity composition of these water

samples indicate that coastal surface waters consist of a …

Arctic Environmental Change Across The Pliocene-Pleistocene Transition, Benjamin Andrew Keisling

Masters Theses

Environmental change in the Arctic proceeds at an unprecedented rate. The Pliocene epoch (5-2.65 million years ago) represents an analog for future climate conditions, with pCO₂ and continental configurations similar to present. Yet conditions in the Pliocene Arctic are poorly characterized because of sparse sampling. The records that do exist indicate periods of extreme warmth, as well as the first expansion of large ice-sheets in the Northern Hemisphere, took place from the end of the Pliocene into the early Pleistocene. Understanding these deposits and their implications for our future requires developing a sense of climatic evolution across the …

Paleoclimate Implications From Stable Isotope Analysis Of Sedimentary Organic Carbon And Vertebrate Fossils From The Cedar Mountain Formation, Ut, U.S.A., Garrett Andrew Hatzell

Graduate Theses and Dissertations

Oxygen and carbon isotopic compositions of fossilized vertebrate teeth and bone were analyzed to determine isotopic values of vertebrate faunal diet from the early Cretaceous Cedar Mountain Formation of Utah. Results for δ18O of PO4 (δ18Op) (Suarez et al., 2014) from the same data set have been compared to the δ18O of CO3 (δ18Oc) portion of teeth and turtle shell to determine if diagenetic alteration of the isotopes has occurred by plotting the line of best fit equation that models the relationship between unaltered δ18OP and δ18OC of modern mammals from Iacumin et al., 1996. Results indicate slight diagenesis of …

Twentieth Century Dust Lows And The Weakening Of The Westerly Winds Over The Tibetan Plateau, Bjorn Grigholm, P. A. Mayewski, S. Kang, Y. Zhang, U. Morgenstern, M. Schwikowski, Susan D. Kaspari, V. Aizen, E. Aizen, N. Takeuchi, K. A. Maasch, S. Birkel, M. Handley, S. Sneed

All Faculty Scholarship for the College of the Sciences

Understanding past atmospheric dust variability is necessary to put modern atmospheric dust into historical context and assess the impacts of dust on the climate. In Asia, meteorological data of atmospheric dust is temporally limited, beginning only in the 1950s. High‐resolution ice cores provide the ideal archive for reconstructing preinstrumental atmospheric dust concentrations. Using a ~500 year (1477–1982 A.D.) annually resolved calcium (Ca) dust proxy from a Tibetan Plateau (TP) ice core, we demonstrate the lowest atmospheric dust concentrations in the past ~500 years during the latter twentieth century. Declines in late nineteenth to twentieth century Ca concentrations significantly correspond with …

Mid-Holocene Speleothem Climate Proxy Records From Florida And Belize, Anna L. Pollock

USF Tampa Graduate Theses and Dissertations

As global temperatures rise due to anthropogenic climate change, water resources, thus economies, are threatened. A geologically recent period of increased temperatures is the mid-Holocene and an investigation of its climate may allow for a better understanding of future precipitation and changes to regional water resources. The regions of interest are tropical Northern Central America and subtropical North America with Belize and Florida representing each climate zone. By reconstructing mid-Holocene climate in Florida and Belize, I hope to provide a better understanding of how increased temperatures and a reduced latitudinal temperature gradient impacts both precipitation patterns and variability. Today, drivers …

Hydroclimatic Shifts In Northeast Thailand During The Last Two Millennia — The Record Of Lake Pa Kho, Sakonvan Chawchai, Akkaneewut Chabangborn, Sherilyn C. Fritz, Minna Väliranta, Carl-Magnus Mörth, Maarten Blaauw, Paul J. Reimer, Paul J. Kusic, Ludvig Löwemark, Barbara Wohlfarth

Department of Earth and Atmospheric Sciences: Faculty Publications

The Southeast Asian mainland is located in the central path of the Asian summer monsoon, a region where paleoclimatic data are still sparse. Here we present a multi-proxy (TOC, C/N, δ13C, biogenic silica, and XRF elemental data) study of a 1.5 m sediment/peat sequence from Lake Pa Kho, northeast Thailand, which is supported by 20 AMS 14C ages. Hydroclimatic reconstructions for Pa Kho suggest a strengthened summer monsoon between BC 170–AD 370, AD 800–960, and after AD 1450; and a weakening of the summer monsoon between AD 370–800, and AD 1300–1450. Increased run-off and a higher nutrient supply after AD …

An Approach To Paleoclimatic Conditions For Devonian (Upper Lochkovian And Middle Givetian) Ironstone Formation, Nw Anatolian Carbonate Platform, İsmai̇l Ömer Yilmaz, Mehmet Cemal Göncüoğlu, Di̇lek Gülnur Demi̇ray, İbrahi̇m Gedi̇k

Turkish Journal of Earth Sciences

Lower-middle Devonian iron-bearing successions were studied along 2 measured stratigraphic sections in the Çamdağ region of NW Anatolia. Ironstones in the upper part of the Fındıklı Formation in Kabalakdere are characterized by alternating red and green mudstones and sandstones at the bottom, followed by a series of dolomite, dolomitic limestone with oolitic ironstones, and chamositic mudstones at the top. Conodonts from these carbonates indicate the delta-pesavis zones of the late Lochkovian. The 12- to 45-m-thick Ferizli Formation unconformably overlies the Fındıklı Formation with a quartz-arenite succession at the bottom. The formation comprises alternating red, iron-rich limestones and dolomitic limestones, where …

The Champlain Sea/Lake Champlain Transition Recorded In The Northeast Arm Of Lake Champlain, Usa-Canada, Ashliegh Theresa Belrose

Graduate College Dissertations and Theses

Sediment accumulated on a lakebed archives information about past climate and changes in the regional environment. Previous studies (Burgess, 2007; Koff, 2011; Palmer, 2012) in the Northeast Arm of Lake Champlain, specifically Missisquoi Bay and Saint Albans Bay, showed a period (~9,400 - 8,600 yBP) of elevated organic matter deposition in both bays, indicating a productive event that pre-dated any possible anthropogenic influence. However, the record was abruptly cut off and any documentation representing the span of time leading up to this event was not found. The elevated organic matter levels were explained as being the result of a warm, …