The goal of dissertation research was to use geochemical, statistical and geological methods to constrain and understand climate variability over several different time scales. Specifically, I have addressed three questions regarding past climate change: (1) how does the record of Irish cirque glaciers constrain the dimensions of the Irish Ice...
The South Pole ice core (SPC14), drilled in the field seasons of 2014/2015 and 2015/2016, is an intermediate length, 1,751-m ice core which preserves a 54,000-year record of past climate and atmospheric composition. The SPC14 ice core adds to the spatial grid of ice cores in Antarctica extending into the...
Antarctic Ice Sheet mass balance and, hence, sea level change is affected by the floating extensions of outlet glaciers and ice streams that take up about 44% of the coastline (Drewry et al., 1982) and are referred to as "ice shelves". Ice sheet mass loss accelerates when these ice shelves...
During the Last Glacial Maximum (LGM, ∼ 21 ky before present) the atmospheric CO2 concentration was about 100 ppm lower than its pre-industrial (PI)value. The missing carbon from the atmosphere must have been stored in thedeep ocean during this period, but the mechanisms driving such re-distribution ofthe carbon cycle are...
Climate model simulations and paleoclimate proxies are two tools that enable an understanding of the climate history of the Earth. When utilized together, they form a powerful paradigm for understanding past changes. Proxies are the only physical link to the past conditions on Earth, and models “fill in the gaps”...
Methane is a product of biogeochemical processes which respond to changes in climate. The history of atmospheric methane is recorded by ice cores providing insight into past changes in these biogeochemical processes. This dissertation is comprised of three studies which focus on centennial- and millenial-scale variability of methane from ice...
New ice cores retrieved from the Taylor Glacier (Antarctica) blue ice area contain ice and air spanning the Marine Isotope Stage (MIS) 5/4 transition, a period of global cooling and ice sheet expansion. Chronologies were determined for the ice and air bubbles in the new ice cores by visually matching...
Ice cores are considered the gold standard for recording past climate and biogeochemical changes. However, gas records derived from ice core analysis have until now been largely limited to centennial and longer timescales because sufficient temporal resolution and analytical precision have been lacking, except during rare times when atmospheric concentrations...
The Global Overturning Circulation (GOC) is a major component of the global climate system. Understanding its behavior is pertinent to our prediction of climate change in the future. The lack of long-term observations of GOC in the modern instrumental era necessitates studies of GOC using paleoceanographic records. Of great interest...
Stratigraphy and chronology are essential to sedimentological study of Earth system histories. And, stratigraphy and chronology are often challenging and interesting problems themselves. The Quaternary (2.588 Ma - present) experienced paleoenvironmental and paleo-geomagnetic variability well outside the range of the recent instrumental record, providing the opportunity to place recent observations...