A5034035198- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Geological Studies and Exploration
- Marine and coastal ecosystems
- Hydrocarbon exploration and reservoir analysis
- Geological and Geophysical Studies
- Geological formations and processes
- earthquake and tectonic studies
- Oceanographic and Atmospheric Processes
- Paleontology and Stratigraphy of Fossils
- Arctic and Antarctic ice dynamics
- Geological and Geochemical Analysis
- Marine Biology and Ecology Research
- Marine and environmental studies
- Pleistocene-Era Hominins and Archaeology
- Advanced Data Processing Techniques
- Aeolian processes and effects
- Marine and fisheries research
- High-pressure geophysics and materials
- Geochemistry and Geologic Mapping
- Protist diversity and phylogeny
- Geological and Tectonic Studies in Latin America
- Mineralogy and Gemology Studies
- Pacific and Southeast Asian Studies
Dalhousie University
2014-2025
GFZ Helmholtz Centre for Geosciences
2012-2014
McGill University
2013
University of British Columbia
1999-2005
Woods Hole Oceanographic Institution
2004-2005
Kiel University
1999
The tropical ocean plays a major role in global climate. It is therefore crucial to establish the precise phase between and high-latitude climate variability during past abrupt events order gain insight into mechanisms of change. Here we present alkenone sea surface temperature (SST) records from South China Sea that show an increase at least 1°C end last glacial period. Within recognized dating uncertainties, this SST synchronous with Bølling warming observed 14.6 thousand years ago...
Past sea surface temperatures (SST) in the northern and southern areas of South China Sea have been reconstructed for past 220 kyr using U K 37 alkenone index. The SST profiles follow glacial/interglacial pattern exhibiting differences between Last Glacial Maximum Holocene that are 1°–3°C larger than those observed at same latitudes Atlantic Pacific Oceans. In Termination I both planktonic foraminiferal δ 18 O exhibit well‐defined Bølling‐Allerød Younger Dryas events with temperature periods...
Abstract 230 Th normalization is a valuable paleoceanographic tool for reconstructing high‐resolution sediment fluxes during the late Pleistocene (last ~500,000 years). As its application has expanded to ever more diverse marine environments, nuances of systematics, with regard particle type, size, lateral advective/diffusive redistribution, and other processes, have emerged. We synthesized over 1000 sedimentary records from across global ocean at two time slices, Holocene (0–5,000 years...
Glacial‐interglacial changes in sedimentary δ 15 N over the last 120 kyr display a remarkably similar pattern timing and amplitude core records extending from denitrification zone eastern tropical North Pacific (ETNP), where subsurface is active, to Oregon margin, no occurs today. Low values (4–6‰) generally characterize glacial stages 2 4, higher (7–10‰) are representative of Holocene, millennial‐scale periods within stage 3, 5. The inferred synchroneity variations along entire margin...
We present sea surface, upper thermocline, and benthic δ 18 O data, as well temperature paleoproductivity proxy from the International Marine Global Change Study Program (IMAGES) Core MD06‐3067 (6°31′N, 126°30′E, 1575 m water depth), located in western equatorial Pacific Ocean within flow path of Mindanao Current. Our records reveal considerable glacial‐interglacial suborbital variability Dome upwelling over last 160 kyr. activity generally intensified during glacial intervals resulting...
Abstract Continental dust input into the ocean‐atmosphere system has significant ramifications for biogeochemical cycles and global climate, yet direct observations of deposition in ocean remain scarce. The long‐lived isotope thorium‐232 ( 232 Th) is greatly enriched upper continental crust compared to oceanic mid‐ocean ridge basalt‐like volcanogenic material. In open sediments, away from fluvial ice‐rafted sources material, Th often assumed be predominantly eolian origin. conjunction with...
Changes of sea surface temperature (SST) in the subarctic NE Pacific over last 16,000 calendar years before present (16 kyr BP) have been inferred from study C 37 alkenone unsaturation a sediment core western Canadian continental slope. Between 16.0 and 11.0 kyr, three distinct cold phases (6–7°C) interrupt two warmer periods (9–10°C). Within 2σ range radiocarbon based time control, observed SST oscillations correspond to Oldest Dryas, Bølling, Older Allerød, Younger Dryas GISP2 δ 18 O...
Research Article| July 01, 2004 Influence of northwest Pacific productivity on North Intermediate Water oxygen concentrations during the Bølling-Ållerød interval (14.7–12.9 ka) John Crusius; Crusius 1U.S. Geological Survey, 384 Woods Hole Road, Hole, Massachusetts 02543, USA Search for other works by this author on: GSW Google Scholar Thomas F. Pedersen; Pedersen 2School Earth and Ocean Sciences, University Victoria, British Columbia V8W 3P6, Canada Stephanie Kienast; Kienast 3Department...
The δ 15 N of surface and down‐core sediments spanning the last 20–200 kyr from entire South China Sea (SCS) ranges only ∼3.0 to ∼6.5‰, with no correlation discernible paleoclimatic/oceanographic changes. Detailed profiles uppermost sediment column, including fluff samples, indicate a minor diagenetic overprint 0.3–1.2‰ at sediment‐water interface. absence any reconstructed (glacial‐interglacial) changes in primary production, terrigenous input, and/or sea level related basin configuration...
An analysis of sedimentary nitrogen isotope records compiled from widely distributed marine environments emphasizes the global synchrony denitrification changes and provides evidence for a strong temporal coupling these variations to in fixation as previously inferred. We explain coherence by simple physical control on flux dissolved oxygen suboxic zones via supply phosphorus diazotrophs suitable environments. According our hypothesis, lower glacial‐stage sea surface temperature increased...
Application of the 230 Th normalization method to estimate sediment burial fluxes in six cores from eastern equatorial Pacific (EEP) reveals that bulk and organic carbon display a coherent regional pattern during Holocene is consistent with modern oceanographic conditions, contrast estimates mass accumulation rates (MARs) derived core chronologies. Two nearby sites (less than 10 km apart), which have different MARs, show nearly identical Th‐normalized fluxes. Focusing factors data at foot...
Research Article| January 01, 2003 Synchroneity of meltwater pulse 1a and the Bølling warming: New evidence from South China Sea M. Kienast; Kienast 1Earth Ocean Sciences, University British Columbia, Vancouver, Columbia V6T 1Z4, Canada Search for other works by this author on: GSW Google Scholar T.J.J. Hanebuth; Hanebuth 2National Institute Advanced Industrial Science Technology, Geological Survey Japan, Marine Resources Environment, Higashi 1-1-1, Tsukuba, Ibaraki 305-8567, Department...
Abstract The timing and magnitude of sea-surface temperature (SST) changes in the tropical southern South China Sea (SCS) during last 16,500 years have been reconstructed on a high-resolution, 14 C-dated sediment core using three different foraminiferal transfer functions (SIMMAX28, RAM, FP-12E) geochemical (U k′ 37 ) SST estimates. In agreement with CLIMAP reconstructions, both FP-12E U estimates show an average late glacial–interglacial difference 2.0°C, whereas RAM SIMMAX28 only minor...
The bulk sedimentary nitrogen isotopic composition of two cores from nearby sites on the northern slope South China Sea (Site 17940 and Ocean Drilling Program (ODP) Site 1144) differs by up to >2‰ during last glacial period. Given their close proximity, both core are located in same biogeographic zone nutrient regime, it is thus unlikely that this offset due a true gradient surface ocean conditions. In an attempt resolve offset, we have investigated possible effects sedimentological...
We have measured 230 Th‐normalized opal fluxes in several cores from the eastern equatorial Pacific (EEP) to test validity of “silica leakage” hypothesis, which purports that redistribution silicic acid Southern Ocean low latitudes was responsible for a significant portion reduction atmospheric carbon dioxide (CO 2 ) during last glacial period. The silica leakage hypothesis predicts higher EEP and lower periods CO . These predictions are not borne by sedimentary record oxygen isotope stage...