Youngsook Huh

Seoul National University | SNU · Department of Earth and Environmental Sciences

We investigated benthic foraminifera in cores GPC03 and GPC04 in the northeast tropical Indian Ocean (TIO) over the past ∼450 ka to evaluate the ballasting effect of particulate organic matter (POM) and the long‐term zonal change during the mid‐Brunhes dissolution interval (MBDI). Today, interannual climate and oceanographic variability in the TIO...

The long-term evolution of the South Asian monsoon system and its influence on the Bay of Bengal (BOB) is of great interest to climate scientists. A number of climate forcings trigger the changes of the Indian summer monsoon (ISM) precipitation centroid, while the ISM rainfall projected by climate models shows a large discrepancy in local precipita...

We reconstructed the past deep-water character of the equatorial Indian Ocean using the isotope ratio of neodymium ( ε Nd ) in the Fe–Mn coating of mixed-species foraminifera. When compared with previous ε Nd records at the same site (ODP 758) and at another site to the west (SK 129), the three datasets were consistent and showed glacial-interglaci...

Neodymium isotope ratios (¹⁴³Nd/¹⁴⁴Nd, εNd) have been used as a quasi-conservative water mass tracer in the Atlantic and Southern oceans. However, boundary exchange and diagenesis can limit their use in areas where extensive interactions between seawater, pore water and bottom sediments can overwrite the original water mass signature. To avoid the...

During International Ocean Discovery Program (IODP) expeditions, shipboard-generated data provide the first insights into the cored sequences. The natural gamma radiation (NGR) of the recovered material, for example, is routinely measured on the ocean drilling research vessel DV JOIDES Resolution. At present, only total NGR counts are readily avail...

Photochemically driven mercury (Hg) exchange between the atmosphere and the Antarctic Plateau snowpack has been observed. An imbalance in bidirectional flux causes a fraction of Hg to remain in the snowpack perennially, but the factors that control the amount of Hg sequestered on the Antarctic Plateau are not fully understood. We analyzed sub-annua...

The Bering Sea is a potential location for the formation of the North Pacific Intermediate Water (NPIW), which drives the global ocean circulation as a counterpart to the North Atlantic Deep Water (NADW). To evaluate the NPIW-NADW seesaw hypothesis, we reconstructed the long-term variation of the bottom water Nd isotopic composition at site U1345 o...

We studied the diagenetic behavior of rare earth elements (REEs) in a highly productive passive margin setting of the Bering Sea Slope. Site U1345 was drilled during the Integrated Ocean Drilling Program Expedition 323 at a water depth of 1008 m currently in the center of an oxygen minimum zone. Pore water concentrations of fourteen REEs were deter...

Concentrations of dissolved silicon in river waters reflect a complex interplay among chemical weathering of primary silicate minerals, formation and weathering of secondary clay minerals, hydrothermal input and biological cycling (formation and dissolution of opal phytoliths and growth of diatoms). We applied the Ge/Si ratio to assess the differen...

Proxies for paleo-circulation are drawing much interest with the recognition that ocean circulation plays an important part in the redistribution of heat and climate change on orbital and millennial timescales. In this review, we will introduce how neodymium isotope ratios of the authigenic fraction of marine sediments can be used as a proxy for oc...

It is often assumed that atmospheric observations at remote sites represent long-range transport of airborne material, and local influences are overlooked. We evaluated the impact of local input on the rainwater composition at Gosan Station, a strategic site for monitoring the continental outflow from Asia. We analyzed a 14-year record of rainwater...

Measuring the mercury content in shallow Antarctic snow pits is useful for understanding the mercury dynamics of the Antarctic Plateau and the global mercury cycle and for interpreting ice core data. We determined the total mercury concentration (Hg-T) in snow samples successively collected at 5 cm intervals from two 4m deep snow pits at Dome Fuji....

We studied the diagenetic behavior of rare earth elements (REEs) in a highly productive passive margin setting of the Bering Sea Slope. Site U1345 was drilled during the Integrated Ocean Drilling Program Expedition 323 at a water depth of 1008 m currently in the center of an oxygen minimum zone. Pore water concentrations of fourteen REEs were deter...

The freshwater budget of the Arctic Ocean is a key component governing the deep water formation in the North Atlantic and the global climate system. We analyzed the isotopic composition of neodymium (εNd) in authigenic phases of marine sediments on the Mendeleev Ridge in the western Arctic Ocean spanning an estimated time interval from present to a...

The freshwater budget of the Arctic Ocean is a key component governing the deep water formation in the North Atlantic and the global climate system. We analyzed the isotopic composition of neodymium (epsilon-Nd) in authigenic phases of marine sediments on the Mendeleev Ridge in the western Arctic Ocean spanning an estimated time interval from prese...

We investigated physical and chemical weathering in south Patagonia, encompassing both the tectonically active Andes with alpine glaciers and the quiescent seaboard plain with arid climate. Chemical denudation rates determined from riverine dissolved major elements were (0.07–5) � 10^5 tons year^-�1, and the long-term rates of CO2 consumption by al...

Dissolved platinum concentrations of eleven large pristine river systems in East Asia (˜200 samples) were determined to better constrain the oceanic platinum budget. Most samples had concentrations less than 1.4 pM; relatively high concentrations up to 5.8 pM were measured in only approximately 6% of the samples. The median Pt concentrations of the...

The total mercury concentration (Hg T) of surface snow samples collected along a ~1500 km transect in east Queen Maud Land was determined using inductively coupled plasma sector field mass spectrometry to address the behavior of Hg on the Antarctic Plateau. Due to the volatile nature of mercury, measures were taken against Hg loss from standard sol...

Antarctic snow preserves an atmospheric archive that enables the study of global atmospheric changes and anthropogenic disturbances from the past. We report atmospheric deposition rates of platinum group elements (PGEs) in Antarctica during the last ∼ 50 years based on determinations of Pt, Ir, and Rh in snow samples collected from Queen Maud Land,...

We studied microbially mediated diagenetic processes driven by carbon mineralization in subseafloor sediment of the northeastern Bering Sea Slope to a depth of 745 meters below seafloor (mbsf). Sites U1343, U1344 and U1345 were drilled during Integrated Ocean Drilling Program (IODP) Expedition 323 at water depths of 1008 to 3172 m. They are situate...

Platinum group elements (PGEs: Pt and Ir) and rare earth elements (REEs) were analyzed in rainwater samples collected in Seoul during the summer of 2008 to identify their sources and quantify their wet-deposition fluxes to the Earth’s surface environment. Major (Na, K, Mg, Ca, NH4+, SO42−, NO3−, Cl− and F−) and minor (Fe, Ba, Y and Hf) elements wer...

The fluvial geochemical data of major rivers draining the Himalayas and the Tibetan Plateau (HTP) are compiled from literature and supplemented with data from the author's group to explore the spatial variability in the major element and strontium isotopic compositions and in rates of silicate weathering and concomitant drawdown of atmospheric CO 2...

We report the dissolved major element, organic carbon, and δ13CDOC, δ13CPOC, δD, δ18O, and 87Sr/86Sr composition of 19 summer samples from the Amur River. The Amur transported 2.6TgC/year of total organic carbon to the Sea of Okhotsk. The physical weathering rate (PWR) based on suspended particulate material was 13 (1.4–14)tons/(km2year), and the c...

A series of tests were carried out to measure total mercury in solution at the picomolar (pM, 10-12 M) level using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). For low-matrix snow and ice samples for which we are developing this method, ICP-SFMS offers advantages over the conventional cold vapor generation method by reducin...

The weathering regime of the Southern Patagonian rivers was studied using dissolved major and minor (U, Sr, Al, Rb, Ba) elements, U-series isotope ratios in the dissolved and suspended load, and 10Be in the bedload. The rivers were broadly Ca-HCO3 type. The U and Th concentrations ranged from 6.72 to 353 pM and from 1.29 to 28.4 pM, respectively. T...

The Duman River and the hot springs and streams of Mt. Baekdu were sampled and analyzed for their major elements, 87Sr/86Sr, δD, δ18O, and δ13C. The Duman River drains an extensive volcanic plateau in northeast Asia and Mt. Baekdu is a volcanic cone on the plateau, and their fluvial geochemistry reflects weathering of volcanic rock. Two different v...

Three large rivers – the Chang Jiang (Yangtze), Mekong (Lancang Jiang) and Salween (Nu Jiang) – originate in eastern Tibet and run in close parallel over 300 km near the eastern Himalayan syntaxis. Seventy-four river water samples were collected mostly during the summer season from 1999 to 2004. Their major element compositions vary widely, with to...

The concentrations of platinum group elements (PGEs) are rapidly increasing in many environmental matrices with the advent of automobile catalytic converters and the utilization of catalysts in diverse industrial processes. Atmospheric precipitation is an important process constituting the global geochemical cycle and can directly impact the ecosys...

We investigated the petrography and major, trace and rare earth element compositions of the bed sediments from the large rivers draining the eastern Tibetan Plateau (ETP) — the Huang He (Yellow), Chang Jiang (Yangtze), Hong He (Red), Mekong and Salween. The combined drainage spans tropical, temperate and arid climate zones. In addition, samples fro...

We investigated the dissolved major elements, $ {}^{87}{\text{Sr/}}{}^{86}{\text{Sr}},\;\delta {}^{34}{\text{S}}_{{\text{SO}}_{\text{4}} } ,\;{\text{and}}\;\delta {}^{18}{\text{O}}_{{\text{SO}}_{\text{4}} } $ composition of the Min Jiang, a headwater tributary of the Chang Jiang (Yangtze River). A forward calculation method was applied to quantif...

The Hong (Red) River drains the prominent Red River Fault Zone that has experienced various tectonic activities—intrusion of magma, exhumation of basement rocks, and influx of thermal waters—associated with the Cenozoic collision of India and Eurasia. We report dissolved major element and Sr isotope compositions of 43 samples from its three tributa...

The Red (Hong) River straddles southwestern China and northern Vietnam and drains the eastern Indo-Asian collision zone. We collected bed sediments from its tributaries and main channel and report the petrographic point counts of framework grains and major oxide compositions as well as organic and inorganic carbon contents. The Q:F:Rf ratios and Q:...

The Amur River is the fourth largest river (~1,855,000 km2) in north Eurasia which flow into the Pacific Ocean. It flows through 4 countries-the Russian Far East, northeast China, east Mongolia and a small territory of North Korea. Climatic and ecological conditions differ significantly from western intercontinental region to eastern coastal area....

The Min Jiang is a major headwater tributary of the Yangtze (Chang Jiang). Its source is in the undeveloped eastern Tibetan Plateau, but it flows through the heavily populated Sichuan (Four Rivers) Basin on its way to join the Yangtze main channel. The dissolved major element composition was determined in the Tibetan headwaters at the rising stage...

Three large rivers - the Chang Jiang (Yangtze), Mekong (Lancang Jiang) and Salween (Nu Jiang) - originate in eastern Tibet and run in close parallel over 300 km near the eastern Himalayan syntaxis. They flow across suture zones and faults generated by the collision of India and Eurasia. Sixty-five water samples were collected in summer of 1999 to 2...

Dissolved reactive phosphorus (DRP) concentrations in large pristine rivers of East Asia (370 samples) are reported and the relationship to lithology (phosphorites, igneous apatite-bearing deposits), relief, climate (precipitation, temperature), and population density are investigated. The DRP concentration and yield of 93% of our samples were dist...

We examined the fluvial geochemistry of the Huang He (Yellow River) in its headwaters to determine natural chemical weathering rates on the northeastern Qinghai-Tibet Plateau, where anthropogenic impact is considered small. Qualitative treatment of the major element composition demonstrates the dominance of carbonate and evaporite dissolution. Most...

1] We examined the pedogenic behavior of lithium (Li) and its isotopes in Hawaii by sampling same-age lava flows under mean annual rainfall ranging from 18 to 300 cm. Lithium concentrations in these soils vary from 1 to 29 ppm. Whereas Na, K, and Ca are completely leached from the soil at the most humid and severely weathered site, Li, Mg, Si, and...

The Cenozoic marine osmium isotope record is largely driven by changes in the continental input. We aid its interpretation by supplying direct measurements of present day riverine Os in known geological and environmental settings. We analyzed Os concentrations and isotopic ratios in the dissolved, suspended, and bed materials of the Mackenzie River...

Red River and the headwaters of the Chang Jiang in western China and Vietnam are in the tectonically active part of the Himalayan-Tibetan orogeny. Riverine fluxes associated with weathering along these rivers contribute to the total weathering yield associated with the main collision. The riverine flux carried by Himalayan rivers is considered to b...

Most treatments of the Phanerozoic evolution of the carbon dioxide content of the atmosphere (PCO2) assume a steady state closed system. Release of CO2 by mantle degassing and by biogenic precipitation of carbonates and their metamorphism in subduction zones balances the consumption by continental aluminosilicate weathering. Small perturbations in...

How has the Earth maintained a habitable environment while its closest neighbors, Venus and Mars, are currently too hot or too cold? This fortunate state has been attributed to a negative feedback hypothesis that has stood unchallenged for years. In this model, any increase in atmospheric CO2 production is balanced by increased CO2 uptake by silica...

Lithium isotopes have the potential to be effective tracers of weathering processes due to their large relative mass difference and therefore fractionation. In this study an attempt is made to fill a major gap in the knowledge of Li isotope fractionation during continental weathering and of the mechanisms involved. Finally the relationship between...

Modern sand from the vast (2430000 km2), high-latitude Lena River watershed occupies a low-lying, mostly unglaciated craton covered by thick, widespread permafrost— totally different from the watersheds of large temperate and tropical rivers, whose sands have been previously studied to establish modern baselines for the interpretation of ancient sa...

Lithium isotopes have the potential to be effective tracers of weathering processes due to their large relative mass difference and therefore fractionation. In this study an attempt is made to fill a major gap in the knowledge of Li isotope fractionation during continental weathering and of the mechanisms involved. Finally the relationship between...

The conventional view of the climatic influence on weathering is that weathering rates are strongly temperature-dependent due to the near-exponential relationship (Clausius-Clapeyron) between temperature and the saturation vapor pressure of water, and hence precipitation and runoff. This is a central theme in the Earth “thermostat” model, i.e., wea...

The present published inventory of fluvial Sr and87Sr/86Sr data, combined with new information from the big rivers of Eastern Siberia (a combined total of ∼ 1,000 measurements), is used to investigate the probable origin of the large rise in the marine isotopic ratio, recorded in limestones, over the last ∼ 20 million years. With the exception of t...

The present published inventory of fluvial Sr and Sr-87/Sr-86 data, combined with new information from the big rivers of Eastern Siberia (a combined total of similar to 1,000 measurements), is used to investigate the probable origin of the large rise in the marine isotopic ratio, recorded in limestones, over the last similar to 20 million years. Wi...

The outstanding problem in the lithium geochemical cycle is the lack of an isotopic mass balance in the ocean. The δ6Li compositions of fresh basalts (−4‰), the hydrothermal fluids derived from them (average −9‰), and seawater (significantly heavier at −32‰) are well understood, but only very sparse river input data are available for Li mass balanc...

Fundamental to the global carbon cycle over geologic time scales is the control of atmospheric CO2 by aluminosilicate weathering. Much of the information on the rates of this process comes from rivers in the tropics and subtropics. To understand the possible climatic influences systematic studies are needed for the arctic/subarctic regions. This is...

The response of continental weathering rates to changing climate and atmospheric PCO2 is of considerable importance both to the interpretation of the geological sedimentary record and to predictions of the effects of future anthropogenic influences. While comprehensive work on the controlling mechanisms of contemporary chemical and mechanical weath...

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1998. Includes bibliographical references. by Youngsook Huh. Ph.D.

The 18O record in benthonic foraminifera over the last 70 million years can only be interpreted in terms of a more-or-less continual climatic deterioration over the period of record.1–2 Abyssal water temperatures record winter conditions in the oceanic areas where climatic extremes generate the densest waters. The isotopic temperatures in the abyss...

New data are presented for major dissolved species in vent fluids from the TAG hydrothermal mound on the Mid-Atlantic Ridge, sampled in 1993, 1994, and 1995. The latter two cruises bracket the drilling of the mound by the Ocean Drilling Program in September-November 1994. Changes in venting patterns have been observed over this time period, both be...

The fluvial geochemistry of the tributaries of the Orinoco draining the eastern branch of the northern Andes in Colombia and Venezuela is determined by lithology and ranges from rivers dominated by aluminosilicate weathering, mainly of shales and mafic rocks, to those bearing the signatures of dissolution of marine limestones and evaporites and of...

A new method of measuring the pH of high-temperature aqueous solutions using optical indicators was developed. The absorbance spectrum of acridine changes as a function of pH, allowing its use as an optical indicator for pH. The pKa of acridine were experimentally determined in KOH-AcOH pH-buffer solutions at temperatures from 5 to 250C at vaporsat...

A contrast in goiter prevalence between populations living north and south of the Main Karakoram Thrust (MKT) in northeastern Pakistan suggests that plate tectonics may be involved. We report ICP-MS measurements of the total dissolved iodine levels in the headwater tributaries of the Indus River draining either side of the MKT. For global geochemic...

Microbially-mediated diagenetic processes driven by carbon mineralization were studied in the subseafloor sediment of the northeastern Bering Sea Slope down to a depth of 745 mbsf. The three study sites, drilled during Integrated Ocean Drilling Program (IODP) Expedition 323, are situated in the high primary productivity ``Green Belt'' region charac...