scholarly journals Middle Holocene Coastal Environmental and Climate Change on the Southern Coast of Korea

2020 ◽  
Vol 11 (1) ◽  
pp. 230
Author(s):  
Hoil Lee ◽  
Jin-Young Lee ◽  
Seungwon Shin
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Stable Carbon Isotopes ◽  
Asian Summer Monsoon ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Freshwater Input ◽  
Reclaimed Land ◽  
Middle Holocene ◽  
Southwest Coast

We obtained a 15 m drill core from Deukryang Bay on the southwest coast of Korea, which is now an area of reclaimed land used for agriculture. We investigated changes in the depositional environment and hydrological climate responses to sea level changes using sedimentary facies, radiocarbon ages, grain-size analysis, total organic carbon (TOC), total sulfur (TS), and stable carbon isotopes (δ13C). Sediment deposition began at 12,000 cal yr BP and was divided into four stages based on changes from fluvial to intertidal environments related to Holocene marine transgression events. Stage 1 (>10,000 cal yr BP) is represented by fluvial sediments; Stage 2 (10,000–7080 cal yr BP) is represented by the deposition of mud facies in an intertidal zone in response to sea level rise; Stage 3 (7080–3300 cal yr BP) was a period of gradually descending sea level following the Holocene maximum sea level and is characterized by gradual changes in TOC, TS, and C/S ratios compared with the mud facies of Stage 2. Stage 4 (3300 to present) was deposited in a supratidal zone and contains low TS and an abundance of TOC. Based on our TS and C/S ratio results, the south coast of Korea was mainly affected by sea level rise between 7000 and 3000 cal yr BP, during the middle Holocene. At 3000 cal yr BP, sea level began to stabilize or gradually decrease. In addition, changes in δ13C values are clearly observed since ca. 5000 cal yr BP, in particular, large hydrological changes via freshwater input are confirmed in 4000–3000 cal yr BP. We consider these shifts in freshwater input indicators of an increased influence of El Niño and La Niña conditions, related to the weakening of the East Asian Summer Monsoon (EASM) and changes in sea surface temperature (SST) of the Western Pacific Ocean during the middle Holocene climatic optimum (between 7800 and 5000 cal yr BP). The cooling periods of SST in East Asia between 8400 and 6600 cal yr BP reported from the west coast of Korea are related closely to changes in vegetation (as evidenced by δ13C) from 7700 cal yrs BP to the present in the southwest coast of Korea. We interpret the freshwater input events at 4000–3000 cal yr BP to be related to changes in SST in response to the weakening of the EASM on the southwest coast of Korea. However, additional research is needed to study the southward migration effect of the westerly jet related to SST and atmospheric circulation controlling terrestrial climate in the middle Holocene.

scholarly journals Centennial Impacts of the East Asian Summer Monsoon on Holocene Deltaic Evolution of the Huanghe River, China

2021 ◽  
Vol 11 (6) ◽  
pp. 2799
Author(s):  
Yanping Chen ◽  
Wenzhe Lyu ◽  
Tengfei Fu ◽  
Yan Li ◽  
Liang Yi
Keyword(s):  
Grain Size ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
River Delta ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sediment Grain Size ◽  
Huanghe River ◽  
Huanghe River Delta ◽  
The Huanghe River

The Huanghe River (Yellow River) is the most sediment laden river system in the world, and many efforts have been conducted to understand modern deltaic evolution in response to anthropological impacts. However, the natural background and its linkage to climatic changes are less documented in previous studies. In this work, we studied the sediments of core YDZ–3 and marine surface samples by grain-size analysis to retrieve Holocene dynamics of the Huanghe River delta in detail. The main findings are as follows: The mean value of sediment grain size of the studied core is 5.5 ± 0.9 Φ, and silt and sand contents are 5.2 ± 2.3% and 8.2 ± 5.3%, respectively, while the variance of clay particles is relatively large with an average value of 86.4 ± 8.5%. All grain-size data can be mathematically partitioned by a Weibull-based function formula, and three subgroups were identified with modal sizes of 61.1 ± 28.9 μm, 30.0 ± 23.9 μm, and 2.8 ± 1.6 μm, respectively. There are eight intervals with abrupt changes in modal size of core YDZ–3, which can be correlated to paleo-superlobe migration of the Huanghe River in the Holocene. Based on these observations, the presence of seven superlobes in the history are confirmed for the first time and their ages are well constrained in this study, including Paleo-Superlobes Lijin (6400–5280 yr BP), Huanghua (4480–4190 yr BP), Jugezhuang (3880–3660 yr BP), Shajinzi (3070–2870 yr BP), Nigu (2780–2360 yr BP), Qikou (2140–2000 yr BP), and Kenli (1940–1780 and 1700–1650 yr BP). By tuning geomorphological events to a sedimentary proxy derived from core YDZ–3 and comparing to various paleoenvironmental changes, we proposed that winter climate dominated Holocene shifts of the Huanghe River delta on millennial timescales, while summer monsoons controlled deltaic evolution on centennial timescales.

Middle Holocene environmental reconstruction and climatic inferences through multi-proxy records from Seymareh lake sediments (Zagros Mts., Iran)

2021 ◽  
Author(s):  
Michele Delchiaro ◽  
Giulia Iacobucci ◽  
Francesco Troiani ◽  
Marta Della Seta ◽  
Paolo Ballato ◽  
...  
Keyword(s):  
Sedimentation Rate ◽  
Water Discharge ◽  
Sediment Supply ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
The Holocene ◽  
Middle Holocene ◽  
Lake System ◽  
Proxy Records ◽  
The Impact

<p>The Seymareh landslide is the largest rock slope failure (44 Gm<sup>3</sup>) ever recorded on the exposed Earth surface. It detached ∼10 ka BP from the northeastern flank of the Kabir-Kuh anticline (Zagros Mts., Iran) originating the natural dam responsible for the formation of a three-lake system (Seymareh, Jaidar, and Balmak lakes, with an area of 259, 46, and 5 km<sup>2</sup>, respectively). The lake system persisted for ∼3000 yr during the Holocene before its emptying phase due to overflow. A sedimentation rate of 21 mm yr<sup>−1</sup> was estimated for the Seymareh lacustrine deposits, which increased during the early stage of lake emptying because of enhanced sediment yield from the lake tributaries. </p><p>To reconstruct the climatic and environmental impact on the lake infilling, we reviewed the geomorphology of the basins and combined the results with multi-proxy records from a 30 m thick lacustrine sequence in Seymareh Lake. Major analyses comprise grain size analysis, carbon and oxygen stable isotopes of carbonate-bearing sediments, and X-ray diffraction analysis of clay minerals.</p><p>Lake overflowing is largely accepted as the main response to variations in water discharge and sediment supply since the alternation from dry to wet phases enhances sediment mobilization along hillslopes decreasing the accommodation space in the downstream sedimentary basins. In this regard, during the early-middle Holocene, the Seymareh area, as well as the entire Middle East, was affected by short-term climate changes at the millennial-scale, as testified by both paleoecological and archaeological evidence. Indeed, several records from Iranian lakes (i.e., Mirabad, Zeribar, Urmia) well documented the temperature and the moisture conditions of the western Zagros Mountains during the Holocene. During the early Holocene, the precipitation remained low up to 6 ka BP, reaching the driest condition around 8-8.2 ka BP. The impact of this abrupt climate change is evident across West Asia, where the first large villages with domesticated cereals and sheeps disappeared, converting to small hamlets and starting habitat-tracking. As regards the Seymareh area, a more irregular distribution of rainfalls and their increasing seasonality may support rhexistasy conditions, during which the scarce vegetation cover enhances both the hillslope erosion and sedimentation rate in the basins, most likely contributing to the overflow of Seymareh Lake. </p>

Relative sea level rise, site distributions, and Neolithic settlement in the early to middle Holocene, Jiangsu Province, China

The Holocene ◽  
2017 ◽  
Vol 28 (3) ◽  
pp. 354-362 ◽  
Author(s):  
Lan Li ◽  
Cheng Zhu ◽  
Zhen Qin ◽  
Michael J Storozum ◽  
Tristram R Kidder
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Jiangsu Province ◽  
Relative Sea Level ◽  
Middle Holocene ◽  
Relative Sea Level Rise

scholarly journals Holocene hydroclimate reconstruction based on pollen, XRF, and grain-size analysis and its implications for past societies of the Korean Peninsula

2020 ◽  
Author(s):  
Jinheum Park ◽  
Jungjae Park ◽  
Sangheon Yi ◽  
Jaesoo Lim ◽  
Jin Cheul Kim ◽  
...  
Keyword(s):  
Grain Size ◽  
Korean Peninsula ◽  
Southern Oscillation ◽  
Asian Summer Monsoon ◽  
Underlying Mechanism ◽  
Kuroshio Current ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Pollen Record ◽  
The Holocene

Abstract. The dynamics of the East Asian Summer Monsoon (EASM) and their link to past societies during the Holocene are topics of growing interest. In this study, we present analyses of a ca. 6,000-year pollen record, as well as X-ray fluorescence (XRF) and grain-size data from the STP18-03 core sampled from Miryang in the Korean Peninsula, which spans ca. 8.3–2.3 ka BP. In-phase relationships of these proxies revealed an imprint of the Holocene Climate Optimum (HCO) during the early to mid-Holocene and subsequent drying toward the late Holocene in accordance with decreasing solar insolation. At centennial timescales, our study indicates wet conditions during ca. 8.3–7.5, 7.1–6.4, 6.0–4.8, and 3.6–2.8 ka BP, and a drier climate during ca. 7.5–7.1, 6.4–6.0, and 4.8–3.6 ka BP. Notably, our finding for ca. 6.4–6.0 ka BP contributes further evidence of a drying event in the Korean Peninsula during this period. We suggest that the Pacific Ocean played a role in the underlying mechanism of hydroclimate change in the region. A strong Kuroshio Current (KC) and long-term El Niño–Southern Oscillation (ENSO)-like variability in the Western Tropical Pacific (WTP) were closely linked to the influence of the EASM over the Korean Peninsula. In particular, dry phases during ca. 4.8–3.6 and 2.8–2.3 ka BP, which were synchronous with a more active ENSO, closely corresponded to lower population levels according to a summed probability distribution (SPD) of archaeological records assembled in the Korean Peninsula. This finding implies that past human societies of Korea were highly vulnerable to climate deterioration caused by precipitation deficits.

A reconstruction of late Pleistocene relative sea level in the south Bohai Sea, China, based on sediment grain-size analysis

2012 ◽  
Vol 281 ◽  
pp. 88-100 ◽  
Author(s):  
Liang Yi ◽  
Hongjun Yu ◽  
Joseph D. Ortiz ◽  
Xingyong Xu ◽  
Xiaoke Qiang ◽  
...  
Keyword(s):  
Grain Size ◽  
Sea Level ◽  
Late Pleistocene ◽  
Bohai Sea ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
The South ◽  
Relative Sea Level ◽  
Sediment Grain Size

Response of sediment grain size to sea-level rise during the middle Holocene on the west coast of the Gulf of Thailand

2022 ◽  
Vol 15 (2) ◽  
Author(s):  
Thanakorn Jiwarungrueangkul ◽  
Akkaneewut Jirapinyakul ◽  
Penjai Sompongchaiyakul ◽  
Shaohua Zhao ◽  
Rawee Rattanakom
Keyword(s):  
Grain Size ◽  
Sea Level Rise ◽  
Sea Level ◽  
West Coast ◽  
Gulf Of Thailand ◽  
The West ◽  
Sediment Grain Size ◽  
Middle Holocene ◽  
The Gulf Of Thailand

Middle Holocene Sea-Level Rise and Highstand at +2 M, Central Texas Coast

2001 ◽  
Vol 71 (4) ◽  
pp. 581-588 ◽  
Author(s):  
M. D. Blum ◽  
T. J. Misner ◽  
E. S. Collins ◽  
D. B. Scott ◽  
R. A. Morton ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Texas Coast ◽  
Middle Holocene ◽  
Central Texas ◽  
Holocene Sea Level
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