Effects of lithology on bedrock channel occurrence: an examination from the Seogang River in South Korea

2021 ◽  
Author(s):  
Hui Chen ◽  
Jongmin Byun
Keyword(s):  
South Korea ◽  
Rock Type ◽  
The Other ◽  
Joint Density ◽  
Transport Capacity ◽  
Stream Power ◽  
Granitic Gneiss ◽  
Bedrock Channel ◽  
Basin Scale ◽  
Bedrock Channels

<div> <p>Bedrock river is rock-bound, its bed and banks are composed mainly of in-place bedrock. Bedrock channel reaches, commonly short and intermittent, often occur where transport capacity exceeds bedload sediment flux. Despite the abundant research on the typical patterns of alluvial channel reaches, the distribution of bedrock channels has not been well studied. Rock type may affect the occurrence of bedrock channels because the strength, joint density, and erosion process of bedrock vary depending on the rock type. Previous studies have viewed the bedrock channel occurrence in the aspect of the excessive sediment transport capacity, but the influence of lithology has not been considered in the literature. To understand the influence of lithology on bedrock channel occurrence in a drainage basin-scale, we investigated the distribution of bedrock channels in relation to varying lithology and unit stream power along the Seogang River in South Korea. We used satellite images with high resolution for the identification of bedrock channel reaches and then verified them through field surveys. Geological maps and 1 arc-second SRTM DEMs were used to analyze lithological effects and calculate unit stream power.  As a result of the analysis, we identified 94 bedrock channels in the studied river, varying depending on lithologies. The frequency of bedrock channels in granitic gneiss areas (0.73/km) is much higher than those in the other rock type areas (granite areas, 0.57/km; limestone areas, 0.16/km). In the more frequent granitic gneiss areas, the bedrock channels are steepened (average channel slope: 0.0074 m/m) and narrow (average channel width: 65 m) and mainly reside within steepened and narrow (average valley width: 123 m) rock-bound valleys so that their occurrence is mainly associated with high unit stream power. In contrast, the bedrock channels over the other lithologies are wider (89 m) and lower-gradient (0.0056 m/m) and occur along flat and broad valleys (391 m). Consequently, the bedrock channels in the studied river were divided into two types: confined and unconfined bedrock channels. The confined bedrock channels are within the steepened and narrow valleys composed of resistant granitic gneiss and show the evidence for recent bedrock incision processes. However, the unconfined bedrock channels are mainly within the broad and flat valleys of weak saprolites and limestone with high joint density have lower unit stream power and don't show any marker for bedrock incision. In conclusion, high-relief landscape mainly composed of more resistant rocks generates steep and narrow valleys, which leads to the formation of continuous and actively incising bedrock channels. However, low-relief landscape underlain by non-resistant rocks shows wider and lower-gradient channels, with intermittent bedrock channels due to locally more resistant rock bodies.</p> </div>

scholarly journals Summer Water Temperatures in Alluvial and Bedrock Channels of the Olympic Peninsula

2009 ◽  
Vol 24 (2) ◽  
pp. 103-108 ◽  
Author(s):  
Mark A. Hunter ◽  
Timothy Quinn
Keyword(s):  
The Other ◽  
Low Flow ◽  
Olympic Peninsula ◽  
Channel Changes ◽  
Bedrock Channel ◽  
Stream Geomorphology ◽  
Alluvial Channel ◽  
Daily Water ◽  
The Individual ◽  
Bedrock Channels

Abstract To better understand how stream geomorphology may affect water temperature, we recorded water temperatures along two channels, one with deep alluvium and the other composed of bedrock and shallow alluvium. Study channels were located in managed forestlands on the Olympic Peninsula. Water temperatures were recorded hourly at 75-m intervals along 1.6 and 1.4 km of the alluvial and bedrock channels, respectively, during the summers of 2003 and 2004. Seasonal maximum and minimum daily water temperatures (i.e., season-long means for individual temperature dataloggers) in the alluvial channel tended to vary less over the course of the summer than temperatures in the bedrock channel. In addition, the means of all the individual dataloggers' daily maximums for each stream (reach mean maximum) and, similarly, the daily minimums (reach mean minimum) varied less for the alluvial channel. Changes in temperature from the upstream to downstream were greater for the bedrock channel, but only at low flow.

scholarly journals Alluvial cover controlling the width, slope and sinuosity of bedrock channels

2018 ◽  
Vol 6 (1) ◽  
pp. 29-48 ◽  
Author(s):  
Jens Martin Turowski
Keyword(s):  
Bedload Transport ◽  
Rate Of Change ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Channel Width ◽  
Transport Capacity ◽  
Bedrock Channel ◽  
Bed Slope ◽  
The 19Th Century ◽  
Bedrock Channels

Abstract. Bedrock channel slope and width are important parameters for setting bedload transport capacity and for stream-profile inversion to obtain tectonics information. Channel width and slope development are closely related to the problem of bedrock channel sinuosity. It is therefore likely that observations on bedrock channel meandering yields insights into the development of channel width and slope. Active meandering occurs when the bedrock channel walls are eroded, which also drives channel widening. Further, for a given drop in elevation, the more sinuous a channel is, the lower is its channel bed slope in comparison to a straight channel. It can thus be expected that studies of bedrock channel meandering give insights into width and slope adjustment and vice versa. The mechanisms by which bedrock channels actively meander have been debated since the beginning of modern geomorphic research in the 19th century, but a final consensus has not been reached. It has long been argued that whether a bedrock channel meanders actively or not is determined by the availability of sediment relative to transport capacity, a notion that has also been demonstrated in laboratory experiments. Here, this idea is taken up by postulating that the rate of change of both width and sinuosity over time is dependent on bed cover only. Based on the physics of erosion by bedload impacts, a scaling argument is developed to link bedrock channel width, slope and sinuosity to sediment supply, discharge and erodibility. This simple model built on sediment-flux-driven bedrock erosion concepts yields the observed scaling relationships of channel width and slope with discharge and erosion rate. Further, it explains why sinuosity evolves to a steady-state value and predicts the observed relations between sinuosity, erodibility and storm frequency, as has been observed for meandering bedrock rivers on Pacific Arc islands.

The Proximity of Other Skins

2019 ◽  
Author(s):  
Celine Parreñas Shimizu
Keyword(s):  
United States ◽  
South Korea ◽  
The United States ◽  
The Philippines ◽  
The Other ◽  
The West ◽  
Pain And Suffering ◽  
The Spectator ◽  
Existing Frames ◽  
The Voice

Transnational films representing intimacy and inequality disrupt and disgust Western spectators. When wounded bodies within poverty entangle with healthy wealthy bodies in sex, romance and care, fear and hatred combine with desire and fetishism. Works from the Philippines, South Korea, and independents from the United States and France may not be made for the West and may not make use of Hollywood traditions. Rather, they demand recognition for the knowledge they produce beyond our existing frames. They challenge us to go beyond passive consumption, or introspection of ourselves as spectators, for they represent new ways of world-making we cannot unsee, unhear, or unfeel. The spectator is redirected to go beyond the rapture of consuming the other to the rupture that arises from witnessing pain and suffering. Self-displacement is what proximity to intimate inequality in cinema ultimately compels and demands so as to establish an ethical way of relating to others. In undoing the spectator, the voice of the transnational filmmaker emerges. Not only do we need to listen to filmmakers from outside Hollywood who unflinchingly engage the inexpressibility of difference, we need to make room for critics and theorists who prioritize the subjectivities of others. When the demographics of filmmakers and film scholars are not as diverse as its spectators, films narrow our worldviews. To recognize our culpability in the denigration of others unleashes the power of cinema. The unbearability of stories we don’t want to watch and don’t want to feel must be borne.

scholarly journals A Study on the Impact of R&D Intensity on Business Performance: Evidence from South Korea

2021 ◽  
Vol 7 (2) ◽  
pp. 135
Author(s):  
Hun Park ◽  
Jun-Hwan Park ◽  
Sujin Lee ◽  
Hyuk Hahn
Keyword(s):  
South Korea ◽  
Research And Development ◽  
Business Performance ◽  
Decision Makers ◽  
The Other ◽  
Research Groups ◽  
Innovative Firms ◽  
The Impact ◽  
Knowledge Services

The role of R&D (research and development) intensity on the effect of knowledge services on the business performance of firms has been discussed by using PLS-SEM and PLS-MGA methods. Research groups were divided into two groups, innovative and non-innovative. Respondents were classified into innovative firms if their R&D intensity was over 3% and vice versa. PLS-SEM and PLS-MGA results were compared for two groups and valuable insights were extracted. For innovative firms, knowledge services seemed to be verified and processed by the decision makers and utilized to achieve their business performance. On the other hand, a large number of non-innovative firms seemed to have a stronger tendency to utilize knowledge services directly for their business without sufficient verification by the decision makers.

Redescription of Butlerius butleri Goodey, 1929 (Nematoda: Diplogastridae) from South Korea

Nematology ◽  
2009 ◽  
Vol 11 (2) ◽  
pp. 161-169 ◽  
Author(s):  
Il-Kweon Yeon ◽  
Gaurav Singh ◽  
Irfan Ahmad ◽  
Chung-Don Choi
Keyword(s):  
South Korea ◽  
Reproductive System ◽  
Type Species ◽  
The Other ◽  
Korean Population ◽  
Female Reproductive System ◽  
Caudal Region ◽  
Additional Information ◽  
Type Population

AbstractThe type species of the genus Butlerius, viz., B. butleri Goodey, 1929, is redescribed and illustrated from specimens collected in South Korea. Additional information is provided for the cuticle, stoma structure, female reproductive system and the male caudal region. The Korean population is 1336-1857 μm long, a = 33.9-43.5, b = 5.41-6.34, c = 3.38-4.20, c′ = 14.13-19.0 and V = 40-45%. Males have spicules 39-49 μm long and a gubernaculum 25-33 μm long. There are nine pairs of genital papillae, three pairs precloacal and six pairs postcloacal. The v5,6,7 clusters are widely separated, one group situated just posterior to the phasmids and the other group at level of pd. Although there are some differences in morphometrics as compared with the type population, the species is easily identified by the similarities in the structure of the stoma, pharynx, spicules and gubernaculum. Butlerius singularis and B. filicaudatus are proposed as synonyms of the type species.

scholarly journals Corruption and Government Intervention on Bank Risk-Taking: Cases of Asian Countries

2018 ◽  
Vol 9 (2) ◽  
pp. 228-237
Author(s):  
Rizky Maulana Nurhidayat ◽  
Rofikoh Rokhim
Keyword(s):  
South Korea ◽  
Risk Taking ◽  
Government Intervention ◽  
The Other ◽  
Bank Risk ◽  
Asian Countries ◽  
Dummy Variables ◽  
Macroeconomic Variables ◽  
Using Data ◽  
The Impact

This paper aims to addresses the impact of corruption, anti-corruption commission, and government intervention on bank’s risk-taking using banks in Asian Countries such as  Indonesia, Malaysia, Thailand, and South of Korea during the period 1995-2016. This paper uses corruption variable, bank-specific variables, macroeconomic variables, dummy variables and interaction variable to estimate bank’s risk-taking variable. Using data from 76 banks in Indonesia, Malaysia, Thailand and South Korea over 21 years, this research finds consistent evidence that higher level of corruption and government intervention in crisis-situation will increase the risk-taking behaviour of banks. In the other hand, bank risk-taking behaviour minimized by the existence of anti-corruption commission. In addition, this paper also finds that government intervention amplifies corruption’s effect on bank’s risk-taking behaviour because of strong signs of moral hazard and weaknesses in the governance and supervision.

scholarly journals A probabilistic framework for the cover effect in bedrock erosion

2016 ◽  
Author(s):  
Jens M. Turowski ◽  
Rebecca Hodge
Keyword(s):  
Time Scales ◽  
Channel Morphology ◽  
Scale Model ◽  
Probabilistic Framework ◽  
Channel Dynamics ◽  
Base Level ◽  
Bedrock Channel ◽  
Bedrock Erosion ◽  
Long Time ◽  
Bedrock Channels

Abstract. The cover effect in fluvial bedrock erosion is a major control on bedrock channel morphology and long-term channel dynamics. Here, we suggest a probabilistic framework for the description of the cover effect that can be applied to field, laboratory and modelling data and thus allows the comparison of results from different sources. The framework describes the formation of sediment cover as a function of the probability of sediment being deposited on already alleviated areas of the bed. We define benchmark cases and suggest physical interpretations of deviations from these benchmarks. Furthermore, we develop a reach-scale model for sediment transfer in a bedrock channel and use it to clarify the relations between the sediment mass residing on the bed, the exposed bedrock fraction and the transport stage. We derive system time scales and investigate cover response to cyclic perturbations. The model predicts that bedrock channels achieve grade in steady state by adjusting bed cover. Thus, bedrock channels have at least two characteristic time scales of response. Over short time scales, the degree of bed cover is adjusted such that they can just transport the supplied sediment load, while over long time scales, channel morphology evolves such that the bedrock incision rate matches the tectonic uplift or base level lowering rate.

Epithermal Precious Metal Deposits in South Korea—History and Pursuit

SEG Discovery ◽  
2021 ◽  
pp. 19-26
Author(s):  
Paul D. Wittwer
Keyword(s):  
South Korea ◽  
Precious Metal ◽  
Tectonic Setting ◽  
Regional Scale ◽  
Mining Operation ◽  
Mining Operations ◽  
Historical Mining ◽  
Mining Areas ◽  
Basin Scale ◽  
Gold Silver

Abstract The gold and silver endowment of Korea has historically been well known, with records alluding to production as far back as 1122 BC. The main gold production period was from 1925 to 1943 during the Japanese occupation of Korea, with more than 1 Moz recorded in 1939. Muguk was the most productive gold mining operation, located within the central region of South Korea, with a recorded 590 koz of gold produced from 1934 to 1998 (first mined in AD 912). The majority of the historical mining operations were closed by government order in 1943 during the Second World War and never reopened. A number of small mines operated between 1971 and 1998, with limited production during a period of gold prices generally lower than at present (~25–50% of current inflation adjusted prices, apart from a four-year period 1979–83). It is likely that significant resources remain within these historical mining areas. Gold-silver deposit types historically recognized and exploited in Korea include placers and orogenic and intrusion-related vein systems. Only more recently have epithermal vein and breccia systems been recognized. This is not surprising, given that the geologic and tectonic setting of the Southern Korean peninsula is prospective for epithermal precious metal deposits, spatially associated with basin-scale brittle fault systems in Cretaceous volcanic terranes. South Korea is an underexplored jurisdiction, with limited modern exploration and drilling until the mid-1990s, when Ivanhoe Mines Ltd. discovered the Gasado, Eunsan, and Moisan epithermal gold-silver deposits, all of which became mines. Exploration was limited for another 20 years until Southern Gold Ltd., an Australian Securities Exchange (ASX)-listed company, commenced regional-scale exploration for epithermal deposits, using a strategy similar to that successfully employed by Ivanhoe.

Top three LNG buyers to search for alternative LNG pricing structure after paying a total cost premium of $56 billion for oil-indexed LNG contracts in 2019 and 2020 – how will this affect Australia as the number one supplier to this market?

2021 ◽  
Vol 61 (2) ◽  
pp. 412
Author(s):  
Sindre Knutsson
Keyword(s):  
Natural Gas ◽  
South Korea ◽  
Spot Market ◽  
Liquefied Natural Gas ◽  
The Other ◽  
Future Market ◽  
Total Cost ◽  
The Future

Increasing spreads between spot liquefied natural gas (LNG) and oil-indexed contracts have resulted in the world’s top three LNG buyers paying a cost premium of $33 billion in 2019 and 23 billion in 2020. The top three buyers are Japan, China and South Korea, which had a combined 151Mt of long-term LNG contracts indexed to oil in 2020. This cost premium shows what top Asian buyers are currently paying for the security of LNG supply through long-term oil-indexed contracts. However, it also shows the potential reward Asian buyers have if they manage to develop a liquid LNG pricing hub in Asia to which they can index their contracts. Japanese buyers’ efforts of increasing flexibility in contracts, both through take-or-pay agreements and destination flexibility and aims of growing the spot market, will increasingly support the liquidity of the LNG market. However, there will be resistance from the other side of the table, for where someone is paying a premium, or making a loss, someone is making money. 2020 was another year of plenty for LNG producers selling oil-indexed volumes to Asian markets. Australia is the largest seller of LNG to Japan, China and South Korea with over 60Mt of long-term LNG contracts indexed to oil in 2020. Australia has benefited from having their contracts indexed to oil, but what’s next? In this paper, Rystad Energy will discuss the future market for Australian LNG exports including development in LNG demand, contract trends and price spreads.

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