Yūsuke Yokoyama

Dados Biográficos

ID	3604585
NOME	Yūsuke Yokoyama
PRENOMES	Yūsuke
SOBRENOME	Yokoyama
ASSINATURA	YOKOYAMA Y
AFILIAÇÕES	Atmosphere and Ocean Research Institute, The University of Tokyo, Japan
ORCID	0000-0001-7869-5891
VERIFICADO	Sim
TOTAL DE OBRAS	49
TOTAL DE CITAÇÕES	61
TOTAL COMO AUTOR	49
TOTAL COMO EDITOR	0
PRIMEIRO ANO DE PUBLICAÇÃO	1998
ANO MAIS RECENTE DE PUBLICAÇÃO	2025
ÍNDICE H	5

The Holocene Temperature Conundrum
Open AccessYūsuke Yokoyama, Yasuto WATANABE et al.ARTICLEJournal of Geography (Chigaku…2025
The Holocene is the current geological era, which started 11,700 years before present and is divided into three stages: 8, 200, and 4,200 years before present. The early stage is the Greenlandian, the middle stage is the Northgrippian, and the late stage is the Meghalayan. According to proxy-based climate reconstructions, the global mean surface temperature during the Greenlandian and the Northgrippain was warmer than the Pre-industrial (PI). How…
Meridional Migrations of the Intertropical Convergence Zone During the Last Deglaciation in the Timor Sea Detected by Extensive Radiocarbon Dating
Open AccessKarin Nemoto, Yūsuke Yokoyama et al.ARTICLERadiocarbon2024Referências: 46
At the Intertropical Convergence Zone (ITCZ), the northern and southern Tradewinds converge, and this region is characterized by low atmospheric pressure and high precipitation. The climate in the Timor Sea is characterized by seasonal precipitation changes driven by meridional migrations of the ITCZ and the monsoonal front. The ITCZ shifts in response to changes in the thermal balance between the northern and southern hemispheres. Thus, reconstr…
Paleo Tsunamis and Storm Surges Recorded by Fossil Coral on Yakushima Island, Japan
Open AccessSabrina G Lloyd, Yūsuke Yokoyama et al.ARTICLERadiocarbon2024
Yakushima is a small, mountainous island off southern Kyushu, Japan. Its proximity to active volcanos and subduction zones leaves Yakushima vulnerable to large megathrust earthquakes and tsunamis, in addition to powerful typhoons and storm surges. These hazardous events deposit beach boulders: large rocks moved above sea-level by powerful waves. By radiocarbon dating the fossilized coral within these boulders, one can derive age estimates of the …
Holocene Overwash Occurrence Age in the Isumi River Lowland, Eastern Boso Peninsula, Japan
Open AccessSoichiro Oda, Stephen P Obrochta et al.ARTICLERadiocarbon2024Referências: 13
Analysis of the chronological data and observation of a lagoonal sediment core reveal sand washover events between around 2.4 to 2.5 cal. ky BP in the Isumi River lowland. We conducted radiocarbon dating with AMS and constructed an age-depth model using the latest calibration curve and appropriate model routine. In the middle to lower part of the core, dark-gray sand layers are repeatedly deposited. Sand layers may exhibit an erosional surface at…
Radiocarbon and Uranium Profiles in Marine Gastropods Around the Japanese Archipelago
Open AccessShoko Hirabayashi, Takahiro Aze et al.ARTICLERadiocarbon2024Referências: 46
In this study, we investigate the distribution of radiocarbon and uranium in the calcified opercula of Turbo sp. collected from Ryukyu region and Chiba, Japan, to explore the potential of U/Th dating using mollusks collected from the Japanese archipelago. We acquired high-resolution radiocarbon and uranium concentration measurements using single-stage accelerator mass spectrometry and laser ablation−inductively coupled plasma−mass spectrometry. O…
Reconstruction of Paleoenvironment and Identification of Historical Tsunami Deposits by Geochemical Analyses in Iwanuma City, Miyagi Prefecture, Japan
Open AccessYusuke OGATA, Kazuhisa GOTO et al.ARTICLEJournal of Geography (Chigaku…2023
Identifying invisible tsunami deposits in the geological record is challenging and requires multiproxy analyses. In particular, geochemical signatures provide useful information for identifying paleo-tsunami deposits, as well as for reconstructing the paleoenvironment history, even when other proxies are equivocal. In addition, geochemical proxies help to provide an understanding of environmental changes that occur post-tsunami. As a result, they…
Beppu Bay, Japan, as a candidate Global boundary Stratotype Section and Point for the Anthropocene series
Open AccessMichinobu Kuwae, B Finney et al.ARTICLEThe Anthropocene Review2023Citada por: 4Referências: 29
For assessment of the potential of the Beppu Bay sediments as a Global boundary Stratotype Section and Point (GSSP) candidate for the Anthropocene, we have integrated datasets of 99 proxies. The datasets for the sequences date back 100 years for most proxy records and 1300 years for several records. The cumulative number of occurrences of the anthropogenic fingerprint reveal unprecedented increases above the base of the 1953 flood layer at 64.6 c…
Lake water dissolved inorganic carbon dynamics revealed from monthly measurements of radiocarbon in the Fuji Five Lakes, Japan
Open AccessKosuke Ota, Yūsuke Yokoyama et al.ARTICLEElementa Science of the…2021
Lakes are sensitive recorders of anthropogenic activities, as human society often develops in their vicinity. Lake sediments thus have been widely used to reconstruct the history of environmental changes in the past, anthropogenic, or otherwise, and radiocarbon dating provides chronological control of the samples. However, specific values of radiocarbon in different carbon reservoirs due to the different pathways of radiocarbon from the upper atm…
Northeast Pacific Seawater Radiocarbon Recorded in Abalone Shells Obtained From Otsuchi Bay, Japan
Open AccessKosuke Ota, Yūsuke Yokoyama et al.ARTICLERadiocarbon2021Citada por: 1Referências: 26
Reconstructing past ocean currents in the coastal regions is necessary to better understand the relationship between oceanographic changes and coastal ecosystems. It is known that variations have occurred with large-scale climate changes such as ENSO (El Niño Southern Oscillations) and PDO (Pacific Decadal Oscillations). Thus, reconstruction of past seawater conditions in coastal regions is needed to better understand the relationship between oce…
Landscape development at Lina myr fen, Eastern Gotland, 9000−2500 cal. yr BP
Open AccessNichola A Strandberg, Aleftin Barliaev et al.ARTICLEThe Holocene2020Citada por: 1Referências: 9
Using diatoms, pollen, and geochemistry, we explore human habitation around Lina myr, Gotland, in relation to shore displacement. Archeological evidence has shown that Lina myr was an important area for its prehistoric human inhabitants. We investigate if and when Lina myr was connected to the sea and could therefore have been part of an inland water system useful for transport. A chronology was based on 14 C AMS dating of terrestrial macrofossil…
Compound-Specific Radiocarbon Analysis of Organic Compounds from Mount Fuji Proximal Lake (Lake Kawaguchi) Sediment, Central Japan
Open AccessShinya Yamamoto, Yosuke Miyairi et al.ARTICLERadiocarbon2020Referências: 49
Differential sources of sedimentary organic compounds in a volcanic region were revealed by determining radiocarbon content (Δ 14 C) of organic compounds in surface sediments from Lake Kawaguchi, at the northern foot of Mount Fuji, central Japan. The Δ 14 C values of C 16 fatty acid (−124‰) and chlorophyll a (Chl a ) (−133‰) were similar to the Δ 14 C of dissolved inorganic carbon (DIC) in surface water (−117‰), suggesting that a significant port…
Insight into Western Pacific Circulation from South China Sea Coral Skeletal Radiocarbon
Open AccessShoko Hirabayashi, Yūsuke Yokoyama et al.ARTICLERadiocarbon2019Referências: 70
The trajectory of the Kuroshio, the western boundary current in the north Pacific, influences regional climate. It intrudes into the South China Sea (SCS) through the Luzon Strait, resulting in the exchange of water, nutrients, heat, and salt between the Pacific and SCS. It has been reported that the trajectory of the Kuroshio has varied with decadal climate changes. However, there has been no report of an observation-based estimate of the variat…
AMS Dating of Potentially the Oldest Wooden Sculptures in Japan from a Shinto Shrine in Akita
Open AccessNaoto Fukuyo, Yūsuke Yokoyama et al.ARTICLERadiocarbon2019Citada por: 2Referências: 13
We analyzed rare wooden Komainu found at Akagami Shrine in Akita prefecture, Japan. The formation of historical objects is often thoroughly recorded in documents, although the formation age of this particular Komainu sculpture is still unknown due to its antiquity. Thus, age determination exercises have been conducted using radiocarbon ( 14 C)-wiggle-matching techniques. Although only a limited quantity was available for sampling, we have success…
Dissolved inorganic Radiocarbon content of the Western Coral sea
Open AccessAymeric PM Servettaz, Yūsuke Yokoyama et al.ARTICLERadiocarbon2019Referências: 46
The South Pacific Ocean contributes to the global carbon cycle by exchanging CO 2 between the atmosphere and intermediate to deep water masses. The path of the Antarctic Intermediate Water (AAIW) in the South Pacific gyre has been inferred from salinity, oxygen, and nutrient measurements, but radiocarbon ( 14 C) measurements—a direct tracer of the carbon cycle—remain sparse. Here, we present the first radiocarbon profiles in the western Coral Sea…
Holocene surface hydroclimate changes in the Indo-Pacific warm pool
Open AccessZiye Li, Min-Te Chen et al.ARTICLEQuaternary International2018
Holocene relative sea level history from phreatic overgrowths on speleothems (POS) on Minami Daito Island, Northern Philippine Sea
Open AccessBlaž Miklavič, Yūsuke Yokoyama et al.ARTICLEQuaternary International2018
Evidence of solar insolation and internal forcing of sea surface temperature changes in the eastern tropical Indian Ocean during the Holocene
Open AccessZiye Li, Min-Te Chen et al.ARTICLEQuaternary International2018
Historical Nankai-Suruga megathrust earthquakes recorded by tsunami and terrestrial mass movement deposits on the Shirasuka coastal lowlands, Shizuoka Prefecture, Japan
Open AccessEd Garrett, Osamu Fujiwara et al.ARTICLEThe Holocene2018Citada por: 2Referências: 4
Geological investigations of coastal sediment sequences play a key role in verifying earthquake and tsunami characteristics inferred from historical records. In this paper, we present a multi-proxy investigation of a coastal lowland site facing the Nankai-Suruga megathrust and appraise evidence for tsunamis and earthquake-triggered terrestrial mass movements occurring over the last 800 years. Combining a high-resolution chronology with X-ray comp…
Radiocarbon dating of coastal boulders from Kouzushima and Miyake islands off Tokyo Metropolitan Area, Japan
Open AccessAkihisa Kitamura, Takafumi Imai et al.ARTICLEQuaternary International2017
Hydrographic variability in the northern South China Sea over the past 45,000 years
Open AccessDa-Cheng Lin, Min-Te Chen et al.ARTICLEQuaternary International2017
Climatic change and its influence on human society in western Japan during the Holocene
Open AccessHodaka Kawahata, Megumi Matsuoka et al.ARTICLEQuaternary International2017
Hydroclimate reconstruction in central Japan over the past four centuries from tree-ring cellulose δ 18 O
Open AccessWataru Sakashita, Hiroko Miyahara et al.ARTICLEQuaternary International2017
Oceanographic influences on the stability of the Cosgrove Ice Shelf, Antarctica
Open AccessRebecca L Totten, Wojciech Majewski et al.ARTICLEThe Holocene2017Referências: 11
Ferrero Bay, located in eastern Pine Island Bay (PIB) of the Amundsen Sea Embayment, is one of the largest and southernmost fjords yet studied in Antarctica. High-resolution multibeam swath bathymetric data, chirp sonar sub-bottom profiles, and three Kasten cores were collected in Ferrero Bay during the IB Oden Southern Ocean 2009–2010 cruise (OSO0910). Core KC-15 from the inner bay yielded two carbonate ages providing a minimum age for ice sheet…
Relationship between early summer precipitation in Japan and the El Niño-Southern and Pacific Decadal Oscillations over the past 400 years
Open AccessWataru Sakashita, Yūsuke Yokoyama et al.ARTICLEQuaternary International2016
Reappraisal of sea-level lowstand during the Last Glacial Maximum observed in the Bonaparte Gulf sediments, northwestern Australia
Open AccessTakeshige Ishiwa, Yūsuke Yokoyama et al.ARTICLEQuaternary International2016

Developing Ultra Small-Scale Radiocarbon Sample Measurement at the University of Tokyo
Open AccessYūsuke Yokoyama, Mamito Koizumi et al.ARTICLERadiocarbon2010Citada por: 13Referências: 15
We have developed accelerator mass spectrometry (AMS) measurement techniques for ultra small-size samples ranging from 0.01 to 0.10 mg C with a new type of MC-SNICS ion source system. We can generate 4 times higher ion beam current intensity for ultra-small samples by optimization of graphite position in the target holder with the new ionizer geometry. CO 2 gas graphitized in the newly developed vacuum line is pressed to a depth of 1.5 mm from th…
Comparison of 14 C and U-Th Ages in Corals from Iodp #310 Cores Offshore Tahiti
Open AccessNicolas Durand, Pierre Deschamps et al.ARTICLERadiocarbon2013Citada por: 11Referências: 84
Shallow-water tropical corals can be used to calibrate the radiocarbon timescale. In this paper, we present a new data set based on the comparison between 14 C ages and U-Th ages measured in fossil corals collected offshore the island of Tahiti during the Integrated Oceanic Drilling Program (IODP) Expedition 310. After applying strict mineralogical and geochemical screening criteria, the Tahiti record provides new data for 2 distinct time windows…
Last Ice Age Millennial Scale Climate Changes Recorded in Huon Peninsula Corals
Open AccessYūsuke Yokoyama, Tezer M Esat et al.ARTICLERadiocarbon2000Citada por: 10Referências: 42
Uranium series and radiocarbon ages were measured in corals from the uplifted coral terraces of Huon Peninsula (HP), Papua New Guinea, to provide a calibration for the 14 C time scale beyond 30 ka (kilo annum). Improved analytical procedures, and quantitative criteria for sample selection, helped discriminate diagenetically altered samples. The base-line of the calibration curve follows the trend of increasing divergence from calendar ages, as es…
New 14 C Determinations from Lake Suigetsu, Japan
Open AccessRichard A Staff, Christopher B Ramsey et al.ARTICLERadiocarbon2011Citada por: 6Referências: 37
Calibration is a fundamental stage of the radiocarbon ( 14 C) dating process if one is to derive meaningful calendar ages from samples' 14 C measurements. For the first time, the IntCal09 calibration curve (Reimer et al. 2009) provided an internationally ratified calibration data set across almost the complete range (0 to 50,000 cal BP) of the 14 C timescale. However, only the last 12,550 cal yr of this record are composed of terrestrial data, le…
Integration of the Old and New Lake Suigetsu (Japan) Terrestrial Radiocarbon Calibration Data Sets
Open AccessRichard A Staff, Gordon Schlolaut et al.ARTICLERadiocarbon2013Citada por: 5Referências: 18
The varved sediment profile of Lake Suigetsu, central Japan, offers an ideal opportunity from which to derive a terrestrial record of atmospheric radiocarbon across the entire range of the 14 C dating method. Previous work by Kitagawa and van der Plicht (1998a,b, 2000) provided such a data set; however, problems with the varve-based age scale of their SG93 sediment core precluded the use of this data set for 14 C calibration purposes. Lake Suiget…
Beppu Bay, Japan, as a candidate Global boundary Stratotype Section and Point for the Anthropocene series
Open AccessMichinobu Kuwae, B Finney et al.ARTICLEThe Anthropocene Review2023Citada por: 4Referências: 29
For assessment of the potential of the Beppu Bay sediments as a Global boundary Stratotype Section and Point (GSSP) candidate for the Anthropocene, we have integrated datasets of 99 proxies. The datasets for the sequences date back 100 years for most proxy records and 1300 years for several records. The cumulative number of occurrences of the anthropogenic fingerprint reveal unprecedented increases above the base of the 1953 flood layer at 64.6 c…
Compound-Specific 14 C Dating of Iodp Expedition 318 Core U1357A Obtained Off the Wilkes Land Coast, Antarctica
Open AccessMasako Yamane, Yūsuke Yokoyama et al.ARTICLERadiocarbon2014Citada por: 4Referências: 30
This study applied compound-specific radiocarbon analysis (CSRA) to a 186-m-long sediment core (U1357A) taken from Adélie Basin located on the continental shelf off Wilkes Land, East Antarctica. The CSRA targeted C 16 fatty acid as well as C 16 ., fatty acid and cyclopheophorbide- a -enol isolated from the sediment. Due to their high degradation rate, these compounds are expected to occur in low abundances in relict organic matter deposited at th…
AMS Dating of Potentially the Oldest Wooden Sculptures in Japan from a Shinto Shrine in Akita
Open AccessNaoto Fukuyo, Yūsuke Yokoyama et al.ARTICLERadiocarbon2019Citada por: 2Referências: 13
We analyzed rare wooden Komainu found at Akagami Shrine in Akita prefecture, Japan. The formation of historical objects is often thoroughly recorded in documents, although the formation age of this particular Komainu sculpture is still unknown due to its antiquity. Thus, age determination exercises have been conducted using radiocarbon ( 14 C)-wiggle-matching techniques. Although only a limited quantity was available for sampling, we have success…
Historical Nankai-Suruga megathrust earthquakes recorded by tsunami and terrestrial mass movement deposits on the Shirasuka coastal lowlands, Shizuoka Prefecture, Japan
Open AccessEd Garrett, Osamu Fujiwara et al.ARTICLEThe Holocene2018Citada por: 2Referências: 4
Geological investigations of coastal sediment sequences play a key role in verifying earthquake and tsunami characteristics inferred from historical records. In this paper, we present a multi-proxy investigation of a coastal lowland site facing the Nankai-Suruga megathrust and appraise evidence for tsunamis and earthquake-triggered terrestrial mass movements occurring over the last 800 years. Combining a high-resolution chronology with X-ray comp…
Sources of Dissolved Inorganic Carbon in Two Small Streams with Different Bedrock Geology
Open AccessNaoto F Ishikawa, Ichiro Tayasu et al.ARTICLERadiocarbon2015Citada por: 2Referências: 35
Radiocarbon natural abundances (Δ 14 C) are being increasingly used to trace carbon cycling in stream ecosystems. To understand the ultimate sources of carbon, we determined the stable carbon isotope ratios (δ 13 C) and Δ 14 C values of dissolved inorganic and organic carbon (DIC and DOC, respectively) and of particulate organic carbon (POC) in two small streams in central Japan, one of which flows over limestone bedrock (Seri) and the other does…
Northeast Pacific Seawater Radiocarbon Recorded in Abalone Shells Obtained From Otsuchi Bay, Japan
Open AccessKosuke Ota, Yūsuke Yokoyama et al.ARTICLERadiocarbon2021Citada por: 1Referências: 26
Reconstructing past ocean currents in the coastal regions is necessary to better understand the relationship between oceanographic changes and coastal ecosystems. It is known that variations have occurred with large-scale climate changes such as ENSO (El Niño Southern Oscillations) and PDO (Pacific Decadal Oscillations). Thus, reconstruction of past seawater conditions in coastal regions is needed to better understand the relationship between oce…
Landscape development at Lina myr fen, Eastern Gotland, 9000−2500 cal. yr BP
Open AccessNichola A Strandberg, Aleftin Barliaev et al.ARTICLEThe Holocene2020Citada por: 1Referências: 9
Using diatoms, pollen, and geochemistry, we explore human habitation around Lina myr, Gotland, in relation to shore displacement. Archeological evidence has shown that Lina myr was an important area for its prehistoric human inhabitants. We investigate if and when Lina myr was connected to the sea and could therefore have been part of an inland water system useful for transport. A chronology was based on 14 C AMS dating of terrestrial macrofossil…