Diatoms

Zong, Yongqiang; Sawai, Yuki

doi:10.1002/9781118452547.ch15

Cited by 6 publications

(4 citation statements)

References 39 publications

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“…Species identification was based on catalogs both from global [ 36 – 40 ] and Japanese references [ 33 , 41 – 43 ]. For the classification of diatom species, we considered factors such as salinity (ranging from marine, marine–brackish, brackish, brackish–freshwater, to freshwater) and life form (comprising planktonic, epontic, and benthic categories), drawing on ecological references [ 32 , 35 , 44 – 46 ]. Diatoms from the Neogene period along the Hidaka coast, as reported by Sagayama et al [ 47 ], were excluded from the assemblage analysis due to their allochthonous contribution linked to the erosion of older deposits [ 48 ].…”

Section: Methodsmentioning

confidence: 99%

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Understanding paleo-earthquakes in the Kuril Trench based on Late-Holocene tsunami deposits in the distal region from wave sources, northern Hidaka, Hokkaido, Japan

Nakanishi,

Ashi,

Okamura

et al. 2024

PLoS ONE

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Geological evidence, such as tsunami deposits, is crucial for studying the largest rupture zone of the Kuril Trench in Hokkaido, Japan, due to its poor historical record. Although 17th-century tsunami deposits are widely distributed across Hokkaido, the presence of multiple wave sources during that period, including the collapse of Mt. Komagatake, complicates the correlation with their wave sources. Understanding the regional distribution of these tsunami deposits can provide valuable data to estimate the magnitude of megathrust earthquakes in the Kuril Trench. The northern part of Hidaka, Hokkaido, where tsunamis from multiple wave sources are expected to overlap, is distant from the Kuril Trench. To clarify the depositional history of tsunami deposits in such distal areas, evaluating the influence of the depositional environments on the event layer preservation becomes even more critical. We conducted field surveys in Kabari, located in the northern Hidaka region, identifying three sand layers from the 10th to the 17th century and two layers dating beyond 2.3 thousand years ago. The depositional ages of most sand layers potentially correlate with tsunami deposits resulting from the Kuril Trench earthquakes. Utilizing reconstructed paleo-sea level data, we estimated that most sand layers reached approximately 2 m in height. However, it is noteworthy that the latest sand layer from the 17th century exhibited an unusual distribution, more than 3 m in height. This suggests a different wave source as the Mt. Komagatake collapse. The discovery of multiple sand layers and their distributions is crucial to constraining the maximum magnitude of giant earthquakes in the Kuril Trench and understanding the volcanic tsunami events related to Mt. Komagatake.

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Section: Methodsmentioning

confidence: 99%

“…A diatom assemblage analysis was conducted to reconstruct the depositional environment, such as its hydraulic conditions and salinity, as sea level index points (SLIPs). Salinity was determined qualitatively based on the indicator species [32][33][34][35].…”

Section: Diatom Analysismentioning

confidence: 99%

Understanding paleo-earthquakes in the Kuril Trench based on Late-Holocene tsunami deposits in the distal region from wave sources, northern Hidaka, Hokkaido, Japan

Nakanishi,

Ashi,

Okamura

et al. 2024

PLoS ONE

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“…For a few samples with lower pollen content, at least 150 pollen grains were counted. The species were identified based on Vos and de Wolf (1993) and Zong and Sawai (2015).…”

Section: Methodsmentioning

confidence: 99%

A 7000‐year record of environmental change: Evolution of Holocene environment and human activities in the Hangjiahu Plain, the lower Yangtze, China

Zhao

Jin

et al. 2022

Geoarchaeology

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The Hangjiahu Plain in the lower Yangtze is one of the core areas that sustained the flourishment of the Liangzhu Civilization. This study reconstructed Holocene environmental change on the Hangjiahu Plain based on a sediment core collected from the Tangqi ZK-3 location situated on the low-lying Hangzhou-Taihu region of the Yangtze Delta. We applied OSL dating, grain size analysis, pollen analysis, and magnetic susceptibility to reconstruct Holocene environmental change and compared our data with other published results. Our results showed that (i) before ~7.0 ka B.P., the ZK-3 core recorded a strong hydrodynamic force, resulting in the widespread deposition of light grayish silt clay or clayey silt in the region. The climate was warm and humid,

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“…Salt-marsh testate amoebae have been sampled along transects across marsh surfaces with the aim of identifying vertical assemblage zones attributable to environmental variables (Charman et al, 1998(Charman et al, , 2002Gehrels et al, 2001Gehrels et al, , 2006Riveiros et al, 2007;Ooms et al, 2011Ooms et al, , 2012Barnett et al, 2013Barnett et al, , 2016. This practise has been applied regularly using salt-marsh foraminifera (Edwards and Wright, 2015) and diatoms (Zong and Sawai, 2015). However, work based on testate amoebae is comparably limited despite the significant potential of this proxy (Charman, 2015).…”

Section: Salt-marsh Testate Amoebaementioning

confidence: 99%

Salt-marsh testate amoebae as precise and widespread indicators of sea-level change

Barnett

Newton

Charman

et al. 2017

Earth-Science Reviews

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Salt-marsh sediments are routinely used to reconstruct sea-level changes over past millennia.These reconstructions bridge an important gap between geological and instrumental sea-level records, and provide insights into the role of atmospheric, oceanic, climatic and anthropogenic sea-level drivers, thereby improving understanding of contemporary and future sea-level changes. Salt-marsh foraminifera, diatoms and testate amoebae are three of the proxies capable of accurately reconstructing former sea level over decadal to millennial timescales. Datasets of surface assemblages are collated along elevational gradients to provide modern analogues that can be used to infer former marsh-surface elevations from fossil assemblages. Testate amoebae are the most recently developed proxy and existing studies suggest that they are at least as precise as the two other proxies. This study provides a synthesis of sea-level research using testate amoebae and collates and analyses existing surface datasets of intertidal salt-marsh testate amoebae from sites throughout the North Atlantic. We test the hypothesis that intertidal testate amoebae demonstrate cosmopolitan intertidal zonation across wide geographical areas in a way that is unique to this proxy.Testate amoebae assemblages are harmonised under a unified taxonomy and standardised into a single basin-wide training set suitable for reconstructing sea-level changes from saltmarsh sediments across the North Atlantic. Transfer functions are developed using regression modelling and show comparable performance values to published local training sets of foraminifera, diatoms and testate amoebae. When used to develop recent (last 100 years) sealevel reconstructions for sites in Norway and Quebec, Canada, the testate amoebae-based transfer function demonstrated prediction uncertainties of ± 0.26 m and ± 0.10 m respectively. These uncertainties equate to 10 % and 11 % of the tidal ranges at each site, which is of comparable precision to other published sea-level reconstructions based on foraminifera or diatoms. There is great scope for further developing intertidal testate amoebae as precise sea-level indicators and their application should be tested at sites beyond the North Atlantic.

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Diatoms

Cited by 6 publications

References 39 publications

Understanding paleo-earthquakes in the Kuril Trench based on Late-Holocene tsunami deposits in the distal region from wave sources, northern Hidaka, Hokkaido, Japan

Understanding paleo-earthquakes in the Kuril Trench based on Late-Holocene tsunami deposits in the distal region from wave sources, northern Hidaka, Hokkaido, Japan

A 7000‐year record of environmental change: Evolution of Holocene environment and human activities in the Hangjiahu Plain, the lower Yangtze, China

Salt-marsh testate amoebae as precise and widespread indicators of sea-level change

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