Further evidence from relic shellcrust sequences for a late Holocene higher sea level for eastern Australia

ABSTRACT The vermetidae fossils of Petaloconchus varians, formed by calcium carbonate, associated with their radiocarbon ages, are the most accurate indicators of paleo sea level due to their restricted occupation in the intertidal zone in the rocky shore. However, the recrystallization of minerals can affect these age calculations and, consequently, the interpretation of the data. The aim of this study is to present new indicators of paleo sea-level changes in Southeast Brazil for the last 6000 years contributing to fill the data gap for the late Holocene. The influence of the recrystallization process was successfully resolved using the CarDS protocol, enabling the separation of the original aragonite fraction by density, prior to radiocarbon dating. This avoids the rejuvenation of ages and ensures greater efficiency for data interpretation. Paleo sea-level indicators were able to show a progressive increase in sea level up to the transgressive maximum of 4.15 m in 3700 BP years, followed by a regression to the current zero. This regression seems to have in addition, here we reinforce the reliability of the use of fossil vermetids as indicators of sea-level fluctuations.

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Impacts of past climate and sea level change on Everglades wetlands: placing a century of anthropogenic change into a late-Holocene context

Climatic Change ◽

10.1007/s10584-011-0078-9 ◽

2011 ◽

Vol 107 (1-2) ◽

pp. 59-80 ◽

Cited By ~ 42

Author(s):

Debra A. Willard ◽

Christopher E. Bernhardt

Keyword(s):

Sea Level ◽

Late Holocene ◽

Sea Level Change ◽

Anthropogenic Change ◽

Past Climate ◽

Level Change ◽

And Sea Level

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Middle to late-Holocene decreased fluvial aggradation and widespread peat initiation in the Ishikari lowland (northern Japan)

The Holocene ◽

10.1177/0959683616646189 ◽

2016 ◽

Vol 26 (12) ◽

pp. 1924-1938 ◽

Cited By ~ 8

Author(s):

Yuji Ishii ◽

Kazuaki Hori ◽

Arata Momohara ◽

Toshimichi Nakanishi ◽

Wan Hong

Keyword(s):

Sea Level ◽

Late Holocene ◽

Climate Changes ◽

Asian Summer Monsoon ◽

Sedimentary Environment ◽

New Approach ◽

Sea Level Fluctuations ◽

Asian Summer ◽

Fluvial Sedimentation ◽

Northern Japan

This study investigated the influence of sea-level and climate changes on the decreased fluvial aggradation and subsequent widespread peat initiation in the middle to late-Holocene in the Ishikari lowland, which is a coastal floodplain formed in response to the postglacial sea-level change. By introducing a new approach to separately evaluate the rates of organic and clastic sediment input, we demonstrated that the peat began to form when the fluvial sedimentation rate was significantly decreased (less than 0.6 mm/yr), while plant macrofossil analysis suggested that lowering of water level is also important to the peat initiation. Such changes in sedimentary environment may be associated with the abrupt abandonment of crevasse splays. The concentrated ages of the peat initiation around 5600–5000, 4600–4300, and 4100–3600 cal. BP suggest that an allogenic control promoted the abandonment of crevasse splays, and different onset ages can be explained by different fluvial responses of the Ishikari River and its tributaries. The abandonment of crevasse splays could result from sea-level fall or decreased precipitation. While submillennial sea-level fluctuations coincident with the peat initiation have not been reported in coastal lowlands of Japan, the close comparison of the onset ages and decreased precipitation recorded in a stalagmite from China, which represents the strength of the East Asian summer monsoon (EASM), suggests that decrease in precipitation led to the abandonment of crevasse splays. Our results may indicate that similar fluvial responses might be common in other coastal floodplains affected by the EASM.

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