Mid to Late-Holocene relative sea-level fluctuations and palaeoenvironment: Evidences from the southern Saurashtra coast, western India

Author(s):  
Falguni Bhattacharya
2020 ◽  
pp. 1-24
Author(s):  
Shubhra Sharma ◽  
Gaurav Chauhan ◽  
Anil Dutt Shukla ◽  
Romi Nambiar ◽  
Ravi Bhushan ◽  
...  

Abstract The relict intertidal deposits from the Kharod River Estuary, Gulf of Kachchh, and the distal end of Kori Creek are used to infer the Mid- to Late Holocene relative sea-level (RSL) change in western India. Employing sedimentology, geochemistry, palynology, ichnology, and optical and radiocarbon dating, the study suggests the dominance of fluvial activity between 16.5 ± 1.6 and 9.9 ± 0.7 ka. After ~7 ka (7.3 ± 0.4, 6.8 ± 0.5 ka), the sea level showed a positive tendency until 4.7 ± 0.2 ka. The tectonically corrected Mid-Holocene RSL change is estimated as 1.45 ± 0.33 m between ~7 and ~5 ka. The study suggests that the Mid-Holocene RSL high was due to the meltwater contribution from the Himalayan cryosphere, with subordinate contribution from glacio-isostatic adjustment and crustal subsidence. The Late Holocene tectonically corrected RSL change at ~1 ka (1.1 ± 0.1 ka and 1045 ± 175 cal yr BP) is estimated as 0.53 ± 0.43 m. This is ascribed to monsoon wind-driven tidal ingression that might have affected the tidal amplitude positively. The study suggests that the Mid-Holocene RSL change did not play a deterministic role in the abandonment of the Harappan coastal settlements.


2021 ◽  
Author(s):  
Majid Pourkerman ◽  
Nick Marriner ◽  
Christophe Morhange ◽  
Morteza Djamali ◽  
Hamid Lahijani ◽  
...  

Radiocarbon ◽  
2021 ◽  
pp. 1-15
Author(s):  
Julia Caon Araujo ◽  
Kita Chaves Damasio Macario ◽  
Vinícius Nunes Moreira ◽  
Anderson dos Santos Passos ◽  
Perla Baptista de Jesus ◽  
...  

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.


The Holocene ◽  
2016 ◽  
Vol 26 (12) ◽  
pp. 1924-1938 ◽  
Author(s):  
Yuji Ishii ◽  
Kazuaki Hori ◽  
Arata Momohara ◽  
Toshimichi Nakanishi ◽  
Wan Hong

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.


2006 ◽  
Vol 66 (2) ◽  
pp. 288-302 ◽  
Author(s):  
W. Roland Gehrels ◽  
Katie Szkornik ◽  
Jesper Bartholdy ◽  
Jason R. Kirby ◽  
Sarah L. Bradley ◽  
...  

AbstractCores and exposed cliff sections in salt marshes around Ho Bugt, a tidal embayment in the northernmost part of the Danish Wadden Sea, were subjected to 14C dating and litho- and biostratigraphical analyses to reconstruct paleoenvironmental changes and to establish a late Holocene relative sea-level history. Four stages in the late Holocene development of Ho Bugt can be identified: (1) groundwater-table rise and growth of basal peat (from at least 2300 BC to AD 0); (2) salt-marsh formation (0 to AD 250); (3) a freshening phase (AD 250 to AD 1600?), culminating in the drying out of the marshes and producing a distinct black horizon followed by an aeolian phase with sand deposition; and (4) renewed salt-marsh deposition (AD 1600? to present). From 16 calibrated AMS radiocarbon ages on fossil plant fragments and 4 calibrated conventional radiocarbon ages on peat, we reconstructed a local relative sea-level history that shows a steady sea-level rise of 4 m since 4000 cal yr BP. Contrary to suggestions made in the literature, the relative sea-level record of Ho Bugt does not contain a late Holocene highstand. Relative sea-level changes at Ho Bugt are controlled by glacio-isostatic subsidence and can be duplicated by a glacial isostatic adjustment model in which no water is added to the world's oceans after ca. 5000 cal yr BP.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Miriam C. Jones ◽  
G. Lynn Wingard ◽  
Bethany Stackhouse ◽  
Katherine Keller ◽  
Debra Willard ◽  
...  

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