Shallow-Marine Benthic Palaeoecology of the Late Pleistocene Paleo - Tokyo Bay: a Moderately Sheltered Bay Fringed with Barrier Islands

2020 ◽  
pp. 108-114
Author(s):  
Yasuo Kondo ◽  
Takanobu Kamatakp ◽  
Yasunori Masaki
Keyword(s):  
Late Pleistocene ◽  
Barrier Islands ◽  
Tokyo Bay ◽  
Shallow Marine

Dactyloidites ottoi (Geinitz, 1849) in Bahamian Pleistocene Carbonates: A Shallowest-marine Indicator

2021 ◽  
pp. SP522-2021-69
Author(s):  
H. Allen Curran ◽  
Bosiljka Glumac
Keyword(s):  
Late Pleistocene ◽  
Carbonate Sediments ◽  
The Bahamas ◽  
Shallow Marine ◽  
Fine Detail ◽  
Plant Remains ◽  
Mis 5E ◽  
Deposit Feeding ◽  
First Time ◽  
Host Sediment

AbstractThe rosetted trace fossil Dactyloidites ottoi (Geinitz, 1849) is reported and described for the first time from late Pleistocene (MIS 5e) carbonates of the Bahama Archipelago in shallowing-upward, shelly calcarenites from Great Inagua and Great and Little Exuma islands. The distinctive, fan-shaped D. ottoi specimens from the Bahamas, while not preserved in fine detail and not revealing a shaft, compare favourably in shape and size with specimens from other localities around the world, including the oldest well-documented specimens from the Jurassic of Argentina. D. ottoi is interpreted as a fodinichnion formed by the activity of a deposit-feeding worm, probably a polychaete, consuming marine-plant remains within host sediment. The late Pleistocene palaeodepositional environment of these carbonate sediments is interpreted as within the lower foreshore-upper shoreface zone in full marine, tropical waters. This discovery of D. ottoi marks an addition to the Bahamian shallow-marine ichnocoenose within the Skolithos ichnofacies.

Variations of fluvial patterns and infilling history of a paleoincised valley system during Late Pleistocene to Holocene, Offshore Pahang River, Peninsular Malaysia

2018 ◽  
Vol 6 (1) ◽  
pp. T39-T50
Author(s):  
Md Mostafizur Rahman ◽  
Edlic Sathiamurthy ◽  
Guangfa Zhong ◽  
Jianghua Geng ◽  
Zhifei Liu
Keyword(s):  
Sea Level ◽  
Late Pleistocene ◽  
Peninsular Malaysia ◽  
Glacial Cycle ◽  
Shallow Marine ◽  
3D Data ◽  
Data Volume ◽  
History Of ◽  
Late Pleistocene To Holocene ◽  
Cover Thickness

High-resolution 2D acoustic profiles, combined with time slices from a 3D data volume, were used to investigate the paleoincised valleys offshore of the present-day Pahang River, South China Sea. Paleovalleys were formed during the regressive phase of the last glacial cycle. They were submerged and possibly filled during valley formation and postglacial marine transgression. Interpretation of acoustic profiles illustrates that the valleys were incised and infilled during the regression and low stand followed by subsequent deglacial sea-level rise. They were overlain by a transgressive ravinement surface suggesting transitional deposits between fluvial-dominated filling and shallow-marine deposition. This ravinement surface is overlain by Holocene shallow marine deposits. A low-sinuosity low-stand valley system changed to a high-sinuosity meander belt and eventually evolved into a deltaic distributary channel system before the complete submergence of the area. The average Late Pleistocene surface lies between 53 and 64 m below present-day mean sea level in the study area with approximately 16–50 m of valley incision. The Holocene shallow marine cover thickness varies from 5 to 10 m.

Aeolian to shallow-marine shelf architecture off a major desert since the Late Pleistocene (northern Mauritania)

Geomorphology ◽  
2013 ◽  
Vol 203 ◽  
pp. 132-147 ◽  
Author(s):  
T.J.J. Hanebuth ◽  
H. Mersmeyer ◽  
H.R. Kudrass ◽  
H. Westphal
Keyword(s):  
Late Pleistocene ◽  
Shallow Marine

Some Effects of Partial Recrystallisation on 14C dating Late Pleistocene Corals and Molluscs

1972 ◽  
Vol 2 (02) ◽  
pp. 244-252 ◽  
Author(s):  
John Chappell ◽  
Henry A. Polach
Keyword(s):  
Sea Level ◽  
Carbon Isotope ◽  
Thin Section ◽  
Late Pleistocene ◽  
Closed System ◽  
X Ray Diffraction ◽  
14C Dating ◽  
Shallow Marine ◽  
X Ray ◽  
Shell Carbonate

The issue of sea level during the last interstadial revolves largely around the problem of achieving reliable 14C dates for shell carbonate from Late Pleistocene shallow marine and littoral deposits. A set of 27 samples were collected from Late Pleistocene reefs in New Guinea, and measurements made of 13C, 14C, plus the degree of recrystallisation (determined by X-ray diffraction). The original fibrous aragonite structure of the samples (corals and clams) is seen in thin section to recrystallise in two quite different modes. The carbon isotope results strongly suggest that one mode, the sparry calcite recrystallisation, represents an open geochemical system which allows contamination by more recent 14C, while the subtle coarsening mode of recrystallisation represents a closed system, often yielding reliable results. The reliability of the latter can be validated if a similarly recrystallised sample, known to be outside the range of 14C dating, shows a background 14C count.

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