Radiocarbon age of Robinson's Head moraine, west Newfoundland, and its significance for postglacial sea level changes

1977 ◽  
Vol 14 (9) ◽  
pp. 2121-2126 ◽  
Author(s):  
Ian A. Brookes
Keyword(s):  
Sea Level ◽  
Late Glacial ◽  
Radiocarbon Date ◽  
Level Curve ◽  
Sea Level Changes ◽  
Radiocarbon Dates ◽  
Radiocarbon Age ◽  
Isostatic Uplift ◽  
First Approximation

A radiocarbon date of 12 600 ± 140 years BP (GSC-2295) is reported on marine shells from sands within the Robinson's Head kame moraine at Stephen ville, Newfoundland. The moraine was deposited simultaneously with a delta-kame distal to it during a brief interval of increased ice marginal activity. This is marked at Stephenville by a temporary halt in landward marginal recession, but in some other localities around St. George's Bay by a lobate readvance into the late-glacial sea. The date refers to the time of moraine and delta-kame construction and confirms an earlier estimation. Other radiocarbon dates from the area, relating more or less closely to past sea level positions at Robinson's, south of Stephenville, are used, with an hypothetical isostatic uplift curve and a published eustatic sea level curve, to produce a first approximation to postglacial changes of local sea level in the St. George's Bay region.

scholarly journals Contraction-expansion dynamics of reef species in response to sea-level changes

2021 ◽  
Author(s):  
Thierry B Hoareau ◽  
Petrus Pretorius
Keyword(s):  
Sea Level ◽  
Subsequent Development ◽  
Population Level ◽  
Marine Species ◽  
Late Glacial ◽  
Sea Level Changes ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
Sea Level Fluctuations ◽  
The Last Glacial

The contraction-expansion model (CEM) describes the dynamics of species that survived in refugia during the last glacial maximum (LGM) and expanded their range when environmental conditions slowly improved from the Late Glacial through to the Holocene. The CEM has been proposed to describe the dynamics of reef species in response to sea-level fluctuations from a range of disciplines, but genetic inferences rather suggest stable population sizes since the last glacial period. Here, we address this paradox by providing a new model of modern reef development, by assessing the effect of LGM bottlenecks using genetic simulations, and by using a survey of the literature on reef species to compile both estimates of times to expansion and applied rates of molecular evolution. Using previously published radiocarbon dates of core data, we propose a synthetic model for the dynamics of modern coral reefs in the Indo-Pacific region. This model describes both an initiation at 9.9 ka and subsequent development that confirms a strong influence of sea-level fluctuations on reef dynamics. Simulations based on mtDNA datasets showed that pre-LGM genetic signatures of expansion are lost. Recent literature shows that, although genetic expansions of tropical marine species are frequent (>95%), the onset of these expansions is old (median ~110 ka), which indicates that most populations have remained stable since before the LGM. These pre-LGM expansions are explained by the low mutation rates (1.66% changes/site/Myr) known to be inadequate to calibrate time at population level. Specific calibrations should help solve the paradox and generalise the CEM for reef species.

Late-Glacial and Early Holocene Sea-Level Fluctuations in the Central Puget Lowland, Washington, Inferred from Lake Sediments

1994 ◽  
Vol 42 (2) ◽  
pp. 149-161 ◽  
Author(s):  
Karl Anundsen ◽  
Sally Abella ◽  
Estella Leopold ◽  
Minze Stuiver ◽  
Sheila Turner
Keyword(s):  
Sea Level ◽  
Late Glacial ◽  
Early Holocene ◽  
Pollen Record ◽  
Sea Level Changes ◽  
Radiocarbon Dates ◽  
Sea Level Fluctuations ◽  
Lake Outlet ◽  
Basal Section ◽  
Holocene Sea Level

AbstractAnalyses of sediments, diatoms, and pollen in a 12.65-m-long sediment core taken from Lake Carpenter in the central Puget Lowland, Washington, provide detailed information regarding the history of deglaciation and late-glacial/early Holocene sea-level changes. The lake outlet, now 8.2 m above sea level, has been lowered 1-1.5 m by postglacial erosion. The lithology and pollen record suggest that no lengthy hiatuses in sedimentation have occurred. The basal sediments are glacialmarine and contain shell fragments and brackish/marine diatoms. Freshwater sediments above the basal section are interrupted only by a short section containing few fossils, most of which are brackish to marine indicators, and by the Mazama tephra at 9.5 m. The pollen record in the basal 4 m reveals a Pinus zone (ca. 13,850-11,000 yr B.P.) with a brief peak of Picea at ca. 13,700 yr B.P., and an Alnus/Pseudotsuga zone (ca. 11,000-6500 yr B.P.). The chronology is based on nine radiocarbon ages. A relative lowering of sea level below the 9.5-m threshold is recorded in the core at 12.41 m and dates 13,850 to 13,700 yr B.P. A marine episode occurred about 13,600 yr B.P., implying that relative sea-level temporarily rose above 9.5 m. No subsequent transgressions above the 9.5-m level have been recorded. Comparison of six radiocarbon dates ≥13,600 yr B.P. suggest that the marine reservoir correction of 760 yr currently used for this area may be too high for this time period.

Postglacial sedimentary and geomorphological evolution of a small sub-Antarctic fjord landscape, Stromness Bay, South Georgia

2012 ◽  
Vol 25 (3) ◽  
pp. 409-419 ◽  
Author(s):  
Nathalie Van Der Putten ◽  
Cyriel Verbruggen ◽  
Helena Alexanderson ◽  
Svante Björck ◽  
Bart Van De Vijver
Keyword(s):  
Sea Level ◽  
Late Glacial ◽  
Sea Level Changes ◽  
Freshwater Environment ◽  
Radiocarbon Dates ◽  
South Georgia ◽  
Isostatic Rebound ◽  
Late Glacial And Holocene ◽  
Geomorphological Evolution

AbstractA detailed stratigraphical, palaeoecological and geomorphological reconstruction of a fjord head on South Georgia (Husvik, Stromness Bay) is presented. Six sites were chosen to reconstruct the lithostratigraphy of the area by means of coring. A maximum depth of 11 m was attained and the sediments encountered vary from coarse gravel over sands to fine silts with, in some cases, intercalated peat layers. Diatom analysis allowed determination of whether the sedimentological units were deposited in a marine or freshwater environment. Six radiocarbon dates constrain the chronology. Deglaciation of the area was completed in the early Holocene and the postglacial geomorphological evolution of Husdal (unofficial name) was controlled by fluvio-deltaic deposition and sea level changes. Relative sea level rise was faster than, or kept pace with the isostatic rebound of the land. Our results challenge the presence of Late Glacial and Holocene raised beach deposits in the area as reported in earlier geomorphological studies.

A new late-glacial sea-level record for St. George's Bay, Newfoundland

2003 ◽  
Vol 40 (8) ◽  
pp. 1053-1070 ◽  
Author(s):  
Trevor Bell ◽  
Martin J Batterson ◽  
David GE Liverman ◽  
John Shaw
Keyword(s):  
Sea Level ◽  
Late Glacial ◽  
Level Curve ◽  
Radiocarbon Dates ◽  
Sea Levels ◽  
Marine Deposits ◽  
Isostatic Adjustment ◽  
Stratigraphic Framework ◽  
Ice Retreat ◽  
Major River

A new relative sea-level curve is presented for St. George's Bay, southwest Newfoundland, based on (i) a revised stratigraphic framework and depositional model for glacial and marine deposits exposed in coastal sections and (ii) 19 new radiocarbon dates on shells from emerged and submerged marine deposits, including fossiliferous diamictons. The data produce a type B sea-level curve, falling steeply from an extrapolated marine limit of 105 m above sea level at 14.0 14C ka BP, passing below modern sea level at ~10.6 14C ka BP, to a lowstand of –25 m at ~9.4 14C ka BP, and rising again close to modern sea level by 5.0 14C ka BP. Marine limits in the northern part of the bay have lower elevations (27–65 m) due to delayed ice retreat of up to 1.2 ka. Between 12.8 and at least 12.3 14C ka BP, glaciofluvial outwash graded to falling sea levels between 27 and 17 m above present throughout the bay, whereas lowstand deltas were constructed in sheltered locations at the outlets of major river systems, when sea level was 25 m below present. Establishment of the sea-level lowstand at ~9.4 14C ka BP is supported by new seismic data and radiocarbon dates from St. George's Bay and also from White Bear Bay on the south coast of Newfoundland. Short-term fluctuations in emergence rates of 1–2 m/century between 12.5 and 9.5 14C ka BP are attributed to variable eustatic sea-level rise, superimposed on a declining local glacio-isostatic adjustment.

Benthic foraminiferal response to relative sea-level changes in the Maastrichtian–Danian succession at the Dakhla Oasis, Western Desert, Egypt

2016 ◽  
Vol 155 (3) ◽  
pp. 729-746 ◽  
Author(s):  
SHERIF FAROUK ◽  
SREEPAT JAIN
Keyword(s):  
Sea Level ◽  
Western Desert ◽  
Level Curve ◽  
Sea Level Changes ◽  
Low Oxygen ◽  
Benthic Environment ◽  
Oxygen Conditions ◽  
Early Paleocene ◽  
Dakhla Oasis ◽  
Regional Tectonics

AbstractThe Maastrichtian–Danian benthic foraminiferal diversity and assemblages through sequence stratigraphy were studied at Dakhla Oasis, Egypt. Benthic foraminifera numbers (BFN), high-flux species and characteristic benthic foraminiferal species and genera distribution are also incorporated to assess palaeobathymetry, palaeoenvironment and palaeoproductivity. All these proxies are then taken together to construct a sea-level curve and interpreted in terms of regional tectonics, climate and eustasy. Data suggest a remarkably highly equitable benthic environment deposited in a brackish littoral and/or marsh setting with moderate (?) to low oxygen conditions and reduced salinity (oligotrophic), possibly due to increased precipitation and terrestrial runoff. The interrupted dominance of calcareous forms and high-organic-flux species suggests occasional marine incursions and high palaeoproductivity, due to local upwelling. The inferred sea-level curve replicates the global eustatic curve and suggests that the curve is more influenced by the prevailing climate and global eustasy rather than by regional tectonics. The post-Cretaceous–Palaeogene boundary displays improvement in the environment in terms of diversity and number of species and specimens, with a marked reduction in the abundance of high-organic-flux species during early Paleocene (Danian) time, indicating a shift from a more mesotrophic open marine environment to much reduced oligotrophic conditions.

scholarly journals Relative sea-level changes in crete: reassessment of radiocarbon dates from Sphakia and west Crete

2002 ◽  
Vol 97 ◽  
pp. 171-200 ◽  
Author(s):  
Simon Price ◽  
Tom Higham ◽  
Lucia Nixon ◽  
Jennifer Moody
Keyword(s):  
Sea Level ◽  
Late Antiquity ◽  
Isotopic Fractionation ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Sea Levels ◽  
Catastrophic Earthquake ◽  
Radiocarbon Data ◽  
Calendar Dates

This article is concerned with the recognition and dating of Holocene relative sea-level changes along the coast of west Crete (an island located in the active Hellenic subduction arc of the southern Aegean) and in particular in Sphakia. Radiocarbon data for changes in sea levels collected and analysed previously must (a) be recorrected to take into account isotopic fractionation, and (b) recalibrated by using the new marine reservoir value. These new radiocarbon dates are analysed using Bayesian statistics. The resulting calendar dates for changes in sea level are younger than previously assumed. In particular the Great Uplift in western Crete in late antiquity must be dated to the fifth or sixth century AD, not to AD 365. Moreover, recent work on tectonics suggests that the Great Uplift need not have been accompanied by a catastrophic earthquake. Finally, we consider the consequences of the Great Uplift for some coastal sites in Sphakia.

scholarly journals An evaluation of climate, crustal movement and base level controls on the Middle-Late Pleistocene development of the River Severn, U.K.

2002 ◽  
Vol 81 (3-4) ◽  
pp. 329-338 ◽  
Author(s):  
D. Maddy
Keyword(s):  
Sea Level ◽  
Late Glacial ◽  
High Energy ◽  
Cold Climate ◽  
Faunal Remains ◽  
Sea Level Changes ◽  
Climate Conditions ◽  
Oxygen Isotope Stage ◽  
Base Level

AbstractThe Pleistocene development of the lower Severn valley is recorded in the fluvial sediments of the Mathon and Severn Valley Formations and their relationship to the glacigenic Wolston (Oxygen Isotope Stage 12), Ridgacre (OIS 6) and Stockport (OIS 2) Formations. The most complete stratigraphical record is that of the Severn Valley Formation, which post-dates the Anglian Wolston Formation and comprises a flight of river terraces, the highest of which is c.50 m above the present river. The terrace staircase indicates that the Severn has progressively incised its valley during the post-Anglian period. The terrace sediments are predominantly composed of fluvially deposited sands and gravels, largely the result of deposition in high-energy rivers under cold-climate conditions. Occasionally towards the base of these terrace deposits low-energy fluvial facies are preserved which contain faunal remains and yield geochronology which support their correlation with interglacial conditions. This simple stratigraphy supports a climate-driven model for the timing of terrace aggradation and incision, with the incision mode at its most effective during the cold-warm transitions and the aggradational mode at its most effective during warm-cold climate transitions. The chronology of terrace aggradation in the lower Severn seems to correspond with the Milankovitch lOOka climate cycles. The timing of incision events suggests that base level (eustatic sea-level) changes do not play a significant role i.e. incision occurs as sea-level is rising.Although climate change is significant in governing the timing of incision, the long-term incision of the River Severn appears to be driven by crustal uplift. A long-term incision rate of 0.15 m ka1, calculated using the base of the terrace deposits, is believed to closely equate with the long-term uplift rate. Superimposed on this long-term uplift are periods of complex terrace sequence development resulting from rapid incision during periods of glacio-isostatic rebound, with large incision events reflecting the rebound adjustment to late glacial stage isostatic depression. However, in no case in the Severn valley has glacial encroachment led to enhanced incision, suggesting that there has been no additional uplift resulting from isostatic compensation for glacial erosion.

Radiocarbon age of rock-boring Hiatella arctica (Linné) and postglacial sea-level change at Cow Head, Newfoundland

1985 ◽  
Vol 22 (1) ◽  
pp. 136-140 ◽  
Author(s):  
Ian A. Brookes ◽  
Robert K. Stevens
Keyword(s):  
Sea Level ◽  
Marine Invertebrate ◽  
Sea Level Change ◽  
Radiocarbon Date ◽  
Radiocarbon Age ◽  
Level Change ◽  
Hiatella Arctica

Carbonate bedrock surfaces recently exposed at Cow Head, Newfoundland (50°14′N, 57°35′W) are densely riddled with boreholes of Hiatella arctica (Linné), many of which are occupied by subfossil specimens of this bivalve as well as with vermiform burrows of a sponge (? Cliona sp.). A radiocarbon date of 8250 ± 320 years BP (GSC-3433) on several Hiatella valves from the burrows gives the age of a sea-level stand at 8 m asl at the locality, during which penecontemporaneous surf erosion or beach gravel deposition led to the demise of the shells. Other unoccupied cavities in longer exposed bedrock outcrops on Cow Head are contrasted in form and distribution with those of Hiatella and are argued to be boreholes of another marine invertebrate, not positively identified.

Submerged speleothem in Malta indicates tectonic stability throughout the Holocene

The Holocene ◽  
2018 ◽  
Vol 28 (10) ◽  
pp. 1588-1597 ◽  
Author(s):  
Stefano Furlani ◽  
Fabrizio Antonioli ◽  
Timmy Gambin ◽  
Sara Biolchi ◽  
Saviour Formosa ◽  
...  
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
Karst Environment ◽  
Marine Deposits ◽  
Archaeological Data ◽  
Decadal Scale ◽  
Term Data

Submerged caves represent potential archives of speleothems with continental and marine biogenic layers. In turn, these can be used to reconstruct relative sea-level changes. This study presents new data on the tectonic behaviour of the island of Malta during the Holocene. These data were obtained from a speleothem sampled, during an underwater survey, at a depth of −14.5 m, inside a recently discovered submerged cave. Since the cave was mainly formed in a subaerial karst environment, the presence of a speleothem with serpulids growing on its continental layers permitted the reconstruction of the chronology for drowning of the cave. The radiocarbon dates obtained from the penultimate and last continental layers of the speleothem, before a serpulid encrustation, were compared with synthetic aperture radar (SAR) and global positioning system (GPS) data, together with published sedimentological and archaeological data. The radiocarbon analyses provided an average age of 7.6 ka BP that perfectly aligns with the Lambeck’s model of Holocene sea level. Morevoer, long-term data agree with published archeological and sedimentological data as well as with SAR interpherometric and GPS trends on a decadal scale. We conclude that the Maltese islands were tectonically stable during the Holocene, and this tectonic behaviour still persists nowadays. On the contrary, new informations on older deposits, such as MIS5e (Maritime Isotope Stage, corresponding to 125 ka ago) were not found in the study area, confirming the lack of older Quaternary marine deposits in these islands.

scholarly journals Late Glacial Marine Transgression and Ecosystem Response in the Landlocked Elefsis Bay (Northern Saronikos Gulf, Greece)

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1505
Author(s):  
Katerina Kouli ◽  
Maria V. Triantaphyllou ◽  
Olga Koukousioura ◽  
Margarita D. Dimiza ◽  
Constantine Parinos ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Glacial ◽  
Ecosystem Response ◽  
Sea Level Changes ◽  
Marine Transgression ◽  
Sea Level Fluctuations ◽  
Geological Processes ◽  
Marginal Areas ◽  
Coastal Landscapes ◽  
Marine Realm

Coastal landscapes are sensitive to changes due to the interplay between surface and submarine geological processes, climate variability, and relative sea level fluctuations. The sedimentary archives of such marginal areas record in detail the complex evolution of the paleoenvironment and the diachronic biota response. The Elefsis Bay is nowadays a landlocked shallow marine basin with restricted communication to the open Saronikos Gulf. A multi-proxy investigation of a high-resolution sediment core recovered from the deepest part of the basin offered a unique opportunity to record the paleoenvironmental and aquatic ecosystem response to climate and glacioeustatic sea level changes since the Late Glacial marine transgression. The retrieved sedimentary deposits, subjected to thorough palynological (pollen, non-pollen palynomorphs, dinoflagellates), micropaleontological (benthic foraminifera, calcareous nannoplankton, ostracods), and mollusc analyses, indicates isolation of the Elefsis Bay from the Saronikos Gulf and the occurrence of a shallow freshwater paleolake since at least 13,500 cal BP, while after 11,3500 cal BP the transition towards lagoon conditions is evidenced. The marine transgression in the Elefsis Bay is dated at 7500 cal BP, marking the establishment of the modern marine realm.

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