scholarly journals Luminescence dating of young coastal deposits from New Zealand using feldspar

2011 ◽  
Vol 38 (4) ◽  
pp. 379-390 ◽  
Author(s):  
Anni Madsen ◽  
Jan-Pieter Buylaert ◽  
Andrew Murray
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Sediment Accumulation ◽  
Luminescence Dating ◽  
Coastal Sediments ◽  
Relative Sea Level ◽  
Infrared Stimulated Luminescence ◽  
Measurement Protocol ◽  
Coastal Deposits ◽  
Fading Rate

Abstract A new measurement protocol has been tested on K-feldspars from Whanganui Inlet and Parengarenga Harbour, New Zealand. A Single Aliquot Regenerative (SAR) dose protocol, using two successive infrared (IR) stimulations (post-IR IR SAR protocol) is setup for these young (<1000 years) coastal sediments. Significant anomalous fading (g2days=7 %/decade) is observed using the conventional IR signal measured at 50°C. In contrast, the fading rate of the IR signal measured at elevated temperature (150°C) after the IR stimulation at 50°C (a post-IR IR signal) is not significant (g2days≤ 1 %/decade). Surprisingly low residual infrared stimulated luminescence (IRSL) signals were observed for a surface sample, suggesting that accurate ages as young as ∼50 years can be obtained for these recent deposits. IRSL ages ranging between 48±6 years and 1050±50 years are obtained from six samples, indicating that sediment accumulation has occurred at the two sites during the last millennia, despite a falling trend in relative sea-level in Whanganui Inlet and a stable relative sea-level at Parengarenga Harbour.

scholarly journals Integrating Geomorphological Data, Geochronology and Archaeological Evidence for Coastal Landscape Reconstruction, the Case of Ammoudara Beach, Crete

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1269
Author(s):  
George Alexandrakis ◽  
Stelios Petrakis ◽  
Nikolaos A. Kampanis
Keyword(s):  
Bronze Age ◽  
Coastal Area ◽  
Luminescence Dating ◽  
Coastal Sediments ◽  
Aerial Photographs ◽  
Coastal Landscape ◽  
Archaeological Evidence ◽  
Dune Field ◽  
Coastal Landscapes ◽  
Coastal Deposits

Understanding the processes that govern the transformation of the landscape through time is essential for exploring the evolution of a coastal area. Coastal landscapes are dynamic sites, with their evolution strongly linked with waves and sea level variations. Geomorphological features in the coastal area, such as beachrock formations and dune fields, can function as indicators of the coastal landscape evolution through time. However, our knowledge of the chronological framework of coastal deposits in the Aegean coasts is limited. Optically Stimulated Luminescence dating techniques are deemed to be very promising in direct dating of the coastal sediments, especially when they are linked with archaeological evidence. The dating of the sediments from different sediment core depths, determined by the method of luminosity, allowed us to calculate the rate of sediment deposition over time. More recent coastal evolution and stability were examined from 1945 to 2020 with the use of aerial photographs and satellite images. This paper presents the 6000 ka evolution of a coastal landscape based on geomorphological, archaeological, and radio-chronological data. Based on the results, the early stages of the Ammoudara beach dune field appears to have been formed ~9.0–9.6 ka BP, while the OSL ages from 6 m depth represented the timing of its stabilization (OSL ages ~5–6 ka). This indicates that the dune field appears to already have been formed long before the Bronze Age (5–10 ka BP). It became stabilized with only localized episodes of dune reactivation occurring. In contrast, while high coastal erosion rates were calculated for modern times.

scholarly journals Last interglacial (MIS 5e) sea-level proxies in southeastern South America

2021 ◽  
Vol 13 (1) ◽  
pp. 171-197
Author(s):  
Evan J. Gowan ◽  
Alessio Rovere ◽  
Deirdre D. Ryan ◽  
Sebastian Richiano ◽  
Alejandro Montes ◽  
...  
Keyword(s):  
South America ◽  
Sea Level ◽  
Last Interglacial ◽  
Amino Acid Racemization ◽  
Exceptional Preservation ◽  
Infrared Stimulated Luminescence ◽  
Spin Resonance ◽  
Coastal Deposits ◽  
Mis 5E ◽  
Terrace Level

Abstract. Coastal southeast South America is one of the classic locations where there are robust, spatially extensive records of past high sea level. Sea-level proxies interpreted as last interglacial (Marine Isotope Stage 5e, MIS 5e) exist along the length of the Uruguayan and Argentinian coast with exceptional preservation especially in Patagonia. Many coastal deposits are correlated to MIS 5e solely because they form the next-highest terrace level above the Holocene highstand; however, dating control exists for some landforms from amino acid racemization, U∕Th (on molluscs), electron spin resonance (ESR), optically stimulated luminescence (OSL), infrared stimulated luminescence (IRSL), and radiocarbon dating (which provides minimum ages). As part of the World Atlas of Last Interglacial Shorelines (WALIS) database, we have compiled a total of 60 MIS 5 proxies attributed, with various degrees of precision, to MIS 5e. Of these, 48 are sea-level indicators, 11 are marine-limiting indicators (sea level above the elevation of the indicator), and 1 is terrestrial limiting (sea level below the elevation of the indicator). Limitations on the precision and accuracy of chronological controls and elevation measurements mean that most of these indicators are considered to be low quality. The database is available at https://doi.org/10.5281/zenodo.3991596 (Gowan et al., 2020).

A foraminiferal proxy record of 20th century sea-level rise in the Manukau Harbour, New Zealand

2012 ◽  
Vol 63 (4) ◽  
pp. 370 ◽  
Author(s):  
Hugh R. Grenfell ◽  
Bruce W. Hayward ◽  
Ritsuo Nomura ◽  
Ashwaq T. Sabaa
Keyword(s):  
New Zealand ◽  
Salt Marsh ◽  
Sea Level Rise ◽  
Sea Level ◽  
20Th Century ◽  
Tide Gauge ◽  
Sediment Accumulation ◽  
Proxy Record ◽  
Tide Gauge Record ◽  
Tidal Salt Marsh

The present study aimed to extract a sea-level history from northern New Zealand salt-marsh sediments using a foraminiferal proxy, and to extend beyond the longest nearby tide-gauge record. Transects through high-tidal salt marsh at Puhinui, Manukau Harbour, Auckland, New Zealand, indicate a zonation of dominant foraminifera in the following order (with increasing elevation): Ammonia spp.–Elphidium excavatum, Ammotium fragile, Miliammina fusca, Haplophragmoides wilberti–Trochammina inflata, Trochamminita salsa–Miliammina obliqua. The transect sample faunas are used as a training set to generate a transfer function for estimating past tidal elevations in two short cores nearby. Heavy metal, 210Pb and 137Cs isotope analyses provide age models that indicate 35 cm of sediment accumulation since ~1890 AD. The first proxy-based 20th century rates of sea-level rise from New Zealand’s North Island at 0.28 ± 0.05 cm year–1 and 0.33 ± 0.07 cm year–1 are estimated. These are faster than the nearby Auckland tide gauge for the same interval (0.17 ± 0.1 cm year–1), but comparable to a similar proxy record from southern New Zealand (0.28 ± 0.05 cm year–1) and to satellite-based observations of global sea-level rise since 1993 (0.31 ± 0.07 cm year–1).

Constraints on the amplitude of Mid-Pliocene (3.6–2.4 Ma) eustatic sea-level fluctuations from the New Zealand shallow-marine sediment record

2008 ◽  
Vol 367 (1886) ◽  
pp. 169-187 ◽  
Author(s):  
Tim R Naish ◽  
Gary S Wilson
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Sediment Accumulation ◽  
Ice Sheet ◽  
Deep Ocean ◽  
Antarctic Ice Sheet ◽  
Shallow Marine ◽  
Sea Level Fluctuations ◽  
Late Neogene ◽  
Sea Level Oscillations

Ice-volume calibrations of the deep-ocean foraminiferal δ 18 O record imply orbitally influenced sea-level fluctuations of up to 30 m amplitude during the Mid-Pliocene, and up to 30 per cent loss of the present-day mass of the East Antarctic Ice Sheet (EAIS) assuming complete deglaciation of the West Antarctic Ice Sheet (WAIS) and Greenland. These sea-level oscillations have driven recurrent transgressions and regressions across the world's continental shelves. Wanganui Basin, New Zealand, contains the most complete shallow-marine Late Neogene stratigraphic record in the form of a continuous cyclostratigraphy representing every 41 and 100 ka sea-level cycle since ca 3.6 Ma. This paper presents a synthesis of faunally derived palaeobathymetric data for shallow-marine sedimentary cycles corresponding to marine isotope stages M2–100 ( ca 3.4–2.4 Ma). Our approach estimates the eustatic sea-level contribution to the palaeobathymetry curve by placing constraints on total subsidence and decompacted sediment accumulation. The sea-level estimates are consistent with those from δ 18 O curves and numerical ice sheet models, and imply a significant sensitivity of the WAIS and the coastal margins of the EAIS to orbital oscillations in insolation during the Mid-Pliocene period of relative global warmth. Sea-level oscillations of 10–30 m were paced by obliquity.

scholarly journals A post-glacial relative sea-level curve from Fiordland, New Zealand

2015 ◽  
Vol 131 ◽  
pp. 104-114 ◽  
Author(s):  
E.K. Dlabola ◽  
G.S. Wilson ◽  
A.R. Gorman ◽  
C.R. Riesselman ◽  
C.M. Moy
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Level Curve ◽  
Relative Sea Level

scholarly journals Developing detailed records of relative sea-level change using a foraminiferal transfer function: an example from North Norfolk, UK

2006 ◽  
Vol 364 (1841) ◽  
pp. 973-991 ◽  
Author(s):  
Robin J Edwards ◽  
B.P Horton
Keyword(s):  
Transfer Function ◽  
Sea Level ◽  
Transfer Functions ◽  
Sediment Cores ◽  
Sea Level Change ◽  
Relative Sea Level ◽  
Level Change ◽  
The North ◽  
Level Information ◽  
Coastal Deposits

This paper provides a brief overview of the transfer function approach to sea-level reconstruction. Using the example of two overlapping sediment cores from the North Norfolk coast, UK, the advantages and limitations of the transfer function methodology are examined. While the selected cores are taken from different sites, and display contrasting patterns of sedimentation, the foraminiferal transfer function distils comparable records of relative sea-level change from both sequences. These reconstructions are consistent with existing sea-level index points from the region but produce a more detailed record of relative sea-level change. Transfer functions can extract sea-level information from a wider range of sedimentary sub-environments. This increases the amount of data that can be collected from coastal deposits and improves record resolution. The replicability of the transfer function methodology, coupled with the sequential nature of the data it produces, assists in the compilation and analysis of sea-level records from different sites. This technique has the potential to bridge the gap between short-term (instrumental) and long-term (geological or geophysical) records of sea-level change.

scholarly journals Integrating Geomorphological Data, Geochronology, and Archaeological Evidence for Coastal Landscape Reconstruction. The Case of Ammoudara Beach, Crete

2021 ◽  
Author(s):  
George Alexandrakis ◽  
Stelios Petrakis ◽  
Nikolaos Kampanis
Keyword(s):  
Bronze Age ◽  
Coastal Area ◽  
Luminescence Dating ◽  
Coastal Sediments ◽  
Aerial Photographs ◽  
Coastal Landscape ◽  
Archaeological Evidence ◽  
Dune Field ◽  
Coastal Landscapes ◽  
Coastal Deposits

Understanding the processes that govern the transformation of the landscape through time is essential for exploring the evolution of a coastal area. Coastal landscapes are dynamic sites, with their evolution strongly linked with waves and sea-level variations. Geomorphological features in the coastal area, such as beachrock formations and dune fields, can function as indicators of the coastal landscape evolution through time. However, our knowledge of the chronological framework of coastal deposits on the Aegean coasts is limited. Optically stimulated luminescence dating techniques are deemed to be very promising indirect dating of the coastal sediments, especially when they are linked with archaeological evidence. The dating of the sediments from different sediment core depths, as they are determined by the method of luminosity, allows us to calculate the rate of sediment deposition over time. Additionally, the coastal evolution and stability were studied from 1945 until today, with the use of aerial photographs and satellite images. This paper presents the 6000 ka years evolution of a coastal landscape based on geomorphological, archaeological, and radio-chronological data. Based on the results, the early stages of the Ammoudara beach dune field appear to be formed ~9.0 &ndash; 9.6 ka BP, while the OSL ages from 6 m depth represented the timing of its stabilization (OSL ages ~5&ndash;6 ka). This indicates that the dune field appears to already have been formed long before the Bronze Age (5-10 ka BP) and became stabilized with only localized episodes of dune reactivation occurring, while high coastal erosion rates are found in modern times.

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