scholarly journals Technical note: Late Pliocene age control and composite depths at ODP Site 982, revisited

2012 ◽  
Vol 8 (1) ◽  
pp. 79-87 ◽  
Author(s):  
N. Khélifi ◽  
M. Sarnthein ◽  
B. D. A. Naafs
Keyword(s):  
North Atlantic ◽  
Technical Note ◽  
Time Span ◽  
Sea Surface ◽  
Ocean Drilling Program ◽  
Late Pliocene ◽  
Ocean Drilling ◽  
Proxy Records ◽  
The North ◽  
Sediment Records

Abstract. Ocean Drilling Program (ODP) Site 982 provided a key sediment section at Rockall Plateau for reconstructing northeast Atlantic paleoceanography and monitoring benthic δ18O stratigraphy over the late Pliocene to Quaternary onset of major Northern Hemisphere glaciation. A renewed hole-specific inspection of magnetostratigraphic reversals and the addition of epibenthic δ18O records for short Pliocene sections in holes 982A, B, and C, crossing core breaks in the δ18O record published for Hole 982B, now imply a major revision of composite core depths. After tuning to the orbitally tuned reference record LR04, the new composite δ18O record results in a hiatus, where the Kaena magnetic subchron might have been lost, and in a significant age reduction for all proxy records by 130 to 20 ky over the time span 3.2–2.7 million years ago (Ma). Our study demonstrates the general significance of reliable composite-depth scales and δ18O stratigraphies in ODP sediment records for generating ocean-wide correlations in paleoceanography. The new concept of age control makes the late Pliocene trends in SST (sea surface temperature) and atmospheric pCO2 at Site 982 more consistent with various paleoclimate trends published from elsewhere in the North Atlantic.

scholarly journals Late Pliocene age control and composite depths at ODP Site 982, revisited

2011 ◽  
Vol 7 (3) ◽  
pp. 1631-1646
Author(s):  
N. Khélifi ◽  
M. Sarnthein ◽  
B. D. A. Naafs
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Time Span ◽  
Ocean Drilling Program ◽  
Late Pliocene ◽  
Ocean Drilling ◽  
Proxy Records ◽  
The North ◽  
Sediment Records ◽  
The North Atlantic

Abstract. Ocean Drilling Program (ODP) Site 982 provided a key sediment section at Rockall Plateau for reconstructing northeast Atlantic paleoceanography and monitoring benthic δ18O stratigraphy over the Late Pliocene to Quaternary onset of major Northern Hemisphere Glaciation. A renewed hole-specific inspection of magnetostratigraphic events and the addition of epibenthic δ18O records for short Pliocene sections in holes 982A, B, and C, crossing core breaks in the δ18O record published for Hole 982B, now imply a major revision of composite core depths. After tuning to the orbitally tuned reference record LR04 the new composite δ18O record results in a hiatus, where the Kaena magnetic event might been lost, and in a significant age reduction for all proxy records by 130 to 20 ka over the time span 3.2–2.7 million yr ago (Ma). Our study demonstrates the significance of reliable composite-depth scales and δ18O stratigraphies in ODP sediment records for ocean-wide correlations in paleoceanography and makes Late Pliocene trends found at Site 982 much better comparable to those published from elsewhere in the North Atlantic.

scholarly journals Dinocyst and acritarch biostratigraphy of the Late Pliocene to Early Pleistocene at Integrated Ocean Drilling Program Site U1307 in the Labrador Sea

2020 ◽  
Vol 39 (1) ◽  
pp. 41-60
Author(s):  
Aurélie Marcelle Renée Aubry ◽  
Stijn De Schepper ◽  
Anne de Vernal
Keyword(s):  
North Atlantic ◽  
Early Pleistocene ◽  
Labrador Sea ◽  
Ocean Drilling Program ◽  
Late Pliocene ◽  
Ocean Drilling ◽  
The North ◽  
Integrated Ocean Drilling Program ◽  
Basin Scale ◽  
The North Atlantic

Abstract. We have analyzed marine palynomorphs (mainly dinocysts and acritarchs) from the Integrated Ocean Drilling Program Site U1307 in the Labrador Sea in order to establish a detailed biostratigraphy for the Late Pliocene to Early Pleistocene. We have defined three magnetostratigraphically calibrated dinocyst and acritarch biozones in the Late Pliocene to Early Pleistocene. Zone LS1 is defined based on the highest occurrence of Barssidinium graminosum and covers the later Pliocene from 3.21 to 2.75 Ma. Zone LS2 is marked by the acme of Pyxidinopsis braboi which occurs between 2.75 and 2.57 Ma, thus encompassing the Plio–Pleistocene transition. Finally, zone LS3 extends from 2.57 to 2.23 Ma in the Early Pleistocene. The palynostratigraphic record of IODP Site U1307 is difficult to correlate to other North Atlantic and Nordic Seas sites mainly because of a different temporal resolution and a lack of well-defined biostratigraphic marker species at the basin scale. The low abundance, discontinuous occurrence and asynchronous events of warm-water Pliocene taxa such as Invertocysta lacrymosa, Impagidinium solidum, Ataxiodinium confusum, Melitasphaeridium choanophorum and Operculodinium? eirikianum suggest cooler conditions in the Labrador Sea than elsewhere in the North Atlantic, reflecting a strong regionalism. Nevertheless, as recorded at other locations in the North Atlantic, the disappearance of many dinocyst and acritarch taxa around 2.75 Ma at Site U1307 reflects a strong ecological response accompanying the intensification of the Northern Hemisphere glaciation.

scholarly journals Late Pliocene to early Pleistocene changes in the North Atlantic Current and suborbital-scale sea-surface temperature variability

2013 ◽  
Vol 28 (2) ◽  
pp. 274-282 ◽  
Author(s):  
Oliver Friedrich ◽  
Paul A. Wilson ◽  
Clara T. Bolton ◽  
Christopher J. Beer ◽  
Ralf Schiebel
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Sea Surface ◽  
Early Pleistocene ◽  
North Atlantic Current ◽  
Late Pliocene ◽  
The North ◽  
The North Atlantic ◽  
Atlantic Current

scholarly journals Cenozoic Biostratigraphy and Global Change

1991 ◽  
Vol 9 (2) ◽  
pp. 117-117
Author(s):  
Brian M. Funnell
Keyword(s):  
Global Change ◽  
North Atlantic ◽  
Ocean Drilling Program ◽  
East Anglia ◽  
Ongoing Research ◽  
Ocean Drilling ◽  
The North ◽  
History Of ◽  
The North Atlantic ◽  
The University

Abstract. INTRODUCTIONIn May 1989 a British Micropalaeontological Society Symposium Meeting was held at the University of East Anglia under the title “Cenozoic Biostratigraphy and Global Change”. Fourteen lectures were given on this theme, many of them originating from investigations of DSDP/IPOD and ODP (Ocean Drilling Program) samples. All addressed the potential of micropalaeontological observations for interpreting the history of global and regional oceanographic and climatic change. Many results of this type of investigation are currently appearing in science journals such as “Paleoceanography” and “Palaeogeography, Palaeoclimatology, Palaeoecology” as well as in the “Proceedings of the Ocean Drilling Program”. British micropalaeontologists are taking an active part in this research, but relatively few of the resultant papers have so far appeared in the Journal of Micropalaeontology.Many of the lectures given at the May 1989 Symposium represented work already recently published, or due to be subsequently published in the Proceedings of the Ocean Drilling Program. Four papers, representing ongoing research not then due to be published, have been brought together here as a small thematic set, illustrating a variety of approaches to “Cenozoic Biostratigraphy and Global Change”. They range across Ostracoda, Coccolithophorida, Planktonic and Benthic Foraminifera, through the entire Cenozoic, including the latest Quaternary, and they include results from both the North Atlantic and Pacific oceans.TITLES“Global Change and the Biostratigraphy of North Atlantic Cenozoic deep water Ostracoda” - Robin C. Whatley and Graham P. Coles.“Palaeoclimatic control of Upper Pliocene Discoaster assemblages in the North Atlantic” - Alex. Chepstow-Lusty, Jan Backman. . .

scholarly journals A revised and improved age model for the middle Miocene part of IODP Site U1318 (Porcupine Basin, offshore southwestern Ireland)

2017 ◽  
Vol 155 (5) ◽  
pp. 1105-1116
Author(s):  
WILLEMIJN QUAIJTAAL ◽  
STEVEN TESSEUR ◽  
TIMME H. DONDERS ◽  
PHILIPPE CLAEYS ◽  
STEPHEN LOUWYE
Keyword(s):  
North Atlantic ◽  
Middle Miocene ◽  
Ocean Drilling Program ◽  
Carbon And Oxygen Isotopes ◽  
Ocean Drilling ◽  
The North ◽  
Integrated Ocean Drilling Program ◽  
Isotope Record ◽  
Porcupine Basin ◽  
Age Model

AbstractIntegrated Ocean Drilling Program Leg 307 Site U1318 is one of the few relatively complete middle Miocene drillcores from the North Atlantic (Porcupine Basin, offshore southwestern Ireland). Using benthic foraminiferal stable carbon and oxygen isotopes, the existing age model for Site U1318 was improved. The stable isotope record displays globally recognized isotope events, used to revise the existing magnetostratigraphy-based age model. Two intervals contained misidentified magnetochrons which were corrected. The sampled interval now has a refined age of 12.75–16.60 Ma with a temporal resolution of c. 29 ka.

scholarly journals Space-Time Sea Surface pCO2 Estimation in the North Atlantic Based on CatBoost

2021 ◽  
Vol 13 (14) ◽  
pp. 2805
Author(s):  
Hongwei Sun ◽  
Junyu He ◽  
Yihui Chen ◽  
Boyu Zhao
Keyword(s):  
North Atlantic ◽  
Function Analysis ◽  
Biological Activities ◽  
Mixed Layer Depth ◽  
Sea Surface ◽  
Coefficient Of Determination ◽  
Mean Bias Error ◽  
Bias Error ◽  
The North ◽  
The North Atlantic

Sea surface partial pressure of CO2 (pCO2) is a critical parameter in the quantification of air–sea CO2 flux, which plays an important role in calculating the global carbon budget and ocean acidification. In this study, we used chlorophyll-a concentration (Chla), sea surface temperature (SST), dissolved and particulate detrital matter absorption coefficient (Adg), the diffuse attenuation coefficient of downwelling irradiance at 490 nm (Kd) and mixed layer depth (MLD) as input data for retrieving the sea surface pCO2 in the North Atlantic based on a remote sensing empirical approach with the Categorical Boosting (CatBoost) algorithm. The results showed that the root mean square error (RMSE) is 8.25 μatm, the mean bias error (MAE) is 4.92 μatm and the coefficient of determination (R2) can reach 0.946 in the validation set. Subsequently, the proposed algorithm was applied to the sea surface pCO2 in the North Atlantic Ocean during 2003–2020. It can be found that the North Atlantic sea surface pCO2 has a clear trend with latitude variations and have strong seasonal changes. Furthermore, through variance analysis and EOF (empirical orthogonal function) analysis, the sea surface pCO2 in this area is mainly affected by sea temperature and salinity, while it can also be influenced by biological activities in some sub-regions.

The North Atlantic atmosphere-sea surface 14C gradient during the Younger Dryas climatic event

1994 ◽  
Vol 126 (4) ◽  
pp. 275-287 ◽  
Author(s):  
Edouard Bard ◽  
Maurice Arnold ◽  
Jan Mangerud ◽  
Martine Paterne ◽  
Laurent Labeyrie ◽  
...  
Keyword(s):  
North Atlantic ◽  
Younger Dryas ◽  
Sea Surface ◽  
The North ◽  
Climatic Event ◽  
The North Atlantic

scholarly journals Technical Note: On methodologies for determining the size-normalised weight of planktic foraminifera

2010 ◽  
Vol 7 (7) ◽  
pp. 2193-2198 ◽  
Author(s):  
C. J. Beer ◽  
R. Schiebel ◽  
P. A. Wilson
Keyword(s):  
Wall Thickness ◽  
North Atlantic ◽  
Technical Note ◽  
Sieve Method ◽  
Planktic Foraminifera ◽  
Test Size ◽  
The North ◽  
Sieve Fraction ◽  
Error Bar ◽  
Fraction Method

Abstract. The size-normalised weight (SNW) of planktic foraminifera, a measure of test wall thickness and density, is potentially a valuable palaeo-proxy for marine carbon chemistry. As increasing attention is given to developing this proxy it is important that methods are comparable between studies. Here, we compare SNW data generated using two different methods to account for variability in test size, namely (i) the narrow (50 μm range) sieve fraction method and (ii) the individually measured test size method. Using specimens from the 200–250 μm sieve fraction range collected in multinet samples from the North Atlantic, we find that sieving does not constrain size sufficiently well to isolate changes in weight driven by variations in test wall thickness and density from those driven by size. We estimate that the SNW data produced as part of this study are associated with an uncertainty, or error bar, of about ±11%. Errors associated with the narrow sieve fraction method may be reduced by decreasing the size of the sieve window, by using larger tests and by increasing the number tests employed. In situations where numerous large tests are unavailable, however, substantial errors associated with this sieve method remain unavoidable. In such circumstances the individually measured test size method provides a better means for estimating SNW because, as our results show, this method isolates changes in weight driven by variations in test wall thickness and density from those driven by size.

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