Response of macrobenthic and foraminifer communities to changes in deep-sea environmental conditions from Marine Isotope Stage (MIS) 12 to 11 at the “Shackleton Site”

Rodríguez‐Tovar, Francisco J.; Dorador, Javier; Martin-Garcia, Gloria M.; Sierro, Francisco J.; Flores, José-Abel; Hodell, David A

doi:10.1016/j.gloplacha.2015.08.012

Cited by 37 publications

(14 citation statements)

References 64 publications

(20 reference statements)

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“…2). They have been successfully applied for ichnofacies characterisation 38 , ichnofabric approach 5,39 , and palaeoenvironmental studies [5][6][7] . These methods are effective for high-resolution pictures, but have also provided good results on 2D images obtained from non-penetrative techniques (i.e., X-ray or CT) 31,40 .…”

Section: Methods Backgroundmentioning

confidence: 99%

Exploring computed tomography in ichnological analysis of cores from modern marine sediments

Dorador

Rodrı́guez-Tovar

Titschack³

2020

Sci Rep

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ichnological analysis is considered a very useful tool in several disciplines of earth Sciences, including palaeoenvironmental studies and hydrocarbon exploration. Sediment cores provide excellent records, despite difficulties encountered during study runs due to specific core features. Previous studies using 2D images have proven the benefits of high-resolution image treatment in improving the visibility of ichnological features, but with limitations. 3D computed tomography (CT) techniques were applied to palaeoichnological studies in lithified cores and other disciplines of palaeontology to solve these limitations, but not used for ichnological studies in unconsolidated sediments due to the low density contrast between host sediment and trace fossils. In this study, a CT processing technique, previously tested in coral research, is applied to facilitate the characterisation of the ichnological signature of cores from modern marine soft sediments. This technique allows for the first time the isolation of burrows within these kinds of sediments and the differentiation of intervals based on burrow orientation. Data obtained from the technique are complemented with the ichnological information from conventional core description, thus providing a more complete characterisation of the trace fossil assemblage with additional ichnological properties such as burrow orientation and branching. this will improve palaeoenvironmental interpretations related to changes in energy or oxygenation, and the analysis of reservoir quality given the impact of burrows on porosity and permeability. Therefore, adopting CT to complement visual core description in the ichnological analysis of soft modern marine cores is a very informative approach.Ichnological research is widely recognised as a very useful tool in the study of drilled marine cores in a wide range of fields. Biogenic structures, reflecting the behaviour of trace-makers in response to palaeoenvironmental conditions, provide valuable information into areas such as palaeoecology, facies analysis, palaeoenvironmental reconstructions, sequence stratigraphy and palaeoceanography 1-8 . In recent decades, the study of trace fossils has also become an essential part of reservoir and aquifer characterisation 9 . Numerous studies have proven that bioturbation is an important factor in the study of reservoir properties, affecting parameters such as porosity and permeability 10-18 . The key factors involved would be grain size re-distribution, morphology of trace fossils (e.g., shape, size, orientation, branching), burrow lining, infilling material of trace fossils, and bioturbation intensity 10,19-21 . For all these reasons, ichnology is seen as a powerful tool in Earth Science research and hydrocarbon exploration 4,13 .Initially, ichnological studies were mostly based on outcrops and modern environments 21,22 , but the study of cores has gradually increased as the amount of core material recovered from oceanic expeditions became more abundant 9,23 . Core material makes it possible to...

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Section: Methods Backgroundmentioning

confidence: 99%

Exploring computed tomography in ichnological analysis of cores from modern marine sediments

Dorador

Rodrı́guez-Tovar

Titschack³

2020

Sci Rep

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“…Site IODP-U1385 (37 • 34 N) lies within this oscillating boundary and has been shown an ideal location to study oceanographic changes in the North Atlantic through glacial-interglacial periods (e.g. Maiorano et al, 2015;Martin-Garcia et al, 2015;Rodríguez-Tovar et al, 2015;Rodrigues et al, 2017). Analyses of planktonic foraminifer assemblages are used to identify the different water masses, and results from IODP-U1385 are compared with published data from other North Atlantic latitudes to reach basin-wide conclusions.…”

Section: Introductionmentioning

confidence: 99%

Change in the North Atlantic circulation associated with the mid-Pleistocene transition

et al. 2018

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Abstract. The southwestern Iberian margin is highly sensitive to changes in the distribution of North Atlantic currents and to the position of oceanic fronts. In this work, the evolution of oceanographic parameters from 812 to 530 ka (MIS20–MIS14) is studied based on the analysis of planktonic foraminifer assemblages from site IODP-U1385 (37∘34.285′ N, 10∘7.562′ W; 2585 m b.s.l.). By comparing the obtained results with published records from other North Atlantic sites between 41 and 55∘ N, basin-wide paleoceanographic conditions are reconstructed. Variations of assemblages dwelling in different water masses indicate a major change in the general North Atlantic circulation during MIS16, coinciding with the definite establishment of the 100 ky cyclicity associated with the mid-Pleistocene transition. At the surface, this change consisted in the redistribution of water masses, with the subsequent thermal variation, and occurred linked to the northwestward migration of the Arctic Front (AF), and the increase in the North Atlantic Deep Water (NADW) formation with respect to previous glacials. During glacials prior to MIS16, the NADW formation was very weak, which drastically slowed down the surface circulation; the AF was at a southerly position and the North Atlantic Current (NAC) diverted southeastwards, developing steep south–north, and east–west, thermal gradients and blocking the arrival of warm water, with associated moisture, to high latitudes. During MIS16, the increase in the meridional overturning circulation, in combination with the northwestward AF shift, allowed the arrival of the NAC to subpolar latitudes, multiplying the moisture availability for ice-sheet growth, which could have worked as a positive feedback to prolong the glacials towards 100 ky cycles.

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“…A multi-tiered ichnofaunal assemblage resembling other deep-sea trace fossil communities was interpreted (Rodríguez-Tovar and Uchman, 2004aUchman, , 2004bUchman, , 2006, associated with relatively good life conditions for tracemakers: a general context of good bottom and pore-water oxygen conditions and organic matter availability, with only few localized dysaerobic intervals (Rodríguez-Tovar and . Moreover, variations in surface water productivity and food supply and in water column and interstitial water oxygen during Marine Isotope Stages and Terminations have been interpreted based on integrative analyses of trace fossil and foraminifer assemblages (Rodríguez-Tovar et al, 2015a, 2015b.…”

Section: Discussionmentioning

confidence: 99%

“…Ichnological assemblages from Late Quaternary sediments of the Iberian Margin located close to the studied Site U1385 have been related to paleoceanographic conditions and shortterm climatic changes, including the Younger Dryas, Heinrich events, and terminations, inducing variations in oxygen conditions and organic matter content (Baas et al, 1997(Baas et al, , 1998Löwemark and Werner, 2001;Löwemark et al, 2004). Recently, changes in ichnological assemblages (composition, diversity and abundance), and in foraminifer assemblages, were correlated to recent millennial-scale climatic events associated with Marine Isotope Stages and Terminations in the context of changes in paleoceanographic dynamics affecting water productivity, food supply, and water/pore oxygenation (Rodríguez-Tovar et al, 2015a, 2015b.…”

Section: Climatic Variability From the Pleistocene: The Record Of Ichmentioning

confidence: 99%

Stratigraphic variation in ichnofabrics at the “Shackleton Site” (IODP Site U1385) on the Iberian Margin: Paleoenvironmental implications

Dorador

Rodrı́guez-Tovar

2016

Marine Geology

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Response of macrobenthic and foraminifer communities to changes in deep-sea environmental conditions from Marine Isotope Stage (MIS) 12 to 11 at the “Shackleton Site”

Cited by 37 publications

References 64 publications

Exploring computed tomography in ichnological analysis of cores from modern marine sediments

Exploring computed tomography in ichnological analysis of cores from modern marine sediments

Change in the North Atlantic circulation associated with the mid-Pleistocene transition

Stratigraphic variation in ichnofabrics at the “Shackleton Site” (IODP Site U1385) on the Iberian Margin: Paleoenvironmental implications

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