Species-specific responses of late Miocene Discoaster spp. to enhanced biosilica productivity conditions in the equatorial Pacific and the Mediterranean

Backman, Jan; Raffi, Isabella; Ciummelli, Marina; Baldauf, J.G.

doi:10.1007/s00367-013-0328-0

Cited by 11 publications

(19 citation statements)

References 26 publications

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“…Here we note that coccoliths are less susceptible to carbonate diagenesis than planktic or BF (Blaj et al, ; McIntyre & McIntyre, ; Steinmetz & Anderson, ), and the studied interval consists of “ooze” as opposed to chalk or limestone. Limited recrystallization of coccolith calcite within upper Neogene and Quaternary sediment also has been documented at other locations across the EEP (Backman et al, ; Flores et al, ; Pälike et al, ; Pälike et al, ; Reghellin et al, ).…”

Section: Discussionmentioning

confidence: 63%

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Understanding Bulk Sediment Stable Isotope Records in the Eastern Equatorial Pacific, From Seven Million Years Ago to Present Day

Reghellin

Dickens

Coxall

et al. 2020

Paleoceanog and Paleoclimatol

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Stable isotope (δ13C and δ18O) records of bulk marine sediment carry information on past carbon cycling and oceanography, but origins and interpretations remain uncertain because such signals represent mixtures of different biogenic components, each with potential offsets from primary parameters. Studies of Neogene sediment from the eastern equatorial Pacific (EEP) exemplify this issue, because stable isotope records of bulk sediment and foraminifera at different sites exhibit similarities and differences in absolute value that somehow relate to depositional age. Here we measure δ13C and δ18O of bulk carbonate, two fine‐grained fractions (<63 and <20 μm), mixed‐species planktic and benthic foraminifera, and foraminifera fragments from sediments deposited over four time intervals within the last 7 Ma at ODP Site 851. These data are compared to published δ13C and δ18O records of multiple single‐species planktic foraminifera from the same site and benthic foraminifera from an adjacent site. Bulk sediment δ13C and δ18O records represent a mixed signal dominated by reticulofenestrid coccolith calcite but modified by variable amounts of different foraminifera. Similarities and differences between stable isotope records result from temporal changes in water chemistry and temperature, depths of calcite precipitation, and vital effects that impact fractionation of various biogenic components. The remarkable correlation of bulk stable isotope records within the EEP suggests that several factors change collectively over time across a broad oceanographic region. Ideally, multiple stable isotope records coupled with other proxy measurements might lead to an internally consistent paleoceanographic perspective of the EEP since the late Miocene.

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Section: Discussionmentioning

confidence: 63%

“…Certainly, numerous high values exist during Int1 (0–0.56 Ma) and numerous high and low values exist during Int 4 (6.40–6.80 Ma). Most low CaCO 3 content values relate to high biosilica (mainly diatom) abundance (Backman et al, ; Farrell et al, ; Lyle & Baldauf, ).…”

Section: Resultsmentioning

confidence: 99%

Understanding Bulk Sediment Stable Isotope Records in the Eastern Equatorial Pacific, From Seven Million Years Ago to Present Day

Reghellin

Dickens

Coxall

et al. 2020

Paleoceanog and Paleoclimatol

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“…The late Miocene average linear sedimentation rate at Site U1338 has been estimated from biomagnetostratigraphic at 2.2 cm/kyr [ Pälike et al ., ]. Here we focus on the 171.92–180.82 m interval (Core 1338C‐20H), falling between the top of Thalssiosira burckliana (161.17 m; 7.84 Ma) [ Backman et al ., ] and the Chron C4An/C4Ar.1r boundary (189.39 m; 9.098 Ma) [ Pälike et al ., ]. During this interval, the available age diagnostic data (calcareous nannofossil, diatom, radiolaria, and magnetostratigraphic) [ Pälike et al ., ] do not perfectly fit the long‐term age model.…”

Section: Methodsmentioning

confidence: 99%

Paleoenvironmental conditions for the development of calcareous nannofossil acme during the late Miocene in the eastern equatorial Pacific

et al. 2014

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Repeated monospecific coccolithophore dominance intervals (acmes) of specimens belonging to the Noelaerhabdaceae family-including the genus Reticulofenestra and modern descendants Emiliania and Gephyrocapsa-occurred during the Neogene. Such acme was recognized during the late Miocene (~8.6 Ma), at a time of a major reorganization of nannofossil assemblages resulting in a worldwide temporary disappearance of larger forms of the genus Reticulofenestra (R. pseudoumbilicus) and the gradual recovery and dominance of its smaller forms (< 5 μm). In this study we present a multiproxy investigation of late Miocene sediments from the east equatorial Pacific Integrated Ocean Drilling Program Site U1338 where small reticulofenestrid-type placoliths with a closed central area-known as small Dictyococcites spp. (< 3 μm)-formed an acme. We report on oxygen and carbon stable isotope records of multispecies planktic calcite and alkenone-derived sea surface temperature. Our data indicate that, during this 100 kyr long acme, the east equatorial Pacific thermocline remained deep and stable. Local surface stratification state fails to explain this acme and thus contradicts the model-based hypothesis of a Southern Ocean high-latitude nutrient control of the surface waters in the east equatorial Pacific. Instead, our findings suggest that external forcing such as an extended period of low eccentricity may have created favorable conditions for the small Dictyococcites spp. growth.

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“…Many individual biohorizons and magnetostratigraphic chron boundaries have been determined from two or all three Site U1338 holes (see the "Site U1338" chapter [Expedition 320/321 Scientists, 2010b]; Baldauf, 2013; Ciummelli, 2013;Backman et al, 2013). It is difficult to determine which hole provides the true or most accurate depth information for individual age-depth indicators.…”

Section: Resultsmentioning

confidence: 99%

“…Ciummelli (2013) provided additional higher resolution calcareous nannofossil biostratigraphic data for the late middle through earliest Pliocene interval that were partly published by Backman et al (2013). Baldauf (2013) provided higher resolution diatom biostratigraphic data.…”

Section: Methodsmentioning

confidence: 99%

Data report: a revised biomagnetostratigraphic age model for Site U1338, IODP Expedition 320/321

Backman¹,

Baldauf²,

Ciummelli³

et al. 2016

Proceedings of the IODP

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The development of late middle Miocene through recent sedimentation rates was determined for Integrated Ocean Drilling Program Site U1338 in the eastern equatorial Pacific using available geomagnetic chron boundaries and biostratigraphic biohorizons provided by calcareous nannofossils and diatoms. These data were set in a revised depth splice of the three holes at Site U1338 and provide a lower resolution image of the sedimentation rate history in the region of Site U1338 through relatively long linear interpolations between 11 chosen age-depth control points encompassing 18 My. The resulting sedimentation rates depict the movement of Site U1338 from just south of the Equator with modest sedimentation rates starting at 11 m/My to tripling of these rates near 13 Ma, when the site moved onto the Equator and into the equatorial high-productivity belt. High sedimentation rates continued into the earliest Pliocene (5 Ma) except for a 50% decrease during the so-called "carbonate crash" centered around 9.6 Ma ± 0.4 My. The site's movement north, away from the equatorial high-productivity belt, began between 5.0 and 4.2 Ma, when the site was located ~75-90 nmi north of the Equator, and resulted in a series of successively decreasing sedimentation rates to the present rate of 11 m/My, identical to the rate when sedimentation began at Site U1338 at nearly 18 Ma, when the site was located ~100 nmi south of the Equator.

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Species-specific responses of late Miocene Discoaster spp. to enhanced biosilica productivity conditions in the equatorial Pacific and the Mediterranean

Cited by 11 publications

References 26 publications

Understanding Bulk Sediment Stable Isotope Records in the Eastern Equatorial Pacific, From Seven Million Years Ago to Present Day

Understanding Bulk Sediment Stable Isotope Records in the Eastern Equatorial Pacific, From Seven Million Years Ago to Present Day

Paleoenvironmental conditions for the development of calcareous nannofossil acme during the late Miocene in the eastern equatorial Pacific

Data report: a revised biomagnetostratigraphic age model for Site U1338, IODP Expedition 320/321

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