Late Miocene to Pleistocene sedimentation and sediment transport on the Cocos Ridge, eastern tropical Pacific Ocean

Liao, Yuantao; Lyle, Mitchell W

doi:10.1016/j.margeo.2014.05.007

Cited by 48 publications

(7 citation statements)

References 45 publications

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“…The highest shipboard LSR occurred in the late Miocene-early Pliocene , where LSR average 15.9 m Myr −1 (7.7-30.5 m Myr −1 ). The shipboard LSR for the Oligocene-early Miocene (30-17 Ma) and Plio-Pleistocene (5.3-0.0 Ma) were confirmed by previous studies on Sites 1264 and 1265, which also support the shipboard notion that these sites are excellent recorders of orbital-scale climate dynamics (Liebrand et al, 2011(Liebrand et al, , 2016(Liebrand et al, , 2017(Liebrand et al, , 2018Bell et al, 2014Bell et al, , 2015.…”

Section: Odp Sites 1264 and 1265supporting

confidence: 81%

Climate, cryosphere and carbon cycle controls on Southeast Atlantic orbital-scale carbonate deposition since the Oligocene (30–0 Ma)

et al. 2021

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Abstract. The evolution of the Cenozoic cryosphere from unipolar to bipolar over the past 30 million years (Myr) is broadly known. Highly resolved records of carbonate (CaCO3) content provide insight into the evolution of regional and global climate, cryosphere, and carbon cycle dynamics. Here, we generate the first Southeast Atlantic CaCO3 content record spanning the last 30 Myr, derived from X-ray fluorescence (XRF) ln(Ca / Fe) data collected at Ocean Drilling Program Site 1264 (Walvis Ridge, SE Atlantic Ocean). We present a comprehensive and continuous depth and age model for the entirety of Site 1264 (∼ 316 m; 30 Myr). This constitutes a key reference framework for future palaeoclimatic and palaeoceanographic studies at this location. We identify three phases with distinctly different orbital controls on Southeast Atlantic CaCO3 deposition, corresponding to major developments in climate, the cryosphere and the carbon cycle: (1) strong ∼ 110 kyr eccentricity pacing prevails during Oligocene–Miocene global warmth (∼ 30–13 Ma), (2) increased eccentricity-modulated precession pacing appears after the middle Miocene Climate Transition (mMCT) (∼ 14–8 Ma), and (3) pervasive obliquity pacing appears in the late Miocene (∼ 7.7–3.3 Ma) following greater importance of high-latitude processes, such as increased glacial activity and high-latitude cooling. The lowest CaCO3 content (92 %–94 %) occurs between 18.5 and 14.5 Ma, potentially reflecting dissolution caused by widespread early Miocene warmth and preceding Antarctic deglaciation across the Miocene Climatic Optimum (∼ 17–14.5 Ma) by 1.5 Myr. The emergence of precession pacing of CaCO3 deposition at Site 1264 after ∼ 14 Ma could signal a reorganisation of surface and/or deep-water circulation in this region following Antarctic reglaciation at the mMCT. The increased sensitivity to precession at Site 1264 between 14 and 13 Ma is associated with an increase in mass accumulation rates (MARs) and reflects increased regional CaCO3 productivity and/or recurrent influxes of cooler, less corrosive deep waters. The highest carbonate content (%CaCO3) and MARs indicate that the late Miocene–early Pliocene Biogenic Bloom (LMBB) occurs between ∼ 7.8 and 3.3 Ma at Site 1264; broadly contemporaneous with the LMBB in the equatorial Pacific Ocean. At Site 1264, the onset of the LMBB roughly coincides with appearance of strong obliquity pacing of %CaCO3, reflecting increased high-latitude forcing. The global expression of the LMBB may reflect increased nutrient input into the global ocean resulting from enhanced aeolian dust and/or glacial/chemical weathering fluxes, due to enhanced glacial activity and increased meridional temperature gradients. Regional variability in the timing and amplitude of the LMBB may be driven by regional differences in cooling, continental aridification and/or changes in ocean circulation in the late Miocene.

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Section: Odp Sites 1264 and 1265supporting

confidence: 81%

Climate, cryosphere and carbon cycle controls on Southeast Atlantic orbital-scale carbonate deposition since the Oligocene (30–0 Ma)

et al. 2021

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“…However, these observations contradict evidence for either oscillating dominant El Niño‐/La Niña‐like conditions during the late Miocene (Nathan & Leckie, ) or stable E‐W equatorial SST gradients for the last 12 Myr (Zhang et al, ). Further complicating understanding of the equatorial Pacific Ocean, is the globally recognized, but not globally synchronous Late Miocene Biogenic Bloom (LMBB), which occurred in both upwelling zones and oligotrophic regions between ~8.0 and 4.5 Ma, and may reflect increased surface ocean nutrient delivery via either increased upwelling of cool nutrient‐rich waters or increased continental runoff (Diester‐Haass et al, , , ; Grant & Dickens, ; Hermoyian & Owen, ; Liao & Lyle, ; Lyle & Baldauf, ; Herbert et al, ). However, a forcing mechanism of increased upwelling (Grant & Dickens, ) is difficult to reconcile with observations of eastern equatorial Pacific surface warmth and a deep E‐W thermocline across the equatorial Pacific Ocean (LaRiviere et al, ).…”

Section: Introductionmentioning

confidence: 99%

Deciphering the State of the Late Miocene to Early Pliocene Equatorial Pacific

Drury

Lee

Gray

et al. 2018

Paleoceanog and Paleoclimatol

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The late Miocene‐early Pliocene was a time of global cooling and the development of modern meridional thermal gradients. Equatorial Pacific sea surface conditions potentially played an important role in this global climate transition, but their evolution is poorly understood. Here we present the first continuous late Miocene‐early Pliocene (8.0–4.4 Ma) planktic foraminiferal stable isotope records from eastern equatorial Pacific Integrated Ocean Drilling Program Site U1338, with a new astrochronology spanning 8.0–3.5 Ma. Mg/Ca analyses on surface dwelling foraminifera Trilobatus sacculifer from carefully selected samples suggest that mean sea surface temperatures (SSTs) are ~27.8 ± 1.1°C (1σ) between 6.4 and 5.5 Ma. The planktic foraminiferal δ18O record implies a 2°C cooling between 7.2 and 6.1 Ma and an up to 3°C warming between 6.1 and 4.4 Ma, consistent with observed tropical alkenone paleo‐SSTs. Diverging fine‐fraction‐to‐foraminiferal δ13C gradients likely suggest increased upwelling between 7.1–6.0 and 5.8–4.6 Ma, concurrent with the globally recognized late Miocene Biogenic Bloom. This study shows that both warm and asymmetric mean states occurred in the equatorial Pacific during the late Miocene‐early Pliocene. Between 8.0–6.5 and 5.2–4.4 Ma, low east‐west δ18O and SST gradients and generally warm conditions prevailed. However, an asymmetric mean climate state developed between 6.5 and 5.7 Ma, with larger east‐west δ18O and SST gradients and eastern equatorial Pacific cooling. The asymmetric mean state suggests stronger trade winds developed, driven by increased meridional thermal gradients associated with global cooling and declining atmospheric pCO2 concentrations. These oscillations in equatorial Pacific mean state are reinforced by Antarctic cryosphere expansion and related changes in oceanic gateways (e.g., Central American Seaway/Indonesian Throughflow restriction).

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“…Hypothetically, if relative sediment focusing at both sites remained constant, the gradient in CaCO 3 MAR should extrapolate to zero CaCO 3 flux at the CCD. Relative sediment focusing over long time frames in the pelagic regime appears reasonably constant (Liao and Lyle, 2014;Mitchell and Huthnance, 2013), and current-5 related anomalies can be discerned from the seismic profiles from site surveys. Sites chosen for drilling were chosen for the lack of anomalous seismic character in both ODP Leg 138 and IODP Exp 320/321.…”

Section: Changes In Depth Dependent Dissolution: Eastern Equatorial Pmentioning

confidence: 87%

Late Miocene to Recent High Resolution Eastern Equatorial Pacific Carbonate Records: Stratigraphy linked by dissolution and paleoproductivity

Lyle¹,

Drury²,

Tian³

et al. 2018

Preprint

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Abstract. We report late Miocene-Recent time series of XRF-derived bulk sediment composition and mass accumulation rates (MAR) from IODP Sites U1335, U1337, U1338 and ODP Site 849, and also report bulk density-derived CaCO3 MAR at Sites 848, 850 and 851. We use physical properties and images to intercorrelate all records for the last 8 Myr with resolutions of 1–2 kyr. Large magnitude changes in CaCO3 and opal MAR occurred within that time period but clay deposition has remained relatively constant. Ratios of CaCO3 % or SiO2 % to clay can be used to emulate biogenic MAR. We define 5 major Plio-Pleistocene Low CaCO3 % (PPLC) intervals since 5.3 Ma. Two were caused primarily by high opal burial that diluted CaCO3 (PPLC-2—1685-2135 ka, and PPLC-5—4465-4737 ka), while 3 were caused by enhanced dissolution of CaCO3 (PPLC-1—51-402 ka, PPLC-3—2248-2684 ka, and PPLC-4—2915-4093 ka). Regional patterns of CaCO3 % minima can distinguish between lows caused by high diatom production versus lows caused by dissolution. High diatom production causes lowest CaCO3 % at equatorial locations, while higher dissolution causes lowest CaCO3 at higher latitudes. The dissolution interval PPLC-4 occurs as the Central American Seaway closed and during a long decline from extreme positive Atlantic-Pacific carbon isotope gradients indicating an abyssal Pacific buildup of uncompensated DIC in the early Pliocene. The two major post-Miocene production intervals, PPLC-2 and PPLC-5, have different geographic footprints because of regional changes in eastern Pacific nutrient storage after the closure of the Panama Seaway.

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Late Miocene to Pleistocene sedimentation and sediment transport on the Cocos Ridge, eastern tropical Pacific Ocean

Cited by 48 publications

References 45 publications

Climate, cryosphere and carbon cycle controls on Southeast Atlantic orbital-scale carbonate deposition since the Oligocene (30–0 Ma)

Climate, cryosphere and carbon cycle controls on Southeast Atlantic orbital-scale carbonate deposition since the Oligocene (30–0 Ma)

Deciphering the State of the Late Miocene to Early Pliocene Equatorial Pacific

Late Miocene to Recent High Resolution Eastern Equatorial Pacific Carbonate Records: Stratigraphy linked by dissolution and paleoproductivity

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