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  • Data  (7)
  • Ocean Drilling Program; ODP  (6)
  • Earthquake catalog
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  • Data  (7)
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  • 1
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    Sea surface temperature reconstruction for the Pliocene-Pleistocene climate transition (2010)
    PANGAEA
    In:  Supplement to: Etourneau, Johan; Schneider, Ralph R; Blanz, Thomas; Martinez, Philippe (2010): Intensification of the Walker and Hadley atmospheric circulations during the Pliocene-Pleistocene climate transition. Earth and Planetary Science Letters, 297(1-2), 103-110, https://doi.org/10.1016/j.epsl.2010.06.010
    Details
    Publication Date: 2024-01-09
    Description: When comparing new sea surface temperature (SST) records between the western and eastern equatorial Pacific spanning the last 3.2 Ma, we found that the zonal temperature gradient over the entire tropical Pacific irreversibly increased by 3 to 4 °C from 2.2 to 2.0 Ma. Here, we suggest a pronounced increase in atmospheric circulation from a weak to a strong zonal Walker circulation (WC) during the early Pleistocene. Evidence from other oceanic areas also suggests a strengthening in the meridional Hadley circulation (HC) during the same time period. Therefore, we also suggest that the invigoration of both atmospheric circulation patterns was intimately coupled during the Plio-Pleistocene transition, and likely linked to a shrinkage in the zonal extension of the tropical to subtropical warm-sphere associated with a prominent increase in the pole to equator temperature gradient. Our conclusion refutes assumptions that the intensification of atmospheric circulation in the tropics and subtropics significantly contributed to the initiation of continental ice sheet formation at high latitudes, since the onset of extensive Northern Hemisphere Glaciation (NHG) occurred ~2.75 Ma ago, in the late Pliocene. Instead, the development of a stronger atmospheric circulation ~2.2-2.0 Ma ago could have significantly contributed to the Plio-Pleistocene climate cooling.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 2
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    Log-ratio of silica to aluminium counts (ln(Si/Al)) from ODP site 108-658 (2013)
    PANGAEA
    In:  Supplement to: Meckler, Anna Nele; Sigman, Daniel M; Gibson, Kelly A; Francois, Roger; Martínez‐García, Alfredo; Jaccard, Samuel L; Röhl, Ursula; Peterson, Larry C; Tiedemann, Ralf; Haug, Gerald H (2013): Deglacial pulses of deep-ocean silicate into the subtropical North Atlantic Ocean. Nature, 495(7442), 495-498, https://doi.org/10.1038/nature12006
    Details
    Publication Date: 2024-01-09
    Description: Growing evidence suggests that the low atmospheric CO2 concentration of the ice ages resulted from enhanced storage of CO2 in the ocean interior, largely as a result of changes in the Southern Ocean1. Early in the most recent deglaciation, a reduction in North Atlantic overturning circulation seems to have driven CO2 release from the Southern Ocean**2, 3, 4, 5, but the mechanism connecting the North Atlantic and the Southern Ocean remains unclear. Biogenic opal export in the low-latitude ocean relies on silicate from the underlying thermocline, the concentration of which is affected by the circulation of the ocean interior. Here we report a record of biogenic opal export from a coastal upwelling system off the coast of northwest Africa that shows pronounced opal maxima during each glacial termination over the past 550,000 years. These opal peaks are consistent with a strong deglacial reduction in the formation of silicate-poor glacial North Atlantic intermediate water**2 (GNAIW). The loss of GNAIW allowed mixing with underlying silicate-rich deep water to increase the silicate supply to the surface ocean. An increase in westerly-wind-driven upwelling in the Southern Ocean in response to the North Atlantic change has been proposed to drive the deglacial rise in atmospheric CO2 (refs 3, 4). However, such a circulation change would have accelerated the formation of Antarctic intermediate water and sub-Antarctic mode water, which today have as little silicate as North Atlantic Deep Water and would have thus maintained low silicate concentrations in the Atlantic thermocline. The deglacial opal maxima reported here suggest an alternative mechanism for the deglacial CO2 release**5, 6. Just as the reduction in GNAIW led to upward silicate transport, it should also have allowed the downward mixing of warm, low-density surface water to reach into the deep ocean. The resulting decrease in the density of the deep Atlantic relative to the Southern Ocean surface promoted Antarctic overturning, which released CO2 to the atmosphere.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 4 datasets
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    DATA PANGAEA
  • 3
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    Stable isotope record and planktonic foraminiferal fragmentation of the late Pleistocene section of ODP Hole 134-828A (1994)
    PANGAEA
    In:  Supplement to: Martínez, José Ignacio (1994): Late Pleistocene dissolution cycles in the Vanuatu region, western Pacific Ocean. In: Green, HG; Collot, J-Y; Stokking, LB; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 134, 293-308, https://doi.org/10.2973/odp.proc.sr.134.012.1994
    Details
    Publication Date: 2024-01-09
    Description: A high-resolution record of foraminiferal fragmentation (a dissolution indicator) for the last 250 k.y. (isotopic Stages 1 to 7) is identified in the upper 61.9 m of Ocean Drilling Program (ODP) Hole 828A, west Vanuatu. This record is comparable in detail to the atmospheric CO2 record and the d18O stack. Phase shifts between preservation spikes and maximum ice volumes (d18O of Globigerinoides sacculifer) are analogous to those on Ontong Java Plateau. Mass spectrometer (AMS14C) dating of a sample taken at the base of dissolution cycle B1 and the position of the last glacial maximum indicates a lag in time of ~8 k.y. in the Vanuatu region for the last glacial termination. When dissolution spikes are compared with minimum ice volumes there is no phase shift for the last two glacial terminations. The difference between Vanuatu and Ontong Java Plateau may be explained by local CO2 sinks and the interplay between intermediate and deep water masses. Terrigenous input increasingly affected sediment of Hole 828A on the North d'Entrecasteaux Ridge (NDR) as it approached Espiritu Santo Island. Mud and silt suspended in mid-water flows become important after 125 ka, while turbidites bypass the New Hebrides Trench only towards the last glacial maximum (LGM). Terrigenous supply seems to affect the lysocline profile that changed from an "open ocean" to a "near continent" type, thus favoring dissolution. Fragmentation of planktonic foraminifers is a more sensitive indicator of lysocline variations than is foraminiferal susceptibility to dissolution, the foraminiferal dissolution index, the abundance of benthic foraminifers, or CaCO3 content. A modern foraminiferal lysocline for the neighboring area (between 10°S and 30°S, and 160°E and 180°E) is found at 3.1 km below sea level, compared to west Vanuatu where it is shallower. The past lysocline level was deeper than 3086 m during intervals of dissolution minima, and ranged from ~2550 to 3000 m during intervals of dissolution maxima. The high sedimentation rates (in the order of 10 to 50 cm/k.y.) found in Hole 828A offer a great potential for future high-resolution studies either in this hole or other western localities along the NDR. Areas of high sedimentation near continental regions have been discarded for paleoceanographic and/or paleoclimatic studies. Nonetheless, conditions analogous to those found in Hole 828A are expected to occur in many trench areas around the world where mid-water flows have preserved as yet undiscovered fine high-resolution sedimentary records.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 5 datasets
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    DATA PANGAEA
  • 4
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    Alkenone accumulation and SST reconstruction for the Benguela upwelling zone (2014)
    PANGAEA
    In:  Supplement to: Rosell-Melé, Antoni; Martínez‐García, Alfredo; McClymont, Erin L (2014): Persistent warmth across the Benguela upwelling system during the Pliocene epoch. Earth and Planetary Science Letters, 386, 10-20, https://doi.org/10.1016/j.epsl.2013.10.041
    Details
    Publication Date: 2024-01-09
    Description: A feature of Pliocene climate is the occurrence of "permanent El Niño-like" or "El Padre" conditions in the Pacific Ocean. From the analysis of sediment cores in the modern northern Benguela upwelling, we show that the mean oceanographic state off Southwest Africa during the warm Pliocene epoch was also analogous to that of a persistent Benguela "El Niño". At present these events occur when massive southward flows of warm and nutrient-poor waters extend along the coasts of Angola and Namibia, with dramatic effects on regional marine ecosystems and rainfall. We propose that the persistent warmth across the Pliocene in the Benguela upwelling ended synchronously with the narrowing of the Indonesian seaway, and the early intensification of the Northern Hemisphere Glaciations around 3.0-3.5 Ma. The emergence of obliquity-related cycles in the Benguela sea surface temperatures (SST) after 3 Ma highlights the development of strengthened links to high latitude orbital forcing. The subsequent evolution of the Benguela upwelling system was characterized by the progressive intensification of the meridional SST gradients, and the emergence of the 100 ky cycle, until the modern mean conditions were set at the end of the Mid Pleistocene transition, around 0.6 Ma. These findings support the notion that the interplay of changes in the depth of the global thermocline, atmospheric circulation and tectonics preconditioned the climate system for the end of the warm Pliocene epoch and the subsequent intensification of the ice ages.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 4 datasets
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    DATA PANGAEA
  • 5
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    TOC, TN, d15N isotopes and alkenone concentration in equatorial Pacific sediments (2013)
    PANGAEA
    In:  Supplement to: Etourneau, Johan; Robinson, Rebecca S; Martinez, Philippe; Schneider, Ralph R (2013): Equatorial Pacific peak in biological production regulated by nutrient and upwelling during the late Pliocene/early Pleistocene cooling. Biogeosciences, 10(8), 5663-5670, https://doi.org/10.5194/bg-10-5663-2013
    Details
    Publication Date: 2024-01-09
    Description: The largest increase in export production in the eastern Pacific of the last 5.3 Myr (million years) occurred between 2.2 and 1.6 Myr, a time of major climatic and oceanographic reorganization in the region. Here, we investigate the causes of this event using reconstructions of export production, nutrient supply and oceanic conditions across the Pliocene-Pleistocene in the eastern equatorial Pacific (EEP) for the last 3.2 Myr. Our results indicate that the export production peak corresponds to a cold interval marked by high nutrient supply relative to consumption, as revealed by the low bulk sedimentary 15N/14N (d15N) and alkenone-derived sea surface temperature (SST) values. This ~0.6 million year long episode of enhanced delivery of nutrients to the surface of the EEP was predominantly initiated through the upwelling of nutrient-enriched water sourced in high latitudes. In addition, this phenomenon was likely promoted by the regional intensification of upwelling in response to the development of intense Walker and Hadley atmospheric circulations. Increased nutrient consumption in the polar oceans and enhanced denitrification in the equatorial regions restrained nutrient supply and availability and terminated the high export production event.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 6
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    Mineralogy, geochemistry and selected chemical formulas of sediments from ODP Holes 161-986B and 161-977A (1999)
    PANGAEA
    In:  Supplement to: Martinez-Ruiz, Francisca C; Comas, Maria C; Alonso, Belen (1999): Mineral associations and geochemical indicators in upper Miocene to Pleistocene sediments in the Alboran Basin. In: Zahn, R; Comas, MC; Klaus, A (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 161, 1-16, https://doi.org/10.2973/odp.proc.sr.161.203.1999
    Details
    Publication Date: 2024-01-09
    Description: Upper Miocene to Pleistocene hemipelagites and resedimented facies recovered at Holes 976B and 977A (Leg 161) in the Alboran Basin consist mainly of biogenic and detrital components, with a minor contribution of neoformed mineral phases. Diagenetic processes have not obliterated the primary deposition signal, and therefore detrital components (quartz, feldspar, detrital dolomite, rock fragments, and clays) provide information about source rocks and provenances. No major bulk or clay mineralogy differences were recognized between resedimented and hemipelagic facies; in fact, similar mineral assemblages in both types of facies suggest common source rocks. However, mineral abundance fluctuations can be related to climate variations and tectonic factors, as the main controls of sediment fill of this basin. A marked increase in smectites in Messinian sediments suggests an extensive development of soils during that time, probably favored by the alternation of wet and dry climate episodes and the relative aridification of the Mediterranean borderlands. A notable increase in detrital components suggests a sea-level fall and/or tectonic uplift during the late Pliocene. The significant increase in detrital dolomite in the uppermost Pliocene deposits suggests the uplift of dolomite-rich rocks as source areas. Mineral components in Pleistocene sediments indicate increasing tectonic stability, and clay-mineral fluctuations during the Pleistocene can be related not only to tectonic events, but also to alternating cooling and warming periods.
    Keywords: Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 9 datasets
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  • 7
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    Seismicity catalog for the Armutlu Peninsula from 2019 derived using the SMARTnet temporary seismic network (2022)
    GFZ Data Services
    Details
    Publication Date: 2022-05-02
    Description: Abstract
    Description: The dataset presented here is an earthquake catalog for the central Sea of Marmara (Turkey) obtained by applying a traditional STA/LTA technique to the continuous waveforms. The magnitude of completeness of this catalog is MW = 1.4. The full description of the data processing and creation of the catalog is provided in the paper “Near - fault monitoring reveals combined seismic and slow activation of a fault branch within the Istanbul-Marmara seismic gap in NW Turkey” published by Martínez-Garzón et al., in Seismological Research Letters. The data are provided as the following two ASCII tables: The file 2021-004_Martinez-Garcon-et-al_Initial_seismicity_catalog contains the seismic events for which we could successfully calculate an earthquake location. The ASCII table has the following columns: columns: id, year, month, day, hour, minute, second, serial time, latitude, longitude, depth [km], magnitude, horizontal error [km], vertical error [km], RMS, maximum azimuthal gap [degree]. The table 2021-004_Martinez-Garcon-et-al_Relocated_seismicity_catalog contains the seismic events for which we could refine the initial location and obtain a double-difference refined location. The ASCII table has the following columns: id, latitude, longitude, depth [km], horizontal error [km], vertical error [km].
    Keywords: Earthquake catalog ; Marmara region ; near-fault monitoring ; SMARTnet ; GONAF ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOMORPHIC LANDFORMS/PROCESSES 〉 TECTONIC LANDFORMS 〉 FAULTS ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES 〉 EARTHQUAKE MAGNITUDE/INTENSITY
    Type: Dataset , Dataset
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