Extraterrestrial Ni-rich spinel in upper Eocene sediments from Massignano, Italy

Pierrard, O.; Robin, Éric; Rocchia, R.; Montanari, A.

doi:10.1130/0091-7613(1998)026<0307:enrsiu>2.3.co;2

Cited by 55 publications

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“…(e.g. Montanari et al 1993;Wei 1995;Clymer et al 1996;Pierrard et al 1998). Therefore, the Late Eocene climatic deterioration may have resulted from impact-related cooling (Vonhof et al 2000).…”

Section: Syngenetic Volcanismmentioning

confidence: 99%

Paleoenvironmental changes across the Eocene-Oligocene boundary: insights from the Central-Carpathian Paleogene Basin

Soták¹

2010

Geologica Carpathica

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Abstract:The sedimentary sequence of the Central-Carpathian Paleogene Basin provides proxy records of climatic changes related to cooling events at the Eocene/Oligocene boundary (TEE). In this basin, climatic deterioration is inferred from the demise of the carbonate platform and oligotrophic benthic biota in the SBZ19 and from the last species of warm-water planktonic foraminifers in the E14 Zone. Upper Eocene formations already indicate warm-temperate to cool-temperate productivity and nutrient-enriched conditions (Bryozoan Marls, Globigerina Marls). Rapid cooling during the earliest Oligocene (Oi-1 event) led to a temperature drop (~11 °C), humidity, fresh water influx and continental runoff, water mass stratification, bottom water anoxia, eutrofication, estuarine circulation and upwelling, carbonate depletion, sapropelitic and biosiliceous deposition, H 2 S intoxication and mass faunal mortality, and also other characteristics of Black Sea-type basins. Tectonoeustatic events with the interference of TA 4.4 sea-level fall and the Pyrenean phase caused basin isolation at the beginning of the Paratethys. The Early Oligocene stage of Paratethyan isolation is indicated by a stagnant regime, low tide influence, endemic fauna development, widespread anoxia and precipitation of manganese deposits. The episodic rise in the sea-level, less humid conditions and renewed circulation is marked by calcareous productivity, nannoplankton blooms and the appearance of planktic pteropods and re-oxygenation. Paleogeographic differentiation of the CarpathoPannonian Paleogene basins resulted from plate-tectonic reorganization during the Alpine orogenesis.

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Section: Syngenetic Volcanismmentioning

confidence: 99%

Paleoenvironmental changes across the Eocene-Oligocene boundary: insights from the Central-Carpathian Paleogene Basin

Soták¹

2010

Geologica Carpathica

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“…1) indicates a global distribution of this ejecta layer, although the number of documented spherule occurrences is much less than for the K/T boundary. This second Late Eocene spherule layer includes melanocratic (dark) and leucocratic microkrystites, clear glass particles (microtektites) as well as shocked minerals (Clymer et al 1996;Langenhorst 1996), a platinum group element anomaly, and exotic Ni-rich spinel crystals (e.g., Pierrard et al 1998;Glass et al 2004b, and references therein). Compared to dark varieties at given silica content, the light-colored microtektites are enriched in CaO and MgO and depleted in Al 2 O 3 , FeO, TiO 2 , and the alkali elements.…”

Section: Late Eocene Impactsmentioning

confidence: 99%

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Deutsch

Koeberl

2006

Meteoritics &Amp; Planetary Science

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, which is in excellent agreement with previously published data for samples of the NAT strewn field. Target rocks with highly radiogenic Sr isotopic composition, as required for explaining the isotopic characteristics of Deep Sea Drilling Project (DSDP) site 612 tektites, were not among the analyzed sample suite. Based on the new isotope data, we exclude any relation between the NA tektites and the Popigai impact crater, although they have identical ages within 2σ errors. The Chesapeake Bay structure, however, is now clearly constrained as the source crater for the North American tektites, although the present data set obviously does not include all target lithologies that have contributed to the composition of the tektites.

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“…Langenhorst (1996) studied the shocked quartz associated with the Ir anomaly at Massignano and concluded that they were probably from the Popigai crater. Pancake-shaped spherules, containing and sometimes coated with Ni-rich spinel crystallites, were reported from this well-defined layer (Pierrard et al 1998). The pancake-shaped spherules are thought to be diagenetically altered cpx spherules (Glass et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Sr and Nd analyses of upper Eocene spherules and their implications for target rocks

Liu

Papanastassiou

Ngo

et al. 2006

Meteoritics &Amp; Planetary Science

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Extraterrestrial Ni-rich spinel in upper Eocene sediments from Massignano, Italy

Cited by 55 publications

References 0 publications

Paleoenvironmental changes across the Eocene-Oligocene boundary: insights from the Central-Carpathian Paleogene Basin

Paleoenvironmental changes across the Eocene-Oligocene boundary: insights from the Central-Carpathian Paleogene Basin

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Sr and Nd analyses of upper Eocene spherules and their implications for target rocks

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