Radiogenic isotopes for deciphering terrigenous input provenance in the western Mediterranean

Rodrigo-Gámiz, Marta; Martı́nez-Ruiz, Francisca; Chiaradia, Massimo; Jiménez-Espejo, Francisco Jose; Ariztegui, Daniel

doi:10.1016/j.chemgeo.2015.06.004

Cited by 18 publications

(21 citation statements)

References 121 publications

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“…Montagna, personal communication, 2016). This is in agreement with εNd results obtained by Jiménez-Espejo et al (2015) from planktonic foraminifera collected from deepwater sites (1989 and 2382 m) in the Alboran Sea (Fig. 4c).…”

Section: Hydrological Changes In the Alboran And Balearic Seas Since supporting

confidence: 82%

“…The Early Holocene is characterized by a collapse of the LIW (Kuhnt et al, 2008;Schmiedl et al, 2010;Toucanne et al, 2012) synchronous with the sapropel S1 deposition (10.2-6.4 cal ka BP; Mercone et al, 2000). Proxies for deep-water conditions reveal the occurrence of episodes of deep-water overturning reinforcement in the eastern Mediterranean basin at 8.2 ka BP (Rohling et al, 1997(Rohling et al, , 2015Kuhnt et al, 2007;Abu-Zied et al, 20082015), responsible for the interruption of the sapropel S1 in the eastern Mediterranean basin (Mercone et al, 2001;Rohling et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

et al. 2017

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Abstract. We present the neodymium isotopic composition (εNd) of mixed planktonic foraminifera species from a sediment core collected at 622 m water depth in the Balearic Sea, as well as εNd of scleractinian cold-water corals (CWC; Madrepora oculata, Lophelia pertusa) retrieved between 280 and 442 m water depth in the Alboran Sea and at 414 m depth in the southern Sardinian continental margin. The aim is to constrain hydrological variations at intermediate depths in the western Mediterranean Sea during the last 20 kyr. Planktonic (Globigerina bulloides) and benthic (Cibicidoides pachyderma) foraminifera from the Balearic Sea were also analyzed for stable oxygen (δ 18 O) and carbon (δ 13 C) isotopes. The foraminiferal and coral εNd values from the Balearic and Alboran seas are comparable over the last ∼ 13 kyr, with mean values of −8.94 ± 0.26 (1σ ; n = 24) and −8.91 ± 0.18 (1σ ; n = 25), respectively. Before 13 ka BP, the foraminiferal εNd values are slightly lower (−9.28 ± 0.15) and tend to reflect higher mixing between intermediate and deep waters, which are characterized by more unradiogenic εNd values. The slight εNd increase after 13 ka BP is associated with a decoupling in the benthic foraminiferal δ 13 C composition between intermediate and deeper depths, which started at ∼ 16 ka BP. This suggests an earlier stratification of the water masses and a subsequent reduced contribution of unradiogenic εNd from deep waters. The CWC from the Sardinia Channel show a much larger scatter of εNd values, from −8.66 ± 0.30 to −5.99 ± 0.50, and a lower average (−7.31 ± 0.73; n = 19) compared to the CWC and foraminifera from the Alboran and Balearic seas, indicative of intermediate waters sourced from the Levantine basin. At the time of sapropel S1 deposition (10.2 to 6.4 ka), the εNd values of the Sardinian CWC become more unradiogenic (−8.38 ± 0.47; n = 3 at ∼ 8.7 ka BP), suggesting a significant contribution of intermediate waters originated from the western basin. We propose that western Mediterranean intermediate waters replaced the Levantine Intermediate WaPublished by Copernicus Publications on behalf of the European Geosciences Union. ter (LIW), and thus there was a strong reduction of the LIW during the mid-sapropel (∼ 8.7 ka BP). This observation supports a notable change of Mediterranean circulation pattern centered on sapropel S1 that needs further investigation to be confirmed.

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Section: Hydrological Changes In the Alboran And Balearic Seas Since supporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

et al. 2017

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“…Despite these low LOI values hydrothermal alteration is likely to have mobilised some of the major elements and the large ion lithophile (LIL) elements (Ba, Rb, Sr, and K), as has been documented in numerous studies (e.g., Pearce, 1996;Polat and Hofmann, 2003). However, the high field-strength (HFS) elements such as Nb, Ta, Zr, Hf, Y and Th are generally regarded to be relatively immobile during low-temperature alteration (e.g., Pearce and Cann, 1973;Polat et al, 2002 Sr seawater (e.g., Kawahata et al, 2001;Godard et al, 2006), Nd and Pb radiogenic isotope ratios are relatively insensitive to alteration and are much more reliable indicators of magmatic sources (Rodrigo-Gámiz et al, 2015;Simon et al, 2017). We therefore use immobile trace elements along with Nd and Pb radiogenic isotope ratios as well as field observations and regional constraints in our assessment of the petrogenesis and tectonic setting of these rocks.…”

Section: Resultsmentioning

confidence: 99%

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Yang

Kerr

et al. 2018

Journal of Asian Earth Sciences

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A B S T R A C T The Carboniferous Bayingou ophiolitic mélange is exposed in the North Tianshan accretionary complex in the southwestern part of the Central Asian Orogenic Belt (CAOB). The mélange is mainly composed of serpentinised ultramafic rocks (including harzburgite, lherzolite, pyroxenite, dunite and peridotite), pillowed and massive basalts, layered gabbros, radiolarian cherts, pelagic limestones, breccias and tuffs, and displays blockin-matrix structures. The blocks of ultramafic rocks, gabbros, basalts, cherts, and limestones are set in a matrix of serpentinised ultramafic rocks, massive basalts and tuffs. The basaltic rocks in the mélange show significant geochemical heterogeneity, and two compositional groups, one ocean island basalt-like, and the other mid-ocean ridge-like, can be distinguished on the basis of their isotopic compositions and immobile trace element contents (such as light rare earth element enrichment in the former, but depletion in the latter). The more-enriched basaltic rocks are interpreted as remnants/fragments of seamounts, derived from a deep mantle reservoir with low degrees (2-3%) of garnet lherzolite mantle melting. The depleted basalts most likely formed by melting of a shallower spinel lherzolite mantle source with ∼15% partial melting. It is probable that both groups owe their origin to melting of a mixture between plume and depleted MORB mantle. The results from this study, when integrated with previous work, indicate that the Junggar Ocean crust (comprising a significant number of seamounts) was likely to have been subducted southward beneath the Yili-Central Tianshan block in the Late Devonian-Early Carboniferous. The seamounts were scraped-off and accreted along with the oceanic crust in an accretionary wedge to form the Bayingou ophiolitic mélange. We present a model for the tectonomagmatic evolution of this portion of the CAOB involving prolonged intra-oceanic subduction with seamount accretion

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“…The apparent lack of coherence in the U1386B/C signal between Sr isotope ratios and the composition of detrital continental or eolian components (Figs. 3C, 9B, C), with climate stages, must be explored further as a matter of process versus source (as in the Alboran Sea by Rodrigo-Gámiz et al, 2015). The glacial-MOW interglacial-AW model is nevertheless in agreement with what occurred over the last glacial-Holocene cycle (Lebreiro et al, submitted for publication).…”

Section: Past Variability Of the Early-pleistocene Mow Fossil Moat Inmentioning

confidence: 86%

“…Their findings do not indicate contrast between the last glacial-Holocene cycle. In the Alboran Sea, however, Rodrigo-Gámiz et al (2015) have reported a Pb shift in terrigenous eolian source from northern Africa and South Iberia and France during the LGM to more European during the Holocene.…”

Section: Introductionmentioning

confidence: 93%

Zooming into the Mediterranean outflow fossil moat during the 1.2–1.8millionyears period (Early-Pleistocene) — An approach by radiogenic and stable isotopes

Lebreiro

Antón

Reguera

et al. 2015

Global and Planetary Change

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Radiogenic isotopes for deciphering terrigenous input provenance in the western Mediterranean

Cited by 18 publications

References 121 publications

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Zooming into the Mediterranean outflow fossil moat during the 1.2–1.8millionyears period (Early-Pleistocene) — An approach by radiogenic and stable isotopes

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Radiogenic isotopes for deciphering terrigenous input provenance in the western Mediterranean

Cited by 18 publications

References 121 publications

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

Accreted seamounts in North Tianshan, NW China: Implications for the evolution of the Central Asian Orogenic Belt

Zooming into the Mediterranean outflow fossil moat during the 1.2–1.8millionyears period (Early-Pleistocene) — An approach by radiogenic and stable isotopes

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Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals