Highly siderophile element and Os isotope systematics of the Cenozoic volcanic rocks from the Eastern Pontides, NE Turkey: Constraints on the origin and evolution of subcontinental mantle-derived magmas

Fine- to medium-grained, phyric and aphyric basalt samples from ODP Leg 105, site 647A, in the Labrador Sea show little evidence of alteration. Chemically, these rocks are low-potassium (0.01–0.09 wt.% K2O), olivine- to quartz-normative tholeiites that compare closely with the very depleted terrestrial Paleocene volcanic rocks in the Davis Strait region of Baffin Island and West Greenland. However, differences exist in the Sr–Nd isotope systematics of the two suites; the Labrador Sea samples have ε Nd values (+9.3) indicative of a more depleted source, and are higher in 87Sr/86Sr (0.7040), relative to the Davis Strait basalts (ε Nd +2.54 to +8.97; mean 87Sr/86Sr 0.7034). The higher 87Sr/86Sr in the Labrador Sea samples may reflect seawater exchange despite no petrographic evidence for significant alteration. The Labrador Sea and early Davis Strait basalts may have been derived from a similar depleted mantle source composition; however, the later Davis Strait magmas were generated from a different mantle. None of the Baffin Island, West Greenland, or Labrador Sea samples show unequivocal geochemical evidence for contamination with continental crust.

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Re-Os isotope systematics in black shales from the Lesser Himalaya: their chronology and role in the 187Os/188Os evolution of seawater

Geochimica et Cosmochimica Acta ◽

10.1016/s0016-7037(99)00201-x ◽

1999 ◽

Vol 63 (16) ◽

pp. 2381-2392 ◽

Cited By ~ 68

Author(s):

Sunil K. Singh ◽

J.R. Trivedi ◽

S. Krishnaswami

Keyword(s):

Black Shales ◽

Lesser Himalaya ◽

Isotope Systematics ◽

Os Isotope

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Coexistence of abyssal and ultra-depleted SSZ type mantle peridotites in a Neo-Tethyan Ophiolite in SW Turkey: Constraints from mineral composition, whole-rock geochemistry (major–trace–REE–PGE), and Re–Os isotope systematics

Lithos ◽

10.1016/j.lithos.2011.11.009 ◽

2012 ◽

Vol 132-133 ◽

pp. 50-69 ◽

Cited By ~ 100

Author(s):

İbrahim Uysal ◽

E. Yalçın Ersoy ◽

Orhan Karslı ◽

Yildirim Dilek ◽

M. Burhan Sadıklar ◽

...

Keyword(s):

Mineral Composition ◽

Sw Turkey ◽

Mantle Peridotites ◽

Isotope Systematics ◽

Os Isotope

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A hydro-thermo-haline numerical approach of the groundwater flow to explain the extreme Li-enrichment in the Salar de Atacama (NE Chile)

10.5194/egusphere-egu2020-9524 ◽

2020 ◽

Author(s):

Miguel Angel Marazuela ◽

Carlos Ayora ◽

Enric Vázquez Suñé ◽

Sebastià Olivella Pastallé ◽

Alejandro García Gil

Keyword(s):

Land Surface ◽

Volcanic Rocks ◽

Numerical Approach ◽

Origin And Evolution ◽

Rare Elements ◽

Salt Flat ◽

Major Cations ◽

Salt Flats ◽

Strong Evaporation ◽

Hydrogeological Systems

Salt flats (salars) are endorheic hydrogeological systems associated with arid to hyperarid climates. The brines of salt flats account the 80 % of the world&#8217;s reserves of Li highly demanded by modern industry. About 40 % of the worldwide Li is extracted from the brine that fills the pores and cavities of the Salar de Atacama. However, the origin of the extreme Li-enrichment of these brines is still unknown.The thick accumulation of salts and brines in salt flats results from the groundwater discharge (phreatic evaporation) near the land surface for thousands to millions of years. The strong evaporation contributes the enrichment in major cations and anions as well as other rare elements (e.g. Li, B, Ba, Sr, Br, I and F) which are very attractive for mining exploitation. However, only evaporation cannot explain by itself the extreme concentrations of some of these elements and the strong decoupling between the most evaporated brines and the most Li-enriched brines in the Salar de Atacama. Several hypotheses have been proposed to explain the extreme Li-enrichment of the salt flat brines: (a) concentrated brines leaking down from salt flats located in the Andean Plateau, (b) leaching of hypothetical ancient salt flats buried among volcanic rocks, and (c) rising of hydrothermal brines from deep reservoirs through faults. However, none of them has been able probed neither validated by a numerical model till the date.The objective of this work is to discuss the feasibility of the different hypotheses proposed until now to explain the formation of the world's largest lithium reserve. To achieve this objective, two sets of numerical simulations of a 2D vertical cross-section of the entire Salar de Atacama basin are carried out to define (1) the origin and evolution of a salt flat and how climate cycles can affect the location of the most Li-concentrated brines by evaporation and (2) the establishment of the hydro-thermo-haline circulation of a mature salt flat basin.

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