نتایج جستجو برای: ایزوتوپهای nd sr
تعداد نتایج: 58174 فیلتر نتایج به سال:
Lavas from Afanasy-Nikitin Rise, possibly the Late Cretaceous product of the Crozet hotspot, cover a wide range of isotopic compositions that includes the lowest (Pb/Pb)t (to 16.77) and «Nd(t) (to 28) values yet found among oceanic islands or spreading centers worldwide, as well as high (Sr/Sr)t (to 0.7066). In contrast, young basalts from the Crozet Archipelago exhibit a narrow range of variat...
Plio–Pleistocene (3.4–0.125 Ma) post-plateau magmatism in the Meseta del Lago Buenos Aires (MLBA; 46.7jS) in southern Patagonia is linked with the formation of asthenospheric slab windows due to ridge collision along the Andean margin f 6 Ma ago. MLBA post-plateau lavas are highly alkaline (43–49% SiO2; 5–8% Na2O+K2O), relatively primitive (6–10% MgO) mafic volcanics that have strong OIB-like g...
Continental flood basalts and mid-ocean ridge (MOR) tholeiitic basalts have distinctly different 14 3 Ndf1 44 Nd which may permit a priori distinctwn between '"continental" and "oceanic" igneous rocks. Initial 14 3 NdJI 4 4 Nd of continental igneous rocks through time fall on a Sm/Nd evolution curve with chondritic REE abundance ratio. These observations indicate that many continental igneous r...
This article reports new geochemical, Sr-Nd-Hf-Pb and Re-Os data on the rocks of Middle Paleoproterozoic (1.99 Ga) Tiksheozero ultramafic-alkaline-carbonatite complex confined to northeastern margin Karelian Craton. We focus poorly studied silicate rocks. Based petrographic geochemical research, are subdivided into two groups: an ultramafic-mafic series depleted in REE, other incompatible eleme...
Abstract The chemical composition of the wood reflects soil over which corresponding tree has developed. Multi-elemental and isotopic signatures, are characteristic underlying rock substrates, potentially powerful tools for determining provenance. These tracers special interest charred archaeological because they circumvent some limitations dendrochronological provenancing linked to tree-ring l...
The discovery of superconductivity in Nd${}_{1\ensuremath{-}x}$Sr${}_{x}$NiO${}_{2}$ has resulted a flurry experimental and theoretical work to understand the nature nickelate as compared that cuprates pnictides. Here, authors use combination LDA+U linear-response methods study magnetic exchange interactions Nd${}_{1\ensuremath{-}x}$Sr${}_{x}$NiO${}_{2}$. analysis reveals an underlying Mott ins...
The Pirrit Hills are located in the Ellsworth–Whitmore Mountains of West Antarctica. granite exhibits significant negative Eu anomalies (Eu/Eu* = 0.01~0.25) and a REE tetrad effect indicating intensive magmatic differentiation. Whole-rock Rb-Sr Sm-Nd geochronologic analysis gave respective ages 172.8 ± 2.4 Ma with initial 87Sr/86Sr 0.7065 0.0087 169 12 144Nd/143Nd 0.512207 0.000017. isotopic ra...
Haleakala volcano on East Maui, Hawaii, consists of a tholeiitic basalt shield which grades into a younger alkalic series that was followed by a post-erosional alkalic series. Fresh, stratigraphically controlled samples from the three volcanic series were analyzed for major element abundances, Sr and Nd isotopic ratios and trace element (K, Rb, Sr, Ba, Th, Ta, Nb, REE, Hf, Zr, Sc, V, Cr, Co, Ni...
A new numerical technique is proposed to study the stochastic resonance (SR) phenomenon. The proposed numerical approach allows to nd characteristics of SR faster than the previous ones. The signal-to-noise ratio and phase shifts for a system of noisy coupled oscillators are simulated. The spatiotemporal synchronization is shown by means of trajectory analysis.
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید