Results 61 to 70 of about 771,265 (286)

A seismological study of the mantle beneath Iceland [PDF]

, 2000
Iceland has long been thought to be underlain by a thermal upwelling, or plume, rising from deep within the mantle. This study tests this hypothesis, by a) seeking evidence for a plume in the lower mantle in azimuth anomalies at the NORSAR array and b ...
Pritchard, Matthew James, Pritchard, M.J.   +1 more
core  

Apatite in Carbonatite Preserving Primary Magmatic, Post‐Magmatic Overgrowth, and Post India‐Asia Collision‐Related Hydrothermal Alteration: Evidenced From U–Pb Isotope and Trace Element Geochemistry

Geological Journal, EarlyView.
U–Pb isotope and trace element geochemistry of apatite from carbonatites of Peshawar Plain Alkaline Igneous Province, western Himalaya shows Permo‐Carboniferous magmatism, an additional magmatic pulse during Cretaceous, and post‐magmatic hydrothermal/metasomatism during Oligocene. ABSTRACT U–Pb isotope and trace element geochemistry of apatite combined
Mehboob ur Rashid, Hafiz U. Rehman, Hao‐Yang Lee, Sun‐Lin Chung, Kaushik Das, Kazumasa Aoki, Muhammad Jawad Zeb, Nasir Ahmad, Muhammad Hussain, Hiroshi Yamamoto   +9 more
wiley   +1 more source

Rethinking the chemical heterogeneity of the mantle

Eos, Transactions American Geophysical Union, 1997
Mantle‐derived magmas are among the best sources of information about the chemistry of the Earth's mantle. For the past two decades, geochemists have used ratios of certain trace elements and isotopes of these magmas, considered to be largely unaffected by crystal‐liquid separation, to argue that the mantle is compositionally heterogeneous.
Wendy A. Bohrson, Jon P. Davidson, John A. Wolff   +2 more
openaire   +1 more source

Noble gases in the Cameroon line and the He, Ne, and Ar isotopic compositions of high mu (HIMU) mantle [PDF]

, 1999
Ultramafic xenoliths, basaltic lavas, and CO2 gases from the Cameroon line volcanic chain provide the first characterization of combined He, Ne, and Ar isotopes in a high-time-integrated 238U/204Pb = μ (HIMU) magmatic system. Helium isotopic compositions
Alex N. Halliday, Barfod, Dan N., Dan N. Barfod, Halliday, AN, J. Godfrey Fitton, Barfod, D. N., Ballentine, Chris J., Fitton, J. G., Halliday, Alex, Barfod, DN, Fitton, J. Godfrey, Ballentine, C. J., Halliday, A. N., Chris J. Ballentine, Fitton, JG, Ballentine, CJ, Halliday, Alex N.   +16 more
core   +1 more source

Heterogeneous Exhumation Mechanisms in Neoproterozoic Collisional Metamorphism: P–T Constraints From Pelotas and Punta del Este Terranes, Southern Brazil and Uruguay

Geological Journal, EarlyView.
Petrography, thermobarometry, and pseudosection modelling reveal peak metamorphic conditions of 3–7.5 kbar and 520°C–800°C in Tonian‐Cryogenian orthogneisses of the Dom Feliciano Belt. Metamorphic field gradients of 27°C/km–39°C/km and variable exhumation mechanisms support correlation of these units as remnants of a Himalayan‐type Piratini Orogeny ...
Thaiane Niederauer‐Santos, Carla Cristine Porcher, Daniel Triboli Vieira, Edinei Koester, Diego Jaldín, Karina Luengo, Luisa Caon   +6 more
wiley   +1 more source

Highly Enriched and Heterogeneous Mantle Signals Recorded in Mantle Pyroxenite Veins

Geochemistry, Geophysics, Geosystems
The Earth's mantle is inherently heterogeneous, reflecting ongoing mantle depletion and crustal recycling driven by plate tectonics. Radiogenic isotopes in oceanic basalts are commonly used to characterize mantle reservoirs, but the full chemical ...
Zhen‐Yu Zhang, Chuan‐Zhou Liu, Yan Liang, Tong Liu, Chang Zhang, Bo‐Da Liu, Wen‐Bin Ji, Wei‐Qi Zhang, Ke Huang   +8 more
doaj   +1 more source

Ancient recycled lower crust in the mantle source of recent Italian magmatism

Nature Communications, 2019
Recycling of Earth’s crust through subduction and delamination contributes to mantle heterogeneity. Here, the authors measure coupled Sr-Nd-Pb isotope compositions of melt inclusions in Italian potassium-rich lavas, they suggest their results indicate a ...
Janne M. Koornneef, Igor Nikogosian, Manfred J. van Bergen, Pieter Z. Vroon, Gareth R. Davies   +4 more
doaj   +1 more source

Interaction of mantle dregs with convection: Lateral heterogeneity at the core‐mantle boundary [PDF]

Geophysical Research Letters, 1986
Preliminary numerical models indicate that chemically denser material (dregs) at the base of the mantle would have substantial lateral variations in thickness induced by convection of the overlying mantle, and might well form discontinuous aggregations below mantle upwellings.
Davies, Geoffrey F., Gurnis, Michael
openaire   +2 more sources

Human biomarker navigator

iMeta, EarlyView.
The Human Biomarker Navigator integrates the disease continuum, biomarker dynamics, cross‐organ biomarker networks, biomarker classification, and technology‐driven paradigms. It maps how biomarkers link multi‐system physiology and pathology across the nervous, respiratory, endocrine, circulatory, immune, digestive, urinary, reproductive, and ...
Meng‐Yao Li, Qian Zhang, Zijie Wang, Zeping Gui, Jing Liu, Jingda Li, Maojun Jiang, Zukang Chang, Qingqing Han, Bendong Yang, Tariq Saeed, Jun Li, Jinghan Jia, Chenghu Song, Tong Shao, Tianhuan Peng, Xueying Zhang, Pingping Guo, Jun Luo, Gangao Yang, Yuan Wan, Gokhan Zengin, Quan Yuan, Lingru Li, Xiaohui Fan, Yang Luo, Lvyun Zhu, Yanfei Zheng, Wenjun Mao, Wenlong Sun   +29 more
wiley   +1 more source

Density structure of Earth’s lowermost mantle from Stoneley mode splitting observations

Nature Communications, 2017
Large-low-shear-wave velocity provinces (LLSVPs) are present at the core–mantle boundary. Here, the authors show that splitting of Stoneley modes is probably due to a lower density of LLSVPs than the surrounding mantle because of the presence of post ...
Paula Koelemeijer, Arwen Deuss, Jeroen Ritsema   +2 more
doaj   +1 more source