Remobilisation of the continental lithosphere by a mantle plume: major-, trace-element, and Sr-, Nd-, and Pb-isotope evidence from picritic and tholeiitic lavas of the Noril'sk District, Siberian Trap, Russia

1993 ◽  
Vol 114 (2) ◽  
pp. 171-188 ◽  
Author(s):  
P. C. Lightfoot ◽  
C. J. Hawkesworth ◽  
J. Hergt ◽  
A. J. Naldrett ◽  
N. S. Gorbachev ◽  
...  
Keyword(s):  
Trace Element ◽  
Mantle Plume ◽  
Continental Lithosphere ◽  
Pb Isotope ◽  
Siberian Trap ◽  
Isotope Evidence

scholarly journals Trace-Element and Pb Isotope Evidence on Extracting Sulfides from Potassic Melts beneath Longmenshan and Molabushan Volcanoes, Wudalianchi, Northeast China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 319 ◽  
Author(s):  
Sergei Rasskazov ◽  
Yi-Min Sun ◽  
Irina Chuvashova ◽  
Tatyana Yasnygina ◽  
Chen Yang ◽  
...  
Keyword(s):  
Trace Element ◽  
Volcanic Rocks ◽  
Volcanic Field ◽  
Lava Flows ◽  
Pb Isotope ◽  
Linear Pattern ◽  
Wide Range ◽  
Mantle Sources ◽  
Isotope Evidence ◽  
Isotope Study

In the Wudalianchi volcanic field, eruptions started with low-Mg potassic lava flows 2.5–2.0 Ma ago and later changed to both low- and moderate-Mg potassic compositions. Volcanic rocks from the Molabushan and Longmenshan volcanoes record an unusually wide range of Pb abundances (from 3.7 ppm to 21 ppm relative to predominant range of 10–15 ppm). To determine the cause of these, we performed a comparative trace-element and Pb isotope study of rocks from these volcanoes and older lava flows. On a uranogenic lead diagram, older low-Mg lavas from lithospheric mantle sources plot on a secondary isochron with a slope corresponding to an age of 1.88 Ga. This contrasts with moderate-Mg volcanic rocks from the Molabushan cone, interpreted to have been derived from a recent convective mantle source, which define a flat linear pattern. Low-Mg rocks from the Molabushan flow have lead isotopic compositions that indicate mixed Gelaqiu and Molabu sources. Relative to rocks from the Molabushan cone, moderate-Mg lavas and slags from the East Longmenshan volcano have modified compositions characterized by Pb, S, and Ni abundances, Ni/Co, Ni/MgO ratios as well as 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb, Ce/Pb, Th/Pb, and U/Pb ratios. We infer that the older Wudalianchi magmas were likely derived from a Paleoproterozoic lithospheric fragment, related to the evolved primordial mantle, and that later magmas were generated in the convecting mantle. These were influenced by segregation of small amounts of sulfides.

scholarly journals The trace element and Sr-Nd-Pb isotope geochemistry of Juan Fernandez lavas reveal variable contributions from a high-3He/4He mantle plume

2018 ◽  
Vol 476 ◽  
pp. 280-291 ◽  
Author(s):  
Thi B. Truong ◽  
Paterno R. Castillo ◽  
David R. Hilton ◽  
James M.D. Day
Keyword(s):  
Trace Element ◽  
Mantle Plume ◽  
Isotope Geochemistry ◽  
Pb Isotope

scholarly journals Major and Trace Element and Sr, Nd, Hf, and Pb Isotope Compositions of the Karoo Large Igneous Province, Botswana–Zimbabwe: Lithosphere vs Mantle Plume Contribution

2007 ◽  
Vol 48 (6) ◽  
pp. 1043-1077 ◽  
Author(s):  
F. Jourdan ◽  
H. Bertrand ◽  
U. Schärer ◽  
J. Blichert-Toft ◽  
G. Féraud ◽  
...  
Keyword(s):  
Trace Element ◽  
Mantle Plume ◽  
Large Igneous Province ◽  
Pb Isotope ◽  
Igneous Province

Trace element and Pb isotopic constraints on the provenance of the Rosroe and Derryveeny formations, South Mayo, Ireland

2002 ◽  
Vol 93 (2) ◽  
pp. 101-110 ◽  
Author(s):  
Peter D. Clift ◽  
Amy E. Draut ◽  
Robyn Hannigan ◽  
Graham Layne ◽  
Jerzy Blusztajn
Keyword(s):  
Trace Element ◽  
Limited Range ◽  
Ion Microprobe ◽  
Pb Isotope ◽  
Metamorphic Belt ◽  
Volcanic Arc ◽  
Trace Element Chemistry ◽  
Lower Ordovician ◽  
Western Ireland ◽  
Laurentian Margin

The Rosroe Formation comprises a series of Lower Ordovician (Llanvirn) conglomerates and sandstones, that lies on the southern limb of the South Mayo Trough, within the Iapetus Suture Zone of western Ireland. Trace element chemistry of granite boulders within the formation indicates a continental, rather than a volcanic arc character that can be correlated to latest Precambrian granites within the Dalradian Metamorphic Block, part of the deformed Laurentian margin. A minority of the clasts may correlate with syn-collisional granites, similar to, but older than, the Oughterard Granite of Connemara. Pb isotope compositions of K-feldspar grains within the sandstones, measured by both ion microprobe and conventional mass spectrometry, show a clear Laurentian affinity, albeit with greater source variability in the sand grains compared to a limited range in the proximal boulders. Palaeo-current indicators demonstrate dominant derivation from the NE, with a significant axial E–W flow. We propose that the Rosroe Formation records unroofing of a rapidly exhuming Dalradian metamorphic belt in North Mayo, following extensional collapse of the Grampian Orogen starting at ˜468 Ma, with minor input from a southerly arc source. The lack of metamorphic input from the S until deposition of the Derryeeny Conglomerate argues that the Connemara terrane was not positioned S of South Mayo Trough through strike-slip faulting until after the end of Rosroe sedimentation (460–443 Ma).

scholarly journals Supplemental Material: Petrogenesis of Ordovician granitoids in Western Kunlun, NW Tibetan Plateau: Insights into the evolution of the Proto-Tethys Ocean

2020 ◽  
Author(s):  
Peng Wang ◽  
Guochun Zhao ◽  
et al.
Keyword(s):  
Tibetan Plateau ◽  
Trace Element ◽  
Partition Coefficients ◽  
Hf Isotope ◽  
Igneous Rocks ◽  
Pb Isotope ◽  
Element Modeling ◽  
Western Kunlun ◽  
Tethys Ocean ◽  
Ordovician Granitoids

Table S1: Zircon U-Pb ages of igneous rocks in the Western Kunlun orogenic belt; Table S2: Results of whole-rock major- (wt%) and trace-element (ppm) data from the three intrusions; Table S3: Zircon U-Pb age of the three intrusions; Table S4: Zircon Hf isotope compositions of the three intrusions; Table S5: Whole-rock Sr-Nd-Pb isotope compositions of the three intrusions; Table S6: Representative analyses of feldspar, amphibole, and pyroxene from the Aqiang and Yutian intrusions; Table S7: Bulk partition coefficients used for trace-element modeling in Figure 14; Figure S1: CL images of zircons showing internal textures and ages of 206Pb/238U (Ma).

scholarly journals Causes and consequences of asymmetric lateral plume flow during South Atlantic rifting

2020 ◽  
Vol 117 (45) ◽  
pp. 27877-27883
Author(s):  
Jason P. Morgan ◽  
Jorge M. Taramón ◽  
Mario Araujo ◽  
Jörg Hasenclever ◽  
Marta Perez-Gussinye
Keyword(s):  
Mantle Plume ◽  
Numerical Experiments ◽  
Three Dimensional ◽  
South Atlantic ◽  
Continental Lithosphere ◽  
Rifted Margins ◽  
Plume Flow ◽  
Rifted Margin ◽  
Asymmetrically Distributed ◽  
Lateral Variations

Volcanic rifted margins are typically associated with a thick magmatic layer of seaward dipping reflectors and anomalous regional uplift. This is conventionally interpreted as due to melting of an arriving mantle plume head at the onset of rifting. However, seaward dipping reflectors and uplift are sometimes asymmetrically distributed with respect to the subsequent plume track. Here we investigate if these asymmetries are induced by preexisting lateral variations in the thickness of continental lithosphere and/or lithospheric stretching rates, variations that promote lateral sublithospheric flow of plume material below only one arm of the extending rift. Using three-dimensional numerical experiments, we find that South Atlantic rifting is predicted to develop a strong southward asymmetry in its distribution of seaward dipping reflectors and associated anomalous relief with respect to the Tristan Plume that “drove” this volcanic rifted margin, and that the region where plume material drains into the rift should experience long-lived uplift during rifting—both as observed. We conclude that a mantle plume is still needed to source the anomalously hot sublithospheric material that generates a volcanic rifted margin, but lateral along-rift flow from this plume, not a broad starting plume head, is what controls when and where a volcanic rifted margin will form.

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