scholarly journals Supplemental Material: Forearc magmatic evolution during subduction initiation: Insights from an Early Cretaceous Tibetan ophiolite and comparison with the Izu-Bonin-Mariana forearc

Author(s):  
Jin-Gen Dai ◽  
et al.

Detailed analytical methods in Text S1, major- and trace-element compositions of clinopyroxene, orthopyroxene, and amphibole, whole-rock major and trace elements, Sr-Nd isotopic data, and zircon U-Pb and Lu-Hf data in Tables S1–S7; Figures S1–S5.

2020 ◽  
Author(s):  
Jin-Gen Dai ◽  
et al.

Detailed analytical methods in Text S1, major- and trace-element compositions of clinopyroxene, orthopyroxene, and amphibole, whole-rock major and trace elements, Sr-Nd isotopic data, and zircon U-Pb and Lu-Hf data in Tables S1–S7.


2020 ◽  
Author(s):  
Jin-Gen Dai ◽  
et al.

Detailed analytical methods in Text S1, major- and trace-element compositions of clinopyroxene, orthopyroxene, and amphibole, whole-rock major and trace elements, Sr-Nd isotopic data, and zircon U-Pb and Lu-Hf data in Tables S1–S7; Figures S1–S5.


2021 ◽  
Author(s):  
Pengsheng Dong ◽  
Guochen Dong

Table S1: Mineral association of samples from the Daocheng batholith; Table S2: LA-ICP-MS U-Pb isotopic data for zircons from the Daocheng batholith; Table S3: Hf isotopic data for zircons from the Daocheng batholith; Table S4: Trace elements data for zircons from the Daocheng batholith; Table S5: Major and trace elements data for the Daocheng batholith; Table S6: Whole-rock Sr-Nd isotopic data of the Daocheng batholith; Table S7: Representative microprobe analyses of amphibole from the Daocheng batholith; Table S8: Partition coefficient for minerals used in geochemical modeling.


Author(s):  
Jin-Gen Dai ◽  
Cheng-Shan Wang ◽  
Robert J. Stern ◽  
Kai Yang ◽  
Jie Shen

Subduction initiation is a key process in the operation of plate tectonics. Our understanding of melting processes and magmatic evolution during subduction initiation has largely been developed from studies of the Izu-Bonin-Mariana forearc. Many suprasubduction zone ophiolites are analogous to the Izu-Bonin-Mariana forearc sequence. However, whether there are differences between Izu-Bonin-Mariana subduction initiation sequences and suprasubduction zone ophiolites remains unclear. Here, we report field geological, geochemical, and geochronological data from mafic and felsic rocks in the Xigaze ophiolite (southern Tibet) mantle and crustal section; the same types of published data from both this ophiolite and the Izu-Bonin-Mariana forearc are compiled for comparison. The ophiolite section is intruded by various late-stage dikes, including gabbroic pegmatite, diabase, basalt, and plagiogranite. The compositions of clinopyroxene and amphibole suggest that gabbroic pegmatite formed from hydrous high-SiO2 depleted melts, while whole-rock compositions of basaltic and diabase dikes show negative Nb and Ta anomalies, suggesting flux melting of depleted mantle. Along with the mafic rocks, plagiogranite has a roughly constant content of La and Yb with increasing SiO2 contents, implying hydrous melting of mafic amphibolite. Early-stage pillow basalts exhibit geochemical affinities with Izu-Bonin-Mariana forearc basalts, but they are slightly enriched. Synthesized with the regional geological setting and compared with Izu-Bonin-Mariana forearc magmatism, we propose that the transition from mid-ocean ridge basalt−like lavas to subduction-related mafic and felsic dikes records an Early Cretaceous subduction initiation event on the southern flank of the Lhasa terrane. However, the mantle sources and the magmatic evolution in the Xigaze ophiolite are more variable than those for the Izu-Bonin-Mariana forearc.


2021 ◽  
Author(s):  
Pengsheng Dong ◽  
Guochen Dong

Table S1: Mineral association of samples from the Daocheng batholith; Table S2: LA-ICP-MS U-Pb isotopic data for zircons from the Daocheng batholith; Table S3: Hf isotopic data for zircons from the Daocheng batholith; Table S4: Trace elements data for zircons from the Daocheng batholith; Table S5: Major and trace elements data for the Daocheng batholith; Table S6: Whole-rock Sr-Nd isotopic data of the Daocheng batholith; Table S7: Representative microprobe analyses of amphibole from the Daocheng batholith; Table S8: Partition coefficient for minerals used in geochemical modeling.


1984 ◽  
Vol 75 (2) ◽  
pp. 259-273 ◽  
Author(s):  
W. E. Stephens ◽  
A. N. Halliday

ABSTRACTNew major- and trace-element data for granitoid plutons from the Grampian Highlands, the Midland Valley and the Southern Uplands of Scotland are presented and discussed. The study is restricted to ‘late granitoids’ (all younger than 430 Ma); the term ‘granitoid’ is used in a wide sense to encompass all plutonic components of a zoned intrusion of this age, sometimes including diorites and ultrabasic cumulate rocks. The data indicate that as a whole the province is chemically high-K calc-alkalic. Other notable enrichments are in Sr and Ba, and a marked geographical difference in these trace-elements is found between plutons of the SW Grampian Highlands and those of the Southern Highlands, the Midland Valley, and the Southern Uplands. Plutons of the NE Highlands tend to be more geochemically evolved than those further SW and those of the Midland Valley and Southern Uplands.When petrographical and geochemical data are considered, three plutonic suites are recognised: (1) the Cairngorm suite comprising plutons of the NE Highlands, (2) the Argyll suite comprising plutons from the SW Highlands, and (3) the S of Scotland suite comprising plutons from the Southern Highlands, Midland Valley and the Southern Uplands excluding Criffell and the Cairnsmore of Fleet. It is proposed that the more acidic granitoids are dominantly the products of I-type crustal sources, but certain diorites and the more basic members of zoned plutons have a substantial mantle component. The elevated Sr and Ba levels in granitoids of the Argyll suite may reflect the influence of incompatible-element-rich fluids from the mantle in the petrogenesis of this suite. The relatively anhydrous pyroxene-mica diorites of the S of Scotland suite are richer in Ni and Cr and appear to represent mantle-derived melts. The relationships between these data and already published isotopic data are discussed.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Sandra Bravo Martín-Consuegra ◽  
Jose A. Amorós Ortíz-Villajos ◽  
Caridad Pérez-de-los-Reyes ◽  
Francisco J. García Navarro ◽  
Rolando Ruedas Luna ◽  
...  

The study of five soil profiles developed on carbonatic sediments of Tertiary Miocene origin has been carried out. The topography of the area was basically flat and the traditional uses of the soils are the cultivation of dry cereals and grapevine. The geochemical characterization of the aforementioned profiles involves a study of the contents of major and trace elements among other pedologic aspects (texture, pH, organic matter, etc.). The results of this study also indicate a superficial enrichment of trace elements due to the leaching of Ca and moderate biological and anthropic activity. We can consider strontium, Sr, as the trace element that characterizes these limy soils (435 mg/kg average content in total soil and 708 mg/kg in the original rock). These contents are similar to the average value in Castilla-La Mancha of 380 mg/kg and are higher than the average in world soils of about 200 mg/kg. High levels of dangerous or pollutant elements (Cd, Hg, Pb, Cu, Zn, or Ni) were not detected. The majority of trace element anomalies are related to calcareous material and the leaching of calcium carbonate (Ca), while the influence of the anthropogenic factor is secondary. Soil quality does not indicate toxicity although surficial enrichment suggests a weak threat from consuming crops.


2010 ◽  
Vol 107 (3) ◽  
pp. 217-226 ◽  
Author(s):  
Manfred Birke ◽  
Clemens Reimann ◽  
Alecos Demetriades ◽  
Uwe Rauch ◽  
Hans Lorenz ◽  
...  

2015 ◽  
Vol 57 ◽  
Author(s):  
Sergio Calabrese ◽  
Sarah Scaglione ◽  
Silvia Milazzo ◽  
Walter D'Alessandro ◽  
Nicole Bobrowski ◽  
...  

<p>Volcanoes are well known as an impressive large natural source of trace elements into the troposphere. Etna (Italy) and Nyiragongo (D.R. Congo) are two stratovolcanoes located in different geological settings, both characterized by persistent passive degassing from their summit craters. Here, we present some results on trace element composition in volcanic plume emissions, atmospheric bulk deposition (rainwater) and their uptake by the surrounding vegetation, with the aim to compare and identify differences and similarities between these two volcanoes. Volcanic emissions were sampled by using active filter-pack for acid gases (sulfur and halogens) and specific teflon filters for particulates (major and trace elements). The impact of the volcanogenic deposition in the surrounding of the crater rims was investigated by using different sampling techniques: bulk rain collectors gauges were used to collect atmospheric bulk deposition, and biomonitoring technique was carried out to collect gases and particulates by using endemic plant species. The estimates of the trace element fluxes confirm that Etna and Nyiragongo are large sources of metals into the atmosphere, especially considering their persistent state of passive degassing. The large amount of emitted trace elements has a strong impact on the close surrounding of both volcanoes. This is clearly reflected by in the chemical composition of rainwater collected at the summit areas both for Etna and Nyiragongo. Moreover, the biomonitoring results highlight that bioaccumulation of trace elements is extremely high in the proximity of the crater rim and decreases with the distance from the active craters.</p>


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