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Incompatible element

About: Incompatible element is a research topic. Over the lifetime, 2420 publications have been published within this topic receiving 154052 citations.


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01 Jan 2001
Abstract: This report presents and discusses geochemical data from the nickeliferous mafic rocks of the Pants Lake Intrusion (PLI) in Labrador, and is a sequel to an earlier descriptive account, which noted petrological similarities between these and the mafic rocks of the Voisey’s Bay area (Voisey’s Bay and Mushuau intrusions). These petrological similarities are supported by similarities in their major- and trace-element geochemistry. The PLI is a relatively primitive, MgO-rich, mafic igneous suite, dominated by olivine gabbro, associated with lesser amounts of troctolite, melagabbro and diabase. The PLI includes two subtly different magma types. The South intrusion is distinguished by higher TiO2, K2O and incompatible element contents, and most closely resembles the Voisey’s Bay intrusion. The North intrusion more closely resembles the Mushuau intrusion, although it is not an exact match. The three main geological units within the North intrusion probably formed from discrete, yet closely related, batches of magma. Contrasting olivine fractionation trends suggest that the South intrusion was a relatively static chamber whose evolution approached closed-system fractionation, whereas the North intrusion was a more dynamic open-system body that was regularly replenished with fresh, more primitive magma. The parental magma composition(s) for the PLI are hard to estimate, but they were probably more primitive than the diabase units associated with it, which are relatively fractionated. Mineralized rocks in both the South and North intrusions share all the geochemical characteristics of spatially associated unmineralized rocks, and are thus closely related to them. Unmineralized rocks throughout the PLI have low Ni and Cu contents and low Cu/Zr ratio values, suggesting that the magmas were depleted in metals by sulphide liquids. First-order calculations suggest that at least 15 million tonnes of Ni metal, several times more than is presently known to be contained at Voisey’s Bay, remain mostly unaccounted for. The low/metal contents of PLI magmas are in accordance with the modest sulphide metal contents (1 to 3% Ni) observed in mineralized samples, and imply a relatively low/mass-ratio (R) of silicate liquid to sulphide liquid (R=180 to 250) compared to Voisey’s Bay (R=600 to >1000). The ubiquitous metal depletion in PLI mafic rocks contrasts with the more localized metal depletion seen at Voisey’s Bay, and may indicate that PLI sulphide liquids were not “upgraded” to the same extent by later undepleted magmas. Thus, although large amounts of sulphides may remain undiscovered in the area of the PLI, there may be inherent limits upon their potential grades.

4 citations

Journal Article
TL;DR: In this article, the ages of trachyandesite, syenite, and biotite monzonite from scientific deep drilling ZK01 in Zhuanqiao, Lujiang-Zongyang volcanic basin are derived from enriched mantle produced by fluid metasomatism of subduction slab, less contaminated by continental material, and magma formed in the tectonic setting of lithosphere tension.
Abstract: LA-MC-ICP MS zircon U-Pb datings yield the ages of 131 29 ± 0 85Ma,130 95 ± 0 56Ma,130 88 ± 0 41Ma for trachyandesite,syenite and biotite monzonite from scientific deep drilling ZK01 in Zhuanqiao,Lujiang-Zongyang volcanic basin Major and trace elements suggest,belonging to metaluminous-peraluminous series,these igneous rocks in ZK01 are characterized by high content of potassium( K2O averaged at 3 7%),rich alkali( K2O + Na2O averaged at 8 4%) and LREEs but depleted strong incompatible elements Most samples plot in the field of shoshonite in SiO2-K2O diagram,indicating the volcanic and intrusive rocks are shoshonite series Mineral fractional crystallization occured during the evolution of magma eHf( t) values of trachyandesite,syenite and biotite monzonite are- 12 9 ~- 7 6,- 10 1 ~- 6 5 and- 11 1 ~- 3 4,respectively It has been inferred that igneous rocks in ZK01 derived from enriched mantle produced by fluid metasomatism of subduction slab,less contaminated by continental material,and magma formed in the tectonic setting of lithosphere tension

4 citations

Journal ArticleDOI
01 Jul 2011-Lithos
TL;DR: In this article, the authors simulate the core drilling of volcanic successions to establish stratigraphic sequences of unexposed lava flows on large complex volcanoes, with the aim of in-depth study of magmatic processes and source geochemistry of otherwise inaccessible lava sequences.

4 citations

Journal ArticleDOI
TL;DR: The Langdu high-K calc-alkaline intrusions are located in the Zhongdian area, which is the southern part of the Yidun island arc.
Abstract: The Langdu high–K calc–alkaline intrusions are located in the Zhongdian area, which is the southern part of the Yidun island arc. These intrusive rocks consist mainly of monzonite porphyry, granodiorite, and diorite porphyry. The K2O content of majority of these rocks is greater than 3%, and, in the K2O-SiO2 diagram, all the samples fall into the high-K calc-alkaline to shoshonitic fields. They are enriched in light rare earth elements (LREEs) and depleted in heavy rare earth elements (HREEs; LaN/YbN= 14.3–21.2), and show slightly negative Eu anomalies (δEu = 0.77–1.00). These rocks have high K, Rb, Sr, and Ba contents; moderate to high enrichment of compatible elements (Cr = 36.7–79.9 ppm, Co = 9.6–16.4 ppm, and MgO = 2.2%-3.4%); low Nb, Ta, and Ti contents, and characteristic of low high field strength elements(HFSEs) versus incompatible elements ratios (Nb/Th = 0.75, Nb/La = 0.34) and incompatible elements ratios (Nb/U = 3.0 and Ce/Pb = 5.1, Ba/Rb = 12.0). These rocks exhibit restricted Sr and Nd isotopic compositions, with (87Sr/86Sr)i values ranging from 0.7044 to 0.7069 and eNd(t) values from −2.8 to −2.2. The Sr-Nd isotope systematic and specific trace element ratios suggest that Langdu high-K calc-alkaline intrusive rocks derived from a metasomatized mantle source. The unique geochemical feature of intrusive rocks can be modeled successfully using different members of a slightly enriched mantle, a slab–derived fluid, and terrigenous sediments. It can be inferred that the degree of partial melting and the presence of specific components are temporally related to the tectonic evolution of the Zhongdian island arc. Formation of these rocks can be explained by the various degrees of melting within an ascending region of the slightly enriched mantle, triggered by the subduction of the Garze–Litang ocean, and an interaction between the slab–derived fluid and the terrigenous sediments.

4 citations

Journal ArticleDOI
TL;DR: In this article, the major-element chemistry of the Martell syenite, a Paleohelikian subvolcanic intrusion, and of some flows of the Christopher Island Formation of the Dubawnt Group, south of Baker Lake, are described.

4 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202216
202157
202056
201960
201851