Chapter 5.2b Erebus Volcanic Province: petrology

2021 ◽  
pp. M55-2018-80 ◽  
Author(s):  
Adam P. Martin ◽  
Alan F. Cooper ◽  
Richard C. Price ◽  
Philip R. Kyle ◽  
John A. Gamble
Keyword(s):  
Mantle Convection ◽  
Sensu Stricto ◽  
Igneous Rocks ◽  
Compositional Variation ◽  
Garnet Lherzolite ◽  
Geochronological Data ◽  
Crustal Component ◽  
Volcanic Province ◽  
Mixed Spinel ◽  
Source Component

AbstractIgneous rocks of the Erebus Volcanic Province have been investigated for more than a century but many aspects of petrogenesis remain problematic. Current interpretations are assessed and summarized using a comprehensive dataset of previously published and new geochemical and geochronological data. Igneous rocks, ranging in age from 25 Ma to the present day, are mainly nepheline normative. Compositional variation is largely controlled by fractionation of olivine + clinopyroxene + magnetite/ilmenite + titanite ± kaersutite ± feldspar, with relatively undifferentiated melts being generated by <10% partial melting of a mixed spinel + garnet lherzolite source. Equilibration of radiogenic Sr, Nd, Pb and Hf is consistent with a high time-integrated HIMU sensu stricto source component and this is unlikely to be related to subduction of the palaeo-Pacific Plate around 0.5 Ga. Relatively undifferentiated whole-rock chemistry can be modelled to infer complex sources comprising depleted and enriched peridotite, HIMU, eclogite-like and carbonatite-like components. Spatial (west–east) variations in Sr, Nd and Pb isotopic compositions and Ba/Rb and Nb/Ta ratios can be interpreted to indicate increasing involvement of an eclogitic crustal component eastwards. Melting in the region is related to decompression, possibly from edge-driven mantle convection or a mantle plume.

New geochronological data on metamorphic and igneous rocks from the Gridino Village area (Belomorian eclogitic province)

2010 ◽  
Vol 432 (1) ◽  
pp. 671-676 ◽  
Author(s):  
K. A. Dokukina ◽  
T. B. Bayanova ◽  
T. V. Kaulina ◽  
A. V. Travin ◽  
A. N. Konilov
Keyword(s):  
Igneous Rocks ◽  
Geochronological Data

scholarly journals New geochemical and geochronological data on the Cenozoic Veneto Volcanic Province: Geodynamic inferences

Lithos ◽  
2021 ◽  
pp. 106507
Author(s):  
V. Brombin ◽  
E.A. Pettitt ◽  
M.F. Fahnestock ◽  
M. Casalini ◽  
L.E. Webb ◽  
...  
Keyword(s):  
Geochronological Data ◽  
Volcanic Province

Geochemical characteristics of the Late Devonian basaltoids of the Kanin Peninsula and the Middle Timan

2021 ◽  
Vol 3 ◽  
pp. 22-31
Author(s):  
A.M. Shmakova ◽  
◽  
K.V. Kulikova
Keyword(s):  
Mantle Source ◽  
Maximum Degree ◽  
Similar Type ◽  
Geochemical Characteristics ◽  
Late Devonian ◽  
Garnet Lherzolite ◽  
Normal Range ◽  
Crustal Component ◽  
Middle Timan ◽  
Kanin Peninsula

The petrochemistry and geochemistry of dolerites and basalts of the Late Devonian Kanin-Timan complex of the Kanin Peninsula and the Middle Timan are considered. Petrochemically, the rocks of the Kanin-Timan complex of the Kanin Peninsula and the Tsilma river area of the Middle Timan correspond to basaltoids of the normal range of alkalinity and partially to moderately alkaline varieties, and belong to the tholeiitic series. The least differentiated varieties are dolerites of the southeastern Kanin Peninsula, the most differentiated are the basalts of the river Tsilma of the Middle Timan. The lowest REE concentrations were found in the rocks of the central part of the Kanin Peninsula (36.5-56.8 g/t); in the same samples, the lowest LaN/YbN values were recorded (1.85 and 2.4, respectively), which indicates an increased degree of melting of the source. The highest REE concentrations were found in basalts from the river Tsilma (77.13-88.33 g/t), LaN/YbN values (2.49-2.7, respectively). The influence of the crustal component in the formation of melts from which rocks of the Kanin-Timan complex were formed, was established. The source of the melt was spinel-garnet lherzolite, the degree of melting varied from 10 to 30%. The maximum degree of melting was 30%, at which melts were formed, that gave rise to the least differentiated rocks of the Northern Timan and the central part of the Kanin Peninsula. The mantle source, that gave rise to the melts from which the rocks of the Kanin-Timan complex were formed, was enriched with subduction and crustal components, a similar type of source is characteristic of the basaltoids of the No-rilsk trough.

Compositional variation of apatite from rift-related alkaline igneous rocks of the Gardar Province, South Greenland

2016 ◽  
Vol 101 (3) ◽  
pp. 612-626 ◽  
Author(s):  
Sara Ladenburger ◽  
Michael A.W. Marks ◽  
Brian Upton ◽  
Peter Hill ◽  
Thomas Wenzel ◽  
...  
Keyword(s):  
Igneous Rocks ◽  
Compositional Variation

scholarly journals 40Ar/39Ar Geochronology of the Malyy (Little) Murun Massif, Aldan Shield of the Siberian Craton: A Simple Story for an Intricate Igneous Complex

2018 ◽  
Author(s):  
Alexei V. Ivanov ◽  
Nikolay V. Vladykin ◽  
Elena I. Demonterova ◽  
Viktor A. Gorovoy ◽  
Emilia Yu. Dokuchits
Keyword(s):  
Siberian Craton ◽  
Middle Jurassic ◽  
Aldan Shield ◽  
Igneous Rocks ◽  
Geochronological Data ◽  
Igneous Complex ◽  
Mineral Associations ◽  
Ar Geochronology ◽  
Hydrothermal Mineral ◽  
Extensional Setting

The Malyy (Little) Murun massif of the Aldan Shield of the Siberian Craton has long been a kind of the geologists&rsquo; Siberian Mecca. It attracted thousands of geologists, prospectors and mineral collectors despite of its remote location. It is famous for a dozen of new and rare minerals, including gemstones charoite and dianite (the latter is the market name for strontian potassicrichrerite), as well as for specific alkaline igneous rocks. Despite of this, the age of the Malyy Murun igneous complex and associated metasomatic and hydrothermal mineral associations remained poorly constrained. In this paper, we provide extensive 40Ar/39Ar geochronological data to reveal its age and temporal history. It appeared that being unique in terms of rocks and constituent minerals, the Malyy Murun is one of multiple alkaline massifs and lavas emplaced in Early Cretaceous (~137-128 Ma) within a framework of extensional setting of the Aldan Shield and nearby Transbaikalian region. The extension has occurred 40-60 million years after the supposed closure of the Mongolia-Okhotsk Ocean and peak of orogeny in Early-Middle Jurassic.

Compositional variation in minerals of the chevkinite group

2002 ◽  
Vol 66 (6) ◽  
pp. 1075-1098 ◽  
Author(s):  
R. Macdonald ◽  
H. E. Belkin
Keyword(s):  
Negative Correlation ◽  
Linear Array ◽  
General Relationship ◽  
Igneous Rocks ◽  
Compositional Variation ◽  
Strong Negative Correlation ◽  
Intermediate Composition ◽  
Structural Formulae ◽  
Charge Balancing

Abstract The composition of chevkinite and perrierite, the most common members of the chevkinite group, is closely expressed by the formula A4BC2D2Si4O22, where A = (La,Ce,Ca,Sr,Th), B = Fe2+, C = (Fe2+,Fe3+,Ti,Al,Zr,Nb) and D = Ti. The A site is dominated by a strong negative correlation between (Ca+Sr) and the REE. Chondrite-normalized REE patterns are very variable, e.g. in LREE/HREE and Eu/Eu*. The C site is dominated by Ti, Al and Fe2+, in very variable proportions. Most chevkinites and perrierites are close to stoichiometric, with cation sums between 12.9 and 13.5, compared to the theoretical 13. There is no single, generally applicable charge balancing substitution scheme in the group; however, the general relationship defines a linear array with r2 = 0.91. Chevkinite and perrierite are shown to be compositionally distinct on the basis of CaO, FeO*, Al2O3 and Ce2O3 abundances. Chevkinite forms mainly in chemically evolved parageneses, such as syenites, rhyolites and fenites associated with carbonatite complexes. Perrierite is more commonly recorded from igneous rocks of mafic to intermediate composition. The compositional characteristics and possible structural formulae of other members of the chevkinite group are reviewed briefly.

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