The transition from granite to banded aplite-pegmatite sheet complexes: An example from Megiliggar Rocks, Tregonning topaz granite, Cornwall

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F18%3A00488627" target="_blank" >RIV/67985831:_____/18:00488627 - isvavai.cz</a>

Alternative codes found

RIV/00216224:14310/18:00107852

Result on the web

<a href="http://dx.doi.org/10.1016/j.lithos.2018.01.010" target="_blank" >http://dx.doi.org/10.1016/j.lithos.2018.01.010</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.lithos.2018.01.010" target="_blank" >10.1016/j.lithos.2018.01.010</a>

Result language

angličtina

Original language name

The transition from granite to banded aplite-pegmatite sheet complexes: An example from Megiliggar Rocks, Tregonning topaz granite, Cornwall

Original language description

The genetic relationship between a granite pluton and adjacent complex of rare-metal pegmatite-aplite-banded sheets (Megiliggar Sheet Complex - MSC) has been studied at the border of the Tregonning topaz granite at Megiliggar Rocks, Cornwall, SW England. Similarities in whole-rock chemical and mineralogical compositions, together with a gradual change in textures away from the granite margin, provide strong evidence for a genetic link between the Tregonning Granite and MSC. The sheets are likely to represent apophyses of residual melt which escaped from the largely crystallized roof of the granite pluton. The escaping melt was peraluminous, had a composition near the F, B, Li slightly enriched granite minimum, and, in comparison with other Cornish granites, was enriched in F, Li, Rb, Cs, Sn, W, Nb, Ta, and U, and depleted in Fe, Mg, Ca, Sr, Th, Zr, and REE. With increasing distance from the Tregonning Granite, the silicate melt crystallized as homogeneous leucogranite sheets and banded complex sheets (i.e. combinations of bands with granitic, aplitic and pegmatitic textures) and layered aplite-pegmatites. This sequence becoming progressively more depleted in the fluxing and volatile elements F, Li, Rb, and Cs, but showing no change in Zr/Hf ratios. The fixed Zr/Hf ratio is interpreted as indicating a direct genetic link (parental melt) between all rock types, however the melt progressively lost fluxing and volatile elements with distance from the granite pluton, probably due to wall-rock reaction or fluid exsolution and migration via fractures. Differentiation of the primary melt into Na-Li-F-rich and separate K-B-rich domains was the dominant chemical process responsible for the textural and mineral diversity of the MSC. On a large (cliff-section) scale, the proximal Na-Li-F-rich leucogranite passes through complex sheets into K-B-rich aplite-pegmatites, whilst at a smaller (<1 cm) scale, the K-B-rich bands are interspersed (largely overlain) by Na-Li-F-rich segregations. The grain size differences between the aplite and pegmatite could be related to pressure fluctuations and/or undercooling.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10505 - Geology

Project

<a href="/en/project/GA14-13600S" target="_blank" >GA14-13600S: Rock Textures and Mineral Zoning: Insights into Open System Processes in Granitoides</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Lithos

ISSN

0024-4937

e-ISSN

—

Volume of the periodical

302/303

Issue of the periodical within the volume

March 2018

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

19

Pages from-to

370-388

UT code for WoS article

000428497500023

EID of the result in the Scopus database

2-s2.0-85044580275