The construction of the Donegal composite batholith, Irish Caledonides: Temporal constraints from U-Pb dating of zircon and titanite

被引：18

作者：

Archibald, Donnelly B. ^{[1
]}

Macquarrie, Lauren M. G. ^{[1
]}

Murphy, J. Brendan ^{[1
]}

Strachan, Robin A. ^{[2
]}

McFarlane, Chris R. M. ^{[3
]}

Button, Mark ^{[4
]}

Larson, Kyle P. ^{[4
]}

Dunlop, Joseph ^{[2
]}

机构：

[1] St Francis Xavier Univ, Dept Earth Sci, 5009 Chapel Sq, Antigonish, NS B2G 2W5, Canada

[2] Univ Portsmouth, Sch Environm Geog & Geosci, Portsmouth PO1 3QL, Hants, England

[3] Univ New Brunswick, Dept Earth Sci, Fredericton, NB E3B 5A3, Canada

[4] Univ British Columbia, Dept Earth Environm & Geog Sci, 3247 Univ Way, Kelowna, BC V1V 1V7, Canada

来源：

GEOLOGICAL SOCIETY OF AMERICA BULLETIN | 2021年 / 133卷 / 11-12期

基金：

加拿大自然科学与工程研究理事会;

关键词：

DALRADIAN SUPERGROUP; GRAMPIAN TERRANE; SCOTTISH CALEDONIDES; MOINE SUPERGROUP; SLAB BREAKOFF; ARDARA PLUTON; SCOTLAND; AGE; GEOCHRONOLOGY; DEFORMATION;

D O I：

10.1130/B35856.1

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

Magmatic and tectonic processes can transport large volumes of magma generated in the deep crust as discrete pulses to shallower crustal depths, resulting in the incremental construction of large, composite batholiths over thousands to tens of millions of years. The Silurian to Early Devonian Donegal composite batholith in Ireland is a classic example of which regional geological syntheses and lithogeochemical data show that emplacement was syn-and post-kinematic with respect to the terminal phases (ca. 437-415 Ma) of the Caledonian orogeny. We used U-Pb dating of zircon and titanite to investigate the construction of the batholith over time. Imaging of these minerals reveals complex, zoned grains with distinct autocrystic (growth during pluton emplacement) and antecrystic (growth during lower crustal incubation) domains as well as xenocrysts (incorporated from wall rocks). To determine the ages of emplacement and of inherited domains, discrete growth zones were targeted for dating using laser ablation-inductively coupled plasma- mass spectrometry (LA-ICP-MS). Taken together, the zircon and titanite U-Pb isotopic data indicate that magmatism occurred over at least 30 m.y., between ca. 430 Ma and 400 Ma. Batholith emplacement is bracketed by the ca. 427-423 Ma Ardara pluton and the latest phases in the Main Donegal and Trawenagh Bay plutons (ca. 400 Ma). Although apparently volumetrically minor, U-Pb data from spatially associated mafic rocks (appinite suite, lamprophyre dikes, and mafic enclaves in granitoid plutons) yield ages ranging from ca. 431-416 Ma, which indicates ongoing mafic magmatism during emplacement of much of the Donegal composite batholith.

引用

页码：2335 / 2354

页数：20

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