Geochronological and mineralogical constraints on depth of emplacement and ascencion rates of epidote-bearing magmas from northeastern Brazil.

Sial, A.N., Vasconcelos, Paulo M.d., Ferreira, V.P., Pessoa, R.R., Brasilino, R.G. and Morais-Neto, Joao M. (2008) Geochronological and mineralogical constraints on depth of emplacement and ascencion rates of epidote-bearing magmas from northeastern Brazil.. Lithos, 105 3-4: 225-238. doi:10.1016/j.lithos.2008.04.002


Author Sial, A.N.
Vasconcelos, Paulo M.d.
Ferreira, V.P.
Pessoa, R.R.
Brasilino, R.G.
Morais-Neto, Joao M.
Title Geochronological and mineralogical constraints on depth of emplacement and ascencion rates of epidote-bearing magmas from northeastern Brazil.
Journal name Lithos   Check publisher's open access policy
ISSN 0024-4937
Publication date 2008-04-22
Sub-type Article (original research)
DOI 10.1016/j.lithos.2008.04.002
Open Access Status
Volume 105
Issue 3-4
Start page 225
End page 238
Total pages 14
Editor Buick, I.
Eby, G.N.
Kerr, A.C.
Place of publication The Netherlands
Publisher Elsivier Science BV
Language eng
Subject C1
970104 Expanding Knowledge in the Earth Sciences
040303 Geochronology
Abstract Calc-alkalic to high-K calc-alkalic granitoid plutons in the Borborema province, northeastern Brazil, have been studied to constrain depth of emplacement by mineralogical and geological methods and to estimate upward magma transport rate based on partial dissolution of magmatic epidote. Laser-probe incremental heating 40Ar/39Ar dating of biotite and hornblende single crystals from the Neoproterozoic Tavares and Brejinho high-K calc-alkalic magmatic epidote (mEp)-bearing plutons reveals age differences of around 60 M.y. between these two minerals in each of these two intrusions. These data suggest solidification at relatively great depth followed by prolonged cooling interval between the closure temperatures of biotite and hornblende. Al-in-hornblende barometry indicates that hornblende in several mEp-bearing plutons in the Transversal Domain of the Borborema province solidified at 5 to 7 kbar, whereas in the Seridó and Macururé terranes, solidification pressures range from 3 to 4 kbar. Partial dissolution of epidote indicates very rapid upward transport. Partial corrosion occurred during 15–35 years (Cachoerinha–Salgueiro terrane), 10–30 years (Alto Pajeú), 15 years (Seridó), and 10 years (Macururé) corresponding to upward transport rates of 450–1300, 650–1050, 1200, and 1800 m/year respectively in these four terranes. Rapid upward magma migration in most cases was probably facilitated by diking simultaneous with regional shearing.
Keyword Magmatic epidote
40Ar/39Ar age
Depth of crystallization
Magma transport rate
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Earth Sciences Publications
 
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Created: Fri, 17 Apr 2009, 06:00:34 EST by Ms Christine Sinclair on behalf of School of Earth Sciences