Skip navigation
Skip navigation

U-Pb geochronology and evolution of Mesoproterozoic basement rocks, western Connecticut

Walsh, Gregory J; Aleinikoff, John N.; Fanning, Christopher

Description

Geologic mapping and U-Pb geochronology by ion microprobe on zircon, titanite, and monazite in the New Milford quadrangle, western Connecticut indicate Mesoproterozoic events at ca. 1.3, 1.05, and 0.99 Ga in the Laurentian basement rocks. Pink granite gneiss (1311 ± 7 Ma) intruded a paragneiss sequence during the early stages of the Elzevirian orogeny. During the Ottawan orogeny, syn-tectonic anatexis produced a belt of stromatic migmatite at 1057 ± 10 Ma. Ottawan igneous activity included...[Show more]

dc.contributor.authorWalsh, Gregory J
dc.contributor.authorAleinikoff, John N.
dc.contributor.authorFanning, Christopher
dc.date.accessioned2015-12-13T23:07:58Z
dc.date.available2015-12-13T23:07:58Z
dc.identifier.isbn0813711975
dc.identifier.urihttp://hdl.handle.net/1885/86445
dc.description.abstractGeologic mapping and U-Pb geochronology by ion microprobe on zircon, titanite, and monazite in the New Milford quadrangle, western Connecticut indicate Mesoproterozoic events at ca. 1.3, 1.05, and 0.99 Ga in the Laurentian basement rocks. Pink granite gneiss (1311 ± 7 Ma) intruded a paragneiss sequence during the early stages of the Elzevirian orogeny. During the Ottawan orogeny, syn-tectonic anatexis produced a belt of stromatic migmatite at 1057 ± 10 Ma. Ottawan igneous activity included syn-tectonic intrusion of abundant sills of biotite granite gneiss, dated at 1050 ± 14 and 1048 ± 11 Ma, and intrusion of the Danbury augen granite at 1045 ± 8 Ma. Overgrowths on igneous zircon and metamorphic zircon in hornblende gneiss indicate that terminal Grenville metamorphism occurred at ca. 993 ± 8 Ma. Late Ordovician syn-tectonic events included intrusion of a leucogranite dike into the Brookfield Gneiss at 453 ± 6 Ma and intrusion of the Candlewood Granite at 443 ± 7 Ma. A monazite age from the Candlewood Granite of 445 ± 9 Ma agrees with the zircon age. A second phase of migmatization in the basement rocks is associated with the injection of numerous granitic leucosomes at 444 ± 6 Ma along the margin of the Candlewood Granite. Titanite ages from 431 to 406 Ma indicate several high-grade heating events from the Silurian to the Early Devonian. The lack of Grenville-age titanite in the basement suggests that post-Taconian heating was sufficient to completely reset old titanite in the massif.
dc.publisherGeological Society of America Inc
dc.relation.ispartofProterozoic tectonic evolution of the Grenville orogen in North America
dc.relation.isversionof1st Edition
dc.subjectKeywords: Candlewood Granite; Danbury augen granite; Elzevirian; Geochronology; Grenville; Hudson Highlands; Monazite; New Milford massif; Ottawan; Taconian; Titanite; Zircon
dc.titleU-Pb geochronology and evolution of Mesoproterozoic basement rocks, western Connecticut
dc.typeBook chapter
local.description.notesImported from ARIES
local.description.refereedYes
dc.date.issued2004
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.ariespublicationMigratedxPub15333
local.type.statusPublished Version
local.contributor.affiliationWalsh, Gregory J, US Geological Survey
local.contributor.affiliationAleinikoff, John N., US Geological Survey
local.contributor.affiliationFanning, Christopher, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.startpage729
local.bibliographicCitation.lastpage753
local.identifier.doi10.1130/0-8137-1197-5.729
dc.date.updated2016-02-24T09:47:30Z
local.bibliographicCitation.placeofpublicationBoulder, Colorado
local.identifier.scopusID2-s2.0-84870822866
CollectionsANU Research Publications

Download

There are no files associated with this item.


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  22 January 2019/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator