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TitleConodonts recovered from the carbonate xenoliths in the kimberlites confirm the Paleozoic cover on the Hall Peninsula, Nunavut
AuthorZhang, S; Pell, J
SourceCanadian Journal of Earth Sciences vol. 51, issue 2, 2014 p. 142-155, https://doi.org/10.1139/cjes-2013-0171
Year2014
Alt SeriesEarth Sciences Sector, Contribution Series 20130185
PublisherNational Research Council of Canada
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNunavut
NTS25O/13; 25O/14; 25O/15; 25O/16; 25P/13; 25P/14; 26A/04; 26B
AreaBaffin Island; Hall Peninsula
Lat/Long WENS-68.5000 -65.0000 65.0000 63.5000
Subjectssedimentology; economic geology; sedimentary rocks; shales; dolostones; breccias; xenoliths; kimberlites; diamond; mineral potential; overburden thickness; Conodonts; Chidliak kimberlite province; Paleozoic
Illustrationslocation maps; photomicrographs
ProgramCanada-Nunavut Geoscience Office, Funding Program
AbstractHall Peninsula, located on southeastern Baffin Island, Nunavut, hosts the newly discovered Chidliak kimberlite province. Presently, this area lacks Phanerozoic sedimentary cover, except for the unconsolidated glacial deposits; however, Late Ordovician and Early Silurian microfossil conodonts have been recovered from carbonate xenoliths preserved in the Late Jurassic - Early Cretaceous kimberlites. Over 1300 conodont specimens were recovered, among which 32 species representing 23 genera are recognized, with four elements indeterminate. The well-preserved conodont faunas provide reliable evidence on the Hall Peninsula for (i) reconstructing the Lower Paleozoic stratigraphic units, including the Upper Ordovician Frobisher Bay, Amadjuak, Akpatok, and Foster Bay formations, and the Lower Silurian Severn River Formation, (ii) estimating a total of 270–305 m in thickness of Lower Paleozoic sedimentary cover prior to the emplacement of the kimberlites, (iii) tracing the erosion history after the emplacement of the kimberlites, and (iv) calculating a minimum erosion rate of 2 m/Ma. The conodonts have a wide range of conodont Color Alteration Index (CAI) values between 1.5 and 8, which is the largest range recorded in any known suite of xenoliths entrained in kimberlites.
Summary(Plain Language Summary, not published)
Hall Peninsula, located on southeastern Baffin Island, Nunavut, hosts the newly discovered Chidliak kimberlite province. Presently, this area lacks Phanerozoic sedimentary cover, except for the unconsolidated glacial deposits; however, Late Ordovician and Early Silurian microfossil conodonts have been recovered from carbonate xenoliths preserved in the Late Jurassic - Early Cretaceous kimberlites. The well-preserved conodont faunas, composed of over 1300 conodont specimens, among which 32 species representing 23 genera were recognized, with 4 elements indeterminate, provide reliable evidence for estimating the thickness of Lower Paleozoic sedimentary cover prior to the emplacement of the kimberlites and tracing the erosion history after the emplacement of the kimberlites. All these conodonts have a wide range of conodont Color Alteration Index (CAI) values between 1.5 and 8; this helps in assessing the variations in temperature recorded by conodonts preserved in sedimentary rock xenoliths within the same kimberlite, and among the different kimberlites.
GEOSCAN ID292910