LA-ICP-MS U-Pb apatite dating of Lower Cretaceous rocks from teschenite-picrite association in the Silesian unit (southern Poland)
Citation:
Szopa, K, Wlodyka, R, Chew, D, LA-ICP-MS U-Pb apatite dating of Lower Cretaceous rocks from teschenite-picrite association in the Silesian unit (southern Poland), Geologica Carpathica, 65, 4, 2014, 273-284Download Item:
Abstract:
The main products of volcanic activity in the teschenite-picrite association (TPA) are shallow, sub-volcanic
intrusions, which predominate over extrusive volcanic rocks. They comprise a wide range of intrusive rocks which fall
into two main groups: alkaline (teschenite, picrite, syenite, lamprophyre) and subalkaline (dolerite). Previous 40Ar/39Ar
and 40K/40Ar dating of these rocks in the Polish Outer Western Carpathians, performed on kaersutite, sub-silicic diopside,
phlogopite/biotite as well as on whole rock samples has yielded Early Cretaceous ages. Fluorapatite crystals were
dated by the U-Pb LA-ICP-MS method to obtain the age of selected magmatic rocks (teschenite, lamprophyre) from the
Cieszyn igneous province. Apatite-bearing samples from Boguszowice, Puńców and Lipowa yield U-Pb ages of 103± 20 Ma,
119.6 ± 3.2 Ma and 126.5 ± 8.8 Ma, respectively. The weighted average age for all three samples is 117.8 ± 7.3 Ma
(MSWD = 2.7). The considerably smaller dispersion in the apatite ages compared to the published amphibole and biotite
ages is probably caused by the U-Pb system in apatite being less susceptible to the effects of hydrothermal alternation
than the 40Ar/39Ar or 40K/40Ar system in amphibole and/or biotite. Available data suggest that volcanic activity in the
Silesian Basin took place from 128 to 103 Ma with the the main magmatic phase constrained to 128—120 Ma
Author's Homepage:
http://people.tcd.ie/chewdDescription:
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Author: Chew, David
Type of material:
Journal ArticleCollections
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Geologica Carpathica65
4
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Full text availableKeywords:
geochronology, U-Pb dating, Outer Western Carpathians, Cieszyn magmatic province, apatite.DOI:
http://dx.doi.org/10.2478/geoca-2014-0018Metadata
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