A high-precision U-Pb age constraint on the Rhynie Chert Konservat-Lagerstatte : time scale and other implications
Parry, S.F.; Noble, S.R.; Crowley, Q.G.; Wellman, C.H.. 2011 A high-precision U-Pb age constraint on the Rhynie Chert Konservat-Lagerstatte : time scale and other implications. Journal of the Geological Society, 168 (4). 863-872. 10.1144/0016-76492010-043Before downloading, please read NORA policies.
An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstätte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved temporal framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental' hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite' intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin. Supplementary material: Details of analytical techniques (ID-TIMS U–Pb geochronology) and photomicrographs of zircon and titanite grains recovered from the Milton of Noth Andesite are available at http://www.geolsoc.org.uk/SUP18463.
|Programmes:||BGS Programmes 2010 > Geology and Landscape (Scotland)|
|Date made live:||03 Aug 2011 11:30|
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