A high-precision U-Pb age constraint on the Rhynie Chert Konservat-Lagerstaette: time scale and other implications

• Published in: Journal of the Geological Society Vol. 168; pp. 863 - 872
• Main Authors: Parry, S F, Noble, S R, Crowley, Q G, Wellman, C H
• Format: Journal Article
• Language: English
• Published: 01.07.2011
• Subjects: British Isles, Scotland, Aberdeenshire, Rhynie; ANE, British Isles, Scotland, Aberdeenshire; British Isles, Scotland
• ISSN: 0016-7649
• DOI: 10.1144/0016-76492010-043

An isotope dilution thermal ionization mass spectrometry U-Pb zircon age of 411.5 plus or minus 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstaette. 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 plus or minus 1.3 Ma, while the Lochkovian-Pragian boundary must predate 411.5 plus or minus 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. [PUBLICATIONABSTRACT]