TY - JOUR
T1 - 40Ar/39Ar dating of hydrothermal activity, biota and gold mineralization in the Rhynie hot-spring system, Aberdeenshire, Scotland
AU - Mark, D. F.
AU - Rice, C. M.
AU - Fallick, A. E.
AU - Trewin, N. H.
AU - Lee, M. R.
AU - Boyce, A.
AU - Lee, J. K W
PY - 2011/1/15
Y1 - 2011/1/15
N2 - This study presents a new high-precision 40Ar/39Ar age for the Devonian hot-spring system at Rhynie. Hydrothermal K-feldspar sampled from two veins that represent feeder conduits and a hydrothermally altered andesite wall rock, date the hydrothermal activity, the fossilised biota, and syn - K-feldspar gold mineralization at 403.9±2.1Ma (2σ). Oxygen isotope data for the parent fluid (-4‰ to 2‰) show that the K-feldspar was precipitated from a dominantly meteoric fluid, which mixed with magmatic fluids from a degassing magma chamber. The 40Ar/39Ar age (403.9±2.1Ma [2σ]) when recalculated (407.1±2.2Ma [2σ]) with respect to the astronomically tuned age for Fish Canyon sanidine (28.201±0.023Ma [1σ]), also provides a robust marker for the polygonalis-emsiensis Spore Assemblage Biozone within the Pragian-?earliest Emsian. Furthermore, the age identifies the Devonian pull-apart volcano-sedimentary basins of the British and Irish Caledonides (and their root zones), as specific targets for future gold exploration.
AB - This study presents a new high-precision 40Ar/39Ar age for the Devonian hot-spring system at Rhynie. Hydrothermal K-feldspar sampled from two veins that represent feeder conduits and a hydrothermally altered andesite wall rock, date the hydrothermal activity, the fossilised biota, and syn - K-feldspar gold mineralization at 403.9±2.1Ma (2σ). Oxygen isotope data for the parent fluid (-4‰ to 2‰) show that the K-feldspar was precipitated from a dominantly meteoric fluid, which mixed with magmatic fluids from a degassing magma chamber. The 40Ar/39Ar age (403.9±2.1Ma [2σ]) when recalculated (407.1±2.2Ma [2σ]) with respect to the astronomically tuned age for Fish Canyon sanidine (28.201±0.023Ma [1σ]), also provides a robust marker for the polygonalis-emsiensis Spore Assemblage Biozone within the Pragian-?earliest Emsian. Furthermore, the age identifies the Devonian pull-apart volcano-sedimentary basins of the British and Irish Caledonides (and their root zones), as specific targets for future gold exploration.
UR - http://www.scopus.com/inward/record.url?scp=78650192120&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2010.10.014
DO - 10.1016/j.gca.2010.10.014
M3 - Article
AN - SCOPUS:78650192120
SN - 0016-7037
VL - 75
SP - 555
EP - 569
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 2
ER -