U-Ph geochronological constraints on the timing of plutonism, volcanism, and sedimentation, Jersey, Channel Islands, UK

Uranium-lead dates for single and small multiple grain zircon separates are presented for the main geological units from Jersey, British Channel Islan ds. A turbiditic sandstone from the Jersey Shale Formation (Brioverian Supe rgroup) contains detrital zircons of a variety of ages, ranging from c. 2.6 to 0.6 Ga. The youngest zircons yielded nearly concordant U-Pb dates of 58 6.7 +/- 3.0 Ma and 587.1 +/- 2.7 Ma providing a maximum depositional age fo r the unit. Zircons from overlying volcanic rocks (Anne Port Rhyolite) give an upper intercept date of 582.8(-2.7)(+3), Ma, considered to be the age o f eruption. The undeformed SW Jersey granite, which intrudes and locally th ermally metamorphoses the folded Jersey Shale Formation, is dated at 580(-1 .6)(+2.3) Ma. These dates constrain tightly the timing of deposition of the Jersey Shale Formation and the age of deformation on Jersey, and indicate a dynamic are environment during the late Neoproterozoic. Zircons from the NW Jersey granite define an upper intercept date of 482.7 +/- 1.6 Ma, simil ar to the previously reported Ar-40/Ar-39 hornblende date of c. 473 Ma, con firming a renewed pulse of magmatism during the Ordovician in this sector o f Cadomia.