10.6084/m9.figshare.3454640.v1
Jeffrey C. Pollock
Jeffrey C.
Pollock
James P. Hibbard
James P.
Hibbard
Paul J. Sylvester
Paul J.
Sylvester
Early Ordovician rifting of Avalonia and birth of the Rheic Ocean: U–Pb detrital zircon constraints from Newfoundland
Geological Society of London
2016
Mesoproterozoic
Avalonia
Ordovician
provenance
Palaeozoic platform units
constraint
Crown Hill formations
Palaeoproterozoic
detrital zircon ages
620 Ma zircons
Neoproterozoic
Rheic Ocean
Geology
2016-06-21 12:15:38
Dataset
https://geolsoc.figshare.com/articles/dataset/Early_Ordovician_rifting_of_Avalonia_and_birth_of_the_Rheic_Ocean_U_Pb_detrital_zircon_constraints_from_Newfoundland/3454640
<p>Avalonia is the largest accreted crustal block in the Appalachian orogen and comprises a collection of late Neoproterozoic
volcano-sedimentary sequences that are overlain by a Palaeozoic platformal sedimentary succession. Detrital zircons from the
Conception Group are dominated by 570–620 Ma ages and contain a significant component generated by erosion of coeval igneous
arc-volcanic rocks. Overlying samples from the Cuckold and Crown Hill formations are dominated by Neoproterozoic populations
with ages between 600 and 650 Ma and are interpreted to be derived from the underlying calc-alkaline arc-plutonic rocks. Early
Palaeozoic platform units are dominated by <em>c</em>. 620 Ma zircons with lesser Mesoproterozoic and Palaeoproterozoic zircons. The range of detrital zircon ages is inconsistent
with a West African provenance and suggests that Avalonia originated along the Gondwanan margin of the Amazon craton. The
influx of Mesoproterozoic and Palaeoproterozoic detritus in the Avalonian platform suggests a major change in tectonic regime.
The prominent change in provenance is interpreted to be related to separation of Avalonia from Gondwana during the Early Ordovician
opening of the Rheic Ocean. The Redmans Formation is interpreted to represent the rift–drift transition of the Rheic Ocean,
which imposes important constraints on the palaeotectonic evolution of Avalonia.
</p>