Abstract
Two felsic volcanic clasts from conglomerates in Fiordland and northwest Nelson provide U–Pb zircon ages of 359 and c. 362 Ma respectively; ages that occur within the interval between voluminous Western Province plutonic S-type magmatism of the Karamea and Ridge suites. Both volcanic clasts have inherited zircon populations, and trace element signatures suggesting derivation from crustal melts. The dacitic clast from the mid-Cretaceous Seek Cove Formation in southwest Fiordland has whole-rock chemistry and an O–Hf–zircon isotopic signature consistent with derivation from the Takaka Terrane. A rhyolite clast from the Pupu Conglomerate in northwest Nelson also has chemistry consistent with derivation from a Takaka Terrane source. We therefore correlate both volcanic clasts to the S-type Ridge Suite. No comparable S-type plutonic source of the same age has been recognised in the northwest Nelson section of the Takaka Terrane. These volcanic clasts represent the oldest recognised episode of S-type Ridge Suite magmatism in the Takaka Terrane.
| Original language | English |
|---|---|
| Journal | New Zealand Journal of Geology and Geophysics |
| Volume | 61 |
| Issue number | 4 |
| Pages (from-to) | 413-427 |
| Number of pages | 15 |
| ISSN | 0028-8306 |
| DOIs | |
| Publication status | Published - 2 Oct 2018 |