Stratigraphy and paleontology of Pleistocene submarine volcanic‐sedimentary sequences at the northern Kermadec Islands

Abstract

Early Pleistocene marine volcanic/sedimentary sequences on Raoul Island and adjacent islets of the northern Kermadec Islands, southwest Pacific, are included in the Herald Group (new) and constituent Boat Cove Formation, Chanter Formation (new) and Dayrell Formation (new). They are the oldest known shallow‐marine deposits in the Kermadec Islands region. The following history is inferred from their stratigraphy, structural relationships and paleontology. (1) Development of a large stratovolcano formed of basaltic andesite lava flows, hyaloclastite breccia and sandstone and epiclastic deposits (Boat Cove Formation). Shallow marine biotas colonised lava, boulder and sandy gravel substrata on the flanks of the volcano, and hermatypic coral patchreefs formed locally. (2) Removal of parts of the upper flanks of the volcano by marine erosion, caldera formation or flank collapse, followed by further eruptions of submarine basaltic andesite lava and tephra from parasitic vents (Chanter Formation). (3) Local cessation of volcanism followed by subsidence of the volcano, and accumulation of an upwards deepening coral patchreef and epiclastic volcaniclastic to detrital bioclastic and coralline algal‐dominated sedimentary sequence (Dayrell Formation). © 1998 Taylor and Francis Group, LLC.