Biostratigraphy of the Ohauan and Lower Puaroan stages (Middle Kimmeridgian to Lower Tithonian), Port Waikato region, New Zealand, with description of a newBelemnopsis

Abstract

Abstract Biostratigraphy of the Ohauan and lower Puaroan stages in the Port Waikato region is described with particular reference to belemnite content. Hibolithes arkelli Stevens and Hibolithes marwicki marwicki Stevens, both characteristic taxa of the lower Puaroan at Kawhia Harbour, are recorded from the Port Waikato sequence for the first time. Belemnop.ris stevens; n. sp. is described from lower Ohauan strata. Correlation with the coastal section at Kawhia Harbour is possible on a biostratigraphical basis but lithological correlation is more difficult. Faunal elements are similar to those described from Kawhia Harbour but some elements are missing. This factor, together with reduced stratigraphic distances between some faunal range-zones, suggests that an ullconformity or condensed sequence occurs within the Ohauan/basal Puaroan part of the Port Waikato sequence. The base of the Ohauan stage at Port Waikato is relocated 200–250 m above its previously mapped position. The base of the Puaroan stage is r...