Stratigraphy and correlation of the Ururoan and Temaikan Stage (Lower‐Middle Jurassic, ?Sinemurian‐Callovian) sequences, New Zealand

Abstract

The biostratigraphy and chronostratigraphy of Ururoan, Temaikan, and earliest Heterian sequences from the Kawhia and Southland Regional Synclines are discussed and new chronostratigraphic divisions proposed. A new definition for the base of the Temaikan Stage is proposed, using the first appearance of either Belemnopsis deborahae or Belemnopsis mackayi. The paucity of suitable Substage markers in the Ururoan is overcome by defining Early and Late Ururoan divisions based on the first and last appearances of Pseudaucella marshalli. New Substage and chronozonal divisions of the Temaikan are based on the first appearances of seven species of Retroceramus. The first appearances of Retroceramus inconditus and R. marwicki are used to mark the bases of the Middle and Late Temaikan, respectively. A zonal scheme for the Middle and Late Temaikan uses the first appearance of Retroceramus brownei (late Middle Temaikan Chronozone), Retroceramus sp. A (Late Temaikan, Chronozone 2), Retroceramus stehni (Late Temaikan, Chronozone 3), Retroceramus sp. C or D (Late Temaikan, Chronozone 4). Correlation of the Ururoan and Temaikan Stages with the International Stage scheme is reviewed with the base of the Temaikan correlated with the latest Toarcian‐Aalenian.

Keywords:

• Ururoan
• Temaikan
• Heterian
• Jurassic
• New Zealand
• lithostratigraphy
• biostratigraphy
• chronostratigraphy
• stage divisions
• Opapaka Sandstone
• Urawitiki Measures
• Wharetanu Measures
• Murihiku Supergroup
• Kawhia Regional Syncline
• Southland Regional Syncline
• Port Waikato
• Kawhia
• Awakino valley
• Rauroa valley
• Catlins
• Hokonui Hills
• Lora valley
• Heale Ridge
• Pseudaucella
• Retroceramus
• Meleagrinella
• Belemnopsis
• ammonoids
• international and national correlation

Notes

Department of Geology, University of Auckland, Private Bag 92 019, Auckland, New Zealand. Email: [email protected]