Hautotara Formation, Mangaopari Basin, New Zealand: Record of a cyclothemic Pliocene‐Pleistocene marine to nonmarine transition

Abstract

The late Pliocene -early Pleistocene Hautotara Formation in southeastern Wairarapa, New Zealand, comprises cyclic estuarine and shallow-marine deposits. The formation conformably overlies the fully marine Pukenui Limestone and is overlain by the fluvio-lacustrine Te Muna Formation. Hautotara Formation is a record of a tectonically induced regression from marine to nonmarine conditions. Within the Hautotara Formation, at least five glacioeustatically controlled cycles are superimposed on this tectonic record. The dual tectonic and glacio-eustatic controls are modified by paleogeographic and hydrodynamic processes, producing a variety of lithofacies. The basal glacio-eustatic cycle possibly represents a preserved lowstand estuary. A reinterpretation of the type section suggests that the top is a faulted repeat of the base of the Hautotara Formation. A new composite standard reference section is described for the Hautotara Formation.

Growth of contractional structures during the last 10 m.y. at the southern end of the emergent Hikurangi forearc basin, New Zealand

“…In particular, Hautotara Formation thins from c. 120-170 m close to the hinge of the Huangarua Syncline (Fig. 3, 7) to 30-50 m immediately east of the seismic line (Collen & Vella 1984;Gammon 1995; this study) and 0-18 m on the hinge of the Windy Peak Anticline (Rampton 1997). This formation therefore thickens from anticline hinge to syncline hinge, which we infer to partly result from changes in accommodation space during folding.…”

“…2,3). Here, outcrop and seismic-reflection lines of these deformed strata (Vella 1963;Vella & Briggs 1971;Collen & Vella 1984;Edwards 1987;Gammon 1995;Shane et al 1995Shane et al , 1996Rampton 1997) are combined with data from tilted and faulted alluvial terraces to analyse the growth histories of reverse faults and folds. These data constrain the styles, timing, and rates of deformation over the last 10 m.y.…”

The Early Quaternary Marine to Terrestrial Transition of the Southeastern Wairarapa, New Zealand

“…Cyclicity present in the Late Miocene to Pleistocene sedimentary deposits of the Eastern Wairarapa Valley has been examined in an attempt to document the pattern of glacio-eustatic sea-level changes in the basin (Gammon, 1995(Gammon, , 1997Vella, 1963a). With advances in the understanding of the sequence stratigraphic framework, subtle changes in the sedimentary deposits, macrofossil assemblages and boundary conditions of the Hautotara Formation will be used to identify Milankovitch-scale variations of sea-level change in increased detail.…”

“…Recent student projects include Rampton (1997) who mapped and interpreted the Late Neogene sequence within the northern part of the study area, and helped redefine a section of steeply dipping Hautotara and Te Muna Formation overlain unconformably by Ahiaruhe Formation (Nicol & Van Dissen, 1997). Gammon (1995Gammon ( , 1997 documented many stratigraphic sections in the region and attempted to identify a sequence-stratigraphic signature, and Clarke (1998) provides a valuable and detailed investigation into the biostratigraphy of the limestones of the lower Ruakokoputuna River and Makara Stream. Andrews (2001) constrained the depositional environment of the Pukenui Limestone in the Hinakura Road area,…”

“…As the number of geological investigations in the southern Wairarapa region increased over the last four decades, the progressive recognition and identification of lithological and biostratigraphic changes in the record forced workers to adopt new formation names, superseding previous definitions (e.g., Collen & Vella, 1984;Gammon, 1995;Vella & Briggs, 1971). As a result, the position of boundaries between formations have been modified and adapted.…”