Thermal history of the early Miocene Waitemata Basin and adjacent Waipapa Group, North Island, New Zealand

Abstract

Apatite fission track (AFT) and vitrinite reflectance (VR) data for early Miocene outcrops from the Waitemata Basin reveal that the basin sequence was subjected to shallow burial before denudation. AFT results suggest that the total sediment thickness within the basin was 1 km and maximum paleotemperatures during burial never exceeded c. 60°C. Statistical analyses of the detrital AFT ages distinguish four dominant sources of sediment supply: contemporaneous volcanism; metagreywacke rocks of the Waipapa Group; the Northland Allochthon; and an unidentified source south of the basin.The apatite and zircon fission track results from the Waipapa Group rocks (Gondwana Terrane) adjacent to the basin suggest two discrete phases of accelerated cooling: the first during the early Cretaceous (c. 117 Ma) and the second during the mid Cretaceous (c. 84 Ma). These events probably reflect key stages in the tectonic development of the New Zealand microcontinent during the Cretaceous period, the earlier event being related to the climax of compressional deformation (Rangitata Orogeny) and the latter to extensional tectonism associated with the opening of the Tasman Sea. Waipapa Group rocks now exposed at the surface cooled from maximum paleotemperatures of c. 250°C at an estimated rate of c. 180-36°C/m.y., involving substantial denudation.

Constraining provenance, thickness and erosion of nappes using low‐temperature thermochronology: the Northland Allochthon, New Zealand

“…In general, both the mean and the ‘best‐fit’ models reproduce the observed data well (Fig. b), except for the oldest ZFT age in the southeast of the model, which most likely represents a mixed age inherited from multiple detrital sources (Raza et al ., ). During the Late Oligocene–Early Miocene, the basement rocks in northern Northland are predicted to have undergone heating to over ca .…”

“…Basement fission‐track ages are from this study and Raza et al . (). Line x–x′ depicts the location of profiles in Figs and .…”

“…Potential source rocks of the allochthon and autochthon are interpreted based on mixture modelling of the fission‐track data (Section ), while the burial and heating histories of the samples are inferred from thermal history models (Section ). From the underlying in situ Mesozoic basement, new and published (Raza et al ., ) data are predicted by a thermo‐kinematic model that simulates the allochthon emplacement and subsequent erosion (Section ). The results of different modelling approaches provide constraints on the provenances, maximum thickness and the post‐emplacement erosion history of the Northland Allochthon (Section ).…”

Thermal history of the Cretaceous Sindong Group, Gyeongsang Basin, Korea based on fission track analysis

“…The thermal history of the sedimentary basin can be reconstructed by the combined use of multiple thermal indicators including FT analysis and vitrinite reflectance (VR, e.g. Raza et al ., 1999), and this involves the following three principal steps: (1) determination of maximum palaeotemperatures; (2) measurement of the time of cooling from maximum palaeotemperatures; (3) determination of palaeogeothermal gradient at the time of maximum palaeotemperatures (Duddy et al ., 1994).…”

Foraminifera‐based estimates of paleobathymetry using Modern Analogue Technique, and the subsidence history of the early Miocene Waitemata Basin

“…The early Miocene Waitemata sedimentary basin in northern New Zealand was a relatively short lived marine depression that accumulated 500-1000 m thickness (Raza et al 1999) of turbiditic sand and interbedded mud (Waitemata Group;Ballance 1974Ballance ,1976, prior to its eversion in the latter part of the early Miocene (Hayward 1979(Hayward ,1993. Subsequent uplift, regional westward tilting, and erosion have resulted in extensive exposures of Waitemata Group rocks throughout the Auckland region.…”