Olistostromes marking tectonic events, East Coast, New Zealand

Abstract

Three discrete, successive tectonic events are marked by olistostromes in the East Coast, North Island. An Eocene Mataikona event is characterised by in situ dismembered beds. A second, Owahanga event is Otaian and preceded wrench faulting coeval with the start of oblique subduction at the East Coast margin. This second event is characterised by extended emplacement of exotic material followed by gliding, gravity-driven nappes that are probably related to obduction along the north coast of the North Island. The third olistostrome is attributed to an early Miocene Mara event synchronous with incipient strike-slip faulting during Altonian times and the commencement of oblique convergence at the Hikurangi margin. From the ages and paleoenvironments of the olistostromes, we propose the Eocene and earliest Miocene syn-sedimentary structures were dragged along the deforming backstop of the Hikurangi prism.

Thermal history and exhumation of basement rocks from Mesozoic to Cenozoic subduction cycles, central North Island, New Zealand

“…Our estimates of the accelerated cooling phase in the hanging wall of the subduction zone concur with the period of increased crustal deformation during the late Oligocene to early Miocene, e.g., the development of thrust belts (~25–20 Ma) in eastern North Island [ Chanier and Ferriere , ; Rait et al ., ] and allochthon obduction in Northland and the East Cape (~25–21 Ma) [ Ballance and Spörli , ; Spörli , ]. The accelerated basement unroofing increased the sediment flux into the adjacent basins, depositing flysch sequences into the East Coast Basins to the east of the proto‐Axial Ranges [ Delteil et al ., ; Lee et al ., ]. In northeastern North Island, terrestrial conglomerates (in the early Miocene Tolaga Group) were suggested to derive from local emergent landmass, which had been uplifted during the subduction initiation [ Marsaglia et al ., ].…”

Olistostromes of the Pieniny Klippen Belt, Northern Carpathians

“…Delteil et al . (2006) described three olistostromes that marked successive tectonic events in the deformed belt of the North Island, New Zealand during Cenozoic time. The oldest shows seafloor instability and the other two were connected with nappe emplacement and strike-slip faults.…”

Origin and significance of olistostromes in the evolution of orogenic belts: A global synthesis

“…The recurrence interval of olistostromes in the geological record may be unrevealed with varying 751 degrees of accuracy, based on the well-constrained timing of olistostrome emplacement, subsequent 29 tectonic deformation events, and metamorphic history of the depositional environment of 753 olistostromes. Although the emplacement of an each single gravitational body is an instantaneous and 754 episodic event, the recurrence time for olistostrome and olistolith emplacement may vary from 755 thousands of years to several millions of years (e.g., Scherba, 1985;Delteil et al, 2006;Graziano, 756 2001;Wise and Ganis, 2008;Camerlenghi and Pini, 2009;Festa et al, 2015c). This time-scale may 757 be strongly affected by the duration of each regional-scale, single tectonic event, or more specifically 758 by the combination of eustatic and geodynamic processes (e.g., sedimentary transgressive -759 regressive cycles, global climate changes, gas-hydrates dissociations).…”