title: Petrogenesis of diachronous mixed siliciclastic-carbonate megafacies in the cool-water Oligocene Tikorangi Formation, Taranaki Basin, New Zealand

authors: Hood, Steven D.

subjects: petrogenesis

abstract: The Oligocene (Whaingaroan-Waitakian) Tikorangi Formation is a totally subsurface, lithostratigraphically complex, mixed siliciclastic-limestone-rich sequence forming an important fracture reservoir within Taranaki Basin, New Zealand. Petrographically the formation comprises a spectrum of interbedded rock types ranging from calcareous mudstone to wackestone to packstone to clean sparry grainstone. Skeletal and textural varieties within these rock types have aided in the identification of three environmentally distinctive megafacies for the Tikorangi Formation rocks-shelfal, foredeep, and basinal. Data from these megafacies have been used to detail previous conclusions on the petrogenesis and to further refine depositional paleoenvironmental models for the Tikorangi Formation in the central eastern Taranaki Basin margin.Shelfal Megafacies 1 rocks (reference well Hu Road-1A) are latest Oligocene (early Waitakian) in age and formed on or proximal to the Patea-Tongaporutu-Herangi basement high. They are characterised by coarse, skeletal-rich, pure sparry grainstone comprising shallow water, high energy taxa (bryozoans, barnacles, red algae) and admixtures of coarse well-rounded lithic sand derived from Mesozoic basement greywacke. This facies type has previously gone unrecorded in the Tikorangi Formation. Megafacies 2 is a latest Oligocene (early Waitakian) foredeep megafacies (formerly named shelfal facies) formed immediately basinward and west of the shelfal basement platform. It accumulated relatively rapidly (>20 cm/ka) from redeposition of shelfal megafacies biota that became intermixed with bathyal taxa to produce a spectrum of typically mudstone through to sparry grainstone. The resulting skeletal mix (bivalve, echinoderm, planktic and benthic foraminiferal, red algal, bryozoan, nannofossil) is unlike that in any of the age-equivalent limestone units in neighbouring onland King Country Basin. Megafacies 3 is an Oligocene (Whaingaroan-Waitakian) offshore basinal megafacies (formerly termed bathyal facies) of planktic foraminiferal-nannofossil-siliciclastic wackestone and mudstone formed away from redepositional influences. The siliciclastic input in this distal basinal setting (sedimentation rates <7 mm/ka) was probably sourced mainly from oceanic currents carrying suspended sediment from South Island provenances exposed at this time.Tikorangi Formation rocks record the Taranaki Basin’s only period of carbonate-dominated sedimentation across a full range of shelfal, foredeep, and basinal settings. Depositional controls on the three contrasting megafacies were fundamentally the interplay of an evolving and complex plate tectonic setting, including development of a carbonate foredeep, changes in relative sea level within an overall transgressive regime, and changing availability, sources, and modes of deposition of both bioclastic and siliciclastic sediments. The mixed siliciclastic-carbonate nature of the formation, and its skeletal assemblages, low-Mg calcite mineralogy, and delayed deep burial diagenetic history, are features consistent with formation in temperate-latitude cool waters.

text: Petrogenesis of diachronous mixed siliciclastic-carbonate megafacies in the cool-water Oligocene Tikorangi Formation, Taranaki Basin, New Zealand The Oligocene (Whaingaroan-Waitakian) Tikorangi Formation is a totally subsurface, lithostratigraphically complex, mixed siliciclastic-limestone-rich sequence forming an important fracture reservoir within Taranaki Basin, New Zealand. Petrographically the formation comprises a spectrum of interbedded rock types ranging from calcareous mudstone to wackestone to packstone to clean sparry grainstone. Skeletal and textural varieties within these rock types have aided in the identification of three environmentally distinctive megafacies for the Tikorangi Formation rocks-shelfal, foredeep, and basinal. Data from these megafacies have been used to detail previous conclusions on the petrogenesis and to further refine depositional paleoenvironmental models for the Tikorangi Formation in the central eastern Taranaki Basin margin.Shelfal Megafacies 1 rocks (reference well Hu Road-1A) are latest Oligocene (early Waitakian) in age and formed on or proximal to the Patea-Tongaporutu-Herangi basement high. They are characterised by coarse, skeletal-rich, pure sparry grainstone comprising shallow water, high energy taxa (bryozoans, barnacles, red algae) and admixtures of coarse well-rounded lithic sand derived from Mesozoic basement greywacke. This facies type has previously gone unrecorded in the Tikorangi Formation. Megafacies 2 is a latest Oligocene (early Waitakian) foredeep megafacies (formerly named shelfal facies) formed immediately basinward and west of the shelfal basement platform. It accumulated relatively rapidly (>20 cm/ka) from redeposition of shelfal megafacies biota that became intermixed with bathyal taxa to produce a spectrum of typically mudstone through to sparry grainstone. The resulting skeletal mix (bivalve, echinoderm, planktic and benthic foraminiferal, red algal, bryozoan, nannofossil) is unlike that in any of the age-equivalent limestone units in neighbouring onland King Country Basin. Megafacies 3 is an Oligocene (Whaingaroan-Waitakian) offshore basinal megafacies (formerly termed bathyal facies) of planktic foraminiferal-nannofossil-siliciclastic wackestone and mudstone formed away from redepositional influences. The siliciclastic input in this distal basinal setting (sedimentation rates <7 mm/ka) was probably sourced mainly from oceanic currents carrying suspended sediment from South Island provenances exposed at this time.Tikorangi Formation rocks record the Taranaki Basin’s only period of carbonate-dominated sedimentation across a full range of shelfal, foredeep, and basinal settings. Depositional controls on the three contrasting megafacies were fundamentally the interplay of an evolving and complex plate tectonic setting, including development of a carbonate foredeep, changes in relative sea level within an overall transgressive regime, and changing availability, sources, and modes of deposition of both bioclastic and siliciclastic sediments. The mixed siliciclastic-carbonate nature of the formation, and its skeletal assemblages, low-Mg calcite mineralogy, and delayed deep burial diagenetic history, are features consistent with formation in temperate-latitude cool waters.

year: 2003

title: Extended identities: The reducibility of non-categorical properties and their bearers

authors: Hubble, Paul

subjects: Extended Mind

abstract: When we take apart big or complicated things—whether events, processes, systems, objects or states—we find smaller or simpler things. Still, some who purport that everything is physical also want to deny that complicated things are sets of simpler things, their relations, and interactions. But that view leads to some confounding puzzles. By contrast, I defend the view that complicated things are nothing over and above simpler things, their relations, and interactions. The latter are all physical and located in space and time, and so are complicated things, like minds and people, and other things defined by what they could or would do. That includes corkscrews and water soluble things. However, the complicated properties of these complicated things show that, very often, these things are either not quite what we think they are, or they are not wholly where we think they are.

Sometimes things aren't what we thought. There is no lumniferous aether or phlogiston. But often, complicated things elude identification with their sets of simpler things, relations and interactions, not because they don't belong in predictively successful models of our world, but because they aren't wholly *where* we tend to look. Their boundaries are wider and untidy. As it happens, our minds are like that, and so are we. Finally, the fact that the extended identity of things like us comes as a surprise means our self-engineering could be more self-aware, and should be more self-reflective.

text: Extended identities: The reducibility of non-categorical properties and their bearers When we take apart big or complicated things—whether events, processes, systems, objects or states—we find smaller or simpler things. Still, some who purport that everything is physical also want to deny that complicated things are sets of simpler things, their relations, and interactions. But that view leads to some confounding puzzles. By contrast, I defend the view that complicated things are nothing over and above simpler things, their relations, and interactions. The latter are all physical and located in space and time, and so are complicated things, like minds and people, and other things defined by what they could or would do. That includes corkscrews and water soluble things. However, the complicated properties of these complicated things show that, very often, these things are either not quite what we think they are, or they are not wholly where we think they are.

Sometimes things aren't what we thought. There is no lumniferous aether or phlogiston. But often, complicated things elude identification with their sets of simpler things, relations and interactions, not because they don't belong in predictively successful models of our world, but because they aren't wholly *where* we tend to look. Their boundaries are wider and untidy. As it happens, our minds are like that, and so are we. Finally, the fact that the extended identity of things like us comes as a surprise means our self-engineering could be more self-aware, and should be more self-reflective.

year: 2020

title: Land/seascapes of exclusion: social order on the coastal margins

authors: Ryks, John

abstract: The hegemonic discourse of coastal planning and development has an impact on the social ordering of Aotearoa/New Zealand’s coastal communities in a number of ways. One way in which social order is controlled and maintained is through the (ab)use of boundaries. Boundaries constructed and maintained under the authority of government and/or funded by development dictate where people may or may not live. In many cases these boundaries are used as instruments of exclusion. Boundaries constructed by hegemonic groups exclude those who define the coast according to other criteria. The hegemonic deployment of boundaries and the domination of coastal people and place generally is explored through an analysis of discourse. This analysis is structured according to differences in social order, coded as places of Otherness (heterotopia), Euclidean coasts, and places in transition reflecting images of both the former and the latter.
Drawing on a number of coastal communities, including the Northland community of Otia (otherwise known as the Seaweed Pickers), Taylor’s Mistake, Whitianga and the wealth enclave of Pauanui, it is shown that the land/seascape of coastal Aotearoa/New Zealand is gradually being disciplined through the design of coasts that are accommodating of a particular patronage. These ‘exclusive’ coasts appear in stark contrast to those places where an alternative social ordering takes place. Here, in the absence of a Euclidean spatiality, uncertainty and liminality feature in the social construction of the coast. Residents of these places mark out and define the coast in a way that is quite different from the accepted norm, a fact that determines a particular ‘cartographic anxiety’ on the part of the dominant. This anxiety is instrumental in the construction of Otherness and the (re)production of exclusion.

text: Land/seascapes of exclusion: social order on the coastal margins The hegemonic discourse of coastal planning and development has an impact on the social ordering of Aotearoa/New Zealand’s coastal communities in a number of ways. One way in which social order is controlled and maintained is through the (ab)use of boundaries. Boundaries constructed and maintained under the authority of government and/or funded by development dictate where people may or may not live. In many cases these boundaries are used as instruments of exclusion. Boundaries constructed by hegemonic groups exclude those who define the coast according to other criteria. The hegemonic deployment of boundaries and the domination of coastal people and place generally is explored through an analysis of discourse. This analysis is structured according to differences in social order, coded as places of Otherness (heterotopia), Euclidean coasts, and places in transition reflecting images of both the former and the latter.
Drawing on a number of coastal communities, including the Northland community of Otia (otherwise known as the Seaweed Pickers), Taylor’s Mistake, Whitianga and the wealth enclave of Pauanui, it is shown that the land/seascape of coastal Aotearoa/New Zealand is gradually being disciplined through the design of coasts that are accommodating of a particular patronage. These ‘exclusive’ coasts appear in stark contrast to those places where an alternative social ordering takes place. Here, in the absence of a Euclidean spatiality, uncertainty and liminality feature in the social construction of the coast. Residents of these places mark out and define the coast in a way that is quite different from the accepted norm, a fact that determines a particular ‘cartographic anxiety’ on the part of the dominant. This anxiety is instrumental in the construction of Otherness and the (re)production of exclusion.

year: 2002