71 results on '"Hamish J. Campbell"'
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2. Zealandia and Australia at Ordovician continental margins: reconciling their similar and differing detrital zircon provenances within Rodinia
- Author
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Chris J. Adams and Hamish J. Campbell
- Subjects
Geophysics ,Earth and Planetary Sciences (miscellaneous) ,Geology - Published
- 2023
3. Age and structure of the Permian Brook Street Terrane, Takitimu Mountains, New Zealand
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Matthew J. Campbell, Nick Mortimer, Gideon Rosenbaum, Charlotte M. Allen, Paulo M. Vasconcelos, and Hamish J. Campbell
- Subjects
Geophysics ,Earth and Planetary Sciences (miscellaneous) ,Geology - Published
- 2022
4. Detrital zircon provenance of Permian to Triassic Gondwana sequences, Zealandia and eastern Australia
- Author
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Christopher J. Adams, Nick Mortimer, Hamish J. Campbell, and William L. Griffin
- Subjects
Gondwana ,Paleontology ,Provenance ,Geophysics ,Basement (geology) ,Permian ,Clastic rock ,Earth and Planetary Sciences (miscellaneous) ,Geology ,Devonian ,Terrane ,Zircon - Abstract
Permian Parapara Group and Triassic Topfer Formation are small clastic sedimentary outliers that rest on Cambrian to Devonian basement terranes in the Western Province of South Island, New Zealand....
- Published
- 2021
5. Correlation between the Warepan/Otapirian and the Norian/Rhaetian stage boundary: implications of a global negative δ13Corg perturbation
- Author
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Hamish J. Campbell and Manuel Rigo
- Subjects
Rhaetian ,Otapirian ,010504 meteorology & atmospheric sciences ,δ ,Boundary (topology) ,boundary ,Gondwana ,Late Triassic ,New Zealand ,Norian ,Warepan ,Zealandia ,13 ,C ,org ,010502 geochemistry & geophysics ,01 natural sciences ,Correlation ,Paleontology ,Stage (stratigraphy) ,Earth and Planetary Sciences (miscellaneous) ,Formal description ,0105 earth and related environmental sciences ,Geology ,Perturbation (geology) ,Geophysics ,Interval (graph theory) - Abstract
The Norian/Rhaetian boundary interval (Late Triassic) is characterised by significant biotic turnover and severe climatic changes. However, this boundary still awaits formal definition. We have inv...
- Published
- 2021
6. Detrital zircon age constraints on depositional history and provenance of the Murihiku Supergroup, Murihiku Terrane, North Island, New Zealand
- Author
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Christopher J. Adams and Hamish J. Campbell
- Subjects
Provenance ,Accretionary wedge ,010504 meteorology & atmospheric sciences ,Permian ,Geology ,010502 geochemistry & geophysics ,01 natural sciences ,Cretaceous ,Paleontology ,Batholith ,Forearc ,0105 earth and related environmental sciences ,Zircon ,Terrane - Abstract
In the Murihiku Terrane of New Zealand, U-Pb detrital zircon ages in Murihiku Supergroup sandstones of Late Triassic, Jurassic and possibly earliest Cretaceous age have a marked youngest age component that is close to, and sometimes coincident with, established biostratigraphic ages, thus reflecting contemporary volcanism. However, youngest Huriwai Group samples yield 137–142 Ma zircon age components (earliest Early Cretaceous) in conflict with palynofloras that suggest only a latest Jurassic age. This is resolved if the age of the Jurassic/Cretaceous boundary is lowered to ca. 140 Ma. Older, reworked zircons are mainly Early Jurassic, Late Triassic and Late Permian reflecting an enduring exhumed magmatic arc source nearby. This might be in the adjacent Median Batholith but as a Murihiku sediment source its Jurassic, Triassic and Permian elements are not well-matched in terms of extent, age and bulk compositions. A connection between the Murihiku (proximal forearc) and Waipapa Composite (distal accretionary wedge) terranes is probable, with a common magmatic arc, speculatively situated in the New England Orogen, eastern Australia.
- Published
- 2020
7. The Norfolk Ridge seamounts: Eocene–Miocene volcanoes near Zealandia’s rifted continental margin
- Author
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Julien Collot, Samuel Etienne, Martin P. Crundwell, Nick Mortimer, Patricia Durance, Arnaud Agranier, Hamish J. Campbell, Gilles Chazot, Martin Patriat, and Phillip B. Gans
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010506 paleontology ,Seamount ,geochronology ,Guyot ,volcanoes ,010502 geochemistry & geophysics ,01 natural sciences ,guyots ,Paleontology ,Continental margin ,Earth and Planetary Sciences (miscellaneous) ,14. Life underwater ,geochemistry ,0105 earth and related environmental sciences ,geography ,geography.geographical_feature_category ,Cenozoic ,Southwest Pacific ,Volcano ,Ridge ,Geochronology ,seamounts ,General Earth and Planetary Sciences ,Norfolk Ridge ,Zealandia ,Geology - Abstract
New age and geochemical data are used to investigate the origin of a ∼670 km-long line of eight seamount volcanoes along the western side of the Norfolk Ridge between New Caledonia and New Zealand. Altered lavas and limestones were dredged from three volcanoes during the 2015 Volcanic Evolution of South Pacific Arcs cruise of N/O l’Atalante, so a total of four, including the northernmost and southernmost, have now been directly sampled and analysed. Dating of lava and volcanic breccia clasts by Ar–Ar methods gives north-to-south ages from these sites of 31.3 ± 0.6, 33 ± 5, 21.5 ± 1.0 and 26.3 ± 0.1 Ma. These ages, along with supporting stratigraphic data on a fifth seamount from IODP borehole U1507, provisionally refute the hypotheses that the seamounts represent a southward-younging, age-progressive, intraplate volcanic chain on the Australian Plate or a subduction-related chain of restricted age range. Geochemically, the upper Eocene to lower Miocene lavas have alkaline and subalkaline basaltic compositions, and some could be shoshonitic. The location of the volcanoes along the western side of the Norfolk Ridge suggests an origin related to late Eocene and early Miocene melting near an intracontinental lithosphere–asthenosphere step. Involvement of a deep slab in petrogenesis is also possible. KEY POINTS Eight seamounts form a line along the Norfolk Ridge. Dating and geochemistry indicate the seamount line is not a hotspot track. A rift-related origin, possibly with influence by subduction, is proposed.
- Published
- 2020
8. Detrital zircon age studies of Haast Schist in western Otago and Marlborough, New Zealand: constraints on their protolith age, terrane ancestry and Au–W mineralisation
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Christopher J. Adams, Hamish J. Campbell, and William L. Griffin
- Subjects
010506 paleontology ,Earth and Planetary Sciences (miscellaneous) ,Haast Schist ,Geochemistry ,General Earth and Planetary Sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Protolith ,Geology ,0105 earth and related environmental sciences ,Terrane ,Zircon - Abstract
Detrital zircon U–Pb ages are reported from the Haast Schist in western Otago and Marlborough, South Island, New Zealand. The majority are from the Aspiring Lithological Association in Otago, which...
- Published
- 2020
9. Fluvial and lacustrine successions in the youngest part of the Murihiku Supergroup, New Zealand
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J. I. Raine, Dominic P. Strogen, Christopher J. Adams, Greg H. Browne, T. R. Sahoo, Hamish J. Campbell, and Elizabeth M. Kennedy
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010504 meteorology & atmospheric sciences ,Geology ,010502 geochemistry & geophysics ,01 natural sciences ,Cretaceous ,Sedimentary depositional environment ,Paleontology ,Source rock ,Macroflora ,Syncline ,Sedimentology ,Siltstone ,0105 earth and related environmental sciences ,Terrane - Abstract
Fossil-bearing Late Jurassic to Early Cretaceous volcaniclastic sandstones and siltstones from the Murihiku Supergroup are described from the Kaimango Syncline South Auckland, New Zealand. These constitute the youngest known sedimentary succession within the Murihiku Supergroup (Murihiku Terrane). We concentrate on the youngest Matira Siltstone Formation which has yielded a rich but relatively low-diversity macroflora of ferns and gymnosperms, diverse miospore palynofloras, with fair to good preservation, and sporadic occurrences of bivalve and gastropod faunas. Collectively, the paleontology and sedimentology of this formation is interpreted to represent paludal and lacustrine deposition, with intercalated sandstones thought to represent fluvial channelised or deltaic settings. U-Pb dating of detrital zircons (DZ) from sandstones in the youngest formations, Mangatara Measures and Matira Siltstone, have provided significant components in the age range 140 to 143 Ma, possibly straddling the Jurassic-Cretaceous boundary, although miospores suggest a Late Jurassic correlation. Lacustrine and paludal depositional environments have not previously been recognised from the Murihiku Supergroup and this raises the prospect of their enhanced petroleum source rock potential in frontier basins to the north and east of New Zealand.
- Published
- 2020
10. Chapter 8 Palaeobiogeography of New Caledonia
- Author
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Hamish J. Campbell and P. Maurizot
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0106 biological sciences ,geography ,geography.geographical_feature_category ,Geology ,Biota ,010502 geochemistry & geophysics ,Geologic record ,010603 evolutionary biology ,01 natural sciences ,Obduction ,Gondwana ,Paleontology ,Archipelago ,Vicariance ,Biological dispersal ,Endemism ,0105 earth and related environmental sciences - Abstract
New Caledonia is known as a global biodiversity hotspot. Like most Pacific islands, its modern biota is characterized by high levels of endemism and is notably lacking in some functional groups of biota. This is the result of its distinctive palaeobiogeographical history, which can be described in terms of three major episodes relating to Gondwana, Zealandia and New Caledonia. The geological record, the fossil record and the modern biota of the archipelago are all reviewed here. The geological record shows that the main island, Grande Terre, was submerged between 75 and 60 Ma. There is a 9 myr interval without any geological record between 34 and 25 Ma, immediately after the obduction of the Peridotite Nappe. Grande Terre may or may not have been submerged during this 9 myr interval. The ages given by molecular biology, independent of any geological calibration points, form a continuous spectrum from 60 Ma up to the present day. The derived lineage ages from molecular phylogenies all post-date 60 Ma, supporting the idea of the continuous availability of terrestrial environments since 60 Ma. Of the three common scenarios for the origin of the New Caledonia biota, long-distance dispersal is the most plausible, rather than vicariance or dispersal over short distances.
- Published
- 2020
11. Chatham Schist
- Author
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Nick Mortimer, Hamish J. Campbell, and Nichole Moerhuis
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Geophysics ,Earth and Planetary Sciences (miscellaneous) ,Geology - Published
- 2019
12. Chapter 13 Permian–Triassic felsic tuffs in South Island, New Zealand: significance for oceanic and active continental margin subduction
- Author
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Alastair H. F. Robertson, Hamish J. Campbell, and Romesh Palamakumbura
- Subjects
Gondwana ,Felsic ,Permian ,Subduction ,Continental margin ,Terrigenous sediment ,Early Triassic ,Geochemistry ,Geology ,Terrane - Abstract
Felsic tuffs play an important role in the Permian–Triassic geology of the Eastern Province in South Island. In the Brook Street Terrane, primary felsic tuff is minor in the south (e.g. Takitimu Mountains) but abundant in the north (Grampian Formation, Nelson area). Felsic fallout tuff dominates one interval of the Maitai Group (Early Triassic Kiwi Burn Formation), south of the Alpine Fault, but is otherwise mainly redeposited by gravity flows. The Murihiku Terrane is characterized by two main intervals of felsic fallout tuff, the Middle Triassic Gavenwood Tuffs and the Late Triassic Bare Hill Tuff Zone, south of the Alpine Fault (e.g. Hokonui Hills and south Otago coast). Counterparts north of the Alpine Fault (Richmond Group) are mainly reworked, with terrigenous admixtures. Tuffaceous sediments are also abundant in the late Middle–early Late Triassic Willsher Group (south Otago coast). Based on combined field, petrographical, semi-quantitative X-ray diffraction (XRD) and chemical evidence, the felsic tuffs of the Brook Street Terrane in the south are interpreted as small-scale eruptions of fractionated oceanic-arc-type magmas. In contrast, the Triassic felsic tuffs of the Murihiku Terrane, Willsher Group and Maitai Group erupted violently and episodically in proximal to distal segments of the SE Gondwana continental margin.
- Published
- 2019
13. Chapter 1 Introduction to Paleozoic–Mesozoic geology of South Island, New Zealand: subduction-related processes adjacent to SE Gondwana
- Author
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Alastair H. F. Robertson, Nick Mortimer, Hamish J. Campbell, and Mike R. Johnston
- Subjects
geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Volcanic arc ,Permian ,Paleozoic ,Geology ,010502 geochemistry & geophysics ,01 natural sciences ,Supercontinent ,Paleontology ,Gondwana ,Basement (geology) ,Forearc ,0105 earth and related environmental sciences ,Terrane - Abstract
This Memoir presents and discusses recent research mainly concerning the Permian and Triassic geological development of South Island in its regional context, which includes New Zealand as a whole, the continent of Zealandia, eastern Australia and Antarctica. The Permian and Triassic geology of the South Island encompasses several geological units which shed light on fundamental geological processes. These include a well-developed oceanic volcanic arc, a classic subduction-related ophiolite (oceanic crust on land) and a very thick succession of continental margin forearc sediments. These, and other related geological units, constitute the oldest extensively outcropping basement of Zealandia, which can be considered as the world's seventh largest continent, albeit 94% submerged (Mortimer et al. 2017). The supercontinent, Gondwana, formed during the Late Neoproterozoic and remained until its progressive break-up into crustal fragments during the Mesozoic. During this prolonged period, New Zealand and adjacent crustal units were located along the SE edge of Gondwana. Subduction took place beneath this margin during the Paleozoic–Mesozoic, until the end of Early Cretaceous time ( c. 100 Ma) when it halted, followed by rifting of the Tasman Sea Basin. This volume consists of 14 contributions, comprising a mix of new-data-based papers (and one note) and several review and synthesis papers. The contributions largely concern igneous and sedimentary geology, tectonics and biostratigraphy. Particular emphasis is placed on field geology, petrography and geochemistry. Some aspects are less well covered (e.g. Permian–Triassic geology of New Zealand's Cordilleran-style Median Batholith; metamorphic geology), primarily because there is a large amount of existing and/or recently published data. While the Permian–Triassic terranes bear imprints of Gondwana break-up and Neogene Alpine Fault development, these topics are outside the scope of this volume. The final chapter discusses various tectonic-based interpretations for the Permian–Triassic development of Zealandia and points the way to an overall synthesis. In this introductory …
- Published
- 2019
14. Chapter 12 A 251 Ma diorite clast from a Maitai Group conglomerate and a c. 259 Ma microdiorite sill intruding the Productus Creek Group, Southland, New Zealand: note
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R.E. Turnbull, Alastair H. F. Robertson, Hamish J. Campbell, and Nick Mortimer
- Subjects
Gondwana ,Provenance ,Permian ,Batholith ,engineering ,Geochemistry ,Geology ,engineering.material ,Terrane ,Diorite ,Hornblende ,Conglomerate - Abstract
We present the results of U–Pb dating of zircons of two Late Permian igneous rocks from the Dun Mountain–Maitai and Brook Street terranes of New Zealand9s South Island. A conglomerate clast of hornblende diorite from the Early–Middle Triassic Stephens Subgroup, Maitai Group, gives an age of 251.1 ± 1.6 Ma. A sample of hypabyssal andesite–microdiorite (Weetwood Formation) that intrudes the Late Permian Productus Creek Group of the Brook Street Terrane gives an age of 258.8 ± 7.9 Ma. The intermediate and subalkaline geochemistry of the two samples is not distinctive of specific tectonic settings, but their ages match plutons of the I-type, subduction-related Longwood Suite of the nearby Median Batholith. Assuming that correlation with the Longwood Suite is correct, the Weetwood sample increases the known areal extent of intrusion of the Longwood Suite; and the Stephens Subgroup Formation clast is consistent with a detrital link between Gondwana and the Dun Mountain–Maitai Terrane by the Middle Triassic. However, because of uncertainties regarding the timing of magmatism along other parts of the Gondwana margin, the data in this paper do not establish any specific provenance links.
- Published
- 2019
15. Chapter 3 Biostratigraphic age review of New Zealand's Permian–Triassic central terranes
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Hamish J. Campbell
- Subjects
Paleontology ,Permian ,Memoir ,Geology ,Terrane - Abstract
This contribution considers the fossil content of the three Eastern Province ‘central’ terranes discussed within this Memoir, namely the Brook Street Terrane, the Dun Mountain–Maitai Terrane and the Murihiku Terrane, and reviews the evidence and/or arguments for the current interpretation of their age ranges as determined from fossils. It also briefly considers the Permian–Triassic record of the Western Province. There has been limited new palaeontological discovery in the past few decades but there has been significant new taxonomic and biostratigraphic analysis of New Zealand Permian faunas in light of new research in eastern Australia. This enables refinement of age correlations and greater confidence in the age significance of the New Zealand Permian record.
- Published
- 2019
16. Chapter 15 Construction of a Paleozoic–Mesozoic accretionary orogen along the active continental margin of SE Gondwana (South Island, New Zealand): summary and overview
- Author
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Romesh Palamakumbra, Mike R. Johnston, Hamish J. Campbell, and Alastair H. F. Robertson
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Paleontology ,Gondwana ,Subduction ,Continental margin ,Batholith ,Geology ,Accretion (geology) ,Ophiolite ,Forearc ,Terrane - Abstract
The Western Province is a fragment of the c. 500 Ma SE Gondwana active continental margin. The Eastern Province is a terrane assemblage, which is partly stitched by the Median Batholith. Fragments of the batholith are preserved in the adjacent Drumduan and Brook Street terranes. Permian arc magmatism of the Brook Street Terrane involved both oceanic and continental margin settings. The Permian (c. 285–275 Ma) supra-subduction zone Dun Mountain ophiolite records subduction initiation and subsequent oceanic-arc magmatism. The Permian Patuki and Croisilles melanges represent detachment of the ophiolitic forearc and trench–seamount accretion. The Murihiku Terrane, a proximal continental margin forearc basin, received detritus from the Median Batholith (or equivalent). The south coast, Early–Late Triassic Willsher Group is another proximal forearc basin unit. The sediments of the Dun Mountain–Maitai Terrane (Maitai basin) represent a distal segment of a continental margin forearc basin. The Caples Terrane is a mainly Triassic trench accretionary complex, dominantly sourced from a continental margin arc, similar to the Median Batholith. The outboard (older) Torlesse and Waipapa terranes are composite subduction complexes. Successively more outboard terranes may restore farther north along the SE Gondwana continental margin. Subduction and terrane assembly were terminated by collision (at c. 100 Ma), followed by rifting of the Tasman Sea Basin.
- Published
- 2019
17. Chapter 14 Crossing Cook Strait: terranes of the Marlborough Schist, Kapiti Island and Wellington
- Author
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William L. Griffin, Christopher J. Adams, Hamish J. Campbell, and Nick Mortimer
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Paleontology ,Basement (geology) ,Paleozoic ,Age groups ,Group (stratigraphy) ,Schist ,Age patterns ,Geology ,Terrane ,Zircon - Abstract
U–Pb detrital zircon age patterns in sandstones from the Wellington and eastern Cook Strait area have broad Permian–Triassic and Precambrian–early Paleozoic age groups that confirm a previously established Triassic Rakaia Terrane correlation. Along the western Cook Strait coast, meta-psammitic Marlborough Schist samples have zircon patterns with a single age group, either Late Triassic or Jurassic, indicating a Waipapa Terrane ancestry. Similar data from the central Cook Strait region suggest that Waipapa Terrane basement continues northeastwards from Marlborough through Fishermans Rock to Kapiti Island. The Rakaia–Waipapa terrane boundary thus lies east of Kapiti Island and Fishermans Rock. The position of a Caples–Waipapa terrane boundary within the Marlborough Schist is less certain but most of the eastern Marlborough Schist is Waipapa Terrane.
- Published
- 2019
18. Seashore Settlement Patterns in the Koné and Naïa Periods: Case Studies from Southwestern New Caledonia
- Author
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Christophe Sand, J.A. Grant-Mackie, Hamish J. Campbell, and Jocelyn Turnbull
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010506 paleontology ,Archeology ,History ,060102 archaeology ,Ecology ,06 humanities and the arts ,Oceanography ,01 natural sciences ,Archaeology ,Geography ,Geological survey ,0601 history and archaeology ,Mainland ,Settlement (litigation) ,0105 earth and related environmental sciences - Abstract
As part of a geological survey in southwest mainland New Caledonia, potsherds were recorded in the profiles at four coastal sites. Subsequent archaeological investigations at two of these s...
- Published
- 2018
19. Chapter 3 Pre-Late Cretaceous basement terranes of the Gondwana active margin of New Caledonia
- Author
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Jean-Yves Collot, Pierre Maurizot, Brice Sevin, Hamish J. Campbell, Sebastien Meffre, Dominique Cluzel, and Université de la Nouvelle-Calédonie (UNC)
- Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics ,010504 meteorology & atmospheric sciences ,Paleozoic ,Permian ,Geology ,15. Life on land ,010502 geochemistry & geophysics ,Ophiolite ,01 natural sciences ,Cretaceous ,Paleontology ,Gondwana ,Basement (geology) ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,14. Life underwater ,Forearc ,0105 earth and related environmental sciences ,Terrane - Abstract
International audience; Abstract The basement under the Late Cretaceous unconformity in New Caledonia consists of three amalgamated terranes. They are all oceanic, arc-related and developed offshore from the eastern Gondwana active margin during periods of marginal basin development. Téremba Terrane is composed of deep sea Permian to Mesozoic arc-derived volcanic rocks and greywackes. The Koh–Central Terrane includes at its base an ophiolite with island arc tholeiites and boninites (Koh Ophiolite) of Late Carboniferous to Early Permian age overlain by a thick sequence of greywacke (Central Range Volcaniclastic Rocks) of Permian to Late Jurassic age. The Téremba Terrane and the Koh–Central Terrane may be part of the same forearc basin, with the rocks from the Koh–Central Terrane deposited in a deeper environment. The Boghen Terrane is a metamorphic complex composed of schists, broken formations and mafic–ultramafic mélange, derived from mixed terrigenous and volcanic sources. The overall fine grain size and laminar bedding suggest deep sea and more distal deposition than the other terranes. The maximum depositional ages from detrital zircons suggest deposition during the Early Jurassic to Early Cretaceous. The terrane is interpreted as a metamorphosed subduction complex that includes blueschist and greenschist facies metamorphic rocks exhumed through the Koh–Central Terrane. At a regional scale, the nature of these three pre-Late Cretaceous terranes confirms the existing palaeogeographical reconstructions, which locate New Caledonia outboard the ocean–continent subduction that surrounded Gondwana during the Paleozoic and Early Mesozoic. A detailed analysis of these terranes and their relationship with East Australian terranes of the same age shows that a marginal basin system probably existed between mainland Gondwana and proto-New Caledonia and closed before the Late Cretaceous. A tentative detailed reconstruction of this margin during the Carboniferous–Early Cretaceous period is proposed.
- Published
- 2020
20. The Late Triassic Extinction at the Norian/Rhaetian boundary: Biotic evidence and geochemical signature
- Author
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Spencer G. Lucas, Manuel Rigo, Matteo Maron, Giuseppe Concheri, Miriam E. Katz, Jaime Cesar, Hamish J. Campbell, Angela Bertinelli, Mariachiara Zaffani, Claudia Agnini, Fabio Tateo, Marco Chiari, Linda Godfrey, Kliti Grice, Lawrence H. Tanner, Lydia S. Tackett, Daisuke Yamashita, and Tetsuji Onoue
- Subjects
Rhaetian ,Disturbance (geology) ,010504 meteorology & atmospheric sciences ,δ ,Large igneous province ,Norian ,010502 geochemistry & geophysics ,01 natural sciences ,Supercontinent ,Mass extinction, δ13Corg, Norian-Rhaetian, Late Triassic, LIPs, Meteorite crater ,Mass extinction ,Carbon cycle ,Paleontology ,Meteorite crater ,Bolide ,LIPs ,org ,Late Triassic ,0105 earth and related environmental sciences ,δ13Corg ,Extinction event ,Extinction ,Norian-Rhaetian ,Biota ,delta13Corg ,General Earth and Planetary Sciences ,13 ,C ,Geology - Abstract
The latest Triassic was an interval of prolonged biotic extinction culminating in the end-Triassic Extinction (ETE). The ETE is now associated with a perturbation of the global carbon cycle just before the end of the Triassic that has been attributed to the extensive volcanism of the Circum-Atlantic Magmatic Province (CAMP). However, we attribute the onset of declining latest Triassic diversity to an older perturbation of the carbon cycle (delta13Corg) of global extent at or very close to the Norian/Rhaetian boundary (NRB). The NRB appears to be the culmination of stepwise biotic turnovers that characterize the latest Triassic and includes global extinctions of significant marine and terrestrial fossil groups. These biotic events across the NRB have been largely under- appreciated, yet together with a coeval disturbance of the carbon cycle were pivotal in the history of the Late Triassic. Here, we present new and published delta13Corg data from widespread sections (Italy, Greece, ODP, Australia, New Zealand, USA, Canada). These sections document a previously unknown perturbation in the carbon cycle of global extent that spanned the NRB. The disturbance extended across the Panthalassa Ocean to both sides of the Pangaean supercontinent and is recorded in both the Northern and Southern Hemispheres. The onset of stepwise Late Triassic extinctions coincides with carbon perturbation (delta13Corg) at the NRB, indicating that a combination of climatic and environmental changes impacted the biota at a global scale. The NRB event may have been triggered either by gas emissions from the eruption of a large igneous province pre-dating the NRB, by a bolide impact of significant size or by some alternative source of greenhouse gas emissions. As yet, it has not been possible to clearly determine which of these trigger scenarios was responsible; the evidence is insufficient to decisively identify the causal mechanism and merits further study.
- Published
- 2020
21. Provenance of Jurassic sandstones in the Rakaia Terrane, Canterbury, New Zealand
- Author
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Hamish J. Campbell, Christopher J. Adams, and William L. Griffin
- Subjects
Provenance ,010504 meteorology & atmospheric sciences ,Muscovite ,Geochemistry ,Geology ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,Geophysics ,Group (stratigraphy) ,Earth and Planetary Sciences (miscellaneous) ,engineering ,0105 earth and related environmental sciences ,Zircon ,Terrane - Abstract
Detrital zircon U–Pb and muscovite 39Ar/40Ar ages from sandstones in the fluviatile to shallow marine mid-Jurassic Clent Hills Group and Wakaepa Formation of mid-Canterbury, South Island, New Zeala...
- Published
- 2018
22. Progressive development of ocean anoxia in the end-Permian pelagic Panthalassa
- Author
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Takaaki Itai, Yoshiaki Aita, Hamish J. Campbell, Paul B. Wignall, Rie S. Hori, Yijun Xiong, Satoshi Yamakita, Atsushi Takemura, Bernard K. Spörli, Simon W. Poulton, Satoshi Takahashi, and Minoru Ikehara
- Subjects
Ocean deoxygenation ,Extinction event ,Global and Planetary Change ,Oceanography ,Water column ,Permian ,Isotopes of carbon ,Ocean current ,Seawater ,Weathering ,Geology - Abstract
The end-Permian mass extinction (EPME) has been linked with the widespread development of oxygen-poor oceanic conditions. However, information on the spatial extent of anoxia in the Panthalassa super-ocean has been limited. This study reports oceanic redox records from a deep-sea chert succession (the Waiheke 1 section, WHK 1, New Zealand) that was located in southern mid-latitudes of Panthalassa. High-resolution carbon isotope (δ13C) correlation between Waiheke and the Permian-Triassic boundary (PTB) type section indicates that the EPME is recorded in a thin black claystone interbedded between siliceous mudstone beds at WHK 1. Pyrite-dominated enrichment in highly reactive iron, coupled with elevated U/Al and Mo/Al ratios, are prevalent through this black claystone bed and the overlying Permo-Triassic transition strata, suggesting the development of euxinic water column conditions. Similar redox variations across the EPME horizon have been reported from other Panthalassic deep-sea PTB sections. Comparison with these PTB sections indicates that euxinic conditions were widespread in low-latitude regions of the Panthalassan ocean, and such conditions developed earlier than in mid-latitude settings, up to 100,000 years before the EPME. This suggests there was a gradual expansion of ocean anoxia from low to middle-high latitude regions during the Permo-Triassic transition. The extent of ocean anoxia resulted in a decrease in the seawater inventory of redox sensitive trace metals (e.g., Mo), which is evident in the earliest Triassic strata of the studied section and other PTB sections. Panthalassic anoxia during the EPME coincides with extreme climate warming and the associated effects (e.g., changes in ocean circulation, marine eutrophication intensified by terrestrial weathering) were likely critical triggers for ocean deoxygenation.
- Published
- 2021
23. An Australian provenance for the eastern Otago Schist protolith, South Island, New Zealand: evidence from detrital zircon age patterns and implications for the origin of its gold
- Author
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William L. Griffin, Christopher J. Adams, and Hamish J. Campbell
- Subjects
Provenance ,Accretionary wedge ,010504 meteorology & atmospheric sciences ,Permian ,Schist ,Geochemistry ,010502 geochemistry & geophysics ,01 natural sciences ,Earth and Planetary Sciences (miscellaneous) ,General Earth and Planetary Sciences ,Shear zone ,Protolith ,Geology ,0105 earth and related environmental sciences ,Terrane ,Zircon - Abstract
Uranium–lead age patterns of detrital zircons in Otago Schist meta-sandstones from eastern Otago, including areas of orogenic gold mineralisation, are mostly consistent with a Rakaia Terrane (Torlesse Composite Terrane) accretionary wedge protolith. Southwest of the Hyde-Macraes and Rise & Shine shear zones the depositional age is regarded as Middle–Late Triassic. At the south and west margins, there are two areas in the Late Triassic Waipapa Terrane protolith. Northeast of the Hyde-Macraes Shear Zone, the schist protolith has Middle to Late Triassic and middle to late Permian depositional ages of Rakaia Terrane affinity. At the northeastern margin of the Hyde-Macraes Shear Zone, there is a narrow strip with a mid-Carboniferous protolith, which may be a counterpart of the Carboniferous accretionary wedge in the New England Orogen, eastern Australia. Ordovician–Silurian zircons are a minor but distinctive feature in many of the protolith age patterns and form significant age components at hard-rock...
- Published
- 2017
24. Oxygen and carbon isotope and Sr/Ca signatures of high-latitude Permian to Jurassic calcite fossils from New Zealand and New Caledonia
- Author
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Robert Frei, Christoph Korte, Clemens V. Ullmann, and Hamish J. Campbell
- Subjects
Calcite ,010506 paleontology ,Permian ,δ13C ,biology ,Geology ,010502 geochemistry & geophysics ,biology.organism_classification ,01 natural sciences ,Isotopes of oxygen ,Carbon cycle ,Paleontology ,chemistry.chemical_compound ,chemistry ,Isotopes of carbon ,Hibolithes ,Belemnopsis ,0105 earth and related environmental sciences - Abstract
Calcite fossils from New Zealand and New Caledonia provide insight into the Permian to Jurassic climatic history of Southern High Latitudes (southern HL) and Triassic Southern Intermediate Latitudes (southern IL). These results permit comparison with widely studied, coeval sections in Low Latitudes (LL) and IL. Oxygen isotope ratios of well-preserved shell materials indicate a partially pronounced Sea Surface Temperature (SST) gradient in the Permian, whereas for the Triassic no indication of cold climates in the southern HL is found. The Late Jurassic of New Zealand is characterized by a slight warming in the Oxfordian–Kimmeridgian and a subsequent cooling trend in the Tithonian. Systematic variations in the δ13C values of southern HL samples are in concert with those from LL sections and confirm the global nature of the carbon isotope signature and changes in the long-term carbon cycle reported earlier. Systematic changes of Sr/Ca ratios in Late Triassic brachiopods, falling from 1.19 mmol/mol in the Oretian (early Norian) to 0.67 mmol/mol in the Warepan (late Norian) and subsequently increasing to 1.10 mmol/mol in the Otapirian (~ Rhaetian), are observed. Also Sr/Ca ratios of Late Jurassic belemnite genera Belemnopsis and Hibolithes show synchronous changes in composition that may be attributed to secular variations in the seawater Sr/Ca ratio. For the two belemnite genera an increase from 1.17 mmol/mol in the Middle Heterian (~ Oxfordian) to 1.78 mmol/mol in the Mangaoran (~ late Middle Tithonian) and a subsequent decrease to 1.51 mmol/mol in the Waikatoan (~ Late Tithonian) is documented.
- Published
- 2016
25. Perspectives on Cretaceous Gondwana break-up from detrital zircon provenance of southern Zealandia sandstones
- Author
-
Christopher J. Adams, Nick Mortimer, William L. Griffin, and Hamish J. Campbell
- Subjects
Provenance ,010504 meteorology & atmospheric sciences ,Taranaki Basin ,Geochemistry ,Geology ,010502 geochemistry & geophysics ,01 natural sciences ,Cretaceous ,Gondwana ,Basement (geology) ,Batholith ,Petrology ,0105 earth and related environmental sciences ,Zircon ,Terrane - Abstract
Detrital zircon U–Pb ages in 37 sandstones from late Early – Late Cretaceous marine and non-marine successions across southern Zealandia indicate a provenance from local basement within present-day Zealandia. Samples from Taranaki Basin were derived from Median and Karamea batholith granitoids with transport directions from west to east. Samples from West Coast, Western Southland and Great South basins contain components derived more locally and more variably from Median Batholith and Rahu Suite granitoids and/or the Palaeozoic Buller Terrane. West Coast Basin samples have more plutonic contributions and Great South Basin localities have more Albian-aged ( c. 110–100 Ma) zircons. Samples from Canterbury Basin were sourced from Torlesse Composite Terrane basement. The provenance variations are present in both marine and non-marine sandstones and suggest localized watersheds. This fits an interpretation of Late Cretaceous deposition in rift-controlled basins across southern Zealandia during pre-Gondwana break-up regional extension. More speculatively, some additional source areas may have been created at the rifted margins of Zealandia during this break-up.
- Published
- 2016
26. New Zealand Geological Timescale NZGT 2015/1
- Author
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Alan G. Beu, Hamish J. Campbell, AF Boyes, Martin P. Crundwell, James S. Crampton, Nick Mortimer, Christopher J. Hollis, Heg Morgans, Roger A. Cooper, and J. I. Raine
- Subjects
Paleontology ,Geophysics ,Geologic time scale ,Permian ,Paleozoic ,Stage (stratigraphy) ,Earth and Planetary Sciences (miscellaneous) ,Geology ,Biostratigraphy ,Chronostratigraphy ,Cenozoic ,Cretaceous - Abstract
An updated age calibration of the New Zealand Geological Timescale, NZGT 2015/1, is presented. This incorporates local stage reassessments and recent international chronostratigraphic calibrations. Of the 54 locally defined New Zealand stages, the basal ages of 17 have undergone changes in age of 1% or more since NZGT 2004 (three since NZGT 2012). Some intervals of Permian and Cretaceous time remain unrepresented by local New Zealand stages.
- Published
- 2015
27. Detrital zircon ages in Buller and Takaka terranes, New Zealand: constraints on early Zealandia history
- Author
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Nick Mortimer, Christopher J. Adams, Hamish J. Campbell, and William L. Griffin
- Subjects
Provenance ,geography ,geography.geographical_feature_category ,Paleozoic ,Volcanic arc ,Geochemistry ,Geology ,Gondwana ,Geophysics ,Earth and Planetary Sciences (miscellaneous) ,Rodinia ,Ordovician ,Zircon ,Terrane - Abstract
Detrital zircon ages are presented for 34 early Palaeozoic sandstones from Buller and Takaka terranes, New Zealand, and formerly adjacent parts of Australia–Antarctica. The Buller–Takaka datasets always have two major groups: Ordovician–late Neoproterozoic, 444–700 Ma (but mainly 540–700 Ma), termed ‘Gondwana Assembly’ (GA), and early Neoproterozoic–Mesoproterozoic, 700–1600 Ma (but mainly 900–1200 Ma), termed ‘Rodinia Assembly’ (RA). In both terranes, significant age components within these groups are strikingly similar and also have RA/GA ratios, 0.6–1.8. The Cambrian volcanic arc of the Takaka Terrane has contributed little to the zircon patterns. Proportions of Late Cambrian–Early Ordovician zircons, characteristic of granitoid sources in the Ross–Delamerian Orogen are low. The zircons are predominantly reworked with contemporary zircons only evident in a few Buller datasets. The zircon patterns suggest that two major sources (late Mesoproterozoic and late Neoproterozoic), enduring over 120 Ma, were w...
- Published
- 2015
28. Zealandia: Earth’s Hidden Continent
- Author
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Christopher J. Adams, Nick Mortimer, Ray Wood, Andy J. Tulloch, Rupert Sutherland, Hamish J. Campbell, M. S. Rattenbury, Julien Collot, Maria Seton, Vaughan Stagpoole, and Peter R. King
- Subjects
010504 meteorology & atmospheric sciences ,Geology ,Earth (chemistry) ,14. Life underwater ,15. Life on land ,010502 geochemistry & geophysics ,01 natural sciences ,0105 earth and related environmental sciences ,Astrobiology - Abstract
A 4.9 Mkm2 region of the southwest Pacific Ocean is made up of continental crust. The region has elevated bathymetry relative to surrounding oceanic crust, diverse and silica-rich rocks, and relatively thick and low-velocity crustal structure. Its isolation from Australia and large area support its definition as a continent— Zealandia. Zealandia was formerly part of Gondwana. Today it is 94% submerged, mainly as a result of widespread Late Cretaceous crustal thinning preceding supercontinent breakup and consequent isostatic balance. The identification of Zealandia as a geological continent, rather than a collection of continental islands, fragments, and slices, more correctly represents the geology of this part of Earth. Zealandia provides a fresh context in which to investigate processes of continental rifting, thinning, and breakup.
- Published
- 2017
29. High-level stratigraphic scheme for New Zealand rocks
- Author
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Hamish J. Campbell, Nick Mortimer, François Bache, Johnston, Dja Barrell, John Begg, R. Jongens, Steven W. Edbrooke, Graham S. Leonard, R.E. Turnbull, Kyle J. Bland, P.J. Forsyth, Peter R. King, Christian Timm, I. M. Turnbull, Julie Lee, James S. Crampton, Simon C. Cox, Dnb Skinner, Dougal Townsend, Rattenbury, J. I. Raine, and Andy J. Tulloch
- Subjects
Metamorphic rock ,Geochemistry ,Geology ,Igneous rock ,Geophysics ,Basement (geology) ,Stratigraphy ,Batholith ,Earth and Planetary Sciences (miscellaneous) ,Haast Schist ,Sedimentary rock ,Petrology ,Terrane - Abstract
We formally introduce 14 new high-level stratigraphic names to augment existing names and to hierarchically organise all of New Zealand's onland and offshore Cambrian–Holocene rocks and unconsolidated deposits. The two highest-level units are Austral Superprovince (new) and Zealandia Megasequence (new). These encompass all stratigraphic units of the country's Cambrian–Early Cretaceous basement rocks and Late Cretaceous–Holocene cover rocks and sediments, respectively. Most high-level constituents of the Austral Superprovince are in current and common usage: Eastern and Western Provinces consist of 12 tectonostratigraphic terranes, 10 igneous suites, 5 batholiths and Haast Schist. Ferrar, Tarpaulin and Jaquiery suites (new) have been added to existing plutonic suites to describe all known compositional variation in the Tuhua Intrusives. Zealandia Megasequence consists of five predominantly sedimentary, partly unconformity-bounded units and one igneous unit. Momotu and Haerenga supergroups (new) comprise lo...
- Published
- 2014
30. Geochemical signatures in Late Triassic brachiopods from New Caledonia
- Author
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Clemens V. Ullmann, Christoph Korte, Hamish J. Campbell, and Robert Frei
- Subjects
Calcite ,chemistry.chemical_classification ,Strontium ,δ18O ,Stable isotope ratio ,Mineralogy ,chemistry.chemical_element ,Geology ,Diagenesis ,chemistry.chemical_compound ,Geophysics ,chemistry ,Earth and Planetary Sciences (miscellaneous) ,Sedimentary rock ,Organic matter ,Terrane - Abstract
Brachiopod fossils from the sedimentary sequences of the Teremba Terrane (New Caledonia) provide a unique opportunity to study the environmental parameters of the Late Triassic. 87Sr/86Sr ratios, δ13C and δ18O values, and Sr/Ca, Mg/Ca and Mn/Ca ratios were measured on brachiopods from Oretian to Otapirian (Norian to Rhaetian) fossil localities of the Baie de St.-Vincent area. Post-depositional impacts on the geochemical proxies were investigated by analysing calcite cements and partly recrystallized shell material. Diagenetic fluids carried strontium with a low 87Sr/86Sr ratio of c. 0.7065, and light δ13C values of c. −20‰, suggesting major contributions by oxidized organic matter. Diagenetic equilibrium was reached at δ18O values of c. −12‰, very low Sr/Ca ratios of < 0.05 mmol/mol and locally variable Mn/Ca ratios of up to 5.9 mmol/mol. Results from the best-preserved samples suggest that calcification temperatures of Warepan and Otapirian brachiopods from New Caledonia were consistently ≥ 15 °C.
- Published
- 2014
31. Depositional setting and paleoenvironment of an alatoconchid-bearing Middle Permian carbonate ramp sequence in the Indochina Terrane
- Author
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Qinglai Feng, Hamish J. Campbell, Chongpan Chonglakmani, Mongkol Udchachon, Clive Burrett, and Hathaithip Thassanapak
- Subjects
Sedimentary depositional environment ,Paleontology ,Permian ,Grainstone ,Facies ,Geology ,Wackestone ,Earth-Surface Processes ,Marine transgression ,Terrane ,Conglomerate - Abstract
A Middle Permian carbonate sequence at Khao Somphot in the south of the Khao Khwang Platform has been measured and analyzed. This sequence is characterized by prolific fossil content and large, bizarre alatoconchid bivalves. Nine major microfacies types are differentiated and consist of: algal-foram facies, fusuline facies, alatoconchid facies, lime mudstone/wackestone facies, laminated bindstone facies, fine-grained cortoid grainstone facies, coral biostrome facies, crinoidal packstone facies and carbonate breccia/conglomerate facies. Laminated bindstone, lime mudstone with fenestral fabric and algal foram facies represent loferites deposited in a restricted intertidal zone of an inner ramp. Fusuline grainstone and cortoid grainstone facies indicate sand shoals of an inner ramp. The fusuline wackestone/packstone and alatoconchid facies were deposited in a subtidal, below fair-weather wave base environment in the mid-ramp. The crinoidal facies, which overlies collapse breccia, possibly accumulated during transgression in the deeper part of the mid-ramp. Storm deposits are prevalent throughout as thin accumulates and as alatoconchid floatstone/rudstone (coquinite) layers and are common in mid-ramp setting. The Khao Khwang Platform probably evolved from a rimmed platform in the Early Permian to a ramp in the Middle Permian. The general trend of δ 13C composition from both brachiopod shell and rock matrix from the lower part of the study section (Wordian) is significantly high. Moreover, the δ 13C signature from this interval is up to 8 VPDB‰, which suggests high productivity on the tropical Tethyan shelf of the Indochina Terrane. An abrupt negative shift in δ 13C in the late Wordian and late Capitanian indicating significant changes in paleoenvironment, productivity and the carbon cycle is probably contemporaneous with the Kamura event recorded from sediments of the mid-Panthalassa Ocean in Japan and elsewhere related to global cooling and a sea-level lowstand.
- Published
- 2014
32. A probable shark dorsal fin spine fragment from the Early Triassic of the Arrow Rocks sequence, Whangaroa, northern New Zealand
- Author
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J.A. Grant-Mackie, Hamish J. Campbell, Satoshi Yamakita, Yoshiaki Aita, Rie S. Hori, Satoshi Takahashi, T Matsumoto, and Atsushi Takemura
- Subjects
Paleozoic ,biology ,Fauna ,Early Triassic ,Geology ,biology.organism_classification ,Dorsal fin ,Spine (zoology) ,Sequence (geology) ,Paleontology ,Geophysics ,Earth and Planetary Sciences (miscellaneous) ,Small fragment ,Conodont - Abstract
The ornament on a small external cast in pink chert shows considerable similarity with that of various Middle Palaeozoic and Triassic fish genera. It comes from the Permian–Triassic Oruatemanu Formation of Arrow Rocks, Whangaroa area, eastern Northland. Conodont faunas from a few metres above and below the sample allow correlation with the Neospathodus pakistanensis zone of the Early Triassic, which is assigned to the late Dienerian (late Induan), with adjacent conodont zone faunas in their correct stratigraphic association. The cast is assumed to be that of a small fragment of fin spine, most likely from the junction area of the crown and root on the right-hand side of a dorsal fin spine, possibly anterior, of a marine ctenacanthoid shark, a basal shark order not previously recorded from New Zealand.
- Published
- 2014
33. Partial diagenetic overprint of Late Jurassic belemnites from New Zealand: Implications for the preservation potential of δ7Li values in calcite fossils
- Author
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Stephen P. Hesselbo, Robert Frei, Clemens V. Ullmann, Philip A.E. Pogge von Strandmann, Christoph Korte, and Hamish J. Campbell
- Subjects
Calcite ,Radiogenic nuclide ,biology ,δ13C ,Geochemistry ,Macrofossil ,biology.organism_classification ,Cretaceous ,Diagenesis ,Paleontology ,chemistry.chemical_compound ,chemistry ,Geochemistry and Petrology ,Belemnopsis ,Belemnites ,Geology - Abstract
The preservation potential and trends of alteration of many isotopic systems (e.g. Li, Mg, Ca) that are measured in fossil carbonates are little explored, yet extensive paleoenvironmental interpretations have been made on the basis of these records. Here we present a geochemical dataset for a Late Jurassic (∼153 Ma) belemnite (Belemnopsis sp.) from New Zealand that has been partially overprinted by alteration. We report the physical pathways and settings of alteration, the resulting elemental and isotopic trends including δ7Li values and Li/Ca ratios, and assess whether remnants of the primary shell composition have been preserved or can be extrapolated from the measured values. The δ18O and δ13C values as well as Sr/Ca and Mn/Ca ratios were analysed along two profiles. In addition, 6 samples were analysed for 87Sr/86Sr, Sr/Ca and Mn/Ca ratios. Five samples from the same specimen and 2 from the surrounding sediment were analysed for δ7Li values, Li/Ca, Sr/Ca and Mn/Ca ratios and are compared to results for 6 other Late Jurassic belemnite rostra (Belemnopsis sp. andHibolithes sp.) from the same region. The 87Sr/86Sr ratios are lower (less radiogenic) in the most altered part of the rostrum, whereas δ7Li values become more positive with progressive alteration. The direction and magnitude of the trends in the geochemical record indicate that one main phase of alteration that occurred in the Late Cretaceous caused most of the diagenetic signature in the calcite. Despite relatively deep burial, down to 4 km, and thus elevated temperatures, this diagenetic signature has subsequently been preserved even for the highly mobile element lithium, suggesting that primary lithium-isotope values can be maintained over geological timescales, at least in thick macrofossil shells. Our best δ7Li estimate for pristine Late Jurassic (∼155–148 Ma) belemnites is +27 ± 1‰, which points to a Late Jurassic seawater δ7Li of ∼29–32‰, compatible with the modern value of 31‰.
- Published
- 2013
34. Recalibrating Australian Triassic Palynostratigraphy to the International Geologic Timescale Using High Resolution CA-IDTIMS Dating
- Author
-
John R. Laurie, Hamish J. Campbell, Arthur J. Mory, Tegan Smith, Daniel Mantle, James L. Crowley, Robert S. Nicoll, Ian Raine, and John McKellar
- Subjects
Foraminifera ,Paleontology ,Geologic time scale ,biology ,Permian ,Group (stratigraphy) ,General Engineering ,Dinocyst ,Coal measures ,Biozone ,Structural basin ,biology.organism_classification ,Geology - Abstract
The Triassic is an important interval for Australian petroleum exploration, with Middle to Upper Triassic Mungaroo Formation reservoirs in the Northern Carnarvon Basin, and recent Lower Triassic discoveries in the Roebuck Basin. The chronostratigraphic understanding of Triassic petroleum systems is underpinned by biostratigraphic dating using palynological zonations. The numerical ages of these zones are usually assigned through inference and interpolation, often via tenuous correlations to the international geologic timescale using scattered marine biota, (primarily foraminifera, and rare ammonites, conodonts and/or dinoflagellates). In contrast, we tie Australian biozones to the timescale through Chemical Abrasion-Isotope Dilution Thermal Ionisation Mass Spectrometry (CA-IDTIMS) dating of interbedded volcanic tuffs. Such ashfalls are reasonably common in Australian basins, and can provide high-precision CA-IDTIMS ages if they contain magmatic zircons. We recently recalibrated Australian middle and late Permian palynozones using this approach and preliminary results suggest that Triassic biozone ages are likewise in need of considerable revision. We have targeted Triassic tuffs across Queensland, (Tarong beds, Brisbane Tuff, Moolayember Formation, Rewan Group), New South Wales (Garie Formation, Coal Cliff Sandstone, Milligan Road Formation), and Tasmania (upper Triassic coal measures) to provide numerical ages for palynozones. Additional dates in New Zealand (Murihiku Supergroup) and Timor-Leste (Wailuli Formation) will allow international correlation of dinocyst and spore-pollen zones. Numerical constraints for Triassic biozone boundaries facilitate correlation of Australian biozones with the international geologic timescale. This can impact burial history models used in petroleum exploration anywhere these biozones are used, often far beyond the basins from which the samples were collected.
- Published
- 2018
35. The mid-Cretaceous transition from basement to cover within sedimentary rocks in eastern New Zealand: evidence from detrital zircon age patterns
- Author
-
Nick Mortimer, William L. Griffin, Hamish J. Campbell, and Christopher J. Adams
- Subjects
Paleontology ,Accretionary wedge ,Basement (geology) ,Rift ,Aptian ,Batholith ,Geology ,Petrology ,Cretaceous ,Zircon ,Terrane - Abstract
Detrital zircon U-Pb ages for 30 Late Jurassic and Cretaceous sandstones from the Eastern Province of eastern New Zealand, combined with previously-published geochronological and palaeontological data, constrain the time of deposition in the Pahau and Waioeka terranes of the Cretaceous accretionary margin of Zealandia, and their adjacent cover strata. The zircon age patterns also constrain possible sediment source areas and mid-Cretaceous geodynamic models of the transition from basement accretionary wedge to passive-margin cover successions. Pahau Terrane deposition was mainly Barremian to Aptian but continued locally through to late Albian time, with major source areas in the adjacent Kaweka and Waipapa terranes and minor inputs from the inboard Median Batholith. Waioeka Terrane deposition was mainly Albian, with distinctive and exclusive sediment sources, principally from the Median Batholith but with minor inputs from the Western Province. Alternative tectonic models to deliver such exclusive Median Batholith and Western Province-derived sediment to the mid-Cretaceous Zealandia continental margin are: (1) the creation of a rift depression across Zealandia or (2) sinistral displacement of South Zealandia with respect to North Zealandia, to expose Western Province rocks directly at the Zealandia margin. Detrital zircon age patterns of Cretaceous cover successions of the Eastern Province of eastern New Zealand demonstrate purely local sources in the adjacent Kaweka and Waipapa terranes. Cretaceous zircon components show a decline in successions of late Early Cretaceous age and disappear by late Late Cretaceous time, suggesting the abandonment or loss of access to both the Median Batholith and Western Province as sediment sources.
- Published
- 2012
36. Detrital zircon geochronology and sandstone provenance of basement Waipapa Terrane (Triassic–Cretaceous) and Cretaceous cover rocks (Northland Allochthon and Houhora Complex) in northern North Island, New Zealand
- Author
-
Hamish J. Campbell, William L. Griffin, Christopher J. Adams, and Nick Mortimer
- Subjects
Paleontology ,Provenance ,Allochthon ,Basement (geology) ,Geochronology ,Geology ,Sedimentary rock ,Cretaceous ,Terrane ,Zircon - Abstract
Detrital zircon U–Pb ages are reported for 14 sandstones of mainly Cretaceous age from the Northland Allochthon, Houhora Complex and Waipapa Terrane of northern North Island, New Zealand. Results from the Waipapa Terrane samples, selected from sequences in the Bay of Plenty, Coromandel Peninsula and Great Barrier Island, show that deposition continued into late Early Cretaceous time and, as in the Torlesse Composite Terrane, finally waned at c. 110–114 Ma. Upper Lower Cretaceous and Upper Cretaceous sedimentary successions in the Houhora Complex and Northland Allochthon have dominant sediment sources derived from local, contemporary volcanism, with a minor older contribution from the Murihiku Terrane to the west. As in eastern North Island, upper Upper Cretaceous sandstones lack major Albian magmatic components and their sources are solely in the Murihiku Terrane, and possibly the Western Province. We propose a Cretaceous palaeogeographic model that invokes a recently extinct orogen and a partially submerged continental borderland, dissected by rivers supplying submarine fans.
- Published
- 2012
37. Recognition of the Kaweka Terrane in northern South Island, New Zealand: preliminary evidence from Rb–Sr metamorphic and U–Pb detrital zircon ages
- Author
-
Nick Mortimer, William L. Griffin, Hamish J. Campbell, and Christopher J. Adams
- Subjects
River valley ,geography ,geography.geographical_feature_category ,Paleozoic ,Metamorphic rock ,Metamorphism ,Geology ,Fault (geology) ,Sedimentary depositional environment ,Paleontology ,Geophysics ,Earth and Planetary Sciences (miscellaneous) ,Terrane ,Zircon - Abstract
Detrital zircon U–Pb ages and Rb–Sr metamorphic ages from low-grade Torlesse Supergroup metasedimentary rocks from North Canterbury and Marlborough provide preliminary evidence for a continuation of the Kaweka Terrane of the central North Island into the Torlesse Composite Terrane of the South Island. This would extend from the south side of the Wairau Fault in the upper Wairau River valley southwards to the Lake Tennyson and Lake Sumner areas, and as far as Hawarden. Rb–Sr ages indicate Jurassic metamorphism, 170±24 Ma, with initial 87Sr/86Sr ratios at that time 0.7073±0.0007 i.e. similar to their North Island counterparts. These Kaweka Terrane rocks have detrital zircon ages that follow the distinctive pattern of the Torlesse rocks in general, i.e. substantial (>30%) Permian–Triassic and Precambrian–Early Palaeozoic groupings, but they also have minor youngest age components c. 175–165 Ma which constrain a maximum Early–Middle Jurassic depositional age. In detail, significant, older zircon components ar...
- Published
- 2011
38. Cenozoic temperate and sub-tropical carbonate sedimentation on an oceanic volcano - Chatham Islands, New Zealand
- Author
-
Campbell S. Nelson, Noel P. James, Hamish J. Campbell, Brian Jones, and Jeremy Quentin Titjen
- Subjects
Calcite ,geography ,geography.geographical_feature_category ,biology ,Stratigraphy ,Aragonite ,Geology ,engineering.material ,biology.organism_classification ,Cretaceous ,Foraminifera ,Paleontology ,chemistry.chemical_compound ,chemistry ,engineering ,Carbonate ,Cenozoic ,Reef ,Paleogene - Abstract
The Chatham Islands, at the eastern end of the Chatham Rise in the South-west Pacific, are the emergent part of a Late Cretaceous to Cenozoic stratovolcano complex that is variably covered with limestones and fossiliferous tuffs. Most of these deposits accumulated in relatively shallow, high-energy, tide-influenced palaeoenvironments with deposition punctuated by periods of deeper-water pelagic accumulation. Carbonate components in these neritic deposits are biogenic and dominated by molluscs and bryozoans – a heterozoan assemblage. The widespread Middle to Late Eocene Matanginui Limestone contains local photozoan elements such as large benthonic foraminifera (especially Asterocyclina) and calcareous green algae, reflecting the general Palaeogene sub-tropical oceanographic setting. More localized Late Eocene to Oligocene deposits (Te One Limestone) as well as Pliocene carbonates (Onoua Limestone) are, however, wholly heterozoan and confirm a generally cooler-water oceanographic setting, similar to today. Early sea floor diagenesis is interpreted to have removed most aragonite components (infaunal bivalves and epifaunal gastropods). Lack of aragonite resulted in the absence of intergranular calcite cementation during subaerial exposure, such that most carbonates are friable or unlithified. Cementation is, however, present at nodular hardground–firmground caps to metre-scale cycles. Such cements are microcrystalline or micrometre-thick isopachous circumgranular rinds with insufficient definitive attributes to pinpoint their environment of formation. The overall palaeoenvironment of deposition is interpreted as mesotrophic, resulting in part from upwelling about the Chatham volcanic massif and in part from nutrient element delivery from the adjacent volcanic terrane and coeval volcanism. Biotic diversity in tuffs is two to three times that in limestones, supporting the notion of especially high nutrient availability during periods of volcanism. These mid-latitude deposits are strikingly different from their low-latitude, tropical, photozoan counterparts in the volcanic island–coral reef ecosystem. Ground water seepage and fluvial runoff attenuate coral growth and promote microbial carbonate precipitation in these warm-water settings. In contrast, nutrients from the same sources feed the system in the Chatham Islands cool-water setting, promoting active heterozoan carbonate sedimentation.
- Published
- 2010
39. Tracing the Caples Terrane through New Zealand using detrital zircon age patterns and radiogenic isotope signatures
- Author
-
Christopher J. Adams, Hamish J. Campbell, and William L. Griffin
- Subjects
Isochron ,Geophysics ,Radiogenic nuclide ,Metamorphic rock ,Early Triassic ,Earth and Planetary Sciences (miscellaneous) ,Schist ,Geochemistry ,Geology ,Cretaceous ,Zircon ,Terrane - Abstract
Rb‐Sr isochron ages and associated initial 87Sr/86Sr ratios of metasedimentary rocks of Caples Group in Southland and Otago, Pelorus Group in Nelson and Marlborough, and their minor North Island correlates in Northland and King Country, reveal the essential continuity of a long Caples Terrane throughout New Zealand. The Rb‐Sr ages, in the range 251–117 Ma, record post‐metamorphic, Early Triassic to Early Cretaceous uplift and cooling, whilst their associated range of initial 87Sr/86Sr ratios, 0.7039–0.7053, allows a discrimination from analogous datasets of neighbouring Torlesse and Waipapa Terranes. Some petrographically and geochemically anomalous Caples Terrane rocks in East Otago, and Otago Schists of the Aspiring Terrane, all with initial 87Sr/86Sr ratios >0.7055, compare best with dataseis of Waipapa Terrane of the North Island. Detrital zircon U‐Pb ages of greywackes from Caples Terrane metasediments have youngest zircon age components from 251 to 215 Ma, and a comparison of dataset patter...
- Published
- 2009
40. Age and isotopic characterisation of metasedimentary rocks from the Torlesse Supergroup and Waipapa Group in the central North Island, New Zealand
- Author
-
William L. Griffin, Hamish J. Campbell, Nick Mortimer, and Christopher J. Adams
- Subjects
Geophysics ,Batholith ,Carboniferous ,Earth and Planetary Sciences (miscellaneous) ,Geochemistry ,Schist ,Metamorphism ,Geology ,Late Devonian extinction ,Supergroup ,Zircon ,Terrane - Abstract
Detrital zircon U‐Pb ages in grey wackes and initial 87Sr/86Sr ratios are reported for low‐grade metasedimentary rocks from Torlesse Supergroup, Waipapa Group, and Kaimanawa Schist in the central North Island, New Zealand. The data reveal the presence of a hitherto unsuspected, areally extensive, Jurassic part of the Torlesse composite terrane in the Kaimanawa, Kaweka, and Ruahine Ranges, which we name the Kaweka Terrane. Kaweka rocks have initial 87Sr/86Sr ratios (at metamorphism) and detrital zircon patterns that in part are transitional between Rakaia and Pahau Terrane rocks and in part similar to Waipapa Terrane rocks. Combined detrital zircon age data for all Torlesse and Waipapa Terrane data reveal an essential unity, with a long persistence (260–120 Ma) of predominant Permian‐Triassic sources in the form of a major Cordilleran‐style batholith, a decline in major early Paleozoic‐Precambrian sources between 260 and 220 Ma, and presence of minor Early Carboniferous to Late Devonian sources be...
- Published
- 2009
41. Age and provenance of basement rocks of the Chatham Islands: An outpost of Zealandia
- Author
-
Hamish J. Campbell, W. J. Griffin, and Christopher J. Adams
- Subjects
Provenance ,Precambrian ,Paleontology ,Geophysics ,Basement (geology) ,Permian ,Paleozoic ,Early Triassic ,Earth and Planetary Sciences (miscellaneous) ,Schist ,Geology ,Protolith - Abstract
Rb‐Sr metamorphic and U‐Pb detrital zircon ages are reported for basement metasediments and cover sandstones of the Chatham Islands. Rb‐Sr metamorphic ages of the Chatham Schist are 180–198 Ma (Early Jurassic), with initial 87Sr/86Sr ratios 0.7075–0.7091, grouping this distinctively with Torlesse Supergroup of the Eastern Province of New Zealand. These ages impose an Early Jurassic minimum age for the sedimentary protoliths. Detrital zircons from two Chatham Schist metagrey wackes have principal age peaks in the interval Late Triassic to Late Permian, and the youngest, 230–250 Ma, suggest maximum early Late Triassic to early Early Triassic ages for sedimentation. The patterns of minor, but significant, Paleozoic components and scattered Precambrian ages in these greywackes resemble those of Permian Torlesse Supergroup greywackes, but that in a greywacke from the Forty Fours islets is closer to possible latest Permian Caples Group greywackes in Otago. A Cretaceous cover sandstone from Pitt Island ...
- Published
- 2008
42. Provenance comparisons of Permian to Jurassic tectonostratigraphic terranes in New Zealand: perspectives from detrital zircon age patterns
- Author
-
Hamish J. Campbell, William L. Griffin, and Christopher J. Adams
- Subjects
Paleontology ,Provenance ,Precambrian ,Paleozoic ,Permian ,Batholith ,Carboniferous ,Geology ,Terrane ,Zircon - Abstract
U–Pb detrital zircon ages (LAM-ICPMS) are reported for 20 greywackes and sandstones from seven major tectono-stratigraphic terranes of the Eastern Province of New Zealand (Cretaceous to Carboniferous) to constrain sediment provenances. Samples are mainly from three time horizons: Late Permian, Late Triassic and Late Jurassic. Age datasets are analysed as percentages in geological intervals, and in histogram and cumulative probability diagrams. The latter discriminate significant zircon age components in terms of terrane, sample stratigraphic age, component age, precision and percentage (of total set). Zircon age distributions from all samples have persistent, large Triassic–Permian, and very few Devonian–Silurian, populations, features which exclude a sediment provenance from the early Palaeozoic, Lachlan Fold Belt of southeast Australia or continuations in New Zealand and Antarctica. In the accretionary terranes, significant Palaeozoic (and Precambrian) zircon age populations are present in Torlesse and Waipapa terranes, and variably in Caples terrane. In the fore-arc and back-arc terranes, a unimodal character persists in Murihiku and Brook Street terranes, while Dun Mountain–Maitai terrane is more variable, and with Caples terrane, displays a hybrid character. Required extensive Triassic–Permian zircon sources can only be found within the New England Fold Belt and Hodgkinson Province of northeast Australia, and southward continuations to Dampier Ridge, Lord Howe Rise and West Norfolk Ridge (Tasman Sea). Small but significant Palaeozoic (and Precambrian) age components in the accretionary terranes (plus Dun Mountain–Maitai terrane), have sources in hinterlands of the New England Fold Belt, in particular to mid-Palaeozoic granite complexes in NE Queensland, and Carboniferous granite complexes in NE New South Wales. Major and minor components place sources (1) for the older Torlesse (Rakaia) terrane, in NE Queensland, and (2) for Waipapa terrane, in NE New South Wales, with Dun Mountain–Maitai and Caples terrane sources more inshore and offshore, respectively. In Early Jurassic–Late Cretaceous, Torlesse (Pahau) and Waipapa terranes, there is less continental influence, and more isolated, offshore volcanic arc sources are suggested. There is local input of plutonic rock detritus into Pahau depocentres from the Median Batholith in New Zealand, or its northward continuation on Lord Howe Rise. Excepting Murihiku and Brook Street terranes, all others are suspect terranes, with depocentres close to the contemporary Gondwanaland margin in NE Australia, and subsequent margin-parallel, tectonic transport to their present New Zealand position. This is highlighted by a slight southeastward migration of terrane depocentres with time. Murihiku and Brook Street terrane sources are more remote from continental influences and represent isolated offshore volcanic depocentres, perhaps in their present New Zealand position.
- Published
- 2007
43. A Revised Calibration of the New Zealand Geological Timescale: NZGT2015
- Author
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Roger A. Cooper, Hugh E. G. Morgans, Hamish J. Campbell, Martin P. Crundwell, James I. Raine, Christopher J. Hollis, Alan G. Beu, James S. Crampton, and Andrew Boyes
- Subjects
Geologic time scale ,Calibration (statistics) ,Climatology ,Geology - Published
- 2015
44. GUEST EDITORIAL: Hello New Zealand
- Author
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Steven A. Trewick, Hamish J. Campbell, and Adrian M. Paterson
- Subjects
Gondwana ,Ecology ,Insular biogeography ,Biogeography ,Fauna ,Vicariance ,Biodiversity ,Radiometric dating ,Ecology, Evolution, Behavior and Systematics ,Natural (archaeology) - Abstract
Islands of the Pacific Ocean have long fascinated evolutionists. Oceanic islands, generally the products of volcanic activity, provide natural experiments as biological populations are well delimited and the age of islands can be determined using radiometric dating. ‘Continental islands’, including New Caledonia and New Zealand, provide equally valuable opportunities for evolutionary study. For students of New Zealand biogeography, the peculiar composition of the biota coupled with a limited interpretation of geology has resulted in the widespread acceptance that the flora and fauna is primarily ancient and of vicariant Gondwanan origin. There is increasing evidence from molecular data that much of this biodiversity is the product of evolution following relatively recent colonization. Such data have prompted biologists to consider geological information on New Zealand in more detail. At the heart of the issue is the question of whether modern New Zealand has a terrestrial link through time with the continent Zealandia that split from Gondwanaland some 80 Ma. Zealandia, which includes New Caledonia, Lord Howe Island and several of the subantarctic islands, is now largely submerged, and New Zealand's present terrestrial existence is the product of tectonic activity initiated around 26 Ma. We argue that for the purposes of biogeographical interpretation, New Zealand can be treated as an oceanic island.
- Published
- 2006
45. Carboniferous conodonts from Rakaia Terrane, East Otago, New Zealand
- Author
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Robert S. Nicoll, John E Simes, Gregory M. Martin, P. Jane Forsyth, and Hamish J. Campbell
- Subjects
Calcite ,Bedding ,biology ,Geology ,biology.organism_classification ,chemistry.chemical_compound ,Paleontology ,Geophysics ,Pumpellyite ,chemistry ,Clastic rock ,Carboniferous ,Pennsylvanian ,Earth and Planetary Sciences (miscellaneous) ,Conodont ,Terrane - Abstract
Conodonts of Late Carboniferous (Pennsylvanian) age have been recovered from marble within a 100 m thick sequence of pure and impure marble, hematitic and chloritic slate, and metachert in Torlesse Supergroup semischist of the Rakaia Terrane. This sequence is exposed near Conical Peak in the Kakanui Mountains, Otago. Bands of marble contain microscopic metavolcanic clasts, quartz grains, and conodont elements in a groundmass of recrystallised calcite. The conodonts include at least three genera: Idiognathodus, Streptognathodus, and Gondolella, which together suggest an age of mid‐Middle Pennsylvanian to latest Pennsylvanian. The red and green slate represents metamorphosed volcani‐clastic beds, and grey slate represents background deposition. Bedding indicators, where present, are subparallel to the plane of cleavage development. No facing directions are recognised. Sandstone and mudstone have been metamorphosed to pumpellyite‐bearing semischist of textural zone IIA. The calcareous, siliceous, an...
- Published
- 2006
46. Murihiku Supergroup, New Zealand: Redefined
- Author
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I. M. Turnbull, Nick Mortimer, and Hamish J. Campbell
- Subjects
Paleontology ,Multidisciplinary ,Permian ,Lithostratigraphy ,Supergroup ,Geology ,Formal description - Abstract
The formal definition of the Murihiku Supergroup is amended, and constituent groups within the supergroup are rationalised. The age of the Murihiku Supergroup is extended back with the inclusion of sequences of Late Permian age, but is restricted upwards with the proposal of the Waipa Supergroup. Topmost Murihiku Supergroup is basal Late Jurassic. The lithological content of the supergroup is broadened to include limestone. Groups recognised herein are defined or in most instances redefined. They are: Kuriwao, North Range, Taringatura, Diamond Peak, Ferndale, Mataura, and Richmond in the South Island, and Newcastle, Rengarenga, and Kirikiri in the North Island. Apotu and Huriwai groups previously accommodated within Murihiku Supergroup are now part of the Waipa Supergroup.
- Published
- 2003
47. A presumed stereospondyl (Amphibia, Stereospondyli) from the marine Triassic of Titiroa Stream, Mataura valley, Southland, New Zealand
- Author
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Hamish J. Campbell, R. Ewan Fordyce, and Anne Warren
- Subjects
Paleontology ,Multidisciplinary ,biology ,Stratigraphy ,Stage (stratigraphy) ,Group (stratigraphy) ,Stereospondyli ,biology.organism_classification ,Supergroup ,Geology ,Terrane - Abstract
A single fossil element from Titiroa Stream, Southland, probably represents a partial clavicle of a roughly 2‐m‐long member of the Stereospondyli (Amphibia). The fossil is from shallow marine rocks of the Wairuna Peak Group (Murihiku Supergroup, Murihiku Terrane), and is probably of early Middle Triassic age (Etalian Stage). This is the first report of presumed stereospondyls from New Zealand.
- Published
- 2003
48. Triassic radiolarians from the ocean‐floor sequence of the Waipapa Terrane at Arrow Rocks, Northland, New Zealand
- Author
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Yoshiaki Aita, Toyosaburo Sakai, K. Bernhard Spörli, Rie S. Hori, Yasushi Higuchi, Hamish J. Campbell, Kazuto Kodama, and Atsushi Takemura
- Subjects
Basalt ,Sequence (geology) ,Plate tectonics ,Paleontology ,Geophysics ,Permian ,Earth and Planetary Sciences (miscellaneous) ,Geology ,Palaeogeography ,Oil shale ,Terrane ,Latitude - Abstract
Triassic radiolarians are reported from two horizons in Waipapa Terrane at Arrow Rocks, Whangaroa area, Northland. This relatively undisturbed succession represents an ocean‐floor sequence, consisting (in ascending order) of basalt with limestone layers, bedded chert, black shale, and red, maroon and green siliceous mudstone. The age of the lower part of the section is Middle‐Late Permian. The radiolarian assemblages reported here indicate Early or Middle Triassic and Middle Triassic (Anisian) ages for maroon siliceous mudstones in the upper part of the section. Between strata of known Permian and Triassic age there is a thin potential Permian/Triassic boundary interval consisting of alternating black shale and grey chert. Radiolarian paleogeography indicates that the Arrow Rocks sequence experienced long distance plate tectonic displacement from a position of relatively low latitude in the Middle Permian and to a high latitude in mid‐Triassic time.
- Published
- 2002
49. Middle to Late Jurassic bivalves of the generaNeocrassinaandTrigonopisfrom New Zealand
- Author
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Ronald N. Gardner and Hamish J. Campbell
- Subjects
Subfamily ,biology ,Ecology ,Astartidae ,Geology ,biology.organism_classification ,Paleontology ,Geophysics ,Boreal ,Genus ,Global distribution ,Earth and Planetary Sciences (miscellaneous) ,Subgenus ,Bay - Abstract
Bivalves of the genera Neocrassina and Trigonopis are described from the Middle‐Late Jurassic of New Zealand. Neocrassina is represented by three new species. The new subfamily Trigonopinae is introduced to accommodate the genus Trigonopis, which was previously classed as a subgenus of Opis. Trigonopis is represented by one previously described species and one new species. Paleobiogeography is analysed in terms of the global distribution of Neocrassina and Trigonopis. Neocrassina was present in most regions of the Boreal and Tethyan realms. In New Zealand, it is first recorded from rocks of Early Temaikan age (Aalenian‐Bajocian). The distribution of Trigonopis shows that this genus was common in European Tethyan regions, but sparsely distributed elsewhere. A comparison of New Zealand species, with forms from other regions, demonstrates that Trigonopis most likely migrated to the Jurassic southern ocean, by way of the temporary seaway connecting the Tethys Sea with the Bay of Antarctica, during th...
- Published
- 2002
50. Middle to Late Jurassic bivalves of the subfamily Astartinae from New Zealand and New Caledonia
- Author
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Ronald N. Gardner and Hamish J. Campbell
- Subjects
Subfamily ,biology ,Ecology ,Astartidae ,Geology ,biology.organism_classification ,Oxyloma ,Paleontology ,Geophysics ,Type (biology) ,Stratigraphy ,Genus ,Earth and Planetary Sciences (miscellaneous) ,Hemimenia ,Bay - Abstract
Bivalves of the family Astartidae are described from the Middle‐Late Jurassic of New Zealand and New Caledonia. The subfamily Astartinae is represented by five genera, namely, Notoastarte n. gen. (five new species), Nicaniella (one new species), Oxyloma n. gen. (six new species), and Hemimenia n. gen. (two new species). The genus Neocrassina is currently under review. An overview of local stratigraphy is provided for astartine type localities. Paleogeography is analysed in terms of paleocurrents, sea‐level changes, faunal comparisons, and faunal distributions. These factors provide evidence for the temporary opening of an epicontinental seaway along the Gondic corridor, linking the Tethys Sea with the Bay of Antarctica, at least twice during the Middle Jurassic. Morphology of astartids is discussed in detail, and a revised hinge formula for the subfamily Astartinae is presented.
- Published
- 2002
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