Most of the South Island of New Zealand lies within an Eocene-Recent continental shear zone related to Pacific-Australia plate motion. Macroscopic finite strain in this shear zone has, in the past, ...been tracked through the deformation of the Dun Mountain Ophiolite Belt. This paper identifies additional sub-vertical basement strain markers including: Buller-Takaka Terrane boundary, Darran Suite and Jurassic volcanic belt within the Median Batholith, Taieri-Wakatipu-Goulter Synform axial trace, Esk Head Melange and bedding form surfaces within the Buller, Takaka and Torlesse terranes. An analysis of the oroclinal bend over the entire Zealandia continent shows that it is a composite feature involving pre- as well as post-Eocene bending of basement structures. Satisfactory paleogeographic reconstructions of Zealandia cannot be made without the use of substantial regional scale, non-rigid intracontinental deformation.
•A compilation of macroscopically-deformed basement structures is made.•The structures define an intra-continental oroclinal bend.•There has been pre-Eocene and post-Eocene development of the bend.•Zealandia paleogeographic reconstructions require substantial non-rigid deformation.
New Zealand is a fragment of Gondwana that, before Late Cretaceous sea floor spreading, was contiguous with Australia and Antarctica. Only about 10% of the area of continental crust in the wider New ...Zealand region (Zealandia) is emergent above sea level as the North and South Islands. No Precambrian cratonic core is exposed in onland New Zealand. The Cambrian to Early Cretaceous basement can be described in terms of nine major volcano-sedimentary terranes, three composite regional batholiths, and three regional metamorphic-tectonic belts that overprint the terranes and batholiths.
The terranes (from west to east) are: Buller, Takaka, Brook Street, Murihiku, Maitai, Caples, Bay of Islands (part of former Waipapa), Rakaia (older Torlesse) and Pahau (younger Torlesse). The western terranes are intruded by three composite batholith (>100 km
2) sized belts of plutons: Karamea-Paparoa, Hohonu and Median, as well as by numerous smaller plutons. Median Batholith (including the Median Tectonic Zone) is a recently-recognised Cordilleran batholith that represents the site of subduction-related magmatism from ca. 375–110 Ma. Parts of the terranes and batholiths are variably metamorphosed and deformed: Devonian and Cretaceous amphibolite-granulite facies gneisses are present in Buller, Takaka, Median and Karamea-Paparoa units; Jurassic-Cretaceous subgreenschist-amphibolite facies Haast Schist overprints the Caples, Bay of Islands and Rakaia Terranes; Cretaceous subgreenschist facies Esk Head and Whakatane Mélanges bound the Pahau Terrane. In the South Island, small areas (<5 km
2 total) of Devonian, Permian, Triassic and Jurassic Gondwana sequences have been identified. In the North Island a widespread Late Jurassic overlap sequence, Waipa Supergroup (part of former Waipapa Terrane), has recently been proposed.
Summary
Toxic epidermal necrolysis (TEN) is a rare disorder characterized by extensive epidermal death. Almost all cases appear to be caused by an idiosyncratic drug reaction. Proposed pathogenic ...mechanisms are conflicting, and the evidence for the benefits of individual treatments is inadequate, and in some cases contradictory. The mortality rate remains high. We review the literature pertaining to the pathogenesis of TEN and drug reactions in general. The rationale for therapeutic interventions, together with reported evidence of efficacy, are considered. We present a composite model of TEN, based on previous work and suggested pathogeneses of TEN, mechanisms of drug reactions and reported cytotoxic lymphocyte (CTL) cytolytic pathways. In this system, TEN, like some other cutaneous drug eruptions, is an HLA class I‐restricted, specific drug sensitivity, resulting in clonal expansion of CD8+ CTLs. Cytotoxicity is mediated by CTL granzyme and possibly death receptor (DR) ligand (DR‐L), probably Fas ligand (FasL). Particular to TEN, there is then an amplification sequence involving further DR‐L expression. FasL is likely to be particularly important but tumour necrosis factor (TNF) may well contribute, via the TNF receptor 1 (TNF‐R1) death pathway. Alternatively, we suggest the possibility of upregulation of an antiapoptotic TNF‐R1–nuclear factor κB pathway, which would proscribe treatments which downregulate this pathway. None of the published data on individual treatment efficacies is sufficiently strong to suggest a definitive single treatment. Currently a multifaceted regimen appears indicated, targeting various likely intermediary mechanisms, including elimination of residual drug, immunosuppression, inhibition of DR pathways, general antiapoptotic strategies, and aggressive supportive care. Particular attention has been directed at avoiding potential conflicts between different treatments and avoiding agents that theoretically might have a net proapoptotic rather than antiapoptotic effect. Nursing on a specialized unit is of paramount importance.
The 2015 VESPA voyage (Volcanic Evolution of South Pacific Arcs) was a seismic and rock dredging expedition to the Loyalty and Three Kings Ridges and South Fiji Basin. In this paper we present 33 ...40Ar/39Ar, 22 micropaleontological, and two U/Pb ages for igneous and sedimentary rocks from 33 dredge sites in this little‐studied part of the southwest Pacific Ocean. Igneous rocks include basalts, dolerites, basaltic andesites, trachyandesites, and a granite. Successful Ar/Ar dating of altered and/or low‐K basalts was achieved through careful sample selection and processing, detailed petrographic and element mapping of groundmass, and incremental heating experiments on both phenocryst and groundmass separates to interpret the complex spectra produced by samples having multiple K reservoirs. The 40Ar/39Ar ages of most of the sampled lavas, irrespective of composition, are latest Oligocene to earliest Miocene (25–22 Ma); two are Eocene (39–36 Ma). The granite has a U/Pb zircon age of 23.6 ± 0.3 Ma. 40Ar/39Ar lava ages are corroborated by microfossil ages from associated sedimentary rocks. The VESPA lavas are part of a >3,000 km long disrupted belt of Eocene to Miocene subduction‐related volcanic rocks. The belt includes arc rocks in Northland New Zealand, Northland Plateau, Three Kings Ridge, and Loyalty Ridge and, speculatively, D’Entrecasteaux Ridge. This belt is the product of superimposed Eocene and Oligocene‐Miocene remnant volcanic arcs that were stranded along and near the edge of Zealandia while still‐active arc belts migrated east with the Pacific trench.
Plain Language Summary
Samples of lava from the seabed between New Zealand and New Caledonia have been dated using atomic clocks and fossils. Most lavas erupted in a big pulse of volcanic activity between 25 and 22 million years ago. They are part of a belt of now‐extinct undersea volcanoes that stretches for more than 3,000 km between New Zealand and the Solomon Islands. These volcanoes were formed by subduction of the Pacific Plate under the Australian Plate.
Key Points
A major pulse of 25–22 Ma volcanism is documented on the Loyalty and Three Kings Ridges, southwest Pacific Ocean
The ridges are part of a more than 3,000 km long belt of Eocene to Miocene remnant volcanic arcs, stranded along the edge of Zealandia
With care in sample selection, and petrological work, meaningful Ar/Ar ages can be obtained from altered and/or very low‐K submarine basalts
Norfolk Ridge bounds the northeastern edge of the continent of Zealandia and is proximal to where Cenozoic Tonga‐Kermadec subduction initiation occurred. We present and analyze new seismic ...reflection, bathymetric and rock data from Norfolk Ridge that show it is composed of a thick sedimentary succession and that it was formed and acquired its present‐day ridge physiography and architecture during Eocene to Oligocene uplift, emergence and erosion. Contemporaneous subsidence of the adjacent New Caledonia Trough shaped the western slope of Norfolk Ridge and was accompanied by volcanism. Neogene extension along the eastern slope of Norfolk Ridge led to the opening of the Norfolk Basin. Our observations reveal little or no contractional deformation, in contrast to observations elsewhere in Zealandia, and are hence significant for understanding the mechanics of subduction initiation. We suggest that subduction nucleated north of Norfolk Ridge and propagated rapidly along the ridge during the period 40‐35 Ma, giving it a linear and narrow shape. Slab roll‐back following subduction initiation may have preserved the ridge and created its eastern flank. Our observations suggest that pre‐existing structures, which were likely inherited from Cretaceous Gondwana subduction, were well‐oriented to propagate rupture and create self‐sustaining subduction.
Plain Language Summary
Plate tectonic theory established and proved that the surface of Earth is composed of rigid moving plates, but it remains unclear how and why these plates sometimes re‐configure their boundaries and motions. Subduction zones are places where two plates converge and one plunges deep into the Earth beneath the other one. As the plate sinks, it drags the rest of the plate with it and acts as an engine that “pulls” the plate and drives horizontal motion. This is what drives the dynamics of plate tectonics. How are subduction zones created? This remains an open question, but we know from geological observations that new subduction zones do get created: more than half of all active subduction zones were created after the dinosaurs died out 65 million years ago. We present new observations from northern Zealandia (a submerged continent between New Zealand and New Caledonia) that document how one of the largest subduction zones on Earth, the Tonga‐Kermadec system, started.
Key Points
We present new marine geophysical and geological data of Norfolk Ridge located along the northeastern edge of the Zealandia continent
We show that the ridge is not inherited from Cretaceous rifting that led to isolation of Zealandia but from the TECTA Cenozoic tectonic event
Analysis of the structure and evolution of Norfolk Ridge underpins our understanding of tectonic processes of subduction initiation
Sixteen metasedimentary rocks from the Waipapa and Torlesse composite terranes of New Zealand's North Island have been analysed for major and trace elements and Sr, Nd and Pb isotope composition. The ...new data provide a comprehensive analytical dataset that can be used for quantitative trace element and isotopic modelling of the petrogenesis of Neogene North Island volcanic rocks. The major and trace element and isotope data confirm previously recognised systematic compositional differences between Waipapa and older Torlesse (Kaweka Terrane) metasedimentary rocks. Kaweka Terrane samples tend to have higher SiO
2
, Al
2
O
3
, Cs, Rb, Th, U, Hf and total rare earth elements (REE) abundances and chondrite normalised REE patterns characterised by light/heavy REE enrichment. Fe
2
O
3
, MgO, Sr and Sc contents are lower in Kaweka samples than those observed in their Waipapa Terrane counterparts.
87
Sr/
86
Sr ratios are lower and
143
Nd/
144
Nd values are higher in Waipapa compared to Kaweka samples, and Pb is isotopically more radiogenic in the Kaweka samples. Younger Torlesse (Pahau Terrane) samples have major and trace element and isotopic compositions that span the Waipapa and Kaweka suites, but overall they are more similar to the former. Mudstones from all terranes converge in bulk composition and there are systematic differences in isotopic composition between mudstones and sandstones from the Kaweka and particularly the Waipapa terranes. Both lithologies need to be considered when estimating the compositions of metasedimentary terranes. Major and trace element and isotope compositions of the metasediments indicate a complex provenance involving subduction-related volcanic and crustal or continental inputs.
A rare cutaneous tumour Seine, A. J.; Aronson, A.; Tallon, B. ...
Clinical and experimental dermatology,
April 2022, Letnik:
47, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A clinicopathological correlation case of a rare cutaneous tumour, which demonstrated a very rare recurrence with uncertainty remaining over the long‐term prognosis for the patient.
Click ...https://www.wileyhealthlearning.com/#/online-courses/a975ab43-2d48-46fb-8dba-7df9792fd778 for the corresponding questions to this CME article.
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 lowermost rift to passive margin (terrestrial to marine transgressive) rock units. Waka Supergroup (new) includes rocks related to maximum marine flooding linked to passive margin culmination in the east and onset of new tectonic subsidence in the west. Māui and Pākihi supergroups (new) comprise marine to terrestrial regressive rock and sediment units deposited during Neogene plate convergence. Rūaumoko Volcanic Region (new) is introduced to include all igneous rocks of the Zealandia Megasequence and contains the geochemically differentiated Whakaari, Horomaka and Te Raupua supersuites (new). Our new scheme, Litho2014, provides a complete, high-level stratigraphic classification for the continental crust of the New Zealand region.
A regional petrographic reconnaissance of psammitic and pelitic rocks in the Otago Schist, New Zealand, has revealed the presence of garnet ("grossalspite" with typical rim composition almandine^sub ...41^, spessartine^sub 25^, grossular^sub 33^, pyrope^sub 1^) and biotite in 37 new samples, more than doubling the previously known number. A new garnet-biotite-albite zone can now be defined in the greenschist facies Otago Schist that is distinct from the better-known biotite, garnet and oligoclase zones in the along-strike Alpine Schist. The garnet-biotite-albite zone is in part metamorphically discontinuous with adjacent schists and does not support models of simple, continuous, progressive Jurassic regional metamorphism in Otago. The structurally higher (lower grade) boundary of the zone coincides in at least three places with previously mapped regional shear zones. The structurally lower (expected higher grade) boundary of the zone appears to be obliterated by a chlorite zone overprint which can be spatially related to Alpine Schist recrystallisation of ?Cretaceous age. The Otago situation serves as an example of the subtle metamorphic discontinuities that probably pervade many orogenic belts.PUBLICATION ABSTRACT
PDF
