Provenance study of the Torlesse Terranes and implications for the origin of the continental crust of eastern New Zealand.

The Torlesse terranes - part of the New Zealand Eastern Province - are accretionary complexes that comprise an enormous volume of quartzofeldspathic sandstones and mudstones with subsidiary conglomerates plus minor oceanic assemblages. Two terranes are recognised in the South Island, the Permian to Late Triassic Rakaia terrane and the Late Jurassic to Early Cretaceous Pahau terrane. Recent studies in detrital petrology and geochemistry have been important in establishing the broad type of source for these two terranes. All studies point to a continental arc/cratonic provenance and various source areas have been proposed. This thesis provides the best evidence yet that the Pahau terrane is locally derived and that an Antarctic source for the Rakaia sediments must be (re)considered. A detailed sampling program and geochronological, geochemical and Sr-Nd isotope analyses of igneous clasts from seven Torlesse terrane conglomerates, in conjunction with SHRIMP U-Pb detrital zircon ages from three Torlesse sandstones, have helped to broadly characterise the igneous protosources for the Pahau and Rakaia terranes. The conglomerate locations were chosen to represent the full stratigraphic range of both terranes, and the geographical distribution of the conglomerates mimics an approximate inboard to outboard transect of the two terranes with respect to the Panthalassan margin of Gondwana. Igneous clasts from the Aptian (Mount Saul and Ethelton) and Albian (Kekerengu) Pahau terrane conglomerates are predominantly volcanic and hypersolvus, calc-alkaline, metaluminous to weakly peraluminous and display a general geochemical concordance that suggests a similar petrogenesis. SHRIMP U-Pb zircon ages of these clasts range from 128-123 Ma and from 147-135 Ma. These clasts are indistinguishable in age (except for the younger group), chemical composition, and petrogenesis from the felsic members of the calc-alkaline I-type granitoids of the Darran Suite, whereas alkaline rhyolitic clasts correlate best with the Electric Granite. The age range of all clasts overlaps with detrital zircon ages of the conglomerate matrix from Ethelton, indicating that Late Jurassic to Early Cretaceous magmatism was penecontemporaneous with the sedimentation of the Pahau terrane. The youngest detrital zircon from the Ethelton conglomerate matrix gives an age of 112±2 Ma that constrains the minimum age of magmatism in the source region. An Early Jurassic calc-alkaline, weakly peraluminous rhyolite clast from Kekerengu (188±3 Ma) correlates with the calc-alkaline, weakly peraluminous to peraluminous Bounty Island Granite. SHRIMP U-Pb zircon ages of Rakaia terrane igneous clasts define three distinct groups. The first group, Permian to Middle Triassic, ranges in age from 292-243 Ma with two subgroups recognisable, a minor one ranging in age from 292-277 Ma and a major one from 258-243 Ma. All these clasts are confined to the Kazanian Te Moana, the Dorashamian McKenzie Pass, and the Carnian Lake Hill conglomerates. The calc-alkaline to high-K calcalkaline, metaluminous to peraluminous clasts range in composition from andesites to rhyolites and their intrusive equivalents. Adakitic, mylonitic and gneissic clasts are especially common at Lake Hill. Carboniferous, calc-alkaline, metaluminous to weakly peraluminous clasts are confined to the (?)Permian Boundary Creek conglomerate, ranging in age from 356-325 Ma, constituting the second group. Pooled individual zircon ages from igneous' clasts from the Boundary Creek conglomerate point towards a possible presence of Carboniferous sediments within the Haast Schist. The third group consists of two Cambrian clasts, a monzogranite from Te Moana (497±8 Ma) and a dacite from Lake Hill (c. 517 Ma). These two clasts indicate that Cambrian plutons and volcanics were a protosource that provided detritus to the Rakaia depocentres. Cambrian magmatism was confined to the New Zealand Western Province and its Australian and Antarctic correlatives as well as the Transantarctic Mountains and their Australian correlatives. The presence of the Cambrian clasts indicates an autochthonous setting of the Rakaia depocentres with respect to the Gondwana margin as early as the Kazanian. Detrital zircon age distributions from the Anisian Kurow Hill and Balmacaan Stream Rakaia sandstones identify a Permian to Triassic arc source as the main contributor of detritus to the Rakaia sedimentary basin. Geochronology, geochemistry and Sr-Nd isotopes of Rakaia igneous clasts correlate broadly with those of Permian to Triassic plutons and volcanics from the Antarctic sector of the Panthalassan margin of Gondwana. Sandstone clasts from two Rakaia and two Pahau conglomerates were collected to investigate the recycling of the older Rakaia rocks. Petrography and geochemistry of Pahau terrane clasts indicate that at the time of the Pahau sedimentation Permian to early Late Triassic Rakaia rocks were exposed and recycled into the Pahau basin. Recycling of the Rakaia sediments into the Pahau terrane is also supported by the detrital zircon age data from this and other studies. Furthermore, the similarities of petrographic and geochemical data between sandstone clasts from the Rakaia terrane and Rakaia sandstones suggest that clasts were derived by autocannibalistic reworking of older, consolidated, Rakaia sediments. Geochronology, geochemistry and Sr-Nd isotopes of igneous clasts from the Pahau terrane identify the Median Tectonic Zone (Darran Suite and Electric Granite) as a detritus contributor to the Pahau depositional basin. Based on sandstone and sandstone clast geochronology, geochemistry and Sr-Nd isotopes, the recycling of the older inboard Rakaia and Caples terranes into the Pahau basin is demonstrated. A multi- source model is proposed in which the uplifted Rakaia and Caples terranes as well as an active volcanic arc contributed detritus to the Pahau sedimentary basin

Clustering tropical cyclone genesis on ENSO timescales in the Southwest Pacific

Tropical cyclones (TCs) as a natural hazard pose a major threat and risk to the human population globally. This threat is expected to increase in a warming climate as the frequency of severe TCs is expected to increase. In this study, the influence of different monthly sea surface temperature (SST) patterns on the locations and frequency of tropical cyclone genesis (TCG) in the Southwest Pacific (SWP) region is investigated. Using principal component analysis and k-means clustering of monthly SST between 1970 and 2019, nine statistically different SST patterns are identified. Our findings show that the more prominent ENSO patterns such as the Modoki El Niño (i.e., Modoki I and Modoki II) and Eastern Pacific (EP) El Niño impact the frequency and location of TCG significantly. Our results enhance the overall understanding of the TCG variability and the relationship between TCG and SST configurations in the SWP region. The results of this study may support early warning system in SWP by improving seasonal outlooks and quantification of the level of TC-related risks for the vulnerable Pacific Island communities.The first author is funded under the Pacific Excellence for Research and Innovation (PERSI) scholarship of the University of the South Pacific (USP)

Understanding ecosystem services for climate change resilience in coastal environments: a case study of low - canopy sub - tidal seagrass beds in Fiji

The Pacific Island Countries (PICs) are exposed to extreme wave conditions which are projected to be exacerbated by rising sea levels due to climate change, prompting the need for strategic planning of coastal communities and assets. Nature-based protection has been proposed as a sustainable solution to promote the resilience of coastal areas from physical impacts such as wave-induced erosion. In this study, we investigate the potential coastal protection service of shallow sub-tidal low-canopy seagrass beds, dominated by Halodule uninervis, on the rate of wave height and wave energy reduction on a barrier and fringing reefs. The data was collected using bottom-mounted pressure sensors to measure wave height and energy reduction as waves moved toward the shoreline across the seagrass beds. The results show that on average, the seagrass beds were able to reduce wave height by 30% and energy by 47% in both reef environments. These reduction rates are strongly influenced by water depth, seagrass characteristics and local reef conditions. Based on these results, seagrasses can strengthen the resilience of coastal shorelines to wave erosion, thus conserving healthy low-canopy seagrass habitats has measurable benefits for shoreline protection in Fiji and other PICs

Understanding ecosystem services for climate change resilience in coastal environments: a case study of low-canopy sub-tidal seagrass beds in Fiji

The Pacific Island Countries (PICs) are exposed to extreme wave conditions which are projected to be exacerbated by rising sea levels due to climate change, prompting the need for strategic planning of coastal communities and assets. Nature-based protection has been proposed as a sustainable solution to promote the resilience of coastal areas from physical impacts such as wave-induced erosion. In this study, we investigate the potential coastal protection service of shallow sub-tidal low-canopy seagrass beds, dominated by Halodule uninervis, on the rate of wave height and wave energy reduction on a barrier and fringing reefs. The data was collected using bottom-mounted pressure sensors to measure wave height and energy reduction as waves moved toward the shoreline across the seagrass beds. The results show that on average, the seagrass beds were able to reduce wave height by 30% and energy by 47% in both reef environments. These reduction rates are strongly influenced by water depth, seagrass characteristics and local reef conditions. Based on these results, seagrasses can strengthen the resilience of coastal shorelines to wave erosion, thus conserving healthy low-canopy seagrass habitats has measurable benefits for shoreline protection in Fiji and other PICs

Clustering tropical cyclone genesis on ENSO timescales in the Southwest Pacific

Tropical cyclones (TCs) as a natural hazard pose a major threat and risk to the human population globally. This threat is expected to increase in a warming climate as the frequency of severe TCs is expected to increase. In this study, the influence of different monthly sea surface temperature (SST) patterns on the locations and frequency of tropical cyclone genesis (TCG) in the Southwest Pacific (SWP) region is investigated. Using principal component analysis and k-means clustering of monthly SST between 1970 and 2019, nine statistically different SST patterns are identified. Our findings show that the more prominent ENSO patterns such as the Modoki El Niño (i.e., Modoki I and Modoki II) and Eastern Pacific (EP) El Niño impact the frequency and location of TCG significantly. Our results enhance the overall understanding of the TCG variability and the relationship between TCG and SST configurations in the SWP region. The results of this study may support early warning system in SWP by improving seasonal outlooks and quantification of the level of TC-related risks for the vulnerable Pacific Island communities

Steps to Develop Early Warning Systems and Future Scenarios of Storm Wave-Driven Flooding Along Coral Reef-Lined Coasts

ABSTRACT: Tropical coral reef-lined coasts are exposed to storm wave-driven flooding. In the future, flood events during storms are expected to occur more frequently and to be more severe due to sea-level rise, changes in wind and weather patterns, and the deterioration of coral reefs. Hence, disaster managers and coastal planners are in urgent need of decision-support tools. In the short-term, these tools can be applied in Early Warning Systems (EWS) that can help to prepare for and respond to impending storm-driven flood events. In the long-term, future scenarios of flooding events enable coastal communities and managers to plan and implement adequate risk-reduction strategies. Modeling tools that are used in currently available coastal flood EWS and future scenarios have been developed for open-coast sandy shorelines, which have only limited applicability for coral reef-lined shorelines. The tools need to be able to predict local sea levels, offshore waves, as well as their nearshore transformation over the reefs, and translate this information to onshore flood levels. In addition, future scenarios require long-term projections of coral reef growth, reef composition, and shoreline change. To address these challenges, we have formed the UFORiC (Understanding Flooding of Reef-lined Coasts) working group that outlines its perspectives on data and model requirements to develop EWS for storms and scenarios specific to coral reef-lined coastlines. It reviews the state-of-the-art methods that can currently be incorporated in such systems and provides an outlook on future improvements as new data sources and enhanced methods become available

Germinal centers determine the prognostic relevance of tertiary lymphoid structures and are impaired by corticosteroids in lung squamous cell carcinoma

In solid tumors, the presence of lymph node-like structures called tertiary lymphoid structures (TLS) is associated with improved patient survival. However, little is known about how TLS form in cancer, how their function affects survival, and whether they are affected by cancer therapy. In this study, we used multi-spectral microscopy, quantitative pathology and gene expression profiling to analyze TLS formation in human lung squamous cell carcinoma (LSCC) and in an experimental model of lung TLS induction. We identified a niche of CXCL13+ perivascular and CXCL12+LTB+ and PD-L1+ epithelial cells supporting TLS formation. We also characterized sequential stages of TLS maturation in LSCC culminating in the formation of germinal centers (GC). In untreated patients, TLS density was the strongest independent prognostic marker. Further, TLS density correlated with GC formation and expression of adaptive immune response-related genes. In patients treated with neoadjuvant chemotherapy, TLS density was similar but GC formation was impaired and the prognostic value of TLS density was lost. Corticosteroids are co-administered with chemotherapy to manage side effects in LSCC patients, so we evaluated whether they impaired TLS development independently of chemotherapy. TLS density and GC formation were each reduced in chemotherapy-naive LSCC patients treated with corticosteroids before surgery, compared to untreated patients, a finding that we confirmed in the experimental model of lung TLS induction. Overall, our results highlight the importance of GC formation in TLS during tumor development and treatment

Robustness and uncertainties in global multivariate wind-wave climate projections

Understanding climate-driven impacts on the multivariate global wind-wave climate is paramount to effective offshore/coastal climate adaptation planning. However, the use of single-method ensembles and variations arising from different methodologies has resulted in unquantified uncertainty amongst existing global wave climate projections. Here, assessing the first coherent, community-driven, multi-method ensemble of global wave climate projections, we demonstrate widespread ocean regions with robust changes in annual mean significant wave height and mean wave period of 5–15% and shifts in mean wave direction of 5–15°, under a high-emission scenario. Approximately 50% of the world’s coastline is at risk from wave climate change, with ~40% revealing robust changes in at least two variables. Furthermore, we find that uncertainty in current projections is dominated by climate model-driven uncertainty, and that single-method modelling studies are unable to capture up to ~50% of the total associated uncertainty