Rozprawy doktorskie na temat „Fiordland”

Eastern Fiordland is an eroded Carboniferous to Cretaceous arc assemblage juxtaposed against the Western Fiordland Gondwana continental margin along the Grebe Shear Zone. In the Manapouri region, Eastern Fiordland is composed of scattered metasedimentary and plutonic rocks of Carboniferous, Jurassic and Jurassic-Early Cretaceous age. Quantitative P-T estimates on rare paragneiss assemblages, coupled with LA-ICP-MS analyses of metamorphic overgrowths on detrital zircon grains, demonstrate metamorphism at low to middle amphibolite facies (<6 kbar, c. 600�C) at 145.0 � 2.8 Ma (all quoted errors at 2[sigma]). The Manapouri-Lake Te Anau area of Eastern Fiordland also exposes scattered fragments of the Mesozoic volcano-sedimentary Loch Burn Formation. Relict sedimentary features within this long-lived Early Jurassic to Early Cretaceous unit indicate deposition in a mostly terrestrial or shallow water environment that was fed by debris flows from proximal granitic and volcanic topographic high points. Deposition of the Loch Burn Formation in the Murchison Mountains is bracketed between a 342.3 � 1.5 Ma basal granite and an intrusive 157.6 � 1.4 Ma quartz diorite. Metamorphism throughout the unit achieved greenschist and amphibolite facies temperatures (P unconstrained) in the Early Cretaceous (post c. 148 Ma and prior to c. 121 Ma). Although metasedimentary rocks provide insights into the tectonic evolution of Eastern Fiordland, a range of compositionally heterogeneous plutonic rocks dominates the geology. At Lake Manapouri, these comprise four principal associations: (1) the composite Pomona Island Granite (Carboniferous-Permian and Jurassic), (2) the Beehive Diorite (148.6 � 2.3 Ma), (3) the heterogeneous Hunter Intrusives (Carboniferous, Jurassic and Early Cretaceous) of the Darran/Median Suite and (4) HiSY granitoid dikes of the Separation Point Suite (123.5 � l.2Ma). The latter suite also occurs in immediately adjacent parts of Western Fiordland, forming the Refrigerator Orthogneiss (120.7 �1.1 Ma), the Puteketeke Granite (120.9 � 0.8 Ma) and the West Arm Leucogranite (116.3 � 1.2 Ma). Geobarometry indicates the Jurassic portions of the Darran/Median Suite were emplaced between 4 - 6 kbar and Western Fiordland Early Cretaceous Separation Point Suite between 5 - 7 kbar. Zircon initial �⁷⁷Hf/�⁷⁶Hf isotopic ratios suggest that Separation Point Suite magma could be derived from the same Paleozoic - Late Neoproterozoic mantle source as the Jurassic portion of the Hunter Intrusives member of the Darran/Median Suite. However, Early Cretaceous plutons west of the Early Cretaceous active margin (and study area) have significantly more evolved source regions, reflecting the influence of continental Gondwana on lithosphere composition. Initial �⁷⁷Hf/�⁷⁶Hf ratios from the Loch Burn Formation Carboniferous basal granite zircon are slightly less primitive than either Darran/Median or Separation Point Suite but nowhere near as evolved as similar-aged zircon in the Eastern Fiordland Mt Crescent Paragneiss unit in the Hunter Mountains. The Cambrian/Early Ordovician Russet Paragneiss, which lies just west of the Grebe Mylonite Zone in Western Fiordland and has been intruded by a range of Early Paleozoic to Mesozoic plutons, was metamorphosed at 7.5 � 1.2 kbar, 633 � 25�C at 348.6 � 12 Ma and exhibits no evidence for Jurassic re-equilibration. Zircon U-Pb isotopes from a pelitic schist enclave within the Western Fiordland Mt Murrell Amphibolite are interpreted to show that these and associated intrusive rocks were also metamorphosed at kyanite-grade in the Carboniferous. This event, �M1�, generated a pervasive lineation and distinctive pargasite-anorthite-kyanite/corundum-bearing assemblages in layered aluminous components to the Mt Murrell Amphibolite, garnet-amphibole-biotite-kyanite-gedrite-plagioclase-quartz in metasomatised tonalite at the Mt Murrell Amphibolite margins, and low CaO-garnet in pelitic schist enclaves within the amphibolite. P-T estimates suggest M1 took place at 6.6 � 0.8 kbar, 618 � 25�C. Both the timing and P-T conditions of M1 overlap with metamorphism of the Russet Paragneiss. However, the layered amphibolites and pelitic schist enclaves partially re-equilibrated in the Early Cretaceous (c. 115 Ma) at higher pressure (8.8 � 0.9 kbar). This event, �M2�, generated static assemblages of margarite, epidote, chlorite, oligoclase-andesine and second-generation kyanite in the layered amphibolites and relict olivine gabbronorite, and high-CaO garnet rims, biotite, plagioclase, quartz, kyanite and staurolite in the pelitic schist enclaves. Trace element chemistries of c. 340 Ma zircon grains in the schist have unusual smoothed Ce/Ce* anomalies and high Th/U ratios. These properties may be result of fluid flow and metasomatism from the enveloping amphibolite during imposition of the penetrative M1 lineation. Early Cretaceous (c. 115 Ma) zircon overgrowths and chemistries (low heavy rare earth elements, low Th/U ratios, large Eu/Eu* anomalies) are compatible with formation in the presence of local M2 garnet and plagioclase. M2 was coeval with amphibolite to garnet-granulite facies metamorphism of the regionally extensive Western Fiordland Orthogneiss and Arthur River Complex, thus demonstrating that high-pressure metamorphism was not restricted to the Western Fiordland Early Cretaceous components and their marginal metasedimentary rocks. The Grebe Mylonite Zone forms a lithologic, metamorphic, isotopic and structural boundary between Eastern and Western Fiordland. This 200 to 300 metre-wide and > 50 km long north-striking mylonitic zone is the prominent manifestation of deformation associated with the wider (c. 30 km) Grebe Shear Zone, which extends into Eastern and Western Fiordland. Qualitative and quantitative P-T estimates indicate the currently exposed level of the Grebe Mylonite Zone was active at amphibolite facies conditions (c. 600�C and c. 6 kbar). Coupled U-Pb and Ar-Ar data indicate the mylonite zone was active at, or between, c. 128 and 116 Ma. Temperature-time profiles constructed along a transect perpendicular to the shear zone, used in conjunction with fabric data and the orientation of nearby Tertiary unconformities, suggest that the currently sub-vertical shear zone was rotated during the Cenozoic from an initially steeply east-dipping geometry with a reverse sense of shear. This style of deformation is consistent with an inclined continuously partitioned transpressional structure. Synkinematic emplacement and deformation of the Refrigerator Orthogneiss implies that Grebe Shear Zone provided a crustal anisotropy that facilitated the movement and emplacement of some Separation Point Suite magmas through the crust. Data collected here are interpreted to show that the Grebe Shear Zone is a terrane-bounding suture. Differences in metasedimentary rock composition, age, provenance and metamorphism across the zone suggest that the crustal framework to Eastern Fiordland did not forth in its current tectonic position. Instead, the Mesozoic portion of Eastern Fiordland is inferred to have developed allochthonously with respect to Western Fiordland, with components internally dismembered and rearranged during Jurassic metamorphism and juxtaposition in the Early Cretaceous. However, the Jurassic portion of the arc may have developed near the Gondwana margin because the Jurassic Borland Paragneiss contains detritus that can be partly matched to sources in the Western and Eastern Provinces of New Zealand, as well as early parts of the Darran/Median Suite and Loch Burn Formation. Recognition that the Eastern Fiordland arc was faulted against and then over Western Fiordland in the Early Cretaceous provides a possible driving mechanism for coeval transpressive shortening, rapid burial and high-pressure metamorphism (e.g., as seen in the Mt Murrell Amphibolite) of the lower Western Fiordland crust.

The bottlenose dolphins of Fiordland, New Zealand, live at the southern limit of the species' worldwide range. They are exposed to impacts from tourism and habitat modification, particularly in Doubtful Sound, and their conservation requirements are presently unclear. Dolphin abundance was estimated in Doubtful Sound using photo-identification census and capture-recapture techniques (56 individuals; 95% CI: 55-57), detecting a decline of 34-39% over 12 years among adults and sub-adults (>3 years old). The cause of this decline was investigated via demographic modelling in Doubtful Sound and a comparative assessment of population status in Dusky Sound. Capture-recapture modelling of photo-identification data compiled since 1990 yielded a constant adult survival rate marginally lower than prior estimates for wild bottlenose dolphins ([phi]a(1990-2008) = 0.9374; 95% CI: 0.9170-0.9530). Survival of calves (<1 year old) declined to an unsustainable level that is thought to be the lowest recorded for wild bottlenose dolphins ([phi]c(2002-2008) = 0.3750; 95% CI: 0.2080-0.5782) coincident with the opening of a second tailrace tunnel for a hydroelectric power station. Reverse-time capture-recapture modelling detected declines in recruitment (f(1994-2008) = 0.0249; 95% CI: 0.0174-0.0324) and population growth ([lambda](1994-2008) = 0.9650; 95% CI: 0.9554-0.9746) over time consistent with the decline in calf survival (<1 year old) and a separate reduction in juvenile survival (1 to 3 years old) reflecting cumulative impacts. Dolphin abundance was estimated in Dusky Sound using photo-identification census and capture-recapture techniques (102 individuals, 95% CI: 100-104) providing no evidence of interchange with Doubtful Sound. A comparative assessment of health status between Doubtful and Dusky Sounds revealed skin lesioning was more severe in Doubtful Sound, particularly among females, and newborn calves appeared to be smaller and were born over a shorter period: factors that may contribute to the low levels of calf survival in Doubtful Sound. The Fiordland bottlenose dolphins were assessed under IUCN Red List regional criteria. The small size of the population (205 individuals, 95% CI: 192-219) combined with the projected rate of decline in stochastic matrix models (average decline 31.4% over one generation) resulted in a recommended classification of Critically Endangered.

Mechanisms of brood reduction were studied in Fiordland crested penguins (Eudyptes pachyrhynchus) on Open Bay Islands from July through October 1989. I quantified behavioural and environmental causes of egg and chick loss at the time of laying, during incubation, and after hatching to evaluate hypotheses advanced to explain the unique patterns of hatching asynchrony and egg dimorphism in eudyptid penguins. Although first eggs experienced lower survival than second eggs and most losses occurred during the laying interval, aggression between adult penguins did not appear to contribute to egg loss at any time. Similarly, egg mortality was not influenced by the effects of nest crowding or cover, or by the degree of intraclutch egg dimorphism. Egg temperatures were measured throughout the incubation period with thermocouples implanted in preserved eggs. Recorded temperatures increased markedly after the laying of the second natural egg, but did not differ between eggs of different sizes within a nest. First eggs were not consistently incubated in the anterior nest position and that position did not confer a thermal disadvantage. However, first eggs hatched later than second eggs. Retarded brood patch development may contribute to lower egg temperatures during the laying interval. Chicks from larger, second-laid eggs were larger at hatching, and grew more rapidly than their siblings. Overt aggression between feeding chicks was not observed and begging and feeding rates appeared to be similar. Nonetheless, large chicks experienced higher survival to the creche stage. Intra-clutch egg dimorphism was negatively correlated with the number of days two chicks survived in the same nest, but there was no relationship between survival and hatching asynchrony.

The bottlenose dolphin Tursiops truncatus is an extremely well-studied species. We have an extensive knowledge of certain aspects of their vocal behaviour, particularly from captive contexts. Bottlenose dolphins produce a rich tapestry of vocalisations, however, which have historically received minimal attention. Resident groups of bottlenose dolphins frequent the waterways of Fiordland in southwest New Zealand. These deep, sheltered fiords are ideally suited for acoustic studies. This thesis presents the first detailed study of bottlenose dolphin acoustics in New Zealand. Both narrowband and broadband systems were used to record the vocalisations of two resident groups. Effort was distributed evenly over three years for both Doubtful Sound and Milford Sound. From 875 recordings, I proposed a repertoire of 15 discrete calls. These categories were subsequently compared using parameters measured from almost 2000 individual vocalisations. Various multivariate techniques revealed some redundancy in the proposed repertoire, and it was subsequently reduced to 12 calls. The 12 call repertoire was compared between the potentially interbreeding populations of Doubtful Sound and Milford Sound. Fiord-specificity was revealed for many of the calls, particularly the sequenced calls and whistles. These differences suggest bottlenose dolphins use dialects, in keeping with studies of killer whales and sperm whales. As Fiordland dolphins are out of sight for 90% of the time, acoustic techniques allow inference in to subsurface behaviour. I investigated sequential relationships among sounds and between sounds and behaviours. Many calls were strongly implicated in social interactions. The vocalisations ratchet, orca and the sequenced calls were associated with periods of conflict. A number of the click-based calls were linked to diving and presumed foraging events. Inference on the functional significance of sounds allowed an interpretation of habitat use. This appears to be the first study relating the entire vocal repertoire of a cetacean population to a complete home range. Areas important for socialising, foraging and resting are proposed. Local management decisions may be well served by this information. This study uses benign techniques to build on previous research in Fiordland, and adds a new dimension to the study of these populations.

Stoats are introduced mammalian carnivores implicated in the decline of several of New Zealand�s endemic species. Most research into stoats in New Zealand has focused on beech forest habitat, especially in years of peak stoat abundance following heavy beech seedfall and peak cohorts of mice. In New Zealand, alpine grasslands occur above the altitudinal limit of beech forest (900-1000 m a.s.l.). Although previous research has shown stoats to be present there, little is known about the ecology of stoats in alpine grasslands. This research aimed to test whether alpine grasslands were a marginal habitat occupied by surplus stoats that had spilled over from beech forest populations, i.e. a sink habitat. The alternative is that alpine grasslands are a desirable habitat deliberately exploited by stoats. This question was answered using mark-recapture, radio-tracking, diet analysis and a food addition experiment. Another objective was to determine whether nest survival is higher in alpine grassland compared to beech forest and whether stoats are likely to be a frequent predator of ground nests in alpine grasslands relative to other introduced mammals that inhabit them. If nest survival is higher in alpine grassland then alpine grasslands may be a refuge from predation. However, if it is not then it is important for management to know the relative risk posed by stoats compared with other predators. An artificial nest experiment was used to answer these questions. This research was undertaken during two years of low to intermediate beech seedfall and therefore provided an opportunity to look at the ecology of stoats in a New Zealand National Park outside years of peak abundance. The principal study site for this research was the Borland Valley, Fiordland National Park. Compositional analysis showed that stoats in alpine grassland selected for it over adjacent beech forest. The range cores of these stoats were high up in alpine grassland away from the ecotone with beech forest. Stoats occurred at similar densities in alpine grasslands as they did in beech forest and observed survival was similar between the two habitats (with the exception of 2004 when it may have been higher in alpine grassland). The most frequent prey of stoats inhabiting beech forest were birds and mice. Although stoats in alpine grasslands also ate birds and mice their most frequent prey were ground weta and hare. Food addition appeared to cause diet switching but did not reduce the distances moved by stoats, suggesting that other factors may be more important in regulating their summer home range size in alpine grasslands. All of these factors lead to the conclusion that alpine grasslands in the Borland are not a marginal habitat for stoats, but may instead be a desirable one. Artificial nests had a higher probability of survival in alpine grassland compared to adjacent beech forest, but survival was too low to support the idea that alpine grasslands are a refuge. Stoats were the most frequent predator of artificial nests in both habitats, but 95 % confidence intervals overlapped the predation rate by possums, which was also high. These findings illustrate the need for a comprehensive landscape approach to stoat control in montane National Parks, for two reasons: 1) endemic biodiversity in alpine grasslands may be under threat from stoat predation, 2) alpine grasslands may act as a source for dispersing stoats that reinvade lowland stoat control areas. In the absence of heavy beech seedfall and peak mouse abundance, stoats occurred at densities of around 1 km⁻� in both habitats and there was recruitment into these populations. This raises the important question: What regulates the distribution and abundance of stoats in years of low beech seedfall and low mouse abundance? In these years birds, ground weta and hares may be as important as mice are in years of peak abundance following heavy beech seedfall.

Fiordland is located southwest of South Island of New Zealand. The field area of this thesis is in northern Fiordland, at the boundary of pristine arc rocks (Median Tectonic Zone) and a belt of Paleozoic paragneisses and orthogneisses of variable age that represent the metamorphosed paleo-Pacific Gondwana margin.

This thesis presents the results of structural analyses and detailed field mapping from a region near Adams Burn in central Fiordland, New Zealand. The region preserves assemblages of metasedimentary and metaigneous rocks deposited, intruded, and ultimately metamorphosed and deformed during the growth of a Gondwana-margin continental arc from Cambrian-Early Cretaceous. Evidence of arc growth is preserved in the Late Devonian-Early Cretaceous Median Batholith, a belt of intrusive rock whose growth culminated with the emplacement of the Western Fiordland Orthogneiss (WFO) into the middle-lower crust of the margin. Following this magmatic flare-up, the margin experienced Late Cretaceous extensional orogenic collapse and rifting. During the Late Tertiary, the margin records oblique convergence that preceded the Alpine fault. The history of arc growth and record of changing tectonic and deformational regimes makes the area ideal for study of structural reactivation during multiple cycles of magmatism, metamorphism and deformation, including during a mid-lower crust magma flare-up. Structural and lithologic mapping, structural analyses, and cross-cutting relationships between superposed structures and three intrusions were used to bracket the relative timing of four tectonic events (D1-D4), spanning the Paleozoic to the Tertiary. The oldest event (D1) created a composite fabric in the metasedimentary and metaigneous rocks of the Irene Complex and Jaquiery granitoid gneiss prior to emplacement of the Carboniferous Cozette pluton. S1 foliation development, set the stage for structural reactivation during the second phase of deformation (D2), where S1 was folded and reactivated via intra-arc shearing. These second-phase structures were coeval with the emplacement of the Misty pluton, (part of WFO in central Fiordland), and record crustal thickening and deformation involving a kinematically partitioned style of transpression. Arc-normal displacements were localized into the rocks of the Irene Complex. Oblique displacements were localized along the Misty-Cozette plutonic contact, forming a ≥1 km-wide, upper amphibolite-facies gneissic shear zone that records sinistral-reverse offset. Second-phase structures are cross-cut by widespread leucocratic pegmatite dikes. S2 in the Cozette and Misty plutons is reactivated by localized, ≤10 m-thick, greenschist-facies (ultra)mylonitic shear zones that record sinistral-normal offsets. S3/L3 shear zones and lithologic contacts were then reactivated by two episodes of Tertiary, fourth-phase faulting compatible with Alpine faulting, everywhere truncating the pegmatite dikes. Early faults accommodated shortening normal to the Alpine fault, and were obliquely reactivated by a younger population of faults during dextral transpression. My results show that structural reactivation occurred repeatedly after D1, and that structural inheritance played a key role in the geometry, distribution, and kinematics of younger deformation events throughout the arc's history. The sheeted emplacement of the Misty pluton was accompanied, and possibly facilitated, by a system of partitioned transpression during Early Cretaceous crustal thickening and arc magmatism. These results show that transpression helped accommodate and move magma through the middle and lower crust during the flare-up. This conclusion is important for the study of continental arcs globally, as evidence of deformation during high-flux magmatism at lower crustal depths (~40 km) is rarely preserved and exhumed to the surface.

Avalanches pose a significant natural hazard in many parts of the world. Worldwide the hazard is being managed in a number of new and traditional methods. In New Zealand, the Milford Road, Fiordland, has a significant avalanche problem which has been managed by the Transit New Zealand Milford Road Avalanche Programme since 1984. This avalanche programme has generated a database of all avalanche occurrences and associated meteorological parameters for the time period 1985 to 2002. Elsewhere around the world, similar and more extensive data sets have been used to examine a wide variety of aspects in relation to the snow cover, avalanching and avalanche hazard. The availability of the Milford Road database has provided the opportunity use new and traditional approaches to examine many aspects of avalanching including; the trends in and relationships with the snow and avalanche regime, evaluation of the avalanche hazard, statistical forecasting of avalanches and the visualisation of avalanche occurrence information in a GIS. Statistical and graphical examination of the inter-annual variation in the snow and avalanche regime revealed relationships between the snow depth, avalanche occurrences and atmospheric circulation similar to those found elsewhere around the world, but not previously examined in New Zealand. Furthermore, the analysis resulted in strong correlations despite using a database significantly shorter than those used elsewhere. Atmospheric circulation types that bring strong winds and precipitation were found to be highly significantly correlated with avalanche occurrences and snow depth. Avalanche occurrences were more highly correlated with atmospheric circulation than snow depth was, reflecting the strong maritime avalanche climate. Risk evaluation was undertaken using two approaches, the avalanche hazard index (AHI) and the probability of death to individuals (PDI) method. The present avalanche risk was compared to a theoretically uncontrolled avalanche regime, using 2002 traffic volumes for AHI and PDI. The AHI analysis highlighted the reduction in the AHI resulting from the control programme, and the significantly lower AHI when compared to Rogers Pass, B.C., Canada. The PDI analysis using equations modified to allow for a range of consequences indicated that the Milford Road is similar in risk to roads in Switzerland, but is far more accessible, with fewer closed days. A new equation for PDI, which accounted for waiting traffic was derived, and suggested that the calculated risk was high and unacceptable compared to standards applied to other hazards. Statistical forecasting using classification tree analysis has been successfully applied to avalanche forecasting in other climatic settings. This study has applied an extension to this technique through 10-fold cross validation to permit classification of an avalanche day in this direct action maritime climate. Using varying misclassification costs two classification trees were generated. The tree that used only wind speed and wind speed and precipitation combined in a temperature sensitive wind drift parameter obtained an overall accuracy of 78%, with correct prediction for an avalanche day at 86%. These predictor variables are considered to be the fundamental controls on avalanche forecasting in this climate, and coincide with important variables inferred from the atmospheric circulation analysis. Following the investigation of various methods for the creation of a high resolution digital elevation model (DEM), a GIS was used for the visualisation and examination of avalanche occurrences. Similar to other studies, qualitative and quantitative analysis of the spatial distribution in terms of aspect of avalanche occurrences was undertaken using the GIS. Colour coding of occurrences highlighted the influence of two storm directions, while an excess ratio showed the clear influence of aspect on avalanche occurrences in relation to two dominant storm directions, avalanche size and avalanche paths. Furthermore, the GIS has many applications for operational forecasting, teaching and the maintenance of institutional memory for the avalanche programme.

In this thesis, I present field, microstructural, and Electron Backscatter Diffraction (EBSD) analyses of rock fabrics from high strain zones in exposures of lower crustal Cretaceous plutons at Breaksea Entrance, Fiordland, New Zealand. The interplay between deformation and metamorphism occurs across multiple scales at the root of a continental arc. I show a series of steps in which retrogressive metamorphism is linked to the accommodation of deformation. I define three main phases of deformation and metamorphism at Breaksea Entrance. The first phase (D1) involved emplacement of dioritic to gabbroic plutons at depths up to 60 km. The second phase (D2) is characterized by deformation and metamorphism at the granulite and eclogite facies that produced high strain zones with linear fabrics, isoclinal folding of igneous layering, and asymmetric pressure shadows around mafic aggregates. New structural analyses from Hāwea Island in Breaksea Entrance reveal the development of doubly plunging folds that define subdomes within larger, kilometer-scale gneiss domes. The development and intensification of S2 foliations within the domes was facilitated by the recrystallization of plagioclase and clinopyroxene at the micro-scale (subgrain rotation and grain boundary migration recrystallization), consistent with metamorphism at the granulite and eclogite facies and climb-accommodated dislocation creep. EBSD data show a strong crystallographic preferred orientation in plagioclase during D2 deformation. The third phase (D3) is characterized by deformation and metamorphism at the upper amphibolite facies that produced sets of discrete, narrow shear zones that wrap and encase lozenges of older fabrics. Structural analyses reveal a truncation and/or transposition relationship between the older S2 and the younger S3 foliations developed during D3. Progressive localization of deformation during cooling, hydration, and retrogression, resulted in the breakdown of garnet and pyroxene to form hornblende, biotite, fine plagioclase and quartz. EBSD data show a strong crystallographic preferred orientation in hornblende. During D3, hornblende and biotite accommodated most of the strain through fluid-assisted diffusion creep. The last two events (D2 and D3) reflect a transition in deformation and metamorphism during exhumation, as well as a focusing of strain and evolving strain localization mechanisms at the root of a continental arc. An examination of structures at multiple scales of observation reveals that fabrics seen in the field are a composite of multiple generations of deformation and metamorphism.

The George Sound Shear Zone (GSSZ) exposed in Bligh Sound within Fiordland, New Zealand allowed us to reconstruct the kinematics of transpressive flow in >100 km2 of exhumed Cretaceous lower crust. We compare the three-dimensional characteristics of the deformation to theoretical models of transpression that assume steady-state flow in a homogeneous medium. This assumption is rarely the case for shear zones that experience metamorphism during deformation. We determined the three-dimensional kinematics of the GSSZ and evaluated the effects of metamorphism on strain accommodation and structural fabric evolution in the GSSZ to determine if metamorphism is an important parameter that transpressional models should account for. We found that metamorphism aided strain localization within the GSSZ and resulted in a style of structural fabric development that deviates from predictions made by theoretical models. We used foliation and lineation orientation data and field observations to determine GSSZ kinematics. Asymmetric pyroxene σ-porphyroclasts and hornblende fish show top-down-to-the-SW apparent normal shear sense with a sinistral component. The Z-axes of oblate SPO ellipsoids define the vorticity normal section and the moderately WNW-plunging vorticity vector. Foliation deflections relative to the shear zone boundaries yielded a vorticity magnitude (Wk) of ≥0.8. Our kinematic results suggest that the GSSZ records inclined, triclinic transpression with sinistral, top-down-to-the-SW simple shear-dominated flow. We used finite strain analysis and petrographic analysis to determine that metamorphism influences strain accommodation. Finite strain analyses were performed in 3D on 16 samples using the Rf/ɸ, Fry, and Intercept methods to determine the SPO fabric ellipsoids at different stages of deformation. Petrographic analysis was performed to identify metamorphic reactions using syn-kinematic minerals and constrain deformational temperatures using deformation mechanisms of plagioclase. Early deformation formed a ~13 km wide prolate fabric at granulite facies. Deformation later localized into a ~2-4.6 km wide oblate, mylonitic fabric at upper amphibolite facies. This fabric cross-cuts the prolate fabric and is characterized by metamorphic hornblende and biotite produced from retrogressive hydration reactions. Samples with syn-kinematic biotite contain more shear bands and display more grain size reduction of plagioclase than samples without this phase, suggesting these samples may have accommodated more strain. Changes in syn-kinematic metamorphic minerals were accompanied by steepening of stretching lineations and by changes in foliation orientation. Our analyses show that retrogressive hydration metamorphism aided strain localization within a cross-cutting oblate fabric, and the uneven distribution of biotite within this domain potentially influenced along strike variation in strain magnitude and fabric ellipsoid symmetry. Our results highlight the influence of fluid-induced metamorphism on shear zone evolution and call for new transpressional models to incorporate changes in rheology due to syn-kinematic metamorphism.

The objectives of this study were two fold. The first was to quantify the nature and extent of current levels of human impact in alpine areas at four sites within Fiordland and Mount Aspiring National Parks along walking tracks at Key Summit, Gertrude Saddle, Borland Saddle and Sugarloaf Pass. In order to do so, a survey was carried out with transects placed perpendicular to the track, and distributed among different vegetation types. In each transect, plant structural and compositional aspects, and soil and environmental parameters were measured. Transects were divided into track, transition, undisturbed and control zones, and changes to dependent variables were compared with distance from the track centre. Damage from visitor impact was largely restricted to within 1m from the track centre. The most significant impacts were to structural aspects of plant and soil properties with significant reductions in plant height, total vegetation cover and bryophyte cover, and increases in bareground and erosion on tracks. Erosion was more prevalent on slopes greater than 25°, while tracks on peat soils contained greater bareground exposure, particularly of organic soil. The second study objective was to investigate the relationship between specific levels of impact and the resulting damage to two key alpine vegetation types, tussock herb field and cushion bog. This was undertaken by carrying out controlled trampling experiments, measuring changes to plant structural and compositional aspects four weeks and one year after treatment. Both vegetation types saw dramatic reductions in total vegetation cover and height immediately after trampling, however overall composition and species richness varied little. These two alpine vegetation types showed moderate-low resistance to initial impact and low resilience, with very little recovery evident one year later. Research intothese two areas is important for managing visitor use within alpine areas in order to meet conservation and recreation goals. The survey indicates that alpine community types are very sensitive to visitor use, showing significant structural damage, however the spatial extent of impact is limited within the broader landscape. Instead, visitor impacts associated with tracks are likely to be more visually and aesthetically significant, influencing the visitor experience. The trampling experiments indicate that use levels over 25-75 passes per year within tussock herbfield and cushion bog vegetation on peat soils will result in ongoing damage to previously undisturbed sites. Methods for minimising impacts include limiting visitor numbers, public education in low impact practices, redirection of tracks and use to areas that are less sensitive, the dispersal of visitor activity at very low use intensities (less than 75 direct passes per year) and the concentration of activity on tracks above this level.

Central southern Fiordland, New Zealand, is underlain extensively by metasediments and associated metavolcanics. These are mapped in three lithostratigraphic units, from west to east Edgecumbe Group, Cameron Group and Cumbrae Supergroup. Lower Cameron Group units lithocorrelate with Central Fiordland Belt lithological associations and with those of Fraser Complex, Westland. Eastern Fiordland Belt metavolcanics and lacustrine metasediments are tectonostratigraphically unrelated to Cameron Group, from which they are separated by the Grebe Fault. They instead have affiliations with the Loch Burn Formation, Largs Volcanics, Drumduan Group and Paterson Group. These units (collectively, "Cumbrae Supergroup") represent remnants of a Triassic-Jurassic calc-alkaline arc. Six deformational episodes are identified in central southern Fiordland. The earliest, D₁, is obliterated by D₂ and M₂ metamorphism. D₃ is restricted to the Southwest Fiordland Block. D₄ occupied a brief interval of M₃ time. D₄ of the Central and Western Fiordland Belts corresponds to earliest deformation in Eastern Fiordland Belt metavolcanics. The Grebe Fault is a left-lateral reverse D₄ fault; now vertical, it previously dipped eastward. The Dusky Fault, a reactivated D₅ left-lateral transfer structure, accommodated the dip-slip component of displacement at low-angle normal faults during mid-Cretaceous extension. Open folds represent D₆. Post-glacial scarps mark the post-D₆ Kilcoy and Vincent Faults. Their merged northward continuation is intersected by the tailrace tunnel of the Manapouri Hydroelectric Power Station. Southwest Fiordland Block pelites were metamorphosed at 665 �C, c. 3 kbar during M₂. Early M₃ is of contact metamorphic aspect. Late M₃ is distinctively polybaric: Central Fiordland Belt kyanite-garnet pelites recrystallised at c. 8.5 kbar after metamorphism in the sillimanite field at c. 3.5 kbar. Western Fiordland Orthogneiss 12 kbar granulite assemblages formed during late M₃. South of the Dusky Fault, late M₃ is almost asymptomatic. The M₃ field gradient is continuous across the Grebe Fault: in the Eastern Fiordland Belt, late M₃ staurolite and garnet supersede chloritoid in lacustrine (meta-)sapropel-silts. The Grebe Fault is an important tectonostratigraphic break; it may separate New Zealand�s Western and Eastern Provinces. Its relationship to any "Median Tectonic Zone" is unclear, as no such zone has been found in southeastern Fiordland. Cumbrae Supergroup rocks within the "Median Tectonic Zone" represent the arc that nourished the Eastern Province�s Barretts Formation, Murihiku Supergroup and Stephens Subgroup. The Cumbrae arc was �obducted� westwards during Early Cretaceous continent-arc collision. This event simultaneously halted Eastern Province volcanogenic sedimentation and tectonically buried Fiordland, imposing late M₃ pressure increments. Drumduan Group lawsonite is coeval. Cretaceous collision induced glaciation. Late Cretaceous climatic deterioration and extensional tectonism caused icecap development. The Otago "Peneplain" is a Late Cretaceous subglacial floor. Accumulation of voluminous perennial Cretaceous ice on Earth has hitherto not been inferred. Facultative psychrophily in New Zealand�s ancient endemics and their preference for dark conditions reflect passage through a hitherto-unsuspected evolutionary bottleneck: prolonged winter darkness and harsh climate of near-polar Late Cretaceous New Zealand exerted extraordinary evolutive pressures on ancestral forms after biotic links with Gondwana were severed. New Zealand�s ancient endemics are the evolutionary derivatives of a Late Cretaceous near-polar fauna.

The secondary productivity of communities is inherently influenced by the availability and quality of food resources. Movement of organic matter (OM) across landscapes can connect adjacent systems by providing subsidies of carbon and nutrients, implying that alterations of environments from their natural state may affect the productivity of neighboring food webs. The intact terrestrial and marine environments of Fiordland provide a setting to study linkages between the land and the sea. The first general objective of this study was to determine if large but nutritionally poor (nitrogen-poor, carbon-rich) inputs of forest litter support marine secondary production, and to identify pathways for incorporation of this material into upper trophic levels. Pools of marine and terrestrial OM had distinct values of [delta]�⁵N, [delta]��C and [delta]�⁴S, providing high power to estimate the relative use of these sources by the food webs of the fjord-head deltas. Deposit feeding invertebrates (e.g. Echinocardium cordatum, Pectinaria australis) directly assimilated plant detritus. Heterotrophic bacteria on the surface of the sediment assimilated forest litter and provided a potential food source for invertebrates. Chemoautotrophic bacteria fix CO₂ that originates from decomposing forest litter, thus providing an indirect pathway for incorporation of forest litter into the food webs. In the deep basins the strength of the flux of uptake by chemoautotrophic bacteria through the benthic food web into the upper trophic levels was demonstrated by hagfish (Eptatretus cirrhatus) obtaining 38-51% of their nutrition from these bacteria. The ability of a community to utilize discrete sources of OM relies on the presence of specific functional feeding guilds. Marine algae provide a highly nutritive (nitrogen-rich) food source for the fjord communities and fluxes of algae into food webs are facilitated by grazing invertebrates and filter feeders. The second general objective of this study was to determine how the effective loss of filter feeders from inner Doubtful Sound would alter the flux of marine-derived OM to the food webs of the delta communities. The low salinity environment imposed by the hydroelectric power station in Doubtful Sound caused a large reduction in the abundance of the infaunal bivalves Austrovenus stutchburyi and Paphies australis from delta habitats. Clams could tolerate periods of freshwater exposure of [less than or equal to]20 days duration, but the constant freshwater conditions in Doubtful Sound decreased survivorship. In 2004/05 the biomass of these species in inner Doubtful Sound (7.28 tonnes) was 29 times smaller than in Bradshaw Sound (214.12 tonnes). The associated loss of biodeposits (~91 tonnes(DW) yr⁻� in Bradshaw Sound vs. 1 tonne(DW) yr⁻� in inner Doubtful Sound) may have also altered the flux of nutritive OM to the infaunal community. The river delta communities in inner Doubtful Sound appear to have a higher reliance on forest litter than those in Bradshaw Sound, which is apparent as low values of [delta]�⁵N and [delta]��C for estuarine fish (Notolabrus celidotus, Hemerocoetes monopterygius), which act as integrators of the benthic community. This study demonstrates important linkages between terrestrial and coastal marine ecosystems and highlights the role of functional diversity in facilitating fluxes of organic material through food webs.

ABSTRACT Doubtful Sound, in SW New Zealand, exposes an exhumed section of lower crust that represents the root of an Early Cretaceous magmatic arc. Here, the lower crust underwent a change from contraction to extension and these tectonic cycles are fundamental to the growth of continental crust. Mafic-intermediate granulite gneisses occur below the extensional Doubtful Sound shear zone (DSSZ) which records the retrogression and transposition of granulite fabrics at the upper amphibolite facies. I compared 3D rock fabrics, microstructures and textures within and below the DSSZ to determine the processes involved in the shift from contraction to extension and to infer the sequential processes of transforming L>S granulites to L=S amphibolites. Below the DSSZ, dehydration zones around felsic veins and leucosome in migmatitic orthogneiss record granulite facies metamorphism. Aggregates of clinopyroxene (cpx) and orthopyroxene (opx) that are rimmed by garnet (grt) and interstitial melt are set in a plagioclase (pl) matrix. Peritectic grt, pl-grt symplectites, beads of pl along grain boundaries, and elongate, inclusion-free pl reflect the anatexis. Pl exhibits a crystal preferred orientation (CPO) and evidence of subgrain rotational recrystallization and grain boundary migration, indicating subsolidus deformation outlasted melting. Mafic aggregates are boudinaged and opx developed subgrains. During peak metamorphism high strain was partitioned to locations enriched in melt, producing L>S fabrics and an upward trajectory in the strain path. A comparison of mineral grain shapes indicates that pl accommodated most of the strain. Granulite-amphibolite transitional rocks inside the DSSZ record a heterogeneous retrogression of the granulites to a polyphase metamorphic assemblage of hornblende (hbl), biotite (bt), and fine pl. Also preserved is the resetting of high strain L>S granulite to low strain, L=S amphibolite. Folia of porphyroblastic hbl + bt progressively penetrate the pl matrix via solution mass transfer. Porphyroblastic pl in the rock matrix becomes increasingly transposed to gneissic layering. A path of decreasing gradient from high strain L>S granulite to low strain L=S amphibolite reflects the development of the DSSZ fabric, growth of new minerals and onset to deformation at the amphibolite facies. Inside the DSSZ, amphibolites show an increasing strain gradient from low strain L=S amphibolite to high strain L=S amphibolite. Pl aggregates lack a CPO and are mostly annealed but preserve grain boundary migration microstructures. Hbl is recrystallized and forms asymmetric fish. Evidence of high fluid activity and reaction softening within the DSSZ include increased hbl + bt and bt beards on pl relative to rocks outside the DSSZ. My observations suggest that magma, heat, and melting initially weakened the lower crust, facilitating the development of high strain zones with L>S fabrics. Partially molten regions deformed by suprasolidus flow and solid portions deformed mostly by dislocation creep in pl and boudinage of cpx + opx. Later, the lower crust was weakened and high strain fabrics were reset from overprinting and transposition as retrogression progressed and low strain L=S fabrics formed. During extension there was an upward trajectory in the strain path to high strain L=S fabrics within the DSSZ, where hbl and bt accommodated more strain. My results illustrate the importance of 1) melting, cooling, and hydration in controlling strain partitioning and the rheological evolution of lower crustal shear zones, and 2) the importance of integrating microstructural and fabric analysis to determine strain paths.

The plate-boundary Alpine Fault runs immediately offshore of the popular tourist destination of Milford Sound, which is visited by more than half a million tourists each year. Glaciers retreated from the fiord between ~24-16 ka, leaving behind a legacy of extreme topography, including some of the world's highest sea cliffs, which tower nearly 2 km above the fiord. Visitors come to view the spectacularly steep and rugged landscape, with many cruising the fiord by boat. This project utilizes surface exposure dating (TCND) of glacially modified surfaces, to gain further insight into the glacier retreat history of Milford Sound. Exposure dates from strategic locations near the entrance to the fiord indicate that the main trunk glacier had retreated about 9 km from its peak LGM position by ~18 ka. Additional TCND and calibrated Schmidt Hammer data from a range of positions within the Milford catchment provide strong evidence that the main trunk glacier receded rapidly after about 18 ka, retreating a further 16 km to a position near the present-day confluence of the Tutoko and Cleddau rivers, by ~16 ka. Available seismic reflection data suggest that post-glacial sediment infill has been strongly influenced by massive deposits of rock avalanche debris. New high-resolution bathymetric and seismic reflection data reveals the presence of at least 18 very large post-glacial rock avalanche deposits which blanket ~40% of the fiord bottom. Geomorphic mapping and field investigation reveal the presence of at least ten additional very large to giant terrestrial landslide deposits in the lower Milford catchment; radiocarbon and surface exposure dating indicate that these events occurred during the Holocene, between ~9-1 ka. Ages of six of these deposits are in agreement with published rupture dates on the southern on-shore portion of the Alpine Fault.

In this thesis, I present structural and kinematic data on rock fabrics, shear zones and fault zones from the Cretaceous Malaspina orthogneiss and some of its satellite plutons in central Fiordland, New Zealand. Central Fiordland exposes a large tract of granulite- to eclogite-facies lower crust that was exhumed between late Mesozoic to Cenozoic times. The deformational structures of interest were formed and preserved during the lifecycle of a Cretaceous continental arc that involved thickening to over 60 km followed by collapse and rifting. As such, they provide an excellent opportunity to study strain localization in the deep crust and the process of exhumation. Detailed structural mapping, analysis, and the construction of a 45-kilometer cross section through the Malaspina orthogneiss and adjacent plutons reveal the spatial distribution, sequence, and kinematics of crosscutting deformational structures. The earliest structures record Cretaceous magmatism, high-grade metamorphism at the granulite and eclogite facies, and ductile flow that resulted in widespread (over 1200 km2), disorganized magmatic foliations. These events were followed by regional extension that resulted in the formation of multiple, ≤0.5 km-thick ductile, upper amphibolite facies shear zones that record cooling, hydration, and horizontal flow during the Late Cretaceous. Extension continued but changed obliquity in the early to middle Tertiary and resulted in sets of strike-slip and normal brittle to semi-brittle faults forming a sinistral transtensional system. These faults are distributed across central Fiordland and crosscut and transpose the ductile shear zones and magmatic foliations. Lastly, a change in relative plate motions resulted in the inception of the Alpine fault and the development of a late Tertiary transpressional fault system that crosscuts all previous structures. The dominant factors controlling strain localization in central Fiordland changed from magma, heat, and melting, to fluid activity, plate boundary reorganization, and reactivation of inherited structures. The succession of contrasting strain localization styles in response to changing tectonic and local conditions led to the development of multiple phases of deformation. These multiple phases of deformation allowed the deep crust to be exhumed in a heterogeneous and fragmented, or 'piecemeal', way. In particular, the inability of late Cretaceous ductile shear zones to fully exhume the lower crust was compensated by the ability of early Tertiary transtensional faults to simultaneously thin and further exhume the lower crust. Investigations of strain localization patterns in central Fiordland shed light on the causes and mechanisms of crustal exhumation, a phenomenon that is integral to the lifecycle of virtually all orogenic belts.

The Fiordland Block, in the southwestern part of the South Island of New Zealand, shows evidence of a complex tectonic evolution dominated by tectonic and intrusive events in the mid-Paleozoic and mid-Cretaceous and is thought to represent a fragment of the Paleozoic margin of Gondwana. Fiordland geology is dominated by the extensive granulite facies Cretaceous Western Fiordland Orthogneiss, which is surrounded by Paleozoic metasediments and intrusive rocks. This study concentrates on an area in southern Fiordland, where rocks of three crustal levels are exposed, separated by steep SW-NE trending faults (for example the Dusky Fault): the granulite facies (-9-12 kbar) Western Fiordland Orthogneiss, the amphibolite facies Cretaceous Supper Cove Orthogneiss which intruded into kyanite-grade ( -6-8 kbar) Paleozoic metasediments, and the andalusite to sillimanite-grade ( -3-4 kbar) Southwestern Fiordland Block. By determining and comparing the structural, metamorphic and thermochronological histories of the different crustal levels, a better understanding of the tectonic evolution of Fiordland, and of the exhumation of Fiordland in particular, has been gained. The Paleozoic history of Fiordland is characterised by andalusite to sillimanitegrade metamorphism and strong deformation associated with the emplacement of voluminous granitic intrusions. New U-Pb SHRIMP zircon dating of granitic intrusions in southern Fiordland yielded ages of ca 370 to 380 Ma, which are consistent with previously determined ages from other parts of Fiordland and from the once contiguous area of Westland-Nelson, in the northwestern part of the South Island of New Zealand. A ca 340 Ma U-Pb zircon age of a posttectonic pegmatite in the Southwestern Fiordland Block and a ca 335 Ma U-Pb zircon age from a weakly deformed metagabbro in the sillimanite-grade Central Fiordland Belt (to the east of the Southwestern Fiordland Block) constrain the younger age limit of the dominant tectonic event. The localised preservation of 220-270 Ma 40Ar-39 Ar hornblende and mica ages indicate that the area cooled to below -300°C by at least the Permian and give a minimum cooling rate of 3°-5°C/Ma for cooling following mid-Paleozoic metamorphic and deformation events. However, because most of the Paleozoic rocks are strongly affected by a Cretaceous thermal event, little is known about the tectonic and cooling history between the mid-Paleozoic and the mid-Cretaceous. The majority of the 40 Ar-39 Ar mica ages from the Paleozoic metasedimentary and intrusive sequence range between ca 100 and 120 Ma and indicate a strong thermal overprint in the Cretaceous. In the Southwestern Fiordland Block, the thermal event is associated with only very little deformation and with a localised, static, kyanite-grade overprint. No evidence for the presence of Cretaceous intrusions has been found in the Southwestern Fiordland Block. Immediately north of the Dusky Fault, which separates the Southwestern Fiordland Block from deeper crustal levels, kyanite-grade Paleozoic rocks are intruded by the voluminous 121 Ma Supper Cove Orthogneiss and are dominated by Cretaceous deformation and metamorphism (at 6-8 kbar and 600-650°C). The Supper Cove Orthogneiss is similar in geochemical composition to the Western Fiordland Orthogneiss, but was metamorphosed at lower pressures and could, therefore, represent higher levels of the Western Fiordland Orthogneiss complex. The Western Fiordland Orthogneiss, the Supper Cove Orthogneiss and the intruded Paleozoic cover experienced rapid cooling to temperatures around 300°C as result of rapid exhumation. 40Ar-39Ar mica ages of 107 Main the Western Fiordland Orthogneiss and 40 Ar-39 Ar hornblende and mica ages of 100 Ma and 90 Ma, respectively, in the Supper Cove Orthogneiss and kyanite-grade Paleozoic cover, indicate that the deeper level Western Fiordland Orthogneiss cooled more rapidly than the higher level Supper Cove Orthogneiss. This could indicate that the Western Fiordland Orthogneiss was exhumed from beneath the Supper Cove Orthogneiss along an extensional detachment zone, thereby bringing the two orthogneisses at a similar crustal level. This is consistent with the observation that, following the rapid cooling, both areas remained at similar temperatures until final exhumation and cooling in the late Tertiary, as indicated by K-feldspar age spectra. A similar model has been proposed for the thermal event in the Southwestern Fiordland Block: middle to lower crustal rocks were exhumed from beneath the Southwestern Fiordland Block, bringing hot lower crustal rocks at shallower levels and increasing the heatflow. The relatively small temperature difference between the Southwestern Fiordland Block and the mid to lower crustal Cretaceous orthogneisses following mid Cretaceous rapid cooling confirms that lower crustal rocks were brought within 5 km of the Southwestern Fiordland Block. These observations may indicate that several detachment zones were active at the same time at various levels in the crust. The continental extension resulted in the break-up of the Gondwana margin. K-feldspar 40 Ar-39 Ar age spectra from the Southwestern Fiordland Block and Central Fiordland Belt indicate slow cooling at rates of 1 °-2°0Ma from about 100 Ma to at least 50 Ma, when temperatures dropped to below ca 200°C. This is consistent with 60- 80 Ma zircon fission track ages. A minor deformation event around 50 Ma is indicated by resetting of the argon isotopic system in K-feldspars from the Western Fiordland Orthogneiss and Supper Cove Orthogneiss and by increased cooling rates indicated by Kfeldspar 40Ar-39 Ar age spectra from the Southwestern Fiordland Block. This is thought to be related to Eocene plate reconfiguration in the southwest Pacific. The initiation of the final exhumation and cooling is well constrained by Kfeldspar 40Ar-39 Ar age spectra from the Western Fiordland Orthogneiss and Supper Cove Orthogneiss, which show a sudden increase in cooling rate from <1 °C/Ma to -13°0Ma around 15 Ma. Final exhumation was probably the result of the start of compression across the precursor of the Alpine Fault and possibly of subduction of the Australian plate under southern Fiordland. Consistent ca 7 Ma apatite fission track ages across southern Fiordland indicate that the brittle Dusky Fault and other equivalent faults were mainly active between 15 and 7 Ma, during which the Western Fiordland Orthogneiss and Supper Cove Orthogneiss were brought up to the same crustal level as the Southwestern Fiordland Block.

Fjords contain a significant quantity of sediments deposited in coastal zones over the last ~100,000 years. Studies of Northern Hemisphere fjords have shown that a large part of the high concentration of sedimentary organic matter (OMsed) is terrestrial in origin (OMterr), composed of a modern detrital fraction and an old mineral-associated fraction (OMfossil). These results suggest that fjords are disproportionately responsible, on a per area basis, for the burial of organic matter in coastal zones. This study, after a rigorous examination of CuO and GDGT biomarker methods used to quantify terrestrial organic matter in coastal environments, demonstrated this hypothesis in a Southern Hemisphere fjord system, Fiordland, New Zealand. CuO analysis of Doubtful Sound surface sediments indicated a large contribution of vascular plant material to fjord sediments. The BIT Index correlated strongly with both delta13C and C/N values in Doubtful Sound surface sediments, indicated that it may accurately trace the relative proportions of marine and soil organic matter (OMsoil) in Fiordland. However, a detailed analysis of the conversion of the BIT Index to quantitative estimates of terrestrial (soil) organic matter revealed that these values are overestimates. Reconstructions of the BIT Index and tetraethers in cores from two locations on the Louisiana continental shelf demonstrated the influence of the crenarchaeol term on BIT Index-based terrestrial organic matter estimates. The differences in the applicability of the BIT Index to these two coastal environments was most likely due to large seasonal changes in productivity on the Louisiana Continental Shelf as well as higher marine relative to terrestrial inputs. Six cores were reconstructed for contributions from marine OM (OMmar), OMfossil, and OMterrestrial representing the last ~500 years of sedimentation. Spatial variations were larger than temporal variations, owing to negligible development and deforestation in the region. OMterr was the dominant fraction in all but one core, and OMfossil inputs were significant. Additionally, source reconstructions from a variety of biomarkers indicated that Landslides deliver large volumes of detrital organic matter to fjord sediments. These results confirm that fjords bury quantitatively significant volumes of organic carbon on a global scale.

The base of the 10-20 km thick, batholithic, Western Fiordland Orthogneiss (WFO) is exposed in northern Fiordland as the Mount Daniel Complex (MDC). It forms a ~100-metre thick, sheeted complex between the WFO and the underlying dominantly dioritic basement of Arthur River Complex (ARC). Although previously called a migmatite aureole at the WFO base, field relations show it formed after the WFO was solidified and injected by numerous rectilinear trondhjemitic dykes. U-Pb zircon analysis confirms emplacement of the WFO at 125 Ma, with MDC formation slightly later, between 120-112 Ma. Successive dyke injection and sheeting during tight to isoclinal folding, and fold asymmetry, indicates that the MDC was emplaced syn-tectonically into an active, sinistral reverse shear zone associated with exhumation of the WFO. The MDC is composed almost entirely of intrusive metre-scale sheets, ranging in composition from mafic dykes, low-Na and high-Na intermediate (trondhjemitic) dykes, high-K granitic dykes and the dominant intermediate-composition Mt Daniel Sheets (MDS) of the complex 55-65% SiO2. The compositional range of MDC vary from 44wt% to 76 wt% SiO2, and has a typically sodic character (Na2O 4-8 wt %). With the exception of very sodic trondhjemitic dykes (Na2O >6 wt%), the MDC is similar to coeval high-level granitic plutons of the Separation Point Batholith (SPB), located northward from the study area. WFO shows a different geochemical trend from the other MDC rocks and a more restricted isotopic composition. This data and field evidence suggests that the WFO was not involved in formation of the MDC. The wide spectrum of MDC rock types requires multiple sources. Flat, MORB-like REE patterns of the mafic dykes indicate derivation from spinel lherzolite (< 70 Km depth). All other rock types come from crustal sources. The trondhjemitic dykes have variably depleted HREE and minor Eu anomalies compared to the other rock-types and high Sr/Y ratios (>40) indicating their derivation from a deep mafic crustal source ≥13 Kb where garnet was stable and plagioclase unstable. The high-K granites have low Rb content, suggesting residual biotite in the source rock. It is argued, based on published experimental data, that the high-K magmas were hydrous and formed near the granite solidus at ~10 kbar. Bimodal (felsic and mafic) magmas dominate the lower section of the MDC, but more homogenized intermediate dioritic magmas dominate the upper section. Mixing of the magmas occurred by stirring during intrusion into the active shear zone. Trondhjemitic dyke injection was continuous throughout MDC formation. The isotopic εNd-initial Sr wholerock data and Hf isotopic data of zircon from different rock types show a crust-mantle mixing array, and the coherent major and trace element variation within the MDC is broadly consistent with mixing, rather than fractionation. Mixing of the (high- and low-Na) intermediate dyke magmas with the mafic and granitic dyke magmas can explain the chemical and isotopic variation within the MDC, including the REE and multielement variation patterns. An alternative explanation for the chemical diversity of the MDC is that bulk assimilation of ARC basement has contributed a major component. Assimilation is most clearly observed in the lower sections of the MDC, but less so in the upper homogenized sections. However, the presence of inherited zircon of Carboniferous age in most samples indicates it was pervasive. The similarities in the Hf isotopic composition of zircons from trondhjemitic dykes and SPB granites with the ARC (136-129 Ma) and Darran Complex (143-136 Ma) suggest they represent the dominant juvenile mafic crustal source or equivalent. Few inherited Mesozoic zircons exist in the MDC, but this probably reflects the lack of zircon in the inferred primitive (gabbroic?) protolith. Evidence for an older evolved source component comes from Carboniferous-aged zircons, which are also present in the ARC. This is probably the major source of the high-K granitic magmas. Thus, this study proposes crustal-assimilation and mixing of four major source components in the lower crust produced the chemical diversity of the MDC. The short time span (120-112 Ma) represented by MDC rocks, the simultaneous presence of Early Cretaceous magmatic and metamorphic zircons, even within the same rock, and the presence of both HREE-depleted and non-depleted rims zircon in granites, suggests a very dynamic transitional magmatic-metamorphic environment associated with the MDC formation. The magmatic to metamorphic condition was associated with a change from open to closed system chemical processes. The formation of trondhjemitic dykes at ~13 Kbar depth after the burial of WFO at ~120 Ma and formation of granites at comparatively lower depth at ~10 Kb (between 120-112 Ma) is consistent with an exhumation path for the MDC at this stage. Thus, the MDC represents the retrograde part of an anticlockwise P-T-t path. Exhumation could have been associated with crustal extension, for which limited evidence exists regionally, or it can be associated with thrusting. If the latter, the crust must have been undergoing rapid erosion during crustal shortening. The MDC represents a rare exposed example of magma generation in the lower crust. The critical aspect for preservation was the presence of hydrous granitic magmas that froze as the Mt Daniel shear zone crossed the saturated granite solidus. Normally, more anhydrous magmas, possibly also hotter because of mafic input, would move out of the source region and lose the evidence for the incremental granite generation process by sheet/dyke focussing along active shear zones, assimilation and mixing. The MDC rock types cover the compositional spectrum of the upper crustal SPB, including its sodic, HiSrY character. However, the MDS spectrum reflects mixing whereas the SPB reflects fractionation from relatively homogeneous parent magma. The evidence from the MDC suggests that HiSrY parental, intermediate-composition magmas are produced by large-scale bulk assimilation of the pre-existing lower crust, itself of sodic character, with more sodic dyke material mixed in. The blended magmas segregate and coalesce in upper crustal chambers, where virtually all evidence of the magma generation process is lost.