Recent mapping of the Eagle Lake Quadrangle, NY, coupled with whole-rock geochemistry and microscopy has offered insight into the petrogenesis of the magnetite-apatite deposits of the Hammondville mining district in the eastern Adirondack Mountains. This study provides insight into the magmatic history of the ca. 1060-1050 Ma Lyon Mountain Granite (Hammondville Pluton) which is intimately related to, and hosts the deposits in this area. Magnetite seams are commonly surrounded by well layered magnetite gneiss, which typically parallel the seams, although in some outcrops appear to be slightly truncated by them. Mineralization is generally concordant with the weak layering found throughout the rest of the pluton, and similarly lacks a pervasive metamorphic fabric. Sub-solidus deformation is recorded in some localized shear zones that occur in both the seams and host-granite indicating post-crystallization and post-mineralization deformation events. These episodes could have provided conduits for fluids responsible for growing younger zircon that past workers dated and interpreted as a separate time of mineralization. We conclude that magnetite mineralization likely occurred as separate magma, or magnetite rich fluid, injected into the Lyon Mountain Granite either as a syn-magmatic process, or while it was still a crystalline mush.

published_or_final_version / Earth Sciences / Doctoral / Doctor of Philosophy

Der weltweit steigende Energiebedarf stellt die Menschheit vor immer größere Herausforderungen. Im Angesicht des Klimawandels und der begrenzten Verfügbarkeit von fossilen Energieträgern liegt eine besondere Verantwortung bei der Entwicklung von erneuerbaren Energieressourcen. Dabei spielt die Geothermie eine besondere Rolle, da sie zur Deckung der Grundlast geeignet ist. Zu der Bewertung von geothermischen Potentialen leisten die Geowissenschaften einen großen Beitrag. Das geothermische Potential eines Standorts hängt vor allem von der Art und Ausbreitung von Störungszonen ab, da sie wesentlich den Grundwasserfluss kontrollieren. In dieser Arbeit werden verschiedene geowissenschaftliche Methoden miteinander kombiniert, um die Wirksamkeit von Störungszonen zu bewerten. Strukturgeologische Kartierungen und hydrogeologische Felduntersuchungen erklären die Ausbreitung und hydraulische Funktion von Störungszonen im Untersuchungsgebiet. Geohydrochemische Untersuchungen geben Auskunft über Fluid- und Gesteinszusammensetzung und deren Wechselwirkungen. Numerische Simulationen des Gebietes zeigen, dass sowohl Störungszonen als auch Fluideigenschaften wichtig für die Verteilung von Druck und Temperatur im Reservoir sind. Das Untersuchungsgebiet ist das Hochenthalpy-Geothermiefeld Lahendong in Sulawesi (Indonesien). Ein Kraftwerk produziert hier 80 MW Elektrizität. Die ersten Untersuchungen im Gebiet starteten in den 1970er Jahren. Jedoch sind Genese und Verteilung der thermalen Wässer noch nicht komplett verstanden. Das aktuelle konzeptionelle Modell zeigt eine Aufteilung in mehrere Reservoirbereiche. Die verschiedenen Bereiche sind durch horizontal impermeable Störungszonen voneinander getrennt. Den nördlichen Bereich kennzeichnen saure Wässer und den südlichen Teil pH-neutrale Wässer. Auch die Produktivität variiert stark zwischen den beiden Reservoirbereichen. In vertikaler Richtung sind Störungszonen jedoch durchlässig, was dazu führt, dass heiße Quellen entlang von Störungen oder deren Kreuzungspunkten auftreten. Die Reservoirgesteine in Lahendong sind basaltische Andesite, Tuffe und vulkanische Brekkzien. Die Permeabilitätsverteilung der Störungszonen wird durch die Ausbreitung von Rissen kontrolliert. Risse sind vor allem in der Bruchzone der Störung verbreitet, was zu einer hydraulischen Durchlässigkeit parallel zur Störung führt. Die Unterteilung des Reservoirs in Lahendong wird durch diese Rissverteilung bestimmt. Der nördliche saure Teil des Reservoirs ist durch höhere Produktivitätsraten, Gasaustritte an der Oberfläche und stark alterierte und geklüftete Gesteine im Untergrund charakterisiert. Der südliche Abschnitt ist heißer und hat weniger stark alterierte Gesteine. Die beobachteten Reservoireigenschaften wurden von hydrochemischen und hydraulischen Modellierungen bestätigt. Der Grundwasserfluss mit Neubildung und Austritten aus dem Reservoir ist im Gelände und im Modell vor allem durch Störungszonen kontrolliert. Jedoch ist der Grundwasserfluss auch durch den Aggregatzustand des Wassers beeinflusst. Für die Modellierung von 2-Phasen-Ausbreitung müssen die Permeabilitäten angepasst werden, um gleiche Temperatur- und Druckbedingungen zu modellieren. Der Hauptbeitrag dieser Arbeit liegt in der Demonstration, dass eine systematische strukturgeologische Analyse für das Verständnis von Grundwasserfluss in geothermischen Reservoiren unentbehrlich ist. Es wurde bestätigt, dass die Kombination von tektonischen, hydrogeologischen und geohydrochemischen Informationen den wichtigsten Beitrag für das Verständnis von Grundwasserströmungen leistet. Die Grundwasserströmung ist der wichtigste Faktor für die Wahl des richtigen Standortes für Produktion und Injektion in geothermischen Feldern. Eine detaillierte Analyse gewährleistet eine nachhaltige Nutzung des Feldes und verringert Risiken, wie schwach produzierende Bohrungen oder die Produktion von stark korrosiven Wässern. Auf dieser Grundlage kann eine Felderweiterung geplant werden, wie es in Lahendong angedacht ist.

The Bouguer correction using a mean sea level reduction datum compensates the gravitational effect of the mass of the terrain above sea level. This correction generally results in long -wavelength Bouguer gravity anomalies if the mass of the terrain is isostatically compensated. These anomalies correlate with regional elevations, especially in areas with significant regional variations in elevation, such as western North America. The adverse effect of this correlation is that other anomalies of potential interest in a tectonic or geologic analysis may be overshadowed. To circumvent this problem in an analysis of gravity in Arizona, a residual Bouguer gravity anomaly map has been constructed for the state in which a trend surface of the elevation is used as the reduction datum in the Bouguer correction. Elevation values from topographic maps and not gravity station elevations have been used to prepare the regional elevation datum because station elevations do not adequately sample the range in elevations. Small- and large-wavelength residual Bouguer gravity anomalies and trends of anomalies are brought out more clearly by the residual Bouguer gravity anomaly map than by previous gravity maps. The most prominent features in the residual anomalies are a strong gravity gradient 50 km wide striking west -northwest across southern Arizona and a large wavelength residual Bouguer gravity anomaly low in the Coconino Plateau of northwest Arizona . The long-wavelength residual Bouguer gravity anomalies reflect lateral density variations in the crust and mantle that may be related to lateral temperature variations.

Golden Gate Mountain appears as a spur projecting westward from the Tucson Mountain range. It is made up of the capping Cat Mountain Rhyolite, the slope - forming Amole Formation, and a variety of intrusions of differing compositions. The emplacement of the andesitic portion of the intrusions occurred during, and probably lasted long after, the deposition of Amole Formation. The hot magma fluidized the wet sediments. Part of the fluidized materials formed pipes and dikes of tuffisites and part was brought up into the basin and contributed to the sedimentation of Amole Formation. During upper Amole time the intrusion of andesite increased in intensity. Part of the basin rapidly subsided and thick deltaic sediments and graywacke were formed. The development of a hinge line accompanied this subsidence. The hinge line controlled the occurrence of fluidization which undercut the Amole beds. The beds slumped into the fluidized parts. The process culminated in forming a large orifice through which the Cat Mountain Rhyolite welled up. The orifice is reflected in the sedimentary beds by the development of a funnel- shaped structure in the central part of which the capping of Cat Mountain Rhyolite is located. The bordering brecciated Amole beds represent the associated slump effects.

Deformační interakce mezi horninami na významném rozhraní k·ra - litosférický pláš' je jedním z hlavních proces·, jejichž pochopení umožní lépe popsat termomechanické procesy probíhající hluboko v rozsáhlých pohořích a především chování kontinentálního pláště během kolize kontinentálních desek. Tato disertační práce obsahuje tři hlavní kapitoly, představující výsledky r·zných geologických metod, využitých při zkoumání p·vodu a deformačního chování peridotitových těles ve spodní k·ře Variského orogenu. První kapitola prezentuje závěry ze strukturní studie Mohelenského peridotitu a okolních granulit· z Náměštského granulitového masívu. Jako jedinou efektivní metodou pro studium vnitřní stavby peridotitu se kv·li rozsáhlé serpentinizaci ukázalo měření přednostní mřížkové orientace (EBSD). V serpentinizovaném peridotitu byly zjištěny dva odlišné olivínové skluzné systémy, jejichž distribuce společně s detailním strukturním mapováním v okolním Náměš'ském granulitovém masívu umožnily vysvětlit reologické chování peridotitového tělesa v prostředí kořene orogenu. V této kapiole jsme se pokusili vytvořit geotektonický model, který popisuje historii peridotitového tělesa v rámci mnoha fází tektonické historie orogenního kořenu. Ve druhé kapitole představujeme výsledky z analýzy serpentinizačních proces· v...

O estudo da hidrogeologia em aqüífero cristalino fraturado apresenta como maior desafio a imprevisibilidade do meio, uma vez que o fluxo ocorre exclusivamente pelas fraturas. Neste sentido informações de atitude, abertura e conectividade de fraturas tornam-se essenciais no entendimento do fluxo da água subterrânea. O presente trabalho busca aplicar o conhecimento da tectônica rúptil para caracterizar o meio fraturado, com intuito de auxiliar o estudo hidrogeológico do aqüífero. A área de estudo está localizada na porção leste do Município de Cotia, SP, no contexto do Complexo Embu, de idade proterozóica, na porção central da Faixa Ribeira. Ocorrem predominantemente rochas granitóides, com permeabilidade primária desprezível, rochas cataclásticas relacionadas às grandes zonas de cisalhamento de Taxaquara e Caucaia do Alto, metassedimentos e coberturas aluviais cenozóicas, estas ao longo das principais drenagens. Os principais eventos tectônicos de caráter rúptil da região estiveram relacionados à reativação mesozóico-cenozóica, inicialmente com a ruptura continental e abertura do Oceano Atlântico Sul e, posteriormente, a formação do Rift Continental do Sudeste do Brasil (RCSB), e seus principais eventos de deformação. Os estudos foram desenvolvidos em duas escalas de trabalho. A primeira de semi-detalhe, em 1:50.000, e a segunda de detalhe, em 1:5.000, esta última em duas porções distintas dentro da área de semi-detalhe. Os resultados obtidos em escala de semi-detalhe, a partir da análise da tectônica rúptil (morfometria, fotogeologia e levantamentos de campo), serviram para direcionar as investigações em escala de detalhe, onde foram usados dados provenientes de sondagens, métodos BHTV (Bore Hole Television), levantamento de perfis de eletrorresistividade e dados hidrogeológicos de poços de monitoramento instalados no aqüífero em meio fraturado. Os estudos de escala de semi-detalhe permitiram delinear lineamentos de direções N-S, E-W, NE-SW e NW-SE, originados pelas diversas fases de deformação rúptil. Esses dados de lineamentos foram correlacionados com dados de atitude de falhas e juntas medidas em afloramento, e, posteriormente, associados às diferentes fases de deformação descritas para o RCSB. Foram definidas seis famílias de juntas: a) família NNW-SSE, com mergulho alto para NE); b) família NE-SW com mergulho sub-vertical; c) família E-W com mergulho alto para NW); d) família WNW-ESE com mergulho alto para NE); e) família NESW com mergulho médio para NW; e f) família NE-SW com mergulho médio para SE. Os resultados dos estudos desenvolvidos em escala de semi-detalhe, somados aos condicionantes geológicos e geomorfológicos das áreas selecionadas para estudos de detalhe, orientaram a instalação de poços de monitoramento verticais e inclinados nessas últimas. Foram instalados 11 poços na área de detalhe A e quatro poços na área de detalhe B. Os poços foram perfilados por televisionamento acústico e as fraturas identificadas nesses poços foram separadas por famílias e subfamílias: Família 1 (sub-horizontal), Família 2A (N-S com mergulho médio para W) e 2B (N-S com mergulho alto para E), Família 3A (NE-SW com mergulho médio para NW) e 3B (NE-SW com mergulho médio para SE) e Família 4 (WNW-ESE sub-vertical). Na maioria dos poços foram realizados ensaios hidráulicos para determinação da condutividade hidráulica (K), que variou de 1,55x10-8 a 2x10-5 cm/s, com média de 2,98x10-6 e desvio padrão de 5,60 x10-6 cm/s. Ensaios de bombeamento indicaram fluxo de água subterrânea através das estruturas N-S, com boa conexão com as estruturas NE-SW. A abertura média das fraturas foi de 1,13x10-3 cm, calculada com base nos valores de condutividade hidráulica correlacionados aos dados estruturais. A partir dos dados hidrogeológicos e estruturais foi proposto um método para se estimar a transmissividade e condutividade hidráulica de um poço instalado no aqüífero fraturado. / The main challenge in a hydrogeological study of a fractured-bedrock aquifer is the unpredictability of media, because the ground-water flows only through the fractures. Informations about strike, dip, opening and connectivity among fractures become essential in order to understand the ground-water flow. This work is an application of the concepts of the brittle tectonics to characterize a fractured media in order to help the hydrogeological study of a fractured-bedrock aquifer. The study area is located at the eastern part of the City of Cotia, State of São Paulo, Southeastern Brazil, in the context of the Proterozoic Embu Complex, in the central part of Ribeira Belt. This area encompass predominantly granitoid rocks (with negligible primary permeability), cataclastic rocks related to the Taxaquara and Caucaia do Alto shear zones, and metasedimentary rocks. Quaternary alluvial deposits occur along the main drainages. The main brittle tectonic events in the region are related to the Mesozoic-Cenozoic reactivation, associated with the continental break-up, the opening of the South Atlantic Ocean, and the formation and deformation of the basins of the Continental Rift of the Southeastern Brazil (CRSB). The study was carried out in two working scales. First in a semi-detail scale, at 1:50,000, of a large area, were brittle tectonic analysis (morphometry, photogeology and field survey in outcrops) was performed. The achieved results were used to select two small areas, within the semi-detail area, for a detailed investigation, on scale of 1:5,000, in which data from rock-boring, BHTV (Bore Hole Television), eletroresistivity and hydrogeology from bedrock monitoring wells were obtained. At a semi-detail scale it was possible to delineate lineaments of N-S, E-W, NE-SW and NW-SE-trending directions, probably originated during several brittle deformational events. Data from lineaments were first correlated with data of fault and joint measured in outcrops and latterly associated with different deformation phases described in CRSB. Six joint families were defined: a) steeply northeastward dipping NNW-SSE-trending family; b) sub-vertically dipping NE-SW trending family; c) steeply northwestward dipping E-W-trending family; d) steeply northeastward dipping WNW-ESE-trending family); e) NE-SW-trending family with moderate dipping towards the NW; and f) NE-SW-trending family with moderate dipping towards the SE. Results of studies in the semi-detail investigation area allowed the selection of sites for drilling of 11 wells in detail area A and 4 wells in the detail area B. All the wells were surveyed by acoustic teleview and the identified fractures were classified in four families and two subfamilies: family 1 (sub-horizontal to gently dipping); family 2A (N-S-trending with moderate dipping towards the W) and 2B (NS-trending with steep dipping towards the E); family 3A (NE-SW-trending with moderate dipping towards the NW) and 3B (NE-SW-trending with moderate dipping towards the SE); and family 4 (WNW-ESE-trending with sub-vertical dipping). Hydraulic conductivity (K) measured in the wells ranged from 1.55x10-8 to 2x10-5 cm/s, with a mean of 2.98x10-6 and standard deviation of 5.60 x10-6 cm/s. Pumping tests showed the groundwater flow through N-S-trending structures and good connection with NE-SW-trending structures. The average opening of fractures attained 1.13x10-3 cm and was calculated on the basis of the amount of hydraulic conductivity correlated with structural data. Based on structural and hydrogeological data it was proposed a method for estimating the transmissivity and hydraulic conductivity of a well installed in the fractured-bedrock aquifer.

Ophiolites - thrust sheets of oceanic lithosphere that have been emplaced onto the continental margin - provide the opportunity to explore the structure and genesis of oceanic crust. As many ophiolites formed above subduction zones, they also allow for the investigation of mantle wedge and subduction interface processes. This the- sis examines the Oman-United Arab Emirates (UAE) ophiolite, which is the largest and most intensely studied ophiolite on Earth. Three distinct problems are addressed. (1) Recent research has proposed that the architecture and tectonic evolution of the ophiolite in the UAE differs from in Oman. In Chapter 2, I test this hypothesis by integrating new geological mapping and field observations with previously published maps of the ophiolite in the UAE. My results indicate that the ophiolite is gently folded, but otherwise largely intact. I demonstrate that the architecture of the ophi- olite in the UAE is not significantly different from in Oman. Thus, there is no basis for a different tectonic evolution as recently proposed. (2) Observations from exper- iments and small-scale natural shear zones indicate that volumetrically-minor phases can control strain localization. In Chapter 3, I test the hypothesis that minor phases control strain-localisation at plate boundaries. To do so, I analyzed peridotites from the base of the ophiolite, a palaeosubduction interface. My results demonstrate that minor phases limited olivine grain growth, which led to rheological weakening. (3) The mechanisms by which metamorphic soles detached from the downgoing slab and accreted to the hanging-wall mantle is unclear. In Chapter 4, I examine a transect across the metamorphic sole in the UAE. My results reveal that granulite formation was more extensive than is typically considered. I propose that granulite formation resulted in rheological strengthening, which caused the subduction interface to migrate into the downgoing slab and accrete the metamorphic sole.

Ce travail porte sur la caractérisation de la source et de la dynamique des fluides de bassin au cours de leur chargement à travers deux exemples complémentaires de demi-grabens tardi-orogéniques pétroliers : Le Bassin Permien de Lodève, aujourd'hui à l'affleurement et un bassin jurassique enfouis dans le North Viking Graben (Mer du Nord). Le cœur de la thèse concerne le Bassin de Lodève où, à partir d'une approche pluridisciplinaire intégrée, nous avons caractérisé l'architecture des minéralisations (Ba, F, Cu, Pb) piégées dans un réseau paléokarstique alimenté par les failles syn-rift, dans le substratum carbonaté à l'apex du roll-over. La source, le calendrier et les conditions de migration des fluides ont été approchés à partir de l'analyse de la micro-fabrique, la microthermométrie sur inclusions fluides, les analyses isotopiques (Sr, S, O, H) et de Terres Rares. Les résultats analytiques ont été enfin croisés avec un modèle thermique et structural du bassin qui conforte la séquence et la dynamique du système fluide en cours d'enfouissement. Une démarche similaire, mais plus limitée, a été conduite dans le bassin du North Viking Graben où l'accès aux marqueurs fluides est restreint aux données de sismique 3D et de carottes. Comme à Lodève, les minéralisations Ba-Pb-Zn colmatent un réservoir dans le substratum à l'apex du roll-over. Elles se présentent sous forme de ciments dans des grès ou des fractures. Cette analyse apporte des contraintes complémentaires et permet de proposer un modèle dynamique général avec des variantes en fonction de la nature des fluides et des réservoirs. On retiendra donc la séquence fluide suivante :(a) Dans le cas du bassin de Lodève sur substratum carbonaté, les chemins préférentiels de drainage se développent dans des paléocanyons N-S couplés à un réseau de fractures et d'endokarsts météoriques. Ces derniers sont élargis en début de rifting par la dissolution hypogène sulfurique produite par l'oxydation bactérienne de la pyrite des blackshales, au contact de l'aquifère oxydant du Cambien.(b) Le déséquilibre de compaction initie la migration des fluides interstitiels en surpression vers les marges avec des températures autour de 150-180°C et des salinités entre 9 et 18wt%eq.NaCl. Les analyses isotopiques (Sr, S, O) révèlent que la majorité des fluides provient de l'altération diagénétique des blackshales riches en métaux. Des interactions sont également mises en évidence avec des fluides profonds (entre 240°C et 260°C ; salinités > à 20wt%eq.NaCl), qui lessivent les granites tardi-hercyniens.(c) Pendant le syn-rift, les conditions de surpression de fluide permettent la réactivation cyclique des failles, les décollements stratigraphiques et la formation de brèches hydrauliques, favorisant la mise en connexions avec les réservoirs superficiels à l'apex du roll-over. Le modèle de Sibson ajusté aux fluides de bassins est alors le moteur de la migration verticale.(d) Les fluides thermogéniques commencent à être expulsés avec les derniers fluides de compaction au cours d'un stade plus évolué de l'enfouissement en empruntant les mêmes chemins jusqu'à l'apex du roll over. Ils sont alors partiellement freinés et déviés par les colmatages minéralisés antérieurs.(e) A Lodève, la continentalisation des minéralisations antérieures au cours de l'exhumation post-rift conduit à leur remaniement partiel au niveau de la transition sulfate-méthane induite par l'interaction entre une playa évaporitique et la dysmigration des hydrocarbures. Des barytines secondaires de basse température, déprimées en Sr sont alors précipitées de manière synsédimentaire dans des karsts météoriques du socle.Outre l'illustration d'un modèle complet (source to sink) de dynamique des fluides dans un bassin, ce travail apporte de nouvelles contraintes dans l'approche du colmatage des réservoirs à hydrocarbures sur les têtes de blocs basculés et sur la genèse des gîtes miniers de type Mississippi Valley-Type. / This work focus on the characterization of the source and dynamic of compactional fluids during sedimentary burial, through two complementary examples of late orogenic oil-field half-grabens: The exhumed Lodève Permian Basin and a deep buried Jurassic basin in the North Viking Graben (North Sea).Constituting the main part of the thesis, a multi-disciplinary approach was conducted in the Lodève Basin where Ba-F-Cu-Pb polymetalic mineralized systems are trapped into synrift faults and paleokarsts in the carbonate basement at the hinge point of the roll-over. The source, timing and P/T conditions of fluid migration were deduced from the analysis of the microfabric, the fluid inclusions microthermometry, and the isotopic (Sr, S, O, H) and Rare Earth Element (REE) signature. Results are then crossed with a structural and thermal modeling that consolidates the sequence and dynamics of fluid during burial.A similar approach was conducted in the North Viking Graben where fluid markers are restricted to 3D seismic and well core data. Comparable Ba-Pb-Zn veins are reported in basin margin, plugging one of the most important siliciclastic hydrocarbon reservoir in the substratum. This analysis provides additional constraints on basinal fluid behavior and allows us to propose a global dynamic model for various compositions of fluids and reservoirs.We conclude to a polyphase fluid sequence history including:(a) In the carbonate basement of the Lodève Basin, karstic paleocanyon incisions and associated cavities coupled to synrift fault, act as major drain for fluids. These structures are early affected by hypogen-sulfuric karstification in response to the interaction between bacterial oxidation of sulfides entrapped within Lower Permian blackshales and the basement oxidizing aquifer.(b) Disequilibrium compaction initiates overpressure-driven basinal fluid migration towards basin margins, characterized by temperatures around 150-180°C and salinities between 9 et 18wt%eq.NaCl. Isotopic (Sr, S, O) and REE analyses reveal that Ba-M+-rich mineralizing fluids derived mainly from buried blackshales diagenesis. External Fluids coming from the lower crust are also identified that play a key role in fluorite precipitation by the leaching of late hercynian granites (mean temperature of 250°C and salinity > 20wt%eq.NaCl).(c) During the synrift period, fluid overpressure is responsible for the periodic reactivation of fault plane according to seismic-valve process, bedded-control shearing and hydraulic brecciation at the basement-seal interface. These mechanisms induce cyclic polymetallic mineralization by the mixing between in situ formation water and deep ascending basinal fluids.(d) Thermogenic fluids expulsion starts with last basinal fluids during late burial stage. Hydrocarbons thus migrate along the same regional pathways up to the rollover crest, where they are partly rerouted by the previous mineralized baffle.(e) In the Lodève basin, post-rift exhumation of the margins led to the remobilization of synrift deposits by subaerial biochemical processes at the sulfate-methane transition. The latter results from the interaction between the still active hydrocarbon dysmigration with a playa lake sulfate-rich aquifer. Secondary low-temperature barite fronts precipitate then within basement meteoric karsts.In addition to the « source to sink » model of basinal fluids, this work provides new insights on the early plugging of hydrocarbon reservoirs and for the metallogenesis of Mississippi Valley-Type deposits.

The Olympic Mountains in northwestern Washington, USA are defined by the arcuate shape of the basaltic Crescent Formation (Fm.) that wraps a faulted and folded meta-sedimentary core. This area was developed through accretion and exhumation by subduction-related processes, but how this relates to the deformational history of the area is not fully understood. The region has been mapped geologically, however little focus has been placed on interpreting meso-scale structures. This study investigates structures along a transect where the Hamma Hamma River crosses the Hurricane Ridge Fault, which juxtaposes the meta-sedimentary core (west) and the basaltic Crescent Fm. (east). In the study area, the meta-sedimentary unit is characterized by outcrop scale folding with a calculated fold axis of 69-->342 and a penetrative foliation with a representative orientation of (178, 75). The folds and foliation are crosscut by two fracture populations with representative orientations of (115, 61) and (303, 76). The pillow basalts of the Crescent Fm. are near vertical, N-S striking beds that are cut by four fault groups. Fault Groups A and B have representative orientations of (304, 37) and (207, 59), respectively, and are associated with similarly oriented fracture populations. Fault Group C crosscuts Groups A and B and has a representative orientation of (031, 61). Fault Group D runs subparallel to the outcrop, cuts all other faults, and has a representative orientation of (087, 50). From an interpretation of this data, a deformation model is presented that proposes three distinct periods of deformation under three different states of stress. The first period was dominated by E-W or ENE-WSW oriented compression, followed by a period of N-S or NNW-SSE oriented compression, followed by vertical compression.