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Geotechnical investigations undertaken by GHD Pty Ltd uncovered a previously undescribed rock type in the suburbs of Footscray and Alphington approximately 5 km west and 6.5 km east of Melbourne CBD respectively. The rock encountered appeared to be a breccia type rock with angular high strength fine gravel to boulder sized fragments of relatively unweathered grey to dark grey basalt surrounded by a matrix of orangish brown fine grained brittle material resembling hard clay. Pillow basalts were also encountered in the deposits in the form of 0.6 m or larger globular but highly fractured basalt bodies within the rock mass. The rock was eventually identified as a hyaloclastite, a rock type formed when basalt lava flows into water bodies and is quench fragmented. The debris forms piles of basalt and volcanic glass fragments. The volcanic glass fragments are thermodynamically unstable and are altered to palagonite within as little as 20 years from initial deposition. No prior reference to the occurrence of hyaloclastite in the Melbourne region could be found. As such, the location, extent and geotechnical properties of this rock type are unknown, posing a potential risk to infrastructure and construction projects. This study aimed to investigate the possible origins of the hyaloclastite; develop a theory of emplacement/origin; identify other locations where this rock type may exist; determine the geotechnical properties and engineering geological behaviour of the rock; and develop a classification system for the rocks encountered. A variety of methods were used to gather sufficient information to allow the occurrences and geological and geotechnical nature of hyaloclastites and pillow basalts in the Melbourne area to be better understood. Samples of the rock were obtained during the geotechnical investigations undertaken in Footscray and Alphington and outcrop mapping was completed on exposures identified during the course of this study. Historical borehole logs and as built drawings were obtained to assist in the understanding of the previous description terminology associated with the rock now identified as hyaloclastite. Standard and “non-standard” laboratory testing was undertaken as well as classification testing. The field of block-in-matrix rocks “bimrocks” was assessed as a possible method to assist in the understanding of the behaviour and geotechnical properties of the hyaloclastite rock with or without pillow basalts. The RMR, Q-System and GSI rock mass classification systems were used to help understand the rockmass characteristics. A weak rock classification system, a weathered rock characterisation system and a ground behaviour characterisation system were also used to provide information on the possible behaviour of the hyaloclastite type rocks. Development of both 2D and 3D geological models of the two sites indicate that the hyaloclastites encountered in Melbourne were deposited in “lava-deltas”. The hyaloclastites were deposited on advancing subaqueous delta fronts with an overlying layer of subaerial basalt above what has been termed the “passage zone” which represents the historical level of water into which the lava flowed. Strength testing undertaken on the various samples suggested that the hyaloclastite should be classified as a weak rock, with UCS values of ranging from approximately 1 MPa to 10 MPa, and a median UCS value of 1.37 MPa. Using the compiled UCS data and PLT data an estimate of the PLT Is50 to UCS conversion factor “k” was calculated as 10.4. The results of jar slake testing and weatherability index testing were variable: whilst the majority of samples showed no sign of slaking, one sample showed a strong reaction. The samples of disaggregated rock were classified as sandy gravel as per AS1726:1995. Whilst the fine to medium gravel was of subangular grains of basalt the sand was found to be made up of angular fragments of palagonite. Plasticity index and XRD testing of fines obtained from the disaggregation process indicated that the fines are comprised of illite and smectite clay minerals and behave as a high plasticity silt. Several categorisation methods utilised indicated that the hyaloclastite type rockmass strength parameters are controlled partly by the strength of the matrix and partly by the discontinuities and that the rock mass strength is dominated by the pillow basalt behaviour (typical hard rock type behaviours) only once the content of these structures in these rocks exceeds a volume content of 75% pillows to 25% hyaloclastite. Rock mass strength and deformation calculations indicate that the hyaloclastite rock mass is both very weak and also highly deformable (rock mass modulus <100 MPa) when compared with the highly weathered subaerial basalt (~500 MPa) and the fresh/slightly weathered basalt (~15000 MPa). A value of petrographic constant mi used in the Generalised Hoek Brown Criterion was also determined to be 7.01. This is considerably different to the values suggested for “breccia” in the literature of 19±8. A modulus ratio of 150 was also estimated using testing data from Melbourne and also Iceland. The extent of hyaloclastite in the Melbourne region remains unknown. Whilst the location of these deposits is associated with the base of palaeovalleys now infilled by volcanic products, hyaloclastite does not occur in the base of all the palaeovalleys and is expected to be controlled by sea level change and also disruption of drainage lines by damming caused by earlier subaerial flows. Geotechnical practitioners must be aware of the potential occurrence of hyaloclastite as both the hyaloclastite and hyaloclastites with pillow basalt rock masses were found to be significantly weaker and more deformable than the highly weathered subaerial basalt rock. Misidentification of the rock as highly weathered basalt during geotechnical investigation may result in significant under-design. In addition, rock mass behaviour categorisation indicates that block-falls of pillow basalt from excavation walls and roofs may be a risk. Increased excavation effort to remove the pillow basalt structures should also be factored in to projects. To aid identification and understanding of the potential hazards associated with hyaloclastite type rocks, a series of reference sheets has been developed. These reference sheets aim to increase practitioners’ knowledge of hyaloclastites, and the implications for excavation and construction. The reference sheets also provide geomechanical details. Three-dimensional simplified engineering geological block models have also been included to provide graphical information on the relationships and possible geohazards of the various rock types. Future research should aim to further define the extent and engineering properties of hyaloclastites in the Melbourne region and to further define the petrographic constant mi, a better estimate of modulus ratio based on instrumented UCS tests. It is also hoped that now this rock has been recognised in Melbourne that the geotechnical community will reassess previous projects and start to build knowledge on the whereabouts of hyaloclastite and pillow basalt type rocks in the Melbourne area.

The thesis map area is located in northeastern Ontario in and west of the Adams Mine site. The Adams Mine produces iron ore and is situated 15 km southeast of the town of Kirkland Lake. Kirkland Lake is the largest population centre in the Kirkland Lake-Larder Lake gold camp. The Adams Mine lies south of this camp. The thesis map area is underlain by volcanics (most of which are komatiitic), clastic, chemical and pelitic sediments and various intrusives (peridotite sills, layered peridotite-gabbro and gabbro sills, discordant gabbro bodies, alkali-rich dykes and diabase dykes. The syenitic Lebel Stock forms the northern boundary of the map area. The map area lies entirely within the Larder Lake Group which forms the lower part of the second major volcanic cycle (cycle II) in the Archean aged Abitibi greenstone belt. The Kinojevis and Blake River Groups overlie the Larder Lake Group north of Kirkland Lake and are also part of cycle II. The Skead Group constitutes the upper most part of cycle I. The top of this group marks the southern boundary of the map area. The fold axis of the Lebel Syncline passes through the northern half of the map area. This fold is isoclinal and has no plunge. The fold axis and the stratigraphy are broadly conformable to the shape of the Lebel Stock. Tight folds with north-south trending axial surface traces and a drag fold occur on the south limb of the Lebel Syncline. The Lebel Syncline and these second-order folds are believed to pre-date Intrusion of the Lebel Stock. The stock may have modified the trend of the Lebel Syncline fold axis so that it and the strata parallel the stock's shape. Five faults with unknown but apparently little displacement were recognized. Faulting is not prominent in the map area. The northern half of the map area has been metamorphosed to the hornblende hornfels facies. This occurred during contact metamorphism following intrusion of the Lebel Stock. Greenschist facies mineralogy is present in the southern half of the map area and developed during an earlier regional metamorphic event. There are eight volcanic sequences on the south limb of the Lebel Syncline. Seven of these are komatiitic. There are three komatiitic sequences on the north limb. Komatiitic sequences are characterized by volcanic flows which show decreases in MgO contents stratigraphically upwards. Komatiites occur at the base of each sequence and are overlain by one or more of high MgO komatiitic basalt, high MgO komatiitic andesite, low MgO komatiitic basalt, low MgO komatiitic andesite, low komatiitic dacite, high A12O3 komatiitic basalt, andesite and dacite and high Fe2O3, Α12Ο3 komatiitic basalt. . Most low MgO komatiitic basalts and andesites on the south limb of the Lebel Syncline have anomously high Cr (>1000 ppm) and Ni (>200 ppm) contents when compared to similar lithologies in other Archean terranes. The high Cr abundances are linked to high chromite contents. Sequences with Cr and Ni-rich volcanics do not contain high A12O3 komatiitic volcanics; the latter have low Cr (approximately 400 ppm) and Ni (approximately 80 ppm) contents. High Fe2O3, Α12Ο3 komatiitic basalt occurs in sequences with high A12O3 komatiitic basalts. High Α120β and high Fe203, Al203 komatiitic basalts are not found in other Archean terranes. Cr and Ni-rich komatiitic volcanics are found in Destor Township in Quebec (within the Abitibi greenstone belt). They are not otherwise found. Sequence 1 basalts are regarded as tholeiitic or calc-alkalic. There are no ultramafic or high MgO flows in this sequence and lithological variation with stratigraphic height is not observed. The high Cr and Ni contents in the komatiitic basalts and andesites are explained by rapid cooling in a magma chamber. This process stops or reduces olivine and chromite crystallization in the magma as it reaches a MgO content of 12 % to 15 %. The residual magma is thus enriched in Cr and Ni. The production of high komatiitic volcanics can also be explained by rapid cooling in a magma chamber. This process lowers the temperature of plagioclase crystallization resulting in A12O3 enrichment in the magma. Many of the sedimentary rocks in the map area are deposits from submarine debris flows and turbidity currents. The flow mechanism is not known for massive sandstones. The presence of conglomerates (debris flow deposits) suggests a proximal depositional environment, using a submarine fan model. The source area is comprised of sedimentary, volcanic and plutonic lithologies. Peridotite sills are believed to syn-volcanic with komatiitic volcanism. Peridotite-gabbro and gabbro sills are likely syn-volcanic with tholeiitic volcanism now preserved in the Kinojevis Group north of Kirkland Lake. The discordant gabbro Intrusions are believed to be syn- volcanic with calc-alkalic volcanism now preserved in the Blake River Group north of Kirkland Lake. Lateral equivalents to both groups may have once overlain the Larder Lake Group but have since been eroded. This is consistent with the fact that higher metamorphic grades prevail south of the Larder Lake Break. The sills and discordant gabbros were emplaced prior to regional metamorphism. The Lebel Stock, syenite, biotite lamphrophyre, feldspar porphyry and diabase dykes were emplaced following deformation and greenschist metamorphism. The alkali-rich intrusions are likely contemporaneous with Archean trachytic volcanism now preserved in the Timiskaming Group. / Thesis / Master of Science (MSc)

<p>Subject Category "Geology" not listed in menu.</p> / <p>An Alkalic suite of proterozoic volcanics and their associated sediments, situated within the Dubawnt Group of the Churchill Province, was mapped and studied. Petrography and geochemical analyses were performed on representative specimens. The extrusives and related dykes are thought to have been derived from the differentiation of a single parent magma, as evidenced by several geochemical trends. The units are as follows; intermediate to felsic trachytes and pyroclastics, typically phlogopite phyric and red alkali rhyolites; later volcaniclastic units. A significantly younger diabase dyke cuts these units, all of which overlie the '307' formation.</p> / Bachelor of Science (BSc)

<p> The "B" horizon at Tilt Cove occurs in subaqueous mafic volcanics near the base of the Silurian Cape St. John Group. It is 3 metres below a well-banded oxide iron formation ("A" horizon). </p> <p> Mineralization in the "B" horizon is analogous to that of the East Mine in that it is volcanogenic and has resulted in extensive chloritization of the footwall rocks, and in the deposition of banded sulphides or the replacement of the existing mafic volcanics by sulphides. There are differences in the geochemistry mineral textures and mineral types. The East Mine host volcanics are alkali depleted basaltic komatiites to magnesium theleiites. The horizon host volcanics are spillitized magnesium tholeiites. Samples of ore from the East Mine show well-developed colloform and framboidal textures. Pyrite, magnetite, hematite and chalcopyrite are the dominant minerals with minor sphalerite and accessory covellite. Samples from the horizon show relict colloform textures and framboids with less internal structure due to overgrowths. Atoll textures indicating extensive replacement are common. Pyrite is the dominant sulphide followed by sphalerite, chalcopyrite, accessory covellite and gold. The chalcopyrite occurs both as replacement of pyrite and exsolution in sphalerite. The most significant difference between samples from the East Mine and "B" horizon is the greater abundance of gold in the "B" horizon and its correlation with sphalerite. </p> / Thesis / Bachelor of Science (BSc)

This thesis aims to create a specific and robust geotechnical data set for the Lyttelton Volcanic Group, and investigate the effect of emplacement and post-emplacement mechanisms on geotechnical characteristics. The thesis provides an engineering geological model of a representative section of the Lyttelton Volcanic Complex, which, in conjunction with field observations, informed the subdivision of the main lithological groups into geotechnical sub-units. The sub-units account for the geological variations within the rock types of this study. Eighteen geotechnical sub-units were identified, sampled and characterised: 1trachytic dykes, 2trachytic domes, 3trachytic lava, 4brecciated basaltic ignimbrite, 5moderately welded basaltic ignimbrite, 6highly welded basaltic ignimbrite, 7red ash, 8crystal dominated tuff, 9lithic dominated tuff, 10rubbly basaltic breccia, 11unweathered basaltic lava, 12slightly to moderately weathered basaltic lava, 13highly to completely weathered basaltic lava, 14highly vesicular basaltic lava bomb, 15basaltic dyke, 16blocky basaltic lava, 17volcanogenic conglomerate and 18volcanogenic tuffaceous sandstone. Thirteen units were able geotechnically tested. Sample preparation and geotechnical testing followed ASTM and ISRM guidelines respectively. Geotechnical testing included: uniaxial compressive strength (σci), point load strength index (Is(50)), porosity (n), density (ρd), P and S wave velocities (Vp and Vs), slake durability (Id2), Young’s Modulus (E), Poisson’s Ratio (υ), shear modulus (G) and bulk modulus (K). The igneous lithologies included in this study have been characterised using the Detailed Engineering Geological Igneous Descriptive Scheme, developed purposely for the needs of the thesis. The results of laboratory testing showed many strong trends with geological characteristics and relationships between geotechnical parameters. Parameters such as porosity, density, P-wave velocities, Young’s Modulus and point load strength showed very strong correlations with uniaxial compressive strength. Variability in the physical and mechanical properties is attributed to the geological factors, which dictate the material behaviour. These include texture, grain size, composition, welding, lithification, flow banding, percentage and size of phenocrysts/clasts/lithics. Geological factors affecting geotechnical behaviour are a function of emplacement mechanism. Four distinct emplacement mechanisms were identified in this study: lava flows, pyroclastic density currents, intrusions (dykes) and airfall deposits. Typically, lava flows and intrusions have higher strength, durability, density and lower porosity than pyroclastics and airfall deposits. Importantly, the data illustrates a considerable variability in some geotechnical parameters within the same unit (e.g. 58-193 MPa strength variation in the unweathered basaltic lava). Variability within rocks with similar emplacement mechanisms is attributed to the effects of post-emplacement mechanisms and processes (e.g. weathering, alteration and micro/macro fracturing leading to lower strength). Evaluation of engineering geological and geotechnical parameters of rock and soil materials are required for engineering purposes, specifically when any form of design is required. This study has highlighted the importance and necessity to identify volcanic lithologies and features correctly as there are consequences for geotechnical behaviour, and that volcanic data from literature data should not be used without the correct degree of ground-truthing and geological context. Location-specific engineering geological data are necessary for the quantitation of variability in engineering geological characterisation for engineering geological models, designs and simulations in the Port Hills Volcanics.

The Eastern Black Sea region of Turkey accomodates indecent residence conditions for people owing to ground conditions comprising of volcanics and concurrent flysch, and its related irregular geomorphology. One of the important difficulties in this region is transportation. Accordingly, the ordu peripheral highway which encompasses various structures such as, open cuts, bridges, viaducts and junctions and double tubed tunnel sections which will be driven in these geological and geomorphological conditions is palnned to be constructed. In regional scale, volcanics, pyroclastics and flysch deposits often intertounge with each other even over very short distances. The accurate determination of the shear strength parameters of these lithologies is vital for the assessment of portal slope stability and support design in regards to tunnel design. Rock mass classification systems, namley, RMR, NGI Q system and GSI, have been employed to obtain the rock mass shear strength parameters. Stress analyses around the tunnel opennings have been executed through employing 2D finite element analysis in an attempt to design tunnel support. The results of the analysis have been correlated with the results obtained from the emprical methods. The overall analyses and interpretations led to the determination of the support systems to be employed during tunnel construction.

This study aims to reveal the geochemical signatures of the basic igneous rocks with well-determined age within the Karakaya Complex in Central and NW Anatolia and also exhibit the relationships between the studied units in terms of geological and petrographical features. The Karakaya Complex comprise a number of tectono-stratigraphic units in the studied regions (the Olukman Melange, the Bah&ccedil / ecik Formation, the Ortaoba Unit and the informally named pillow basalt-limestone association) and the pre-Karakaya basement unit (the Eymir Complex). The basic igneous rocks have been all intensely affected by hydrothermal metamorphism as reflected by the secondary products strongly overprinting the primary mineral phases and most of them exhibit vesicular structures which are filled by mainly calcite. The primary mineral assemblage dominating the basaltic rocks is clino-pyroxene, plagioclase and olivine, whereas secondary phases are characterized by actinolite, pistacite, zoisite/clinozoisite group and chlorite. Kaersutite, as a late stage magmatic mineral, is distinctive for Ti-augite bearing imrahor basalts / on the other hand, the diabase dykes include hornblende as an essential primary phase. The basic rocks are represented by three groups / sub-alkaline, alkaline and transitional. The alkaline samples from imrahor, Hasanoglan, Kadirler and Ortaoba are of Anisian age and akin to oceanic-island basalts (OIB). The sub-alkaline and transitional samples from imrahor and Ortaoba reflect P-MORB features and are younger than the first group. The diabase dykes cross-cutting the Eymir Complex, on the other hand, are too dissimilar, indicating back-arc basin signatures. Based on the data obtained from this study, the Karakaya Complex is characterized by a number of tectonic components (seamount, plume-related mid ocean ridge and back-arc basin) with different ages and origins, which were later amalgamated during the Cimmerian orogeny.

The Simpson Mountains have long been of economic interest and have renewed interest in their potential value. Field mapping of the project area redefined structural relationships between stratigraphic units. Geometric and kinematic analysis of structures in the Simpson Mountains show the range is deformed by the three most recent tectonic events: the Sevier Orogeny, the Laramide Orogeny, and Basin and Range Extension. Laramide structures define the range with a significant E-W normal fault and an E-W thrust fault, which are both likely related to Eocene-age igneous intrusions. Principal component analysis (PCA) of regional quartzite X-ray Fluorescence (XRF) data resulted in distinctive populations between the Eureka Quartzite and the Mutual and Prospect Mountain Quartzites. The PCA was paired with petrographic analysis of regional quartzites where samples were diagnostically classified to help validate the PCA results. XRF analysis of volcanic rocks show volcanic arc origin. 40Ar/39Ar dating of the volcanic rocks associated with the intrusions yield new ages of 34.09±0.10 to 37.05±0.06 Ma and 19.11±0.02 to 19.18±0.03. Lithostratigraphy of the map area was validated by identification of fossil samples. The Eocene intrusions are likely sources of mineralization in the range along older Sevier structures.

The Station Creek Igneous Complex (SCIC) is one of the largest Middle-Late Triassic plutonic bodies in the northern New England Orogen of Eastern Australia. The igneous complex comprises of five plutons - the Woonga Granodiorite (237 Ma), Woolooga Granodiorite (234 Ma), Rush Creek Granodiorites (231 Ma) and Gibraltar Quartz Monzodiorite and Mount Mucki Diorite (227 Ma respectively), emplaced as high-level or epizonal bodies within the Devonian-Carboniferous subduction complex that resulted from a westward subduction along the east Australian margin. Composition of the SCIC ranges from monzogabbro to monzogranite, and includes diorite, monzodiorite, quartz monzodiorite and granodiorite. The SCIC has the typical I-type granitoid mineralogy, geochemistry and isotopic compositions. Its geochemistry is characteristics of continental arc magma, and has a depleted-upper mantle signature with up to 14 wt% supracrustal components (87Sr/86Srinitial = 0.70312 to 0.70391; Nd = +1.35 to +4.9; high CaO, Sr, MgO; and low Ni, Cr, Ba, Rb, Zr, Nb, Ga and Y). The SCIC (SiO2 47%-76%) has similar Nd and Sr isotopic values to island-arc and continentalised island-arc basalts, which suggests major involvement of upper mantle sourced melts in its petrogenesis. SCIC comprises of two geochemical groups - the Woolooga-Rush Greek Granodiorite group (W-RC) and the Mount Mucki Diorite-Gibraltar Quartz Monzodiorite group (MMD-GQM). The W-RC Group is high-potassium, calc-alkalic and metaluminous, whereas the MMD-GQM Group is medium to high potassium, transitional calc-alkalic to tholeiitic and metaluminous. The two geochemical groups of the SCIC magmas are generated from at least two distinct sources - an isotopically evolved Neoproterozoic mantle-derived source with greater supracrustal component (10-14 wt%), and an isotopically primitive mafic source with upper mantle affinity. Petrogenetic modeling using both major and trace elements established that the variations within respective geochemical group resulted from fractional crystallisation of clinopyroxene, amphibole and plagioclase from mafic magma, and late fractionation of alkalic and albitic plagioclase in the more evolved magma. Volcanic rocks associated with SCIC are the North Arm Volcanics (232 Ma), and the Neara Volcanics (241-242 Ma) of the Toogoolawah Group. The major and trace element geochemistry of the North Arm Volcanics is similar to the SCIC, suggesting possible co-magmatic relationship between the SCIC and the volcanic rock. The age of the North Arm Volcanics matches the age of the fractionated Rush Creek Granodiorite, and xenoliths of the pluton are found within epiclastic flows of the volcanic unit. The Neara Volcanics (87Sr/86Sr= 0.70152-0.70330, 143Nd/144Nd = 0.51253-0.51259) differs isotopically from the SCIC, indicating a source region within the HIMU mantle reservoir (commonly associated with contaminated upper mantle by altered oceanic crust). The Neara Volcanics is not co-magmatic to the SCIC and is derived from partial melting upper-mantle with additional components from the subducting oceanic plate. The high levels emplacement of an isotopically primitive mantle-derived magma of the SCIC suggest periods of extension during the waning stage of convergence associated with the Hunter Bowen Orogeny in the northern New England Orogen. The geochemical change between 237 to 227 Ma from a depleted-mantle source with diminishing crustal components, to depleted-mantle fractionate, reflects a fundamental change in the source region that can be related to the tectonic styles. The decreasing amount of supracrustal component suggests either thinning of the subduction complex due to crustal attenuation, leading to the late Triassic extension that enables mantle melts to reach subcrustal levels.