1 10 2 https://theses.otagogeology.org.nz/files/original/1b43e45fdfba09d0aad1465cfa58ad68.pdf da59ffefe477a9c064298a5e5dc8ea37 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format POLYGON ((163.378953558654871 -78.244129495695148,163.320451391143621 -78.24399711408131,163.289129795634267 -78.239039087695318,163.223953103289858 -78.228697807990926,163.021908104769608 -78.196431555031523,163.022455241220285 -78.189724459182656,163.022634293744574 -78.187527903959761,163.024993598917746 -78.158509345475423,163.056682040419474 -78.153071896379089,163.126425354737165 -78.141074798320034,163.217779473052445 -78.125298088248812,163.342141622797953 -78.103707029200748,163.452640433283364 -78.10354058335993,163.505619187428607 -78.103445532892835,163.597444721003626 -78.103257376214529,163.712650340725361 -78.102979315955864,163.734187422125501 -78.102922148109315,163.837061729357657 -78.116479442583199,163.861344668558957 -78.119669704847993,163.935214505393787 -78.12935153118022,163.935318932901822 -78.136936959188574,163.935545277817056 -78.153345586071509,163.935779761392126 -78.170297289583502,163.9360470408445 -78.189561742054025,163.620311001580689 -78.226923820518422,163.604456902633473 -78.22878459782082,163.515357308887332 -78.239215072326232,163.471650573727345 -78.244314865654502,163.434518452475544 -78.244244201288069,163.415921545302155 -78.244207007010019,163.378953558654871 -78.244129495695148)) Author last name Last name of the Author Jones Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Craw, D. Abstract The Abstract for this thesis Four granitoid plutons, belonging to the DV1a and DV1b plutonic suites, intrude Koettlitz Group metasediments in the Walcott Bay area, South Victoria Land, Antarctica. The plutons display markedly different structural styles, reflecting their emplacement during progressive uplift in the Paleozoic Ross Orogeny. In order of intrusion: 1) Bonney Pluton (530-520 Ma), a regionally extensive hornblende-biotite body, with the southern end mapped in the Walcott Bay area. The pluton syn-kinematically intrudes the metasediments at mid-upper amphibolite fades conditions, 7<>0°C, 5±1 kbars. Fabric development is variable with magmatic flow fabrics at the NE margin and central parts of the body changing to solid-state fabrics along the SW margin Host rock foliations are parallel to pluton margins. 2) Armitage Pluton is a hornblende-biotite DV1a body, chemically distinct from Bonney Pluton, which intrudes central parts of Bonney Pluton at a late stage of the host granite crystallisation. A weak magmatic lineation is present, sub-parallel to magmatic lineations in central parts of Bonney Pluton. 3) Chancellor Orthogneiss is a strongly deformed biotite DV1b body which discordantly intrudes metasediments as randomly orierued dykes and stocks. Solid-state deformation fabrics overprint magmatic fabrics throughout the body indicating post-emplacement ductile deformation. This body was emplaced close to or at the brittle-ductile transition, at least biotite zone, 250-350°C, 10-15 km depth. 4) Hidden Granite is an undeformed DV1b biotite granite which discordantly intrudes metasediments and older granitoid bodies as randomly oriented dykes and stocks. The granite was emplaced into a brittle host rock, above the brittle-ductile tranisition, less than 250-350°C. Hidden Granite is coevally intruded by a swarm of gabbroic to intermediate plugs, dykes and near horizontal· sills (1-40m thick) of the Keyhole Mafic Suite, a genetically related group of mafic bodies with high-K calc-alkaline affinities. Contact relations between the mafic bodies and host granite such as: lobate to crenulate boundaries; enclave swarms; diffuse flame-like contacts; a lack of chilled margins and back-dyking of the mafic bodies indicates the mafic bodies are coeval with Hidden granite. The mafic bodies are divided into two end-member groups (irregular plugs and sheet-like bodies), based on structural features. Contact relations of the irregular plugs and the host granite are generally more variable than the sheet-like bodies. The orientation of the plugs is random whereas the consistent NE-SW orientation of vertical sheet-like bodies indicates a degree of regional structural control on their emplacement. The degree of interaction between mafic and felsic phases generally decreases as the mafic bodies become more sheet-like in form. These changes could reflect the increasing crystallinity of the host granite.Field observations, petrology and geochemical data indicates chemical interaction accompanies physical mixing in the strongly mingled margins to form hybrid zones (at least at a centimetre scale). However, chemical mixing is most likely insignificant at margins of the sheet-like bodies, even though in detail, these boundaries are quite gradational. Vertical NE-SW oriented bodies of the Keyhole Mafic Suite are parallel to a younger swarm of mafic and felsic porphyry dykes which consistently strike 040°. The dyke orientation suggests crusta! extension during dyke emplacement was oriented NW-SE. This extension direction is approximately parallel to the elongation direction of post-emplacement ductile deformation fabrics in Chancellor Orthogneiss and suggests a geometric relationship between the ductile and brittle fabrics. The younger dyke swarm was emplaced towards the end of the Paleozoic Ross Orogeny and forms the dominant NE-SW brittle fabric in the basement rocks. A sequence of brittle fabrics in Hidden Valley indicates repeated reactivation of the inherited crustal anisotropy. The sequence is as follows: 1) Paleozoic NE-SW oriented dykes; 2) hydrothermally altered quartz-filled extensional fractures which occur within or parallel to the dykes; 3) NW-SE dextral faults offset dykes and fractures at right angles and are steeply dipping (to near vertical) with strikes between 110° to 140°; 4) NE-SW oriented structures crosscut young s'urface features and lie parallel to the dykes. These brittle features represent a late Quaternary sinistral reactivation of the pre-existing anisotropy. The late Quaternary faults indicate that this area of South Victoria Land is still tectonically active as indicated by the high topographic relief and active alkaline volcanism in the rift zone. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Walcott Bay South Victoria Land Antarctica Thesis description Number of pages, maps, CDs, etc. xiii, 198 p. : ill. (some col.), maps (some col.) ; 30 cm. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 1995Jones_S Creator An entity primarily responsible for making the resource Jones, Sarah Anne. Date A point or period of time associated with an event in the lifecycle of the resource 1995 Title A name given to the resource Structural evolution of northern Walcott Bay, South Victoria Land, Antarctica / Sarah Anne Jones. Subject The topic of the resource Structural geology Antarctica South Victoria Land structure Walcott Bay https://theses.otagogeology.org.nz/files/original/0365a07b8afd3f780d4b60021c6f1e2f.pdf 2d352518c71f6d3a458a0867ebabeca0 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format POLYGON ((163.184684990983726 -77.004224674025849,163.332660983376911 -77.081152379097816,163.394226518531099 -77.112870112136449,163.402256698733765 -77.116994784092427,163.490879044486917 -77.162326972036595,163.59980123093996 -77.217573808142902,163.669309860408248 -77.252562070896957,163.735767946975415 -77.285821862858015,163.791314848680287 -77.31347744139606,163.935743462084076 -77.384779968177227,163.957015544151858 -77.395208506100673,163.996806338550499 -77.414665704807604,164.003085985126177 -77.41773042870058,164.048192239690195 -77.439696689411718,164.616271439963697 -77.709388945869776,164.664958486730171 -77.731918731860972,164.700671752835575 -77.748387806526921,164.700151275948144 -77.776300262808675,164.698992552648804 -77.837993399512357,164.695775949569594 -78.006079615959351,164.69277005797116 -78.159067598202824,164.690106032397154 -78.291475107198579,164.690106036297237 -78.291475174387074,164.689788549228609 -78.307060446426647,164.557982328973821 -78.368215768190026,164.55322246620895 -78.370411333527542,164.476436720779219 -78.405706718185257,164.459226862968251 -78.413585690543954,164.370725610088954 -78.453920997092183,164.343728304506641 -78.466164917794814,164.237731084494385 -78.51396672300352,164.226820859117112 -78.518862605037171,164.138736791028975 -78.558224730296871,164.059085671554016 -78.593567530867062,163.877291943318255 -78.673352994510182,163.840415464971329 -78.68938977455737,163.541157617841435 -78.817727764777345,163.098249149913499 -79.00195791217277,162.7998833172405 -79.122374233387504,162.58742894019025 -79.206372686142174,162.42164414809298 -79.270936730235562,159.66027579076362 -79.24490118471013,159.704301191911156 -79.126357204783488,159.810095172874924 -78.830649952258071,159.815275017275212 -78.815763006727124,159.941518882926516 -78.783260124630303,160.228524357893349 -78.708470446592003,160.455576076954685 -78.648406365778825,160.550735279900834 -78.622993460720011,161.42795976482833 -78.381844145189675,161.439738442065391 -78.331718593851335,161.48921834210617 -78.116404401405788,161.490209012932013 -78.112013360469049,161.497397507886575 -78.080055046342409,161.515140540943889 -78.000443418646455,161.52536465975632 -77.954090347333164,161.531059537761678 -77.928123124147461,161.321945332845615 -77.852287030835001,161.254014668217422 -77.829920108827011,161.187485882623236 -77.816551583703969,161.145690122503538 -77.808129970911509,161.137701176121539 -77.806518219132926,161.12603445560481 -77.804163316044523,161.099882392755319 -77.798879533679909,161.079362605873825 -77.794728811589664,160.857521895441522 -77.749579112128515,160.745786082554957 -77.726645606640204,160.719616552025002 -77.721255580417164,160.671714288238093 -77.711370808764244,160.680526643571739 -77.668981242093452,160.680861813615678 -77.667363302372848,160.683591891348499 -77.654168974590235,160.686524417612503 -77.639965150271848,160.686669235036589 -77.639262893878723,160.472097268278105 -77.565317678911995,160.361907665308365 -77.24508434456051,160.463265720341724 -76.951841082443337,161.110754371935684 -76.926448199750055,161.550425820804179 -77.001486652438913,161.697868653902077 -77.001725441471038,161.737731827573697 -77.001775587283902,161.854699325938498 -77.001887489977591,161.955243292230449 -77.001941673254194,161.997167812697967 -77.001952794306959,162.352799900627332 -77.001775569852995,162.430004611660365 -77.001672909089649,162.830551004176186 -77.000772673481094,162.926049329750157 -77.000467020922969,162.991125506021632 -77.000238655414861,163.010951387428719 -77.000165847198346,163.010986568013379 -77.000165716572695,163.032111822790341 -77.000086471925115,163.17566302551981 -76.999502540245956,163.184684990983726 -77.004224674025849)) Author last name Last name of the Author Cook Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Craw, Dave Abstract The Abstract for this thesis South Victoria Land basement consists of Neoproterozoic metasediments and metavolcanic rocks which make up the Skelton Group. The Skelton Group was intruded by mafic and felsic plutons and dykes of the Granite Harbour Intrusives during the Ross Orogeny. Ages of plutonic rocks indicate that the Ross orogeny lasted from at least 550Ma (latest Neoproterozoic) to 477Ma (Ordovician) The metasediments of the Skelton Group are now metamorphosed and deformed but originally included intraformational conglomerates, greywacke, siltstone, mudstone, limestone and impure limestone. Coeval with sedimentation was intrusion and extrusion of basaltic plugs, sills and pillow lavas with P- and TMORB chemistry, and trachyte and rhyolite extrusives. These igneous rocks have an origin involving crustal contamination and indicate that the Skelton Group formed in a continental rift environment younger than 680Ma and probably younger than 630Ma. There has been variable deformation and metamorphism of the Skelton Group between lower green schist and upper amphibolite facies. Lithostratigraphic mapping of south Victoria Land is not possible due to extensive disruption and reconstitution of the Skelton Group during the Ross Orogeny. The Lower Baronick Formation (conglomerate and bimodal volcanics) is the only formation that is recognised and is sufficiently undeformed that bedding can be recognised. For mapping purposes, south Victoria Land is sub-divided into fault bounded sub-blocks (c.l-20km in size) each of which has had a relatively coherent geological history during the Ross Orogeny. These sub-blocks are grouped into one of four main structural blocks. Some of these four main blocks contain rocks with a wide range of structures and metamorphic grade. The southernmost block is the Skelton Block which covers 1400km2 and consists of 9 recognisable sub-blocks. Some of the sub-blocks, including Lower Baronick Formation, are relatively undeformed whereas others are totally reconstituted. The Skelton Block contains the least deformed rocks which yield the most information on the origin of the Skelton Group. The Koettlitz Block (290km2) contains two greenschist facies sub-blocks which are relatively unstrained, but very little is known about this block due to limited exposure. The Walcott Block (730km2) is made up of 5 sub-blocks. The sub-blocks include greenschist facies rocks preserving clastic textures, mid to upper amphibolite facies schists and migmatites and there are some high strain gradients between less deformed and more deformed rocks. The Walcott Block underwent extensional tectonics during the Ross Orogeny. The northernmost Dry Valleys Block (4600km2) consists of thoroughly transposed and reconstituted upper amphibolite facies schists and no sub-blocks have been recognised. Dry Valleys Block underwent extensional, compressional and strike slip tectonics during the Ross Orogeny. The boundaries between structural blocks appear to be steeply dipping NW striking faults. Only one of these faults, the Frio Shear Zone, is exposed and forms the boundary between Walcott Block and Dry Valleys Block. Frio Shear Zone has had a complex structural history of reactivation throughout the Ross Orogeny and the latest movement along which uplift of the Dry Valleys Block occurred is sinistralnormal. Some block boundaries are cut by Granite Harbour Intrusives whereas other block boundaries cut Granite Harbour Intrusives. The geological histories of the four main blocks indicate that compressional and extensional tectonics were probably coeval during the Ross Orogeny. The geological histories also reveal that uplift of the four structural blocks may have occurred at different periods during the Ross Orogeny resulting in a complex interrelation between plutonism and deformation of the Skelton Group. Structural blocks of the type mapped in south Victoria Land can be mapped in north Victoria Land and elsewhere in the Transantarctic Mountains. These blocks preserve results of Ross Orogenic processes at different times and places and at different crustal levels throughout the Transantarctic Mountains. A series of NW striking faults are recognised in north Victoria Land which are related to the same tectonic regime as those NW striking faults identified in south Victoria Land and indicate offset of the Ross Orogen in the Victoria L~nd segment of Antarctica. Neoproterozoic continental rifting in south Victoria Land is younger than that of Windermere rift related metasediments in North America and is not a direct temporal correlative has been suggested in association with the SWEAT hypothesis. Correlation with possible rift events near the Cambrian-Precambrian boundary in North America is also plausible. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/3573">http://hdl.handle.net/10523/3573</a> OURArchvive access level Abstract Only Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. South Victoria Land Antarctica Thesis description Number of pages, maps, CDs, etc. 502 p. : ill. (some col.), maps (some col.) ; 30 cm. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 1997Cook Creator An entity primarily responsible for making the resource Cook, Yvonne Anne, 1967- Date A point or period of time associated with an event in the lifecycle of the resource 1997 Title A name given to the resource The Skelton Group and the Ross Orogeny : late Neoproterozoic to early Ordovician evolution of South Victoria Land, Antarctica Subject The topic of the resource Map Geochemistry Volcanology geochemistry Ross Orogeny Skelton Group South Victoria Land Volcanology