The purpose of this study was to define the lithofacies and areal extent of the Fort Atkinson Formation (Maquoketa Group, Upper Ordovician) in the subsurface in Indiana. Two distinct lithologic facies (Members) of the Fort Atkinson Formation can be distinguished in the subsurface. The upper Shoaling Member consists of coarse grained crinoid-bryzoan grainstone deposited in a high energy depositional environment. Beneath the Shoaling Member is the Transition Member of the Fort Atkinson. This Member consists of alternating beds of shale and limestone which were deposited in depositional environments that varied from high to low energy. The Fort Atkinson is an important stratigraphic marker used to define four depositional provinces within the Maquoketa Group in Indiana. The four depositional provinces include the Maquoketa Shelf, the Overlap Ramp. the Cincinnati Shelf, and Michigan Shelf. / Department of Geology

Thesis (M.S.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references (leaves 228-234). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1990. / Typescript (photocopy). Includes mounted photographs. Includes folded plates in pocket. Includes bibliographical references (leaves 377-396). Also available via the World Wide Web.

Thesis (Ph.D.)--University of Alberta, 2009. / Title from PDF file main screen (viewed on Mar. 18, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Earth and Atmospheric Sciences, University of Alberta. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains viii, 87 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 81-87).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains ix, 148 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 145-148).

M.Sc. / The Mesoarchean Witwatersrand and Pongola Supergroups of South Africa are the oldest, well preserved supracratonic successions worldwide. Various banded iron formation (BIF) and iron-rich mudstone units occur within the West Rand Group of the Witwatersrand Supergroup and the Mozaan Group of the Pongola Supergroup. A granular iron formation (GIF) occurs in a single unit in the Nconga Formation of the Mozaan Group. The Witwatersrand Supergroup and Mozaan Group have been lithostratigraphically correlated and are interpreted to have been part of the same sedimentary basin. The studied BIF units occur in two associations: shale-associated and diamictiteassociated BIF. The GIF seem to have been deposited in shallower environments with greater hydrodynamic activity. The iron-rich mudstone shows a similar stratigraphic setting to that of the shale-associated BIF. The lithostratigraphic setting of the Witwatersrand-Mozaan basin BIFs are similar to what is seen for Superior-type ironformations, with the mudstones and associated BIFs marking marine transgressions. Various mineralogical facies of BIF were identified, including oxide, carbonate and silicate facies BIF, as well as mixed facies between these end members. The GIF is a unique facies and shows abundant petrographic evidence for biological activity. The iron-rich mudstone has been subdivided into iron-silicate rich, magnetite-bearing, carbonate-bearing, magnetite-carbonate-bearing and garnet-bearing subtypes. BIF, GIF and iron-rich mudstone have been subjected to lower greenschist facies metamorphism with some occurences of localized contact metamorphism. The abundance of magnetite shows that oxidation played an important part in BIF deposition, whereas the occurrence of 12C-enriched iron-rich carbonates suggests post depositional reduction of the deposited oxidized iron-rich minerals by organic matter. Al-bearing minerals are rare in the BIFs xxi and abundant in the iron-rich mudstones. Apatite and rare earth element (REE)- phosphates occur throughout. The major element geochemistry shows an inverse proportionality for Fe and Si in all the studied samples. BIFs show slightly higher Fe- and lower Si- and Al-concentrations compared to iron-rich mudstones which show higher Si- and Al- and lower Feconcentrations. The studied BIFs show major element geochemical attributes intermediate to those of Superior- and Algoma-type iron-formations. Provenance studies on some of the iron-rich mudstones illustrate that they were sourced from a mixture of mafic and felsic sources. The rare earth element (REE) geochemistry suggests strong hydrothermal input into the units, and positive correlation with the Fe-concentrations suggests that the Fe was introduced by high temperature hydrothermal fluids. The majority of the REEs are hosted by apatite and the REE-phosphates monazite and xenotime. The REEs were reconcentrated into these phosphates during diagenesis. A comparison of the studied lithostratigraphically correlatable units between the Witwatersrand Supergroup and Mozaan Group makes it possible to construct a depositional model for basin-wide BIF deposition in the Witwatersrand-Mozaan basin. Shale-associated BIF was deposited during the peak of transgression when reduced Ferich hydrothermal bottom waters were introduced into shallow ocean water that was either oxygenated or filled with anoxygenic phototrophic bacteria. Diamictite-associated BIF, in contrast, was deposited during interglacial periods when the melting of glacial ice introduced sunlight, nutrients and oxygen to the reduced, hydrothermally influenced Ferich ocean water. GIF was probably deposited in shallow, above wave base waters cut off from clastic input, and then washed into deeper depositional environments. Iron-rich mudstone was deposited in a similar setting as the shale-associated BIF, but in environments that were not completely cut off from detrital influx. The study shows that it is impossible to construct a general depositional model for Precambrian BIFs, since the lithostratigraphic and depositional settings vary between different examples of BIF.

This study is an extensive lithological, petrographical, mineralogical and geochemical description of fresh Collingham Formation core samples collected from borehole SFT 2, located on the farm Slangfontein, south of Jansenville in the Eastern Cape, South Africa. The borehole, drilled to 295 m on the northerly limb of a shallow westerly plunging syncline, intersected the lower Ecca Group rocks of the Ripon, Collingham, Whitehill and Prince Albert Formations and terminated in the upper Dwyka Group. A comprehensive log and stratigraphic column were compiled for the Collingham Formation and fresh core samples were analysed using X-Ray Diffraction (“XRD”), X-Ray Fluorescence (“XRF”), mercury porosimetry, and Total Organic Carbon (“TOC”). Thin section microscopy and Scanning Electron Microscopy (“SEM”) analyses were carried out on selected samples of core from borehole SFT 2. The matrix supported, massive to laminated lithological units of the Collingham Formation are interpreted as detrital, terrigenous sediments. These sediments are composed of intercalated fine-grained, poorly sorted, non-fissile mudstone; fine- to very fine-grained, predominantly pyroclastic airfall tephra; and less common fine-grained sandstones. Sediments of the Collingham Formation are considered to be immature, composed primarily of clay and aluminosilicates. The predominance of a clay fraction and aluminosilicates in mudstone samples is indicated by elevated K2O/Al2O3 ratio values, and the relationship of Zr, Al2O3 and TiO2. The presence of glauconite within the Collingham Formation indicates deposition in a mildly alkaline, slightly reducing marine environment. Rb/K ratio values (1.9 – 2.3 x 10-3) indicate brackish to slightly marine conditions, while low Zr/Rb ratio values indicate a low hydro-energy environment, with stable bottom water conditions. Hf and Nb concentrations indicate that detrital input was greatest during the deposition of tuffaceous units; while stable mineral assemblages and a low Fe2O3/K2O ratio values indicate deposition close to the source. A variation in Si/Ca values indicate times when sediments were affected by turbidity, interspersed with times of relative quiescence. The predominance of K2O over Na2O indicates that the Collingham Formation is alkali-rich, while SiO2/Al2O3 ratio values and the relationship of Zr, Al2O3 and TiO2 indicate that sediments are immature. In the lower portion of the formation, non-sulphidic, anoxic conditions are indicated by Mn/Al, V/(V+Ni), V/Cr ratio values, the Fe-Mn- V content, and the correlation between V and TOC. The upper portion of the formation is considered dysoxic, due to the presence and distribution of pyrite framboids, which indicate a fluctuating O2 level, likely indicating deposition at the interface between anoxic and slightly more oxic conditions. V/Cr ratio values indicate that the O2 regime was lowest during the deposition of the mudstones. The Chemical Index of Alteration (“CIA”) indicates a consistent weathering regime throughout the deposition of the Collingham Formation, associated with a temperate climate on the interface between glacial and tropical conditions. Although an anoxic and low hydro-energy environment is generally favourable for hydrocarbon accumulation, the Collingham Formation contains low levels of Total Organic Carbon (well below 0.9 per cent) and low porosities (ranging from 0.35 per cent to a maximum of 2.22 per cent), both of which are characteristic of a poor source for gas accumulation. Due to the laminate nature, permeability and fracturability of the Collingham Formation, there is the potential that the formation may form a good sealing sequence to the potentially gas-rich Whitehill Formation below. The metamorphic impact related to the Cape Orogeny (± 250 Ma), and reflected in the textures of the minerals making up the sediments of the Collingham Formation, suggests the enhancement in the sealing efficiency of this formation.

Nodules within the lower Bokkeveld shales often contain well-preserved invertebrate fossil material. The aim of this study was to describe some characteristics seen at various scales (macro-, micro- and ultra -) within nodules that might contribute to an understanding of aspects of nodule formation and the reasons for the excellent preservation of the fossil material within these nodules. Detailed, high quality macro-photographs were taken of sliced and whole nodule surfaces and a catalogue was produced to tentatively identify fossils present and illustrate the variations seen within nodules. Selected nodules were then subjected to petrographic, ultra-structural (SEM) and some chemical (EDS, XRD & XRF) analysis to investigate the possible reasons for these variations. The chemical results have indicated that nodules are enriched with quartz compared to the surrounding shale. Quartz is also the dominant mineral replacing trilobite carapace material within nodules, while trilobite material within shales is replaced with equal proportions of hematite, biotite and quartz. It appears that the higher resistance of quartz to weathering is the dominant factor leading to the preservation of both nodules within the shales and trilobite material within the nodules examined. A comparison with some Western Cape nodules highlighted possible variations in overall nodule chemical composition along strike. Western Cape nodules are predominantly composed of apatite whereas the Cockscomb nodules are mainly composed of quartz. This quartz-apatite compositional variation in nodules occurring within a single formation has been reported from nodules found in the Armorican Massif of France which are very similar in a number of respects to the Bokkeveld nodules described in this study. Based on various features of the fossils present and the structure of nodules they were probably formed during early diagenesis within an epeiric marine deposit greatly affected by sea level fluctuations.

MSc., Faculty of Science, University of the Witwatersrand, 2011 / Granitoid intrusions are numerous in southwestern Rajasthan and are useful because they can provide geochronological constraints on tectonic activity and geodynamic conditions operating as the time of intrusion, as well as information about deeper crustal sources. The particularly voluminous Neoproterozoic felsic magmatism in the Sirohi region of Rajasthan is of particular interest as it may have implications for supercontinental (Rodinia and Gondwana) geometry. The Mt. Abu granitoid pluton is located between two major felsic suites, the older (~870-800 Ma) Erinpura granite and the younger (~751-771 Ma) Malani Igneous Suite (MIS). The Erinpura granite is syn- to lateorogenic and formed during the Delhi orogeny, while the MIS is classified as alkaline, anorogenic and either rift- or plume-related. This tectonic setting is contentious, as recent authors have proposed formation within an Andean-type arc setting. The Mt. Abu granitoid pluton has been mapped as partly Erinpura (deformed textural variant) and partly younger MIS (undeformed massive pink granite). As the tectonic settings of the two terranes are not compatible, confusion arises as to the classification of the Mt. Abu granitoid pluton. Poorly-constrained Rb-Sr age dating place the age of formation anywhere between 735 ± 15 and 800 ± 50 Ma. The older age is taken as evidence that the Mt. Abu intrusion was either a late phase of the Erinpura granite. However, U-Pb zircon geochronology clearly indicates that the Mt. Abu felsic pluton is not related to- or contiguous with- the Erinpura granite suite. The major results from this study indicate that the all textural variants within the Mt. Abu pluton were formed coevally at ~765 Ma. Samples of massive pink granite, mafic-foliated granite and augen gneiss from the pluton were dated using U-Pb zircon ID-TIMS at 766.0 ± 4.3 Ma, 763.2 ± 2.7 Ma and 767.7 ± 2.3 Ma, respectively. The simple Mt. Abu pluton is considered as an enriched intermediate I- to A-type intrusion. They are not anorogenic A-types, as, although these felsic rocks have high overall alkali and incompatible element enrichment, no phase in the Mt. Abu pluton contains alkali rich amphibole or pyroxene, nor do REE diagrams for the most enriched samples show the gull-wing shape typical of highly evolved alkaline phases. The alkali-enriched magma may be explained by partial melting of a crustal source such as the high-K metaigneous (andesite) one suggested by Roberts & Clemens (1993), not derivation from a mantle-derived mafic magma. The fairly restricted composition of Mt. Abu granitoids suggests that partial melting and a degree of assimilation/mixing may have been the major factors affecting the evolution of this granitoid pluton; fractional crystallization was not the major control on evolution of these granitoids. Revdar Rd. granitoids that are similar in outcrop appearance and petrography to Mt. Abu granitoids also conform to Mt. Abu granitoids geochemically and are classified as part of the Mt. Abu felsic pluton. Mt. Abu samples from this study have a maximum age range of 760.5-770 Ma, placing the Mt. Abu pluton within the time limits of the Malani Igneous Suite (MIS) as well as ~750 Ma granitoids from the Seychelles. Ages of the Sindreth-Punagarh Groups are also similar. These mafic-ultramafic volcanics are thought to be remnants of an ophiolitic mélange within a back-arc basin setting at ~750-770 Ma. The three Indian terranes are spatially and temporally contiguous. The same contiguity in space and time has been demonstrated by robust paleomagnetic data for the Seychelles and MIS. These similarities imply formation within a common geological event, the proposed Andean-type arc (Ashwal et al., 2002) on the western outboard of Rodinia. The implications are that peninsular India did not become a coherent entity until after this Neoproterozoic magmatism; Rodinia was not a static supercontinent that was completely amalgamated by 750 Ma, as subduction was occurring here simultaneous with rifting elsewhere. Pageiv The Mt. Abu pluton has undergone deformation, with much of the pluton having foliated or augen gneiss textures. The timing of some of the deformation, particularly the augen gneiss and shear zone deformation, is thought to have occurred during intrusion. The Mt. Abu and Erinpura granitoids have experienced a common regional metamorphic event, as hornblende (Mt. Abu) and biotite (Erinpura) give 40Ar/39Ar ages of 508.7 ± 4.4 Ma and 515.7 ± 4.5 Ma, respectively. This event may have reactivated older deformatory trends as well. The temperature of resetting of argon in hornblende coincides with temperatures experienced during upper-greenschist to lower-amphibolite facies metamorphism. These late Pan-African ages are the first such ages reported for the Sirohi region and southern part of the Aravalli mountain range. They offer evidence for the extension of Pan-African amalgamation tectonics (evidence from southern India) into NW India. The age of formation of the Erinpura augen gneiss magma is 880.5 ± 2.1 Ma, thus placing the Erinpura granitoids within the age limits of the Delhi orogeny (~900-800 Ma; Bhushan, 1995). Most deformation observed here would have been caused by compression during intrusion. The Erinpura granitoids are S-type granitoids due to their predominantly peraluminous nature, restricted SiO2-content, normative corundum and the presence of Al-rich muscovite and sillimanite in the mode. Weathered argillaceous metasedimentary material may also have been incorporated in this magma, while the presence of inherited cores suggests relatively lower temperatures of formation for these granitoids as compared to the Mt. Abu granitoids. The age of inheritance (1971 ± 23 Ma) in the Erinpura augen gneiss is taken as the age of the source component, which coincides with Aravalli SG formation. The Sumerpur granitoids differ from the Erinpura granitoids in terms of macroscopic and microscopic texture (undeformed, rarely megaporphyritic) but conform geochemically to the Erinpura granitoid characteristics and may thus be related to the Erinpura granitoid suite.The Revdar Rd. granitoids that are similar in macroscopic appearance to Erinpura granitoids also conform geochemically, and may similarly belong to the Erinpura granite suite. A Revdar Rd. mylonite gneiss with the Erinpura granitoids’ geochemical signature was dated at ~841 Ma, which does not conform to the age of the type-locality Erinpura augen gneiss dated here, but later intrusion within the same event cannot be ruled out because of the uncertainty in the age data (~21 Ma). The presence of garnet in one Revdar Rd. (Erinpura-type) sample implies generation of these granitoids at depth and/or entrainment from the source, similar to the S-type Erinpura granitoids. The Ranakpur granitoids differ significantly from both the Erinpura and Mt. Abu intrusives due to their low SiO2-content and steep REE profiles (garnet present in the source magma); they are thought to have been generated under higher pressures from a more primitive source. The deeper pressure of generation is confirmed by the absence of a negative Eu-anomaly. The Ranakpur quartz syenite dated at 848.1 ± 7.1 Ma is younger by ~30 m.y. than the Erinpura augen gneiss. It is within the same time range as numerous other granitoids from this region as well as the Revdar Rd. granitoid dated in this study. The prevalence of 830- 840 Ma ages may indicate that a major tectonic event occurred at this time. The Ranakpur quartz syenite may have been generated near a subduction or collision zone, where thickened crust allows for magma generation at depth. The deeply developed Nb-anomaly in the spider diagram also implies a larger subduction component to the magma. The Swarupganj Rd. monzogranite is interpreted to have formed by high degrees of partial melting from a depleted crustal source and is dissimilar to other granitoids from this study. More sampling, geochemical and geochronological work needs to be done in order to characterize this intrusion. Pagev The Kishengarh nepheline syenite gneiss is situated in the North Delhi Fold Belt and is the oldest sample dated within this study. The deformation in this sample is due to arc- or continental- collision during a Grenvillian-type orogeny related to the amalgamation of the Rodinia supercontinent (and peninsular India), dated by the highly reset zircons at ~990 Ma. This is considered a DARC (deformed alkaline rock and carbonatite) and represents a suture zone (Leelanandam et al., 2006). The primary age of formation of this DARC is older than 1365 ± 99 Ma, which is the age of xenocrystic titanites from the sample. The granitoid rocks from this study area (Sirohi region) range widely in outcrop appearance, petrography and geochemistry. Granitoids from the Sirohi region dated in this study show a range of meaningful ages that represent geological events occurring at ~880 Ma, ~844 Ma, ~817 Ma, ~789 Ma, ~765 Ma and ~511 Ma. Granitoid magmatism (age of formation) in this region is predominantly Neoproterozoic, and the number of events associated with each granitoid intrusion as well as diverse tectonic settings implies a complexity in the South Delhi Fold Belt that is not matched by the conventional and simplified view of a progression from collision and orogeny during Grenvillian times (Rodinia formation), through late orogenic events, to anorogenic, within-plate (rift-related) alkaline magmatism during Rodinia dispersal. Instead, it is envisaged that convergence and subduction during the formation of Rodinia occurred at ~1 Ga (Kishengarh nepheline syenite deformation), with a transition to continental-continental collision at ~880-840 Ma (Erinpura and Ranakpur granitoids). This was then followed by far-field Mt. Abu and MIS magmatism, related to a renewed period of subduction at ~770 Ma. The last deformatory event to affect this region was that associated with the formation of Gondwana in the late Pan-African (~510 Ma).