PRIMEIRAS OBSERVAÇÕES DA FORMAÇÃO PITANGA (GRUPO SERRA GERAL) NO ESTADO DE SÃO PAULO

Stratigraphy and volcanic facies architecture of the Torres Syncline, Southern Brazil, and its role in understanding the Paraná–Etendeka Continental Flood Basalt Province

Genesis of the E1 group of iron oxide-copper-gold deposits, Cloncurry district, North West Queensland

We present a new geological map of Warrumbungle Volcano created from volcanic facies field mapping, new geophysical, geochemical and geochronological data as well as data from previous studies. Field mapping and petrography defined 19 volcanic and two mixed volcanic--sedimentary facies. Facies identification and distribution in conjunction with geochemical analyses indicate an early shield-forming phase of predominantly mafic and intermediate lavas and pyroclastic deposits, and minor felsic lavas deposited on an irregularly eroded basement of Surat and Gunnedah basin rocks. The shield was subsequently intruded by felsic intermediate to felsic magmas that formed dykes and other intrusions, including possible cryptodomes, and also erupted as lava domes and block-and-ash-flow deposits. A radial dyke swarm cross-cuts most units, although it is concentrated within basement sandstone surrounding the central area of the volcano, suggesting late inflation accompanied by dyke emplacement. Geochemistry indicates differentiation of a single although repeatedly recharged alkaline magmatic suite. Fractionation of olivine, Ti-magnetite and clinopyroxene occurred in mafic magmas, and after reaching 62 wt% SiO2, crystallisation of apatite and alkali feldspar took place. A new U–Pb zircon SHRIMP magmatic crystallisation age of 16.25 ± 0.12 Ma on a felsic block-and-ash flow deposit is in agreement with the recalculated 40Ar/39Ar isochron dates of previous workers. Based on our mapping and the use of volcanic facies to define mappable units, we recommend that the previous Warrumbungle Volcanics be elevated from formation to group status and renamed the Warrumbungle Volcanic Complex. KEY POINTS New geological map of Warrumbungle Volcano based on volcanic facies mapping. The volcanic facies and their distribution suggest a complex alkaline shield volcano erupted along regional-scale basement lineaments over an intracontinental ‘hot-spot’ or heat plume, and intruded by lava domes, cryptodomes, dykes and a radial dyke swarm. New and previous geochemical data suggest differentiation of a single, although repeatedly recharged, alkaline magmatic suite. A new U–Pb zircon SHRIMP date of 16.25 ± 0.12 Ma is in agreement with the recalculated 40Ar/39Ar isochron dates of previous workers.

The mode of emplacement of Neogene flood basalts in eastern Iceland: Facies architecture and structure of simple aphyric basalt groups

The Kufra basin located in the southeastern part of Libya is an elongate SW-NE trending (?Hercynian) depression defining a zone of crustal weakness of the trans-Africa lineament (Turner, 1980; 1995). The basin covers an aerial extent of approximately 400,000 sq km extending into Chad, Sudan and Egypt. Two major tectonic elements are known to have significantly controlled the structural style of the basin and consequently affected lithology distribution namely the Hercynian and the Caledonian events of Early Carboniferous and Late Silurian age respectively (Bellini and Massa, 1980). The basin fill consisting of a clastic Mesozoic and essentially Palaeozoic sequence attains an approximate thickness of 4000 m in basin centre. Lower Palaeozoic strata are exposed in three major outcrops surrounding the basin; Jabal Dalma in the NE, Awaynat massif including Jabal Asba in SE and Jabal Eighe in the W-SW. The existence of these outcrops provided ideal opportunity to examine the Palaeozoic succession from within a sedimentological/stratigraphic framework. As the only non-producing basin of Libya, Kufra Basin has recently re-captured the intention of oil companies for a detailed work in a bid to solve uncertainties still surrounding the basin hydrocarbon potential. In the same context, Remsa has conducted a field campaign to the area with the aim of investigating the depositional packages of the Lower Palaeozoic sequence as the main possible hydrocarbon plays may have exist in the subsurface counterpart. Two separate campaigns have been carried out during March-April 2005/2006 in the NE of Kufra (Jabal Asba, Arkunu and Garda area) and in the NE of Kufra (Jabal Dalma area) during which more than 80 localities were visited. Lower Palaeozoic sequence is investigated including the InfraCambrian, Cambrain Hassawna Fm, Ordovician sequence of Hawaz, Melaz Shugran, and Mamuniyat Fms, Silurian Tanezzuft and Akakus Fms and the Devonian sequence of Tadrat/Oan Casa Fms and the Binem (Blitah Fm). Packages are dealt with in a large-scale architecture i.e. facies associations without considering details of facies scale. The aim is to predict depositional mode and palaeogeographic reconstruction within a sequence stratigraphic approach applying method of facies recognition, stacking pattern, palaeoflow data, surface logging and composite log reconstruction. The field campaign is augmented in some instances by geochemical, petrographic and petrophysical analysis for units of interest in addition to shallow hole drilling. The systematic and/or genetic evolution of the Lower Palaeozoic succession of the Kufra Basin seems to have been largely affected by the interaction of tectonics and sea level changes demonstrating a pronounced variation in facies architecture and stacking pattern as it varies from proximal in the SE “Awaynat Massif-Jabal Asba outcrops” into distal setting of the “Jabal Dalma outcrop” which provided the key of reconstructing the palaeogeography of individual time slices and their inferred depositional models.

The paper is devoted to the problem of the development level and organization models of mining within the Eurasian metallurgical province of the Late Bronze Age in the 2nd millennium BC. The main research aim is to determine the chain of technological processes taking place at the Novotemirsky ancient mine in the Southern Trans-Urals. The sources of raw materials, traces of use, and functional identification of stone (n=58) and bone tools (n=1) were determined using traceological, petrographic, X-ray fluorescence, and X-ray diffraction analysis. All tools were divided into three groups depending on their use: mining (a casting mould for a pick), ore crushing (hammers, small hammers), supporting devices (“bases”, counterweights for lifting ore). The absence of mining and processing (grinding pestles, grinding stones) and metal-working (blacksmith hammers) tools at the Novotemirsky mine indicates a narrow range of technical operations associated only with direct mining of copper ore and ore-preparing (crushing large blocks). It is assumed that there is a partial specialization of mining, which consists in the formation of temporary miners’ collectives, who are seasonally involved in these operations. Keywords: stone tools, ancient mine, Late Bronze Age, Southern Trans-Urals, Alakul culture, traceological analysis, X-ray fluorescence analysis, X-ray diffraction analysis

The Middle to Late Cambrian Mount Read Volcanics, western Tasmania, comprise compositionally and texturally diverse lavas and volcaniclastic rocks, most of which were emplaced in submarine environments below wave base. The facies architecture reflects the contrasting character and geometry of primary volcanic and volcaniclastic facies which are strongly controlled by eruption style and eraplacement processes. In the northern Mount Read Volcanics the principal volcanic facies are (1) silicic, intermediate, and mafic lavas; (2) juvenile volcaniclastic deposits, generated in association with the extrusion of lava flows, or else produced by explosive eruptions; and (3) synvolcanic intrusions involving silicic and mafic magmas emplaced into unconsolidated host sequences. Distribution and lithofacies characteristics suggest that deposits from both intrabasinal submarine and extrabasinal subaerial and/or shallow-marine volcanic centers are present. The volcanic facies are interbedded with a sedimentary facies association comprising black mudstone and/or graded bedded sandstone of mixed volcanic and Precambrian basement provenance. The predicted facies geometry of the principal volcanic facies has guided our approach to correlation in the Mount Read Volcanics. Mass-fiow-emplaced pumiceous volcaniclastic facies provide the best framework for correlation, because these are produced in large volumes, erupted infrequently, eraplaced rapidly, and are widely distributed. Distinctive units of this type that occur near Hellyer (in the Southwell Subgroup) and 40 km to the south at White Spur-Howards Road (White Spur Formation) could each be part of the same regionally extensive volcaniclastic facies association. A similar volcaniclastic facies association hosts the Hercules and Rosebery massive sulfide deposits and clearly demonstrates that such associations are prospective for this style of mineralization.

The volcanic island of Milos, Greece, comprises an Upper Pliocene –Pleistocene, thick (up to 700 m), compositionally and texturally diverse succession of calc-alkaline, volcanic, and sedimentary rocks that record a transition from a relatively shallow but dominantly below-wave-base submarine setting to a subaerial one. The volcanic activity began at 2.66±0.07 Ma and has been more or less continuous since then. Subaerial emergence probably occurred at 1.44±0.08 Ma, in response to a combination of volcanic constructional processes and fault-controlled volcano-tectonic uplift. The architecture of the dominantly felsic-intermediate volcanic succession reflects contrasts in eruption style, proximity to source, depositional environment and emplacement processes. The juxtaposition of submarine and subaerial facies indicates that for part of the volcanic history, below-wave base to above-wave base, and shoaling to subaerial depositional environments coexisted in most areas. The volcanic facies architecture comprises interfingering proximal (near vent), medial and distal facies associations related to five main volcano types: (1) submarine felsic cryptodome-pumice cone volcanoes; (2) submarine dacitic and andesitic lava domes; (3) submarine-to-subaerial scoria cones; (4) submarine-to-subaerial dacitic and andesitic lava domes and (5) subaerial lava-pumice cone volcanoes. The volcanic facies are interbedded with a sedimentary facies association comprising sandstone and/or fossiliferous mudstone mainly derived from erosion of pre-existing volcanic deposits. The main facies associations are interpreted to have conformable, disconformable, and interfingering contacts, and there are no mappable angular unconformities or disconformities within the volcanic succession.

The Deccan Traps large igneous province (LIP) comprises one of the largest continental flood basalt provinces on Earth with the main phase of volcanism spanning the Cretaceous‐Palaeogene boundary. The oldest volcanism of the province is encountered in the northwest of modern‐day India where Deccan stratigraphy is often buried beneath thick Cenozoic sedimentary sequences. The Raageshwari Deep Gas (RDG) Field, located onshore in the central Barmer Basin, NW India, produces gas from the early Deccan Raageshwari Volcanics which are subdivided into two members, the Agni Member and the overlying Prithvi Member. The RDG comprises a globally important example of a producing volcanic reservoir whilst also offering unique insights into the early volcanism of the Deccan with the aid of extensive high quality sub‐surface data. Within this study, the volcanic facies of the RDG sequences are investigated from five cored intervals (total 160 m). Core‐based facies determinations are compared with geochemical analyses, petrophysical analyses of the cores (density, porosity and permeability), and wireline data including micro‐resistivity borehole images (FMI) and Nuclear Magnetic Resonance (NMR) data. A wireline based volcanic lithofacies scheme is developed and applied to the uncored parts of the sequence which in turn is compared to 3D seismic data. Results of the study reveal the Agni Member to comprise a compositionally bimodal (basalt through to trachyte), dominantly alkaline series with mixed volcanic facies including spectacular felsic ignimbrites, basic‐intermediate simple lava flows, volcaniclastic units and newly identified shallow intrusions. The Prithvi Member in contrast is dominated by tholeiitic basalt compositions with less common basic‐intermediate alkaline compositions and comprises a sequence dominated by classic tabular lava flow facies inter‐digitated with boles, volcaniclastic units, rare compound braided lava facies and evolved tuffaceous ash layers. In one interval of the Prithvi Member, evidence for agglutinated spatter is recorded inferring potential proximity to a palaeo‐eruption site within the area. Comparison between core data and volcanic facies reveals a first order control of volcanic facies on reservoir properties highlighting the importance of volcanic facies appraisal in the development of volcanic reservoirs.

We present the results of a pilot study that integrates automated drill core scanning technology based on simultaneous X-ray computed tomography (XCT) and X-ray fluorescence (XRF) analyses to provide high-spatial-resolution (<0.2 mm) information on 3-D rock textures and structures, chemical composition, and density. Testing of its applicability for mineral exploration and research was performed by scanning and analyzing 1,500 m of drill core from the Paleoproterozoic Lovisa stratiform Zn-Pb sulfide deposit, which is part of a larger mineral system also including Cu-Co and Fe-(rare earth element) mineralization, hosted by the highly strained West Bergslagen boundary zone in south-central Sweden. The obtained scanning data complements data derived from structural field mapping, drill core logs, and chemical analysis as well as from multiscale 3-D geologic modeling at Lovisa. Data integration reveals macro- and mesoscopic folding of S0/S1 by asymmetric steeply SE-plunging F2 folds and N-striking vertical F3 folds. Stretching lineations, measured directly from the scanning imagery, trend parallel to F2 fold hinges and modeled ore shoots at the nearby Håkansboda Cu-Co and Stråssa and Blanka Fe deposits. The textural character of the Lovisa ore zones is revealed in 3-D by XCT-XRF scanning and highlight remobilization of Zn and Pb from primary layering into ductile and brittle structures. The downhole bulk geochemical trends seen in scanning and traditional assay data are generally comparable but with systematic variations for some elements due to currently unresolved XRF spectral overlaps (e.g., Co and Fe). The 3-D deformation pattern at Lovisa is explained by D2 sinistral transpression along the West Bergslagen boundary zone in response to regional north-south crustal shortening at ca. 1.84–1.81 Ga. Local refolding was caused by D3 regional east-west crustal shortening resulting in dextral transpression along the West Bergslagen boundary zone, presumably at ca. 1.80–1.76 Ga. Based on polyphase ore textures and modeled ore shoots aligned to F2 fold hinges, we postulate that D2 and D3 transpressive deformation exerted both a strong control on ore remobilization and the resulting orebody geometries at Lovisa and neighboring deposits within the West Bergslagen boundary zone. We conclude that the combined XCT-XRF drill core scanning technique provides a valuable tool for 3-D ore and rock characterization, generating continuous downhole data sets, with the potential for increasing precision and efficiency in mineral exploration and mining.

<p>The project “Inflatable Lunar Habitat” is develop by a group of students, master's degree in architecture, from Germany and is a part of this year's edition of IGLUNA, supported by Swiss Space Center.</p> <p>The idea of ​​the project is to be created an easily portable laboratory for conducting scientific experiments in extreme weather conditions, here on Earth. But at the same time, the project is designed so that in the future this type of construction will be used to be build a habitat villige located in lava tubes on the moon or even on Mars.</p> <p>The habitat is designed as an inflatable structure with an aerodynamic shape that is easy and fast to transport, carry out an assembly, it is also designed to be on a temporary basis and generate the least possible impact on the environment at the time of the investigation. For being inflatable is more vulnerable from the outside and the inside as well, because of that it is necessary to ensure the habitat subsystems such as the skin development and connections, the floor connections, the airlock and the climate control.</p> <p>The structure is arranged of several different in type and function layers. Starting from inside with inflatable transparent skin of ETFE-foil, serving to provide a safe and sterile place for the experiments, followed by a support system of two layers of  crossing inflatable tubes,  and ending with another layer of ETFE- foil serving to protect the support structure from external mechanical impacts. And at the top, the entire prototype is protected from wind, rain and sun by a final layer. The whole inflatable structure is firmly attached to a steel frame, which in turn is attached to the ground. Inside the steel frame is the floor, which is made of aluminum honeycomb panels, which provide the necessary stability, flat surface and protection against slipping.</p> <p>Due to the impossibility of the actual build of the prototype during this year's field campaign, due to the global pandemic, we included in the project and developed our vision for the lunar village, using as a modular unit for its design, the prototype of the  habitat constructed for the Earth.</p> <p>Although this year the project remained at the level of technical drawings and 3D computer model, next year with the help of our current sponsors and hopefully new ones, as well as with the support of the Swiss Space Center we expect to build a real prototype of inflatable lunar habitat and to test it on Mount Pilatus in Switzerland during the field campaign of IGLUNA 2021.</p>

Comparative geology and metamorphic evolution of the Luswishi Dome, Copperbelt, Zambia: Implications for exploration targeting

[Extract] This thesis applies a multidisciplinary approach to better understand the geology of the Kukuluma Terrain and the geological controls on gold mineralization. I used a combination of field, computer and laboratory based techniques to help me constrain a variety of factors influencing the gold mineralization. This thesis is subdivided into 6 chapters with appendices as follows: Chapter 1 is the introduction to the thesis study topic and the geological setting of the Tanzania craton and Geita Greenstone Belt. It also provides a brief history of the Geita Gold Mine. Chapter 2 presents the methodologies followed in compiling the data sets presented in chapters 3, 4 and 5. I report on data collected from internal mine reports, regional and pit scale geological mapping, drill core logging, cross-section interpretations, and 3D modelling using Leapfrog (software version 3.1.1), and provide an overview of the methodologies used in the structural (chapter 3), geochemical (chapters 4 and 5) and geochronological (chapter 5) studies. Chapter 3 presents the first detailed structural evolution history of the Kukuluma Terrain and discusses the structural controls on gold mineralization. The structural evolution of the area was developed based on overprinting relationships observed from detailed regional and deposit-scale geological mapping, drill core logging and the review of historical datasets such as maps and geophysical images, the details of which are included in chapter 2. I use the relationships between the distribution of gold mineralization and different structures to place spatial and temporal correlation between the structural evolution and the mineralizing event. I also constrained the relative timing of dykes and intrusive rocks emplacement in relation to deformation and mineralization. This chapter has been prepared for publication. Chapter 4 deals with the petrogenesis of the dykes and intrusive units within the Kukuluma Terrain. I present detailed petrographic descriptions of the igneous rocks and high quality major and trace element geochemical analyses. The igneous rocks that intruded the Kukuluma Terrain form three suites: a monzonite suite, a diorite suite, and a granodiorite suite. Because the three suites overlap in space and partly in time I grouped them into the Kukuluma Intrusive Complex. The monzonite and the diorite suites form a ~ northwestsoutheast oriented body that runs through the middle of the Kukuluma Terrain and they are virtually undistinguishable in the field while the granodiorite suite occurs mostly as dykes with various orientations and locally form small intrusive bodies. The petrogenetic evolution of the igneous rocks is of particular importance, because of their close spatial relationship with the gold mineralization. It is also possible that fluids related to the emplacement of the igneous rocks may have played a role in gold mineralization. For example, the timing of emplacement and the geochemical characteristics of sanukitoid-type igneous rocks have been linked to gold mineralization in many Archaean gold deposits (Mikkola et al., 2014). This chapter has been submitted for publication. Chapter 5 presents the first zircon ages and Hf isotope data from igneous rocks and sediments from the Kukuluma Terrain. The geochronological results are used to constrain the absolute timing of emplacement and deformation where possible. The results of zircon dating made it possible to place a maximum mineralization age in the area. The detrital age data is used to understand the timing of sedimentation in the area, but also set up the timing on the beginning of deformation in the area. I used the Hf isotope data to better constrain the sources and to understand the processes of crustal growth in this part of the Tanzania Craton. This chapter has been submitted for publication. Chapter 6 contains the conclusions of the thesis and provides recommendations for further work in the area.

The mode of emplacement of Neogene flood basalts in Eastern Iceland: Facies architecture and structure of the Hólmar and Grjótá olivine basalt groups

Bangka Island is an important tin producer in Indonesia, mostly from the secondary tin deposits. However, the secondary tin deposit is depleting, causing further exploration shifted to the primary tin mineral. The purpose of this study is to make a mineralization model of primary tin deposit in Bangka Island. Methods that implemented in this study are petrographic analysis, mineragraphic analysis, XRD (X-Ray Diffraction), and XRF (X-Ray Fluorescence) analysis. The studied rock samples that consisted of granite, meta-sandstone, and sandstone. Some of the rocks are altered rocks with varying intensity. Petrographic and mineragraphic analysis show the presence of minerals that indicate the primary tin deposits, such as cassiterite, tourmaline, topaz, sericite, pyrite, and sphalerite. XRF analysis shows data about the value of Sn elements so that they can be classified into two classes, very high grade (> 800 ppm), and low grade (100–200 ppm). XRD analysis is necessary to do to determine the type and intensity of alterations that occur in the study area. The results of each analysis will provide supporting information regarding the primary tin mineralization process in Bangka Island.