Orientador: Antonio Misson Godoy / Banca: Antenor Zanardo / Banca: Marco Aurélio Farias de Oliveira / Banca: Romulo Machado / Banca: Ticiano José Saraiva dos Santos / Resumo: O Maciço do Rio Apa ocorre no sudoeste do estado de Mato Grosso do Sul e corresponde à porção meridional do Cráton Amazônico de idade dominantemente Paleoproterozóica. O Complexo Rio Apa, mais antigo, é constituído por ortognaisses migmatíticos, além de anfibolitos, tonalitos e granodioritos. O Grupo Alto Tererê é composto por xistos, biotita - muscovita gnaisses e quartzitos micáceos, comumente granatíferos, além de rochas metabásicas, em fácies anfibolito baixa. O Grupo Amonguijá é definido pela Suíte Intrusiva Alumiador que representa um batólito de composição sieno- a monzogranítica e pela Suíte Vulcânica Serra da Bocaina composta por rochas vulcanoclásticas de composição álcali - riólito a monzoriólitos e produtos piroclásticos. Sobreposta, a leste e a sul ocorrem as rochas metassedimentares Neoproterozóicas da Faixa de Dobramento Paraguai (grupos Cuiabá, Corumbá e Jacadigo-Formação Urucum). O quadro estrutural - metamórfico é identificado por 5 fases deformacionais, mas sua atual estruturação tectônica-metamórfica passa pelo arranjo tectônico superimposto da Faixa de Dobramentos Paraguai. As rochas do Complexo Rio Apa, Grupo Alto Tererê e Grupo Amonguijá registram uma evolução estrutural reliquiar antiga definida pelas fases (Dn-1 e Dn). As fases deformacionais (Dn+1 e Dn+2) encontram-se visíveis principalmente nas rochas da Faixa de Dobramento Paraguai, enquanto deformações (Dn+3) superimpõem a todas as sequências / Abstract: Geological and structural frame of the Rio Apa Massif, southeastern of the Amazonian Craton (MS), Brasil Rio Apa Massif crops out in the Mato Grosso do Sul state and corresponds to the southeastern portion of the Amazonian Craton dominantly Paleoproterozoic in age. Rio Apa Complex is oldest and it is composed mainly by migmatitic orthogneisses, beyond amphybolites, tonalities and granodiorite. Alto Tererê Group is composed by schists, biotite-muscovite gneisses and micaceous quartzites generally rich in garnets, beyond metabasic rocks of low amphibolite facies. The Amonguijá Group is constituted by Alumiador Intrusive Suite, which is represented by a sieno to monzogranitic batholith and Serra da Bocaina Volcanic Suite composed of volcanoclastic rocks of alkali riolites to monzoriolites compositions and pyroclastic products. Overlaying towards East and South occurs Neoproterozoic metasedimentary rocks from the Paraguai Folded Belt (Cuiabá, Corumbá and Jacadigo Groups-Urucum Formation). Structural-metamorphic framewok is identified by five deformational phases but the actual tectonic and metamorphic structure shows the superposed tectonic array of the Paraguai Folded Belt. Rocks from Rio Apa Complex, Alto Tererê Group and Amonguijá Group record an older structural evolution defined by (Dn-1 and Dn). The deformational phases (Dn+1 and Dn+2) are visible mainly in rocks of Paraguai Folded Belt beyond the last deformation (Dn+3) that imprints all sequences / Doutor

Made available in DSpace on 2014-06-11T19:32:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-09-09Bitstream added on 2014-06-13T19:42:58Z : No. of bitstreams: 1 manzano_jc_dr_rcla.pdf: 3069122 bytes, checksum: cf569dcb57546619aa77beff7754c326 (MD5) / O Maciço do Rio Apa ocorre no sudoeste do estado de Mato Grosso do Sul e corresponde à porção meridional do Cráton Amazônico de idade dominantemente Paleoproterozóica. O Complexo Rio Apa, mais antigo, é constituído por ortognaisses migmatíticos, além de anfibolitos, tonalitos e granodioritos. O Grupo Alto Tererê é composto por xistos, biotita - muscovita gnaisses e quartzitos micáceos, comumente granatíferos, além de rochas metabásicas, em fácies anfibolito baixa. O Grupo Amonguijá é definido pela Suíte Intrusiva Alumiador que representa um batólito de composição sieno- a monzogranítica e pela Suíte Vulcânica Serra da Bocaina composta por rochas vulcanoclásticas de composição álcali - riólito a monzoriólitos e produtos piroclásticos. Sobreposta, a leste e a sul ocorrem as rochas metassedimentares Neoproterozóicas da Faixa de Dobramento Paraguai (grupos Cuiabá, Corumbá e Jacadigo–Formação Urucum). O quadro estrutural - metamórfico é identificado por 5 fases deformacionais, mas sua atual estruturação tectônica-metamórfica passa pelo arranjo tectônico superimposto da Faixa de Dobramentos Paraguai. As rochas do Complexo Rio Apa, Grupo Alto Tererê e Grupo Amonguijá registram uma evolução estrutural reliquiar antiga definida pelas fases (Dn-1 e Dn). As fases deformacionais (Dn+1 e Dn+2) encontram-se visíveis principalmente nas rochas da Faixa de Dobramento Paraguai, enquanto deformações (Dn+3) superimpõem a todas as sequências / Geological and structural frame of the Rio Apa Massif, southeastern of the Amazonian Craton (MS), Brasil Rio Apa Massif crops out in the Mato Grosso do Sul state and corresponds to the southeastern portion of the Amazonian Craton dominantly Paleoproterozoic in age. Rio Apa Complex is oldest and it is composed mainly by migmatitic orthogneisses, beyond amphybolites, tonalities and granodiorite. Alto Tererê Group is composed by schists, biotite-muscovite gneisses and micaceous quartzites generally rich in garnets, beyond metabasic rocks of low amphibolite facies. The Amonguijá Group is constituted by Alumiador Intrusive Suite, which is represented by a sieno to monzogranitic batholith and Serra da Bocaina Volcanic Suite composed of volcanoclastic rocks of alkali riolites to monzoriolites compositions and pyroclastic products. Overlaying towards East and South occurs Neoproterozoic metasedimentary rocks from the Paraguai Folded Belt (Cuiabá, Corumbá and Jacadigo Groups-Urucum Formation). Structural-metamorphic framewok is identified by five deformational phases but the actual tectonic and metamorphic structure shows the superposed tectonic array of the Paraguai Folded Belt. Rocks from Rio Apa Complex, Alto Tererê Group and Amonguijá Group record an older structural evolution defined by (Dn-1 and Dn). The deformational phases (Dn+1 and Dn+2) are visible mainly in rocks of Paraguai Folded Belt beyond the last deformation (Dn+3) that imprints all sequences

Two suites of intermediate-felsic plutonic rocks were recovered by dredges RD63 and RD64 (R/V KK81-06-26) from the northern wall of the Mariana trench near Guam, which is located in the southern part of the Izu-Bonin-Mariana (IBM) island arc system. The locations of the dredges are significant as the area contains volcanic rocks (forearc basalts and boninites) that have been pivotal in explaining processes that occur when one lithospheric plate initially begins to subduct beneath another. The plutonic rocks have been classified based on petrologic and geochemical analyses, which provides insight to their origin and evolution in context of the surrounding Mariana trench. Based on whole rock geochemistry, these rocks (SiO2: 49-78 wt%) have island arc trace element signatures (Ba, Sr, Rb enrichment, Nb-Ta negative anomalies, U/Th enrichment), consistent with the adjacent IBM volcanics. Depletion of rare earth elements (REEs) relative to primitive mantle and excess Zr and Hf compared to the middle REEs indicate that the source of the plutonic rocks is similar to boninites and transitional boninites. Early IBM volcanic rocks define isotopic fields (Sr, Pb, Nd and Hf-isotopes) that represent different aspects of the subduction process (e.g., sediment influence, mantle provenance). The southern Mariana plutonic rocks overlap these fields, but show a clear distinction between RD63 and RD64. Modeling of the REEs, Zr and Hf shows that the plutonic suites formed via melting of boninite crust or by crystallization from a boninite-like magma rather than other sources that are found in the IBM system. The data presented support the hypothesis that the plutonic rocks from RD63 and RD64 are products of subduction initiation and are likely pieces of middle crust in the forearc exposed at the surface by faulting and serpentine mudvolcanoes. Their existence shows that intermediate-felsic crust may form very early in the history of an intra-oceanic island arc system. Plutonic rocks with similar formation histories may exist in obducted suprasubduction zone ophiolites and would be evidence that felsic-intermediate forearc plutonics are eventually accreted to the continents.

Isolated granitic rock bodies (granites, granodiorites, quartz monzonites) in the vicinity of Benson in southeastern Arizona were studied to trace the behavior of rock weathering. Thin sections of fresh granites were examined to characterize the original mineralogy which consisted mainly of quartz, feldspars, and micas. The weathering products show up on the granites as grus and soil profiles as well as down slope in the basin deposits. X -ray diffraction studies of the < 2 micrometers fraction of the weathering products proved illite, smectite, illite-smectite mixed layer, and kaolinite to be the dominant clays; quartz and feldspar also persisted into this size fraction. Silt sized material produced similar results. The quartz monzonite of Texas Canyon afforded a special study of the initial weathering stages of feldspars and micas. In the < 2 micrometers fraction obtained from granitic material placed in an ultra sonic bath, the feldspars weathered to a Na-montmorillinite while biotite weathered to vermiculite.

The geological history of the Early Palaeozoic in eastern Australia is not known precisely. The eastern margin of the outcropping Precambrian Craton 'Tasman Line' is poorly understood. The Thomson Orogen, which underlies much of eastern Queensland, lies to the east of the Tasman Line. Basement to the Tasman Orogenic Zone is poorly understood, but knowledge of this basement is critical to our understanding to the processes that formed the eastern margin of the Precambrian craton. The Lolworth-Ravenswood Province lies to the east of the Tasman Line in northeast Queensland. A study of basement terranes in the Lolworth-Ravenswood Province will therefore provide some insights as to the nature of crust beneath this area, and therefore to the basement to the Thomson Orogen. The Fat Hen Creek Complex comprises para-authchthonous bodies of granitoid within middle to upper amphibolite facies metamorphic rocks. Data contained herein demonstrate that the composition and geochemistry of the granitoid are compatible with the generation of the granitoid by partial anatexis of the metamorphic rocks that are part of the Cape River Metamorphics. Temperature and pressure of anatexis is determined to be between 800-850OC and 5-9kb. Under these conditions, experimental data indicate that meta-pelite and meta-greywacke will produce between 5-10% melt coexisting with biotite, cordierite, garnet and plagioclase. The mineralogy of the granitoid bodies in the Fat Hen Creek Complex is consistent with partial anatexis of meta-greywacke at these temperatures and pressures. 5-10% melt is generally insufficient to allow efficient separation of melt and restite. The granitoids of the Fat Hen Creek Complex are interpreted as being a closed system with melt generated during high-grade metamorphism not separating from the residium. U/Pb dating of zircon from the Fat Hen Creek Complex indicate two distinct periods of zircon growth. The older episode occurred during the Late Cambrian to Early Ordovician. A second episode is dated as Middle Ordovician. This younger age coincides with the onset of regional compression, and may be related to exhumation of a mid-crustal layer during thrusting. The Lolworth Batholith is one of three granite batholiths in the Lolworth-Ravenswood Province. It comprises mainly muscovite-biotite granite, with smaller areas of hornblende-biotite granite to granodiorite. Sills and dykes of muscovite and garnet-muscovite leucogranite extensively intrude both of these types. The hornblende-biotite granite to granodiorite is metaluminous, with petrographic and geochemical characteristics similar to the adjacent Ravenswood Batholith. U-Pb SHRIMP ages also overlap with those from the Ravenswood Batholith. ENd(tc) values of ~-3 suggest a significant crustal contribution in the magma. Zircon populations determined using the SHRIMP suggest some inheritance from a Neoproterozoic source. The two-mica granites make up over 80% of the batholith and show little variation throughout. Aluminium Saturation indices range dominantly from 1-1.1, in keeping with the muscovite-bearing nature of the granites. U-Pb ages are significantly younger than the hornblende-biotite granitoids. ENd(tc) is ~-10, suggesting a greater role for crustal material in these granites than in the hornblende-bearing varieties. Previously, these granites were interpreted as S-types, mainly on the basis of the presence of muscovite. Low Na/Ca and Na greater than K are both considered as indicators of source compositions and both are characteristic of a mafic igneous rather than a meta-sedimentary source. Anatexis of mafic igneous rocks at temperatures less than~1000OC are found experimentally to produce peraluminous melts similar to those which produced the two-mica granites. The third major rock-type in the Lolworth Batholith is muscovite leucogranite, which occurs as sills and dykes intruding older granites and basement. The age of the leucogranite was not determined, but it has sharp contacts with the two-mica granite suggesting that the latter had cooled prior to intrusion of the former. The leucogranite is strongly peraluminous and is deemed to have been derived from anatexis of a supra-crustal (meta-sedimentary) source. The batholith is therefore deemed to comprise three different elements. The hornblende-biotite granitoids are the western extension of the adjacent Ravenswood Batholith. The two-mica granite and muscovite leucogranite are derived from different sources, but may be part of the same crustal anatexis event. During the Early Palaeozoic, the Lolworth-Ravenswood Province saw the intrusion of three granite batholiths into a basement of Late Neoproterozoic to Cambrian meta-sedimentary rocks. Also, Late Cambrian to Early Ordovician and Middle Ordovician high-grade metamorphism accompanied by partial anatexis is recorded at several sites across northeast Queensland. Although this metamorphism is restricted to these sites, they are widespread across the area suggestive of a widespread metamorphic event at these times. Similar metamorphism is recorded in the Arunta Inlier in Central Australia increasing the possible extent of this event. The geochemistry, isotopic characteristics and zircon populations of granites in the Lolworth-Ravenswood Province are used to characterise their source rocks; and thus the basement to the Province. Precambrian basement is indicated to underlie the entire province. However, the source rocks for the eastern part of the Province (Ravenswood and into the Lolworth Batholiths) are different to source rocks for the western part of the Province. Georgetown-type crust extends eastwards from the outcropping area, extending under the western Lolworth-Ravenswood Province. Late Mesoproterozoic rocks are recorded from the Cape River area adjacent to the Lolworth Batholith. They are also indicated as source-rocks for granites in the Ravenswood Batholith. Rocks of this age are characteristic of Grenvillian-age mobile belts in the United States. Their presence in north Qeensland has implications for the breakup of Rodinia, the Mesoproterozoic-age super continent that broke up during the Neoproterozoic.

A quartz diorite intrusion of probable early Tertiary age that crops out over at least 6 square miles in the Palo Verde Ranch area in Pinal County, Arizona was mapped as a distinct intrusion. The quartz diorite intrudes an area comprising Pinal Schist, Oracle granite, andesitic flows, granoaplite, and dike rocks including both pegmatite and diabase. Two major physical features, the Owl Head Buttes and Chief Buttes volcanic areas, both remnants of an extensive early Tertiary series of flows of intermediate composition that covered the area, now remain as lava-capped buttes above the pediment. Weak but persistent fracture-controlled copper mineralization is found in the quartz diorite and the Pinal Schist at or near their mutual contacts in the form of chrysocolla, malachite, black copper oxides, chalcocite, chalcopyrite, and bornite, in decreasing order. Pyrite is rare. Alteration related to northeast and northwest-trending fractures increases in intensity from the common propylitic to argillic to the northeast toward the San Juan claims area. A barely discernible increase in copper sulfides mirrors the alteration zoning, although geochemical sampling showed background copper in the quartz diorite to be more uniform away from fractures.

Use of Re-Os systematics in sulfides from the Bagdad porphyry Cu-Mo deposit provide information on the timing of mineralization and the source of the ore -forming elements. Analyzed samples of pyrite, chalcopyrite and molybdenite mainly from the quartz monzonite and porphyritic quartz monzonite units are characterized by a moderate to strong potassic alteration (secondary biotite and K- feldspar). Rhenium concentrations in molybdenite are between 330 and 730 ppm. Two molybdenite samples from the quartz monzonite and porphyritic quartz monzonite provide a Re-Os isotope age of 71.7 ± 0.3 Ma. A third sample from a molybdenite vein in Precambrian rocks yields an age of 75.8 ± 0.4 Ma. These molybdenite ages support previous suggestions of two mineralization episodes in the Bagdad deposit. An early event at 76 Ma and a later episode at 72 Ma. Pyrite Os and Re concentrations range between 0.008-0.016 and 3.9-6.8 ppb, respectively. Chalcopyrite contains a wide range of Os (6 to 91 ppt) and Re (1.7 to 69 ppb) concentrations and variable ¹⁸⁷Os/¹⁸⁸Os ratios that range between 0.13 to 22.27. This variability in the chalcopyrite data may be attributed to different copper sources, one of them the Proterozoic volcanic massive sulfides in the district, or to alteration and remobilization of Re and Os. Analyses from two pyrite samples yield an eight point isochron with an age of 77 ± 15 Ma and an initial ¹⁸⁷Os/¹⁸⁸Os ratio of 2.12. This pyrite Re-Os isochron age is in good agreement with the molybdenite ages. We interpret the highly radiogenic initial 1870s/188Os as an indication that the source of Os and, by inference, the ore-forming elements for the Bagdad deposit, was mainly the crust. This conclusion agrees with previous Pb and Nd isotope studies and supports the notion that a significant part of the metals and magmas have a crustal source.