Farid Chemale Jr.
Universidade de Brasília - UnB, Geociencias, Faculty Member
- Since 2015, I am senior professor at the Geology Graduate Program of Vale do Rio dos Sinos University, where I gradu... moreSince 2015, I am senior professor at the Geology Graduate Program of Vale do Rio dos Sinos University, where I graduate in Geology (1978). I received my Master Degree in Geochemistry from Federal University of Rio Grande do Sul (UFRGS, 1982) and Ph.D degree in Naturwissenschaften from Technische Universität Clausthal (1987). I worked as associated and senior professor at the Ouro Preto University (UFOP, 1987-19991), UFRGS (1994-2009), and University of Brasília (UnB, 2010-2015). I have experience in Geosciences, focusing on Tectonics, acting on the following subjects: isotope geology, structural geology, analysis of sedimentary basin and metallogeny in South America, Southern Africa and Antarctic. Recently, I started to work with the International Ocean Development Program (IODP) in the Sumatra Seismogenic Zone as well as member of Executive Committee of the IODP (International Ocean Development Program) - CAPES-Brazil (Brazilian Federal Agency for Support and Evaluation of Graduate Education) program.edit
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Abstract The Mesoproterozoic crust of remnant terranes such as Maurice Ewing Bank can provide crucial clues about Rodinia supercontinent. Petrological and geochemical studies were conducted to unravel the metamorphic history of the... more
Abstract The Mesoproterozoic crust of remnant terranes such as Maurice Ewing Bank can provide crucial clues about Rodinia supercontinent. Petrological and geochemical studies were conducted to unravel the metamorphic history of the Maurice Ewing Bank Complex (MEBC). The MEBC is a polyphase metamorphic terrane with four progressive tectono-metamorphic events in subduction-related rocks. The first two episodes (R1-R2) occurred under conditions of progressive amphibolite- and granulite-facies metamorphism related to an orogenic hinterland. The R2 episode (P = 1.05 GPa, T = 800 °C) coincided with an older syn-deformational metagranitoid age of 1068 ± 28 Ma. The third episode (R3) involved granulite-facies metamorphism (P = 0.7–0.9 GPa, T = 830–930 °C) during tectonic exhumation that led to generation of syn- to late metagranitoids at 1032 ± 12 Ma. Episode four (R4) was marked by a regional anatectic process linked to crustal delamination at 1006 ± 13 Ma. Late retrograde metamorphic events, demonstrated by Rb-Sr and K-Ar isotopes, were generated by far-field thermal anomalies of Neoproterozoic-Palaeozoic tectonic events such as the Pan-African orogeny and Gondwanides. The correlation of the geotectonic environment and coeval magmatic-metamorphic events indicates that the MEBC comprises the roots of an orogenic hinterland of the Natal-Maurice-Maud belt during Rodinia-forming orogenies caused by the interaction of Kaapvaal and Patagonia cratons.
Research Interests: Geology, Geochemistry, Geophysics, Rodinia, Orogeny, and 4 moreMetamorphism, Supercontinent, Craton, and Granulite
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Drilling the input materials of the north Sumatran subduction zone, part of the 5000 km long Sunda subduction zone system and the origin of the Mw ∼9.2 earthquake and tsunami that devastated coastal communities around the Indian Ocean in... more
Drilling the input materials of the north Sumatran subduction zone, part of the 5000 km long Sunda subduction zone system and the origin of the Mw ∼9.2 earthquake and tsunami that devastated coastal communities around the Indian Ocean in 2004, was designed to groundtruth the material properties causing unexpectedly shallow seismogenic slip and a distinctive forearc prism structure. The intriguing seismogenic behavior and forearc structure are not well explained by existing models or by relationships observed at margins where seismogenic slip typically occurs farther landward. The input materials of the north Sumatran subduction zone are a distinctively thick (as thick as 4-5 km) succession of primarily Bengal-Nicobar Fan-related sediments. The correspondence between the 2004 rupture location and the overlying prism plateau, as well as evidence for a strengthened input section, suggest the input materials are key to driving the distinctive slip behavior and long-term forearc structure. During Expedition 362, two sites on the Indian oceanic plate ∼250 km southwest of the subduction zone, Sites U1480 and U1481, were drilled, cored, and logged to a maximum depth of 1500 meters below seafloor. The succession of sediment/rocks that will develop into the plate boundary detachment and will drive growth of the forearc were sampled, and their progressive mechanical, frictional, and hydrogeological property evolution will be analyzed through postcruise experimental and modeling studies. Large penetration depths with good core recovery and successful wireline logging in the challenging submarine fan materials will enable evaluation of the role of thick sedimentar y subduction zone input sections in driving shallow slip and amplifying earthquake and tsunami magnitudes, at the Sunda subduction zone and globally at other subduction zones where submarine fan-influenced sections are being subducted.
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This composite report includes data from two analyses (total carbon from \Elemental analysis [CHNS]\ and inorganic carbon from \[Coulometer]\). Each row combines the CHNS and Coulometer data from measurements made on the same sample at... more
This composite report includes data from two analyses (total carbon from \Elemental analysis [CHNS]\ and inorganic carbon from \[Coulometer]\). Each row combines the CHNS and Coulometer data from measurements made on the same sample at the same time for a particular section and section offset (depth). If data do not exist for a particular expedition, the column does not appear. To identify individual samples and tests, see each separate data type (Elemental analysis and Coulometer). If the same sample was measured multiple times by any of the methods, results in the report will be combined on one line where possible. Each additional replicate result will be shown in subsequent rows and will be combined where possible. Report includes results for carbon forms: total, inorganic, calcium carbonate, and organic by difference, along with total hydrogen, nitrogen, and sulfur.
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Data 1 Overview of recalculated ages for palynological and geochemical samples (based on Gradstein et al., 2012). Data 2 Datasheet with the percentages of the taxa in the ecological groups counted in the samples from Well 2 (see also... more
Data 1 Overview of recalculated ages for palynological and geochemical samples (based on Gradstein et al., 2012). Data 2 Datasheet with the percentages of the taxa in the ecological groups counted in the samples from Well 2 (see also Methods section).
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Drilling the input materials of the north Sumatran subduction zone, part of the 5000 km long Sunda subduction zone system and the origin of the Mw ∼9.2 earthquake and tsunami that devastated coastal communities around the Indian Ocean in... more
Drilling the input materials of the north Sumatran subduction zone, part of the 5000 km long Sunda subduction zone system and the origin of the Mw ∼9.2 earthquake and tsunami that devastated coastal communities around the Indian Ocean in 2004, was designed to groundtruth the material properties causing unexpectedly shallow seismogenic slip and a distinctive forearc prism structure. The intriguing seismogenic behavior and forearc structure are not well explained by existing models or by relationships observed at margins where seismogenic slip typically occurs farther landward. The input materials of the north Sumatran subduction zone are a distinctively thick (as thick as 4-5 km) succession of primarily Bengal-Nicobar Fan-related sediments. The correspondence between the 2004 rupture location and the overlying prism plateau, as well as evidence for a strengthened input section, suggest the input materials are key to driving the distinctive slip behavior and long-term forearc structur...
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Abstract The investigation of the deep structures of Precambrian mobile belts is crucial for defining the tectonic evolution of Phanerozoic intraplate basins. The magnetotelluric (MT) method provides high-resolution two-dimensional (2-D)... more
Abstract The investigation of the deep structures of Precambrian mobile belts is crucial for defining the tectonic evolution of Phanerozoic intraplate basins. The magnetotelluric (MT) method provides high-resolution two-dimensional (2-D) electrical resistivity models for the major deep-basement structures of a passive margin in southern Brazil. We obtained the resistivity models by applying mathematical inversion of 106 MT stations distributed along four profiles. The resistivity contrast between basement and basin and lateral discontinuity between basement terranes outline the geometry of the basins and the variation of the block physical properties and terrane of the Sul-Rio-Grandense shield. This information allowed to characterize and delimit the main structures, such as the Dorsal do Cangucu Shear Zone (DCSZ), the Passo do Marinheiro Shear Zone (PMSZ), and the depth of sedimentary cover of the onshore portion of the Pelotas Basin along the coast of the state of Rio Grande do Sul (RS), Brazil. The resistivity models extend 15 km deep, several kilometers below the top of the Precambrian basement. The top of the Precambrian basement varies from one profile to another from meters to kilometers and is covered in some places by packages of sedimentary rocks of different ages. The passive basin sediments of the Pelotas Basin can reach up to 4 km in thickness with structural control due to the inherited basement lineaments. Our MT data combined with data from wells and gravimetry data support a tectonic model for main structures of Sul-Rio-Grandense Shield in Neoproterozoic and for Phanerozoic sedimentary basin thicknesses.
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The Lu-Hf method has been used in the investigation of geological samples in order to understand processes and sources of magmatic rocks. This paper discusses the reference materials GJ-01, 91.500 and Mud Tank isotopic composition by... more
The Lu-Hf method has been used in the investigation of geological samples in order to understand processes and sources of magmatic rocks. This paper discusses the reference materials GJ-01, 91.500 and Mud Tank isotopic composition by LA-ICP-MS to investigate how suitable they are for the zircon analysis through this technique. The results show that the three zircons have homogeneous compositions for the proposed objectives. Considering that relatively high Yb contents produce isobaric interference, the results of this work have shown that the Mud Tank is the best reference material, since it has lower values of this element. Thus, the Mud Tank allows to obtain more reliable results due to lower correction requirements. In addition, it should be emphasized that the presented data corroborate the application of Hf isotopes for geological evolution and characterization of magmatic sources. The high abundances of Hf in the zircon grains allow to preserve the isotopic signatures of its c...
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A long-standing debate regarding the configuration of Pangea during the Late Paleozoic has been going on among the paleomagnetic community concerning the validity of one of two significantly different Pangea reconstructions (Pangea A vs... more
A long-standing debate regarding the configuration of Pangea during the Late Paleozoic has been going on among the paleomagnetic community concerning the validity of one of two significantly different Pangea reconstructions (Pangea A vs Pangea B) since the proposal of Pangea B. Although, Pangea B avoids any continental overlap marring classical Pangea A configuration (Wegener's type), it requires a Carboniferous-Permian megashear of up to 1500 km to achieve the pre-Jurassic configuration. The existence of this megashear is controversial and has led to a wide range of hypotheses, in order to avoid Pangea A continental overlaps and consequently the need for major intra-Pangea movements and to accommodate the paleomagnetic database within a Pangea A reconstruction. We present paleomagnetic results from Permian volcanic rocks of the El Centinela, La Pampa, Argentina. Undeformed volcanic rocks are not affected by any inclination bias and are, therefore, ideal to test different paleog...
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Plate-boundary fault rupture during the 2004 Sumatra-Andaman subduction earthquake extended closer to the trench than expected, increasing earthquake and tsunami size. International Ocean Discovery Program Expedition 362 sampled incoming... more
Plate-boundary fault rupture during the 2004 Sumatra-Andaman subduction earthquake extended closer to the trench than expected, increasing earthquake and tsunami size. International Ocean Discovery Program Expedition 362 sampled incoming sediments offshore northern Sumatra, revealing recent release of fresh water within the deep sediments. Thermal modeling links this freshening to amorphous silica dehydration driven by rapid burial-induced temperature increases in the past 9 million years. Complete dehydration of silicates is expected before plate subduction, contrasting with prevailing models for subduction seismogenesis calling for fluid production during subduction. Shallow slip offshore Sumatra appears driven by diagenetic strengthening of deeply buried fault-forming sediments, contrasting with weakening proposed for the shallow Tohoku-Oki 2011 rupture, but our results are applicable to other thickly sedimented subduction zones including those with limited earthquake records.
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Research Interests: American Studies, Archaeology, Anthropology, Archaeological Soil Micromorphology, Anthropology of Death, and 15 moreArchaeology of Ritual and Magic, Archeologia, Archaeology of Ritual, Antiquity, Archaeology of burials, Antropología cultural, Antropología Social, Antropología, Archaeology of death and burial, Archéologie, Anthropology of Lowland South America, Archaeological Fire Structures Studies, Archaeological Record, Archeologia Funeraria, and Archéologie funéraire
Research Interests: Geology, Geochemistry, Geophysics, Precambrian, Geoquímica, and 8 moreMagmatism, Zircon, Biotite, Craton, Granite, A-type granites, Magmatismo, and Granito
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Research Interests: Geology, Geochemistry, Provenance, Chemical Geology, Archean, and 4 moreGondwana, RIFT, Zircon, and Detritus
... 1. Departamento de Geologia, IG, UFRGS Laboratório de Geologia Isotópica, CP 15001, Porto Alegre-RS, Brazil. rommulo.conceicao@ufrgs.br 2. Laboratório de Geologia Isotópica, IG, UFRGS, Brazil. ... EPSL, 101:1-18. Mercier, JCC and... more
... 1. Departamento de Geologia, IG, UFRGS Laboratório de Geologia Isotópica, CP 15001, Porto Alegre-RS, Brazil. rommulo.conceicao@ufrgs.br 2. Laboratório de Geologia Isotópica, IG, UFRGS, Brazil. ... EPSL, 101:1-18. Mercier, JCC and Nicolas, A. 1975. ...
Research Interests: Geology and Lithosphere
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Research Interests: Earth Sciences, Geology, Geochemistry, Tectonics, Precambrian, and 7 morePetrography, Magmatism, Basalt, Zircon, Craton, Volcanic Rock, and Amazonian
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Abstract The Ouricuri do Ouro Formation represents sedimentary deposits of the Statherian period in Sao Francisco Craton. Previous works have focused just on the Formation mapping, interpreting the depositional system only in general... more
Abstract The Ouricuri do Ouro Formation represents sedimentary deposits of the Statherian period in Sao Francisco Craton. Previous works have focused just on the Formation mapping, interpreting the depositional system only in general aspects. However, this study focuses on detailed facies analysis and geochronological investigations of the Ouricuri do Ouro Formation in the central area of Sao Francisco Craton, Brazil. Four facies associations are recognized: i) Proximal deposits dominated by non-cohesive debris flow; ii) Proximal sheetfloods; iii) Intermediate sheetfloods; and iv) Sandy plains of distal floods. Paleocurrent directions derived from cross-bedding indicate a radial pattern to NE-N. The vertical stacking of distal deposits overlying the proximal facies association suggests a retrogradation of the alluvial fan system, indicating a change in the dynamic of the depositional system. Retrogradation might have been caused by a decrease in the regional gradient declining of the tectonic activity or the retreat of the basin's margin faults system. Furthermore, the presence of higher frequency fining-upward cycles also suggests a climatic control in those deposits. These cycles could be results of the progressive decrease in flow capacity and competence, associated with a decrease of superficial runoff over time. Allied with the dominant paleocurrent, the geochronological data of four tuffaceous sandstones reveal the contribution of Rhyacian to Mesoarchean zircons, suggesting that they came with sediments transported from SW and S of the studied area during the Statherian. The transported sediments came from the southern portion of Gaviao Paleoplate. The contribution of volcanic zircons recognized in the tuffaceous sandstones is related to syndepositional magmatism of Statherian Rift of Espinhaco Supergroup. The tuff layer at the base of drill hole (Sample FLV-61 A) contains a zircon age with dominant fraction represented by Statherian zircons defining the syn-sedimentary age of 1722 ± 13 Ma at the basal section of the Ouricuri do Ouro Formation. The present results and available geochronological data constraints the depositional interval of Lower Espinhaco Basin or Megasequence (in sense of Chemale et al., 2012; Guadagnin et al., 2015a, b) between 1.68 Ga in the Chapada Diamantina Region.
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INTRODUCTION The northwestern Roraima region – the Parima Mountains – is one of the least known regions in the world. Reconnaissance studies identified two main units in the Parima region basement: The Urariquera Complex (Pinheiro et al.,... more
INTRODUCTION The northwestern Roraima region – the Parima Mountains – is one of the least known regions in the world. Reconnaissance studies identified two main units in the Parima region basement: The Urariquera Complex (Pinheiro et al., 1981; CPRM, 2002) and the Parima Group (Arantes & Mandetta, 1970). Parima Group is an association of green schist facies volcano-sedimentary rocks and amphibolite facies paragneisses. The Urariquera Complex is an amphibolite facies orthogneiss unit including amphibolites and granitoid. Based on reconnaissance field data, the Parima Group was interpreted as a greenstone belt of Archean (Pinheiro et al., 1981) or Paleoproterozoic (Reis et al., 1994; Gaudette et al., 1996) age. Some authors (Tassinari & Macambira, 1999; Tassinari et al., 2000) propose the existence of a large Archean block in northern Roraima and southeastern Venezuela (the Roraima block), while others include the Parima Group in the Trans-Amazonian Orogeny (Reis et al., 1994; Gaudett...
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1. Companhia de Pesquisa de Recursos Minerais, Rua Banco da Província 105, Porto Alegre-RS, 90110-150. orestes1@.uol.com.br 2. Companhia de Pesquisa de Recursos Minerais, Rua Lauro Sodré 2561, 78904-300, Porto Velho-RO 3. Instituto de... more
1. Companhia de Pesquisa de Recursos Minerais, Rua Banco da Província 105, Porto Alegre-RS, 90110-150. orestes1@.uol.com.br 2. Companhia de Pesquisa de Recursos Minerais, Rua Lauro Sodré 2561, 78904-300, Porto Velho-RO 3. Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970, Porto Alegre, Rio Grande do Sul, Brazil 4. Centre for Global Metallogeny, Crawley 9007, Western Australia, Australia
Research Interests: Geology and Geochronology
The latest studies on the tectonic evolution of the Malvinas (Falkland) Islands and their adjacent continental plateau further east are analyzed to assess a long controversy regarding the origin of these islands. Although there has been a... more
The latest studies on the tectonic evolution of the Malvinas (Falkland) Islands and their adjacent continental plateau further east are analyzed to assess a long controversy regarding the origin of these islands. Although there has been a controversy for several decades on this subject, new technologies and exploratory drilling have brought new data, however the debate of the geological evolution of this area remains open. The two dominant hypotheses are analyzed by assessing the eventual collision between the islands and the South American continent, the presence of a large transcontinental fault such as Gastre, the potential 180º rotation of the Malvinas Islands, and the occurrence of a mega-decollement with opposite vergence. These hypotheses are contrasted with the processes that have occurred in Patagonia, especially those based on the new isotopic data on the Maurice Ewing Bank at the eastern end of the Malvinas Plateau, and the current knowledge of the adjacent Malvinas Basin...
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The iron protores of the Quadrilatero Ferrifero in Minas Gerais, Brazil, are quartz- or carbonate-banded laminated rocks (itabirite) which still display primary features similar to those encountered in non-metamorphic jaspilites, such as... more
The iron protores of the Quadrilatero Ferrifero in Minas Gerais, Brazil, are quartz- or carbonate-banded laminated rocks (itabirite) which still display primary features similar to those encountered in non-metamorphic jaspilites, such as sedimentary layering, slump structures and porous granoblastic martite fabric with relictic kenomagnetite. Synmetamorphic deformation initiated recrystallization of the platy hematite variety (specularite) and by this gave rise to a variety of secondary grain fabrics and textures portrayed by the intensity of magnetic (low-field) susceptibility and by the geometry of corresponding anisotropy ellipsoids. Folded ores usually have a foliation roughly parallel to the compositional banding, an axial plane schistosity, lepidogranoblastic fabric and textures dominantly resulting from flexural slip. The stereogram of the corresponding (11.0) texture shows a single maximum parallel to the intersection line of banding and schistosity. The AMS is generally low; its ellipsoid is triaxial. Increasing strain and shearing obliterates the primary layering and induced the formation of ore mylonites with lepidoblastic (S-tectonites) or nematoblastic (L-tectonites) grain fabrics which results in varying shapes of the AMS ellipsoids. Schistose ores, finally, have girdle arrangements of hematite-(11.0) poles, high susceptibilities and oblate shapes of the AMS ellipsoids, whereas strongly lineated ores display a single maximum parallel to the stretching direction, low to moderate susceptibilities and AMS ellipsoids with prolate shape. Secondary recrystallization and grain growth does not affect the lattice-preferred orientation.