Estratigrafia da faixa de dobramentos Paraguai-Araguaia no centro-norte do Brasil

A Faixa de Dobramentos Paraguai-Araguaia, constituída no Ciclo Brasiliano, estende-se para o norte da Ilha do Bananal, com orientação sub-meridiana. Acima do paralelo 9º30'S ela se faz representar pelo Grupo Baixo Araguaia, uma faixa ofiolítica, alguns corpos graníticos e pela Formação Rio das Barreiras. O Grupo Baixo Araguaia se constitui de três formações, Estrondo, Couto Magalhães e Pequizeiro, esta última de caráter magmático-sedimentar associada à faixa ofiolítica. A faixa ofiolítica é associada à Geossutura Tocantins-Araguaia, que parece se manifestar à superfície através da falha de empurrão entre o Rio Vermelho e Tucuruí, em associação à qual incide fáceis xisto verde glaucofanítica. A evolução da faixa de dobramentos mostra polaridade para oeste dos vários fenômenos, com exceção do magmatismo básico-ultrabásico.

Aspectos texturais do magmatismo e tramas da tectônica impostas ao Granito Chaval na Zona de Cisalhamento Santa Rosa, extremo Noroeste da Província Borborema

A região Noroeste da Província Borborema apresenta uma diversidade de corpos graníticos de natureza e evolução tectônica diversificadas, do Paleoproterozoico ao Paleozoico, com maior incidência relacionada ao Neoproterozoico e alojamento em diferentes fases da orogenia Brasiliana. Um desses exemplos é o Granito Chaval, que representa um batólito aflorante próximo à costa Atlântica do Ceará e Piauí, intrusivo em ortognaisses do Complexo Granja e supracrustais do Grupo Martinópole. Ele é, em parte, coberto por depósitos cenozoicos costeiros e rochas sedimentares paleozoicas da Bacia do Parnaíba. O Granito Chaval tem como característica marcante a textura porfirítica, destacando-se megacristais de microclina, em sienogranitos e monzogranitos, e outras feições texturais/estruturais de origem magmática, Essas permitiram interpretar sua evolução como de alojamento relativamente raso do plúton, conduzido por processos de cristalização fracionada, mistura de magmas com fluxo magmático e ação gravitacional em função da diferença de densidade do magma, levando à flutuação e ascensão de megacristais de microclina no magma residual, com alojamento de leucogranitos e pegmatitos nos estágios finais da evolução deste plutonismo. Por outro lado, em toda a metade Leste do plúton, encontra-se um rico acervo de estruturas tectógenas de cisalhamento, relacionada à implantação da Zona de Cisalhamento Transcorrente Santa Rosa, que levou a transformações tectonometamórficas superpostas às feições magmáticas, as quais atingiram condições metamórficas máximas na fácies anfibolito baixo. Cartograficamente, foram individualizados três domínios estruturais em que estão presentes uma gama de variações petroestruturais do Granito Chaval, sejam feições texturais/estruturais ígneas e tectônicas. As rochas plutônicas foram deformadas e modificadas progressivamente à medida que se dirige para Leste, no qual as rochas mudam-se para tonalidades mais escuras do cinza e os processos de cominuição e recristalização dinâmica reduzem, progressivamente, a granulação grossa desses granitos bem como o tamanho dos fenocristais para dimensões mais finas, mantendo-se suas características porfiroides. Desse modo, a trama milonítica se torna evidente, acentuando-se ao atingir a porção principal da Zona de Cisalhamento Transcorrente Santa Rosa. Como principais feições estruturais, destacam-se extinção ondulante forte; encurvamento e segmentação de cristais; geminação de deformação; rotação de cristais; microbudinagem; foliação anastomosada, inclusive S-C; lineação de estiramento; formas amendoadas de porfiroclastos, fitas e folhas de quartzo e recristalização. Os produtos desses processos de cisalhamento resultam na formação de protomilonitos, milonitos e ultramilonitos. Essas faixas miloníticas representam os locais de maior concentração da deformação, por isso é possível acompanhar progressivamente suas modificações texturais e mineralógicas, configurando uma sequência clássica de deformação progressiva heterogênea, por cisalhamento simples, em condições frágil-dúctil e dúctil. O alojamento do Granito Chaval aconteceu no final do Criogeniano (aproximadamente 630 Ma) e pode ser interpretado como magmatismo sin a tardi-tectônico em relação ao evento Brasiliano. O processo de cisalhamento que gerou a Zona de Cisalhamento Transcorrente Santa Rosa se formou nos incrementos finais da deformação de uma colisão continental em um sistema de cavalgamento oblíquo, em que se edificou o Cinturão de Cisalhamento Noroeste do Ceará, devido ao extravasamento lateral de massas crustais em fluxo dúctil acontecido no final da orogenia Brasiliana no Noroeste da Província Borborema.

Reconhecimento da tectônica mezozóica-cenozóica na borda leste da Bacia do Paraná através da aplicação de traços de fissão em apatitas no Domo de Pitanga (Sudoeste de Rio Claro, SP)

A tectônica Mesozóica-Cenozóica na borda leste da Bacia do Paraná foi interpretada com base no estudo geocronológico de uma importante feição estrutural conhecida como Domo de Pitanga (sudoeste de Rio Claro, SP), que, como outras estruturas do mesmo tipo presentes na borda da bacia, coincide com grandes alinhamentos estruturais formados pela reativação de estruturas preexistentes no seu embasamento. O método utilizado foi o de datação por análise de traços de fissão em apatitas, o qual permite a modelagem térmica entre 120oC e a temperatura ambiente. Utilizando apatitas de rochas sedimentares, foi possível a modelagem da história térmica da área, graças à homogeneidade dos dados que cada amostra apresentou em função do aquecimento no Eocretáceo pelo magmatismo Serra Geral. Além do resfriamento posterior ao magmatismo marcado pelas idades (Eocretáceo), foram detectadas as principais épocas de resfriamento na área de estudo, sendo elas do Neocretáceo, Paleoceno e, com menor importância, do Mioceno. Estes períodos remontam a importantes eventos tectônicos ocorridos no Sudeste brasileiro, bem descritos no embasamento cristalino. Fica clara a influência desta tectônica de caráter ascensional do embasamento adjacente no interior da bacia, atuando na formação de estruturas, como é o caso do Domo de Pitanga.

Nutrição potássica em soqueira de cana-de-açúcar colhida sem queima

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Mapeamento da ilha da Trindade, Atlântico Sul

The area chosen for this study is the island of Trinidade, which is located 1167 km off the Brazilian coast, in parallel Victory at 20 ° 30'S and 29 º 19'W, being the most easterly point of our continent. The isolation of oceanic island of Trinidade leaves no noticeable that she is part of a large submarine volcanic chain oriented east-west lineament known as Vitória- Trindade. Along with the island of Martin Vaz, who is Federal Territory is administered by the Navy of Brazil. Both correspond to Source alkaline volcanic islands. The area of the island of Trinidad has approximately 10 km2. Geologically consisting ankaratritic spills, spills tannbuschiticos, volcanic tuff spills analcite-ankaratrite, phonolite spills, spills nefelinite, pyroclastics, spills grazinite, tinguaitos, olivine-analcitito, calcarenite dunes and wind according to Almeida (1961). The island has its base on the ocean floor, at 5,800 m depth. It is the only place still recognizes preserved volcanic necks and plugs, as well as remnants of a volcano in Brazil. Magmatism occurred here a sodium alkali-silica subsaturated where his wrist was last 50,000 years according to Almeida (1961). It is a place with restricted access due to their distance from the coast, his contribution and hard to be an exclusive area of the Navy. On the island with peaks occur up to 620 meters high, and its rugged mountainous terrain and difficult access to very specific points, as the peak of Desire, peak Fazendinha, Monument and other points on the island. Because of its location far from the coast, its small infrastructure, difficulty of landing and restricted access by sea, the island of Trinidad offers no possibility of tourism, being a military outpost, and scientific basis of great importance, which conduct research in area of marine biology, oceanography, geology and others

Radioatividade e hidroquímica em águas subterrâneas do município de Botucatu (SP)

The main objective of this study is to determine the activity of Po-210, Pb-210 and gross alpha/beta radioactivity in groundwater collected in Botucatu, municipality of the São Paulo state, Brazil. Samples were collected in wells to perform the radiochemical analysis. Most wells are registered in DAEE, Sabesp or CPRM. The activity of polonium was obtained by the method of alpha spectrometry, held in LABIDRO at UNESP, Rio Claro. All samples showed radioactivity values below the maximum allowed by WHO, that are: gross alpha radioactivity = 0,5 Bq/L, gross beta radioactivity = 1,0 Bq/L, Po210 = 0,2 Bq/L and Pb210 = 0,1 Bq/L. The results of hydrochemical analysis were compared with the 1469 Ordinance of the Health Ministry, and all values are bellow the maximum allowed. The data also allowed obtain the samples classification using the Piper diagram. The samples AAB, Quinta do Manacás, Faz. Quatro Irmãs, Sesi, Sitio São José and ITE are classified as calcic bicarbonate; the samples Staroup and Caio are potassic; the samples Banespa and BTC are bicarbonate and mixed interms of dissolved cations; Sitio das Palmeiras sample is sodium bicarbonate; the sample Faz. São Paulo is chlorinated calcic; the sample Sítio Btu-Pardinho chlorinated and mixed interms of dissolved cations

Quimioestratigrafia do vulcanismo ácido mesozóico da província magmática do Paraná: porção SE do estado de Santa Catarina

The Mesozoic acid volcanism of the Paraná-Etendeka Province can be considered as one of the biggest events of its kind in the Earth's surface, and its study have attracted special interest in characterizing the end of magmatism that preceded the rupture process and the formation of continental Africa and South America Although significant, the acid volcanism featuring Members Chapecó Palmas and Serra Geral Formation represents only 2.5% of the total generated by the magmatic rocks and perhaps therefore the existing literature on these rocks is well less significant than that on the basalts. However, there are still aspects still unclear about the origin and evolution of these rocks in relation to the associated basalts. Thus, two profiles were selected, called RA and TA, which be a systematic collection of samples from the base where the Botucatu Formation sandstones occur at the top, where they observe Palmas acid rock type. These samples should be analyzed for major, minor and trace elements and treated in specific diagrams to define the vertical variation lithochemistry and their possible relationships with the associated basalts

Fontes potássicas na produção do pimenteiro em substrato fertirrigado

Pós-graduação em Agronomia (Horticultura) - FCA

Geochemistry and Pb-207/Pb-206 zircon ages of granitoids from the southern portion of the Tamboril-Santa Quiteria granitic-migmatitic complex, Ceara Central Domain, Borborema Province (NE Brazil)

The Tamboril-Santa Quiteria Complex is an important Neoproterozoic granitic-migmatitic unit from the Ceara Central Domain that developed from ca. 650 to 610 Ma. In general the granitoids range in composition from diorite to granite with predominance (up to 85%) of granitic to monzogranitic composition with biotite as the main mafic AFM phase. Geochemical and Pb-207/Pb-206 evaporation zircon geochronology studies were applied in a group of these abundant monzogranitic rocks from the region of Novo Oriente in the southern portion of the Ceara Central Domain. In this area the granitoids are weakly peraluminous biotite granitoids and deformed biotite granitoids of high-K calc-alkaline and ferroan composition, which we interpreted as primary magmas (segregated diatexites) derived from the partial melting of crustal material. The close temporal relation of this magmatism with local eclogitic and regional high temperature metamorphism in Ceara Central Domain point out to an orogenic setting, arguably emplaced during the collisional stage. Subordinate coeval juvenile mantle incursions are also present. This crustally derived magmatism is the primary product of the continental thickening that resulted from the collision between the rocks represented by the Amazonian-West African craton (Sao Luiz cratonic fragment) to the northwest and the Paleoproterozoic-Archean basement of the Borborema Province to the southeast along the Transbrasiliano tectonic corridor. (C) 2011 Elsevier Ltd. All rights reserved.

Petrogenesis of syntectonic granites emplaced at the transition from thrusting to transcurrent tectonics in post-collisional setting: Whole-rock and Sr-Nd-Pb isotope geochemistry in the Neoproterozoic Quatro Ilhas and Mariscal Granites, Southern Brazil

The Neoproterozoic post-collisional period in southern Brazil (650-580 Ma) is characterized by substantial volumes of magma emplaced along the active shear zones that compose the Southern Brazilian Shear Belt. The early-phase syntectonic magmatism (630-610 Ma) is represented by the porphyritic, high-K, metaluminous to peraluminous Quatro Ilhas Granitoids and the younger heterogranular, slightly peraluminous Mariscal Granite. Quatro II has Granitoids include three main petrographic varieties (muscovite-biotite granodiorite mbg; biotite monzogranite - bmz: and leucogranite - lcg) that, although sharing some significant geochemical characteristics, are not strictly comagmatic, as shown by chemical and Sr-Nd-Pb isotope data. The most primitive muscovite-biotite granodiorite was produced by contamination of more mafic melts (possibly with some mantle component) with peraluminous crustal melts; the biotite monzogranite, although more felsic, has higher Ca, MgO,TiO2 and Ba, and lower K2O, FeOt, Sr and Rb contents, possibly reflecting some mixing with coeval mafic magmas of tholeiitic affinity; the leucogranite may be derived from pure crustal melts. The Mariscal Granite is formed by two main granite types which occur intimately associated in the same pluton, one with higher K (5-6.5 wt.% K2O) high Rb and lower CaO, Na2O, Ba and Zr as compared to the other (3-5 wt.% of K2O). The two Mariscal Granite varieties have compositional correspondence with fine-grained granites (fgg) that occur as tabular bodies which intruded the Quatro Ilhas Granoitoids before they were fully crystallized, and are inferred to correspond to the Mariscal Granite feeders, an interpretation that is reinforced by similar U-Pb zircon crystallization ages. The initial evolution of the post-collisional magmatism, marked by the emplacement of the Quatro Ilhas Granitoids varieties, activated sources that produced mantle and crustal magmas whose emplacement was controlled both by flat-lying and transcurrent structures. The transition from thrust to transcurrent-related tectonics coincides with the increase in the proportion of crustal-derived melts. The transcurrent tectonics seems to have played an essential role in the generation of mantle-derived magmas and may have facilitated their interaction with crustal melts which seem to be to a large extent the products of reworking of orthogneiss protoliths. (C) 2012 Elsevier B.V. All rights reserved.

A new Pennsylvanian Oriocrassatellinae from Brazil and the distribution of the genus Oriocrassatella in space and time

Oriocrassatella Etheridge Jr., 1907 is a long range crassatellid bivalve genus well recognized in shallow waters of epeiric seas throughout the upper part of Paleozoic. The first occurrences of this genus are recorded in the sedimentary successions of the Gondwana, both in Australia and South America. However, the geographic and age distribution of Oriocrassatella in Late Mississippian deposits of Australia and Argentina may indicate an earliest Visean or even a pre-Visean origin for the genus. Following its origin in Early Carboniferous a complex paleobiogeographic history from Southern to Northern Hemisphere took place in the Permian. During its initial dispersal phase from Late Carboniferous to the Early Permian the genus thrived in cold water environments associated to the Late Paleozoic Gondwana glaciation. Shallow-water bottoms of the warm waters of the central Gondwana fringe and Laurussia were colonized by Oriocrassatella only during Early Permian times when the genus became cosmopolitan. A new species of this genus is described herein, Oriocrassatella piauiensis n. sp., recorded from the Piaui Formation, Pennsylvanian of the Parnaiba Basin. This new species may represent an early adaptation to warm waters. However, based on available data, species of this genus seem to have adapted definitely to warm water environments probably related the Late Pennsylvanian interglacial phases. In these phases, climatic barrier were interrupted allowing the faunal interchange and larval dispersion following a South to North migration route through the eastern margins of Gondwana and the eastern Paleotethys.

Re-Os isotope and highly siderophile element systematics of the Parana continental flood basalts (Brazil)

Basalts of the Parana continental flood basalt (PCFB) province erupted through dominantly Proterozoic continental crust during the Cretaceous. In order to examine the mantle source(s) of this major flood basalt province, we studied Os, Sr, Nd, and Pb isotope systematics, and highly siderophile element (HSE) abundances in tholeiitic basalts that were carefully chosen to show the minimal effects of crustal contamination. These basalts define a precise Re-Os isochron with an age of 131.6 +/- 2.3 Ma and an initial Os-187/Os-188 of 0.1295 +/- 0.0018 (gamma Os-187 = +2.7 +/- 1.4). This initial Os isotopic composition is considerably more radiogenic than estimates of the contemporary Depleted Mantle (DM). The fact that the Re-Os data define a well constrained isochron with an age similar to Ar-40/Ar-39 age determinations, despite generally low Os concentrations, is consistent with closed-system behavior for the HSE. Neodymium, Sr, and Pb isotopic data suggest that the mantle source of the basalts had been variably hybridized by melts derived from enriched mantle components. To account for the combined Os, Nd, Sr, and Pb isotopic characteristics of these rocks, we propose that the primary melts formed from metasomatized asthenospheric mantle (represented by arc-mantle peridotite) that underwent mixing with two enriched components, EM-I and EM-II. The different enriched components are reflected in minor isotopic differences between basalts from southern and northern portions of the province. The Tristan da Cunha hotspot has been previously suggested to be the cause of the Parana continental flood basalt magmatism. However, present-day Tristan da Cunha lavas have much higher Os-187/Os-188 isotopic compositions than the source of the PCFB. These data, together with other isotopic and elemental data, preclude making a definitive linkage between the Tristan plume and the PCFB. (C) 2012 Elsevier B.V. All rights reserved.

Investigation of the Goias Alkaline Province, Central Brazil: Application of gravity and magnetic methods

We investigate the strong magnetic and gravity anomalies of the Goias Alkaline Province (GAP), a region of Late Cretaceous alkaline magmatism along the northern border of the Parana Basin, Brazil. The alkaline complexes (eight of which are present in outcrops, two others inferred from magnetic signals) are characterized by a series of small intrusions forming almost circular magnetic and gravimetric anomalies varying from -4000 to +6000 nT and from -10 to +40 mGal, respectively. We used the Aneuler method and Analytical Signal Amplitude to obtain depth and geometry for mapped sources from the magnetic anomaly data. These results were used as the reference models in the 3D gravity inversion. The 3D inversion results show that the alkaline intrusions have depths of 10-12 km. The intrusions in the northern GAP follow two alignments and have different sizes. In the anomaly magnetic map, dominant guidelines correlate strongly with the extensional regimes that correlate with the rise of alkaline magmatism. The emplacement of these intrusions marks mechanical discontinuities and zones of weakness in the upper crust. According to the 3D inversion results, those intrusions are located within the upper crust (from the surface to 18 km depth) and have spheres as the preferable geometry. Such spherical shapes are more consistent with magmatic chambers instead of plug intrusions. The Registro do Araguaia anomaly (similar to 15 by 25 km) has a particular magnetic signature that indicates that the top is deeper than 1500 m. North of this circular anomaly are lineaments with structural indices indicating contacts on their edges and dikes/sills in the interiors. Results of 3D inversion of magnetic and gravity data suggest that the Registro do Araguaia is the largest body in the area, reaching 18 km depth and indicating a circular layered structure. (C) 2011 Elsevier Ltd. All rights reserved.

U-Pb zircon ages of orthogneisses and supracrustal rocks of the Cariris Velhos belt: Onset of Neoproterozoic rifting in the Borborema Province, NE Brazil

New geochronological and geochemical constraints on Precambrian sedimentary and volcanic successions exposed in the western part of the Central Domain of the Borborema Province, NE Brazil, indicate the presence of two distinct tectono-stratigraphic complexes: Riacho Gravata and Sao Caetano. Both complexes and associated orthogneisses are referred in the literature as the Cariris Velhos belt, having depositional, extrusive, or intrusive ages within the interval 985-913 Ma. The Riacho Gravata complex consists of bimodal (but mostly felsic) volcanic and volcanoclastic rocks, muscovite+/-graphite schists, quartzites, and marble with local occurrences of banded-iron-formation. The Sao Caetano complex mainly consists of metagreywackes, marbles, calc-silicate rocks, and rare meta-mafic rocks. Meta-mafic rocks from both complexes have geochemical signatures similar to those of continental flood basalts, with epsilon Nd (1.0 Ga) values ranging from -1.0 to -2.8. Felsic volcanic rocks from the Riacho Gravata complex show epsilon Nd (1.0 Ga) values ranging from -1.0 to -7.4 and geochemical signatures similar to A(2)-type granitoids. New SHRIMP U-Pb zircon data from felsic volcanic rocks within the Riacho Gravata complex yielded ages of 1091 +/- 13 Ma and 996 +/- 13 Ma. In contrast, meta-graywackes from the Sao Caetano complex show a maximum deposition age of ca. 806 Ma in the northern part and ca. 862 Ma in the southern part of the outcrop area. The orthogneisses show epsilon Nd (1.0 Ga) values ranging from 1.0 to -4.2 with U/Pb TIMS and SHRIMP ages ranging from 960 to 926 Ma and geochemical signatures of A(2)-type granitoids. The data reported in this paper suggest at least two periods of extension within the Central Domain of the Borborema Province, the first starts ca. 1091 Ma with magmatism and deposition, creating the Riacho Gravata basin and continued intrusion of A-type granites to 920 Ma. A second rift event, which reactivated old faults, generated a basin with a maximum deposition age of ca. 806 Ma. Furthermore, the oldest granitoids cutting these metasedimentary rocks have crystallization ages of ca. 600 Ma. This suggests that the second rift event could be early Brasiliano in age. The resulting Sao Caetano basin received detritus from a variety of sources, although detritus from the Riacho Gravata complex dominated. Deposition ages of the Riacho Gravata and the Sao Caetano complexes are coeval with deposits in other basins of the Borborema Province (Riacho do Tigre in the Central Domain; Macurure and Maranco in the Sergipano Belt of the Southern domain). The Macaubas Group from SE Brazil and its counterparts in Africa, the Zadanian and Mayumbian Groups, in the western edge of the Congo Craton are also coeval. Closure of the Riacho Gravata and Sao Caetano basins occurred during the Brasiliano convergence (705-600 Ma). During the last stage of convergence, ca. 612 Ma, pull-apart basins were created and filled; final basin closure took place 605-592 Ma, after deposition ceased. (C) 2011 Elsevier B.V. All rights reserved.

Metamorfismo ercinico di bassa-pressione: evoluzione tettonico-metamorfica del complesso di mandatoriccio (massiccio della Sila - Calabria)

Low-pressure/high-temperature (LP/HT) metamorphic belts are characterised by rocks that experienced abnormal heat flow in shallow crustal levels (T > 600 °C; P < 4 kbar) resulting in anomalous geothermal gradients (60-150 °C/km). The abnormal amount of heat has been related to crustal underplating of mantle-derived basic magmas or to thermal perturbation linked to intrusion of large volumes of granitoids in the intermediate crust. In particular, in this latter context, magmatic or aqueous fluids are able to transport relevant amounts of heat by advection, thus favouring regional LP/HT metamorphism. However, the thermal perturbation consequent to heat released by cooling magmas is responsible also for contact metamorphic effects. A first problem is that time and space relationships between regional LP/HT metamorphism and contact metamorphism are usually unclear. A second problem is related to the high temperature conditions reached at different crustal levels. These, in some cases, can completely erase the previous metamorphic history. Notwithstanding this problem is very marked in lower crustal levels, petrologic and geochronologic studies usually concentrate in these attractive portions of the crust. However, only in the intermediate/upper-crustal levels of a LP/HT metamorphic belt the tectono-metamorphic events preceding the temperature peak, usually not preserved in the lower crustal portions, can be readily unravelled. The Hercynian Orogen of Western Europe is a well-documented example of a continental collision zone with widespread LP/HT metamorphism, intense crustal anatexis and granite magmatism. Owing to the exposure of a nearly continuous cross-section of the Hercynian continental crust, the Sila massif (northern Calabria) represents a favourable area to understand large-scale relationships between granitoids and LP/HT metamorphic rocks, and to discriminate regional LP/HT metamorphic events from contact metamorphic effects. Granulite-facies rocks of the lower crust and greenschist- to amphibolite-facies rocks of the intermediate-upper crust are separated by granitoids emplaced into the intermediate level during the late stages of the Hercynian orogeny. Up to now, advanced petrologic studies have been focused mostly in understanding P-T evolution of deeper crustal levels and magmatic bodies, whereas the metamorphic history of the shallower crustal levels is poorly constrained. The Hercynian upper crust exposed in Sila has been subdivided in two different metamorphic complexes by previous authors: the low- to very low-grade Bocchigliero complex and the greenschist- to amphibolite-facies Mandatoriccio complex. The latter contains favourable mineral assemblages in order to unravel the tectono-metamorphic evolution of the Hercynian upper crust. The Mandatoriccio complex consists mainly of metapelites, meta-arenites, acid metavolcanites and metabasites with rare intercalations of marbles and orthogneisses. Siliciclastic metasediments show a static porphyroblastic growth mainly of biotite, garnet, andalusite, staurolite and muscovite, whereas cordierite and fibrolite are less common. U-Pb ages and internal features of zircons suggest that the protoliths of the Mandatoriccio complex formed in a sedimentary basin filled by Cambrian to Silurian magmatic products as well as by siliciclastic sediments derived from older igneous and metamorphic rocks. In some localities, metamorphic rocks are injected by numerous aplite/pegmatite veins. Small granite bodies are also present and are always associated to spotted schists with large porphyroblasts. They occur along a NW-SE trending transcurrent cataclastic fault zone, which represents the tectonic contact between the Bocchigliero and the Mandatoriccio complexes. This cataclastic fault zone shows evidence of activity at least from middle-Miocene to Recent, indicating that brittle deformation post-dated the Hercynian orogeny. P-T pseudosections show that micaschists and paragneisses of the Mandatoriccio complex followed a clockwise P-T path characterised by four main prograde phases: thickening, peak-pressure condition, decompression and peak-temperature condition. During the thickening phase, garnet blastesis started up with spessartine-rich syntectonic core developed within micaschists and paragneisses. Coevally (340 ± 9.6 Ma), mafic sills and dykes injected the upper crustal volcaniclastic sedimentary sequence of the Mandatoriccio complex. After reaching the peak-pressure condition (≈4 kbar), the upper crust experienced a period of deformation quiescence marked by the static overgrowths of S2 by Almandine-rich-garnet rims and by porphyroblasts of biotite and staurolite. Probably, this metamorphic phase is related to isotherms relaxation after the thickening episode recorder by the Rb/Sr isotopic system (326 ± 6 Ma isochron age). The post-collisional period was mainly characterised by decompression with increasing temperature. This stage is documented by the andalusite+biotite coronas overgrown on staurolite porphyroblasts and represents a critical point of the metamorphic history, since metamorphic rocks begin to record a significant thermal perturbation. Peak-temperature conditions (≈620 °C) were reached at the end of this stage. They are well constrained by some reaction textures and mineral assemblages observed almost exclusively within paragneisses. The later appearance of fibrolitic sillimanite documents a small excursion of the P-T path across the And-Sil boundary due to the heating. Stephanian U-Pb ages of monazite crystals from the paragneiss, can be related to this heating phase. Similar monazite U-Pb ages from the micaschist combined with the lack of fibrolitic sillimanite suggest that, during the same thermal perturbation, micaschists recorded temperatures slightly lower than those reached by paragneisses. The metamorphic history ended with the crystallisation of cordierite mainly at the expense of andalusite. Consequently, the Ms+Bt+St+And+Sill+Crd mineral assemblage observed in the paragneisses is the result of a polyphasic evolution and is characterised by the metastable persistence of the staurolite in the stability fields of the cordierite. Geologic, geochronologic and petrographic data suggest that the thermal peak recorded by the intermediate/upper crust could be strictly connected with the emplacement of large amounts of granitoid magmas in the middle crust. Probably, the lithospheric extension in the relatively heated crust favoured ascent and emplacement of granitoids and further exhumation of metamorphic rocks. After a comparison among the tectono-metamorphic evolutions of the different Hercynian crustal levels exposed in Sila, it is concluded that the intermediate/upper crustal level offers the possibility to reconstruct a more detailed tectono-metamorphic history. The P-T paths proposed for the lower crustal levels probably underestimate the amount of the decompression. Apart from these considerations, the comparative analysis indicates that P-T paths at various crustal levels in the Sila cross section are well compatible with a unique geologic scenario, characterized by post-collisional extensional tectonics and magmas ascent.