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A magnetic fabric study was performed on the Redenção pluton in an attempt to understand its emplacement history. The Redenção pluton is part of the 1.88 Ga, anorogenic, A-type Jamon suite that intruded 2.97-2.86 Ga-old Archean granitoids of the Rio Maria Granite-Greenstone Terrane in the eastern Amazonian craton (northern Brazil). Previous gravity survey indicates that the pluton is a 6 km-thick, tabular intrusion. It is characterized by a concentric distribution of facies, with rings of seriated and porphyritic granite that cut across the main facies of even-grained monzogranites. The whole set is intruded by leucogranites that occupy the center of the pluton. Petrographic examination, magnetic susceptibilities, coercivity-spectra and thermomagnetic curves indicate that the magnetic fabric is primarily carried by coarse-grained multidomain magnetite. This is reinforced by the coincidence of magnetic susceptibility and remanence anisotropy principal axes. The absence of solid-state deformation features and the low anisotropy degrees indicate that the magnetic fabric is magmatic in origin. The magnetic fabric displays a systematic pattern, with all facies, including the rings of porphyritic granite, being characterized by concentric, gently dipping foliations associated with gently plunging lineations. Only the central leucogranitic facies shows a slightly discordant pattern with steeply dipping fabrics at its northeastern sector. An emplacement model by vertical stacking of successive magma batches is proposed for the construction of the Redenção pluton, which reconciles the tabular shape of the intrusion, the petrographic and geochemical zoning, and the magnetic fabric pattern. Initially, two magma batches were emplaced as sills. First the even-grained monzogranite, then the seriated and porphyritic granites, which formed by mingling of a leucogranitic melt with the host biotite-monzogranitic magma as attested by geochemical data and field evidence. The final shape of the pluton was acquired after the intrusion and inflation of the central leucogranite giving raise to the concentric pattern of facies in map view.

Leucocratoblastic metablastic rock series and their derivatives (known as granite/granitoid, gabbro/gabbroid, diorite/dioritoid, charnockite/charnockite and carbonatite/carbonatoid intrusions, plutons and batholiths of magmatic origin), which are a type of new modern metamorphic rocks, developed within the regional dynamothermal Tarhan metamorphism cycle, and are in the Abukuma type reversed regional regressive dynamothermal metamorphism type/stage where temperatures are effective compared to pressures (T>P, temperatures mark the metamorphism); The pre-exiting primary source rock units (cosmic upper mantle peridotites, continental magmatic rock sequence/ocean crust sequence/ophiolite series, ensialic-ensimatic island arc origin volcanosedimentary series, volcanic and different sedimentary rock units etc.) formed at different ages, origins and environments and the classical metamorphic equivalent of Barrow type regional progressive dynamo-thermal metamorphism where the pressures are effective compared to the temperatures of the primary source rock units (P>T, pressures mark the metamorphism) within different metamorphic rocks (micacite, amphibolite, marble etc.) are derived from them in solid phase and in-situ (autochthonous where they exist). Modern leucocratoblastic metablastic rock series and derivatives of metamorphic origin; They correspond to modern metamorphic rocks that are different in physical properties (texture, structure, color, mineralogical composition) from the known classical metamorphic rocks (mica schist, amphibolite, marble, etc.) of the known classical regional progressive dynamo-thermal metamorphism (also known as the single type, single component, unidirectional regional metamorphism that forms metamorphic belts) of the previously existing (pre-exiting) primary source rocks from which they were derived in solid phase and insitu; but have the same chemical composition, are allotropic and a kind of new generation (3rd generation metamorphic source material/rock/minerals, etc.). In other words; modern leucocratoblastic metablastic rock series and their derivatives of metamorphic origin have developed as a result of the allotropic phase change of previously existing (pre-exiting) solid matter/rock/minerals in the regional dynamothermal Tarhan metamorphism cycle into another new generation (3rd generation) solid matter/rock/minerals with different physical properties in the solid phase and in-situ but the same chemical composition. This phase change, which occurs with the change and transformation of solid matter/rock/minerals in the solid phase and in-situ to allotropic new matter/rock/minerals in another solid phase, was first defined and named as superionic metablastic solid matter/rock/minerals. For this reason; granite mineralogical composition enriched and dominant superionic metablastic solid leucocratoblastic metablastic rock series and derivatives and superionic metablastic solid rock forming felsicoblast crystalloblast neominerals correspond to the 5th state of matter. Superionic metablastic solid matter/metablastic rock/crystalloblast neominerals corresponding to the 5th state of the mineral have developed spontaneously in the natural environment and under natural conditions. They have not developed under any external influence, coercion, intervention or extraordinary conditions (artificial means in a laboratory environment). They have been included in the classical states of matter (solid, liquid, gas, plasma) that can be seen in our daily lives as the 5th state of matter. Or, they should be accepted and proposed as a separate, new modern 5th state of matter.

In the Variscan fold belt of Morocco, the Jebilet massif is characterized by Palaeozoic metasedimentary rocks intruded by syntectonic magmatism that includes an ultramafic-granitoid bimodal association and peraluminous granodiorites emplaced c. 330 Ma, intruded by younger leucogranites c. 300 Ma. The mafic-ultramafic rocks belong to a tholeiitic series, and display chemical and isotopic signatures consistent with mixing between mantle-derived and crust-derived magmas or assimilation and fractional crystallization. The granites within the bimodal association are mainly metaluminous to weakly peraluminous microgranites that show characteristics of A 2 -type granites. The peraluminous, calc-alkaline series consists mainly of cordierite-bearing granodiorites enclosing magmatic microgranular enclaves and pelitic xenoliths. Detailed element and isotope data suggest that the alkaline and the peraluminous granitoids were formed in the shallow crust (<30 km) by partial melting of tonalitic sources at high temperatures (up to 900°C) and by partial melting of metasedimentary protoliths at relatively low temperatures (c. 750°C), respectively. Mixing between the coeval mantle-derived and crust-derived magmas contributed to the large variation of initial ɛ Nd values and initial Sr isotopic ratios observed in the granitoids. Further contamination occurred by wall-rock assimilation during ascent of the granodioritic plutons to the upper crust. The ultramafic-granitoid association has been intruded by leucogranites that have high initial Sr isotopic ratios and low initial ɛ Nd values, indicating a purely crustal origin. The heating events that caused emplacement of the Jebilet magmatism are related to cessation of continental subduction and convective erosion/thinning of the lithospheric mantle during plate convergence.

Journal of Earth System Science

We report the monazite dates of the granulites from Daltonganj (Palamau), Chhotanagpur granite-gneiss complex (CGGC) which covers the significant part of the granulite blocks in central India by using an electron micro probe analyser dating. The monazite grain varies between 70 and 80 lm and shows the distribution of U, Th and Pb in all monazite grains of both samples. Two different dates were obtained from different monazite grains; the first age suggests that the granulite from CGGC preserves the first remnant of the protolith of the Mesoproterozoic era at *1424 Ma and second one at *972 Ma which provides evidence of metamorphism of the protolith. The CGGC rocks preserve four regional metamorphic events, namely M 1 , M 2 , M 3 and M 4. But in this work, two different ages from the Daltonganj granulites were obtained which are similar to the M 2 (\1500 Ma, i.e., the age of protolith of the granulitic gneiss) and M 3 (1200-930 Ma) metamorphic events as reported in the CGGC. The M 3 metamorphism attained its average P-T condition at *7.35 kbar/792°C, and it represents the prograde metamorphic event. The M 3 metamorphic event supported the Grenville-orogeny, and it was responsible for the metamorphism of the magmatic protolith of granulitic gneiss from the CGGC at the time of amalgamation of the Rodinia supercontinent. The Rodinia assembly had occurred through the global Grenville-orogenic events between 1100 and 900 Ma, with continental blocks which exist at that time.

We present major and trace element analyses combined with U-Pb zircon crystallization ages from an intermediate to granitic intrusion sequence within the Dur Kan Complex, in the Iranian North Makran. The sampled granites-diorites-trondhjemites-plagiogranites and basaltic to andesitic lavas have tholeiitic and calc-alkaline chemical features. Field observations, petrographic relationships, trace element compositions and isotope chemistry indicate three different melt sources for granites, granitoids and the volcanic rocks. Granites yield 170-175Ma ages and represent the last crystallized melt of a continentally derived magma. The fractional crystallization dominated diorite-trondhjemite-plagiogranite sequence was crystallizing over 12Ma (165-153Ma) from the same source which has a mantle and minor continental component. East-west trending mafic dykes intruded the granitoids, which were eroded before being covered by lavas and their Cretaceous (Valangian) sedimentary cover. The source of dykes and lavas is mantle derived. Temporal correlation with plutonites from the Sanandaj-Sirjan Zone suggests a narrow northwest-southeast striking belt of Jurassic granitoid intrusions that extends over nearly 2000km. Different than previous studies in the Sanandaj-Sirjan Zone, that interpreted these rocks as a magmatic arc and proof for Jurassic subduction of the Neotethys, we suggest extension, that separated the Sanandaj-Sirjan Zone and Central Iran. The increasing mantle inf luence in the magma source is explained by continuous thinning of continental crust and related mantle up-welling. This extensional phase resulted in the formation of the North Makran Ophiolites.

Petrology and Structural Geology, 1997

Information theory, proposed originally by Shannon (1948), has been applied to the formation of granitoid rocks. Application of the theory allows the four main elements involved in granite formation viz.: partial melting (M), melt segregation (S), magma ascent (A) and emplacement (E) to be analysed qualitatively as a single, holistic process. The information content (chemical, isotopic and mineralogical) is contained in the magma, and the received message is the crystallised pluton. Noise added (c.g., by tectonism, weathering or sample collection) can lead to distortion or even irretrievable loss of information. Against this is the energy introduced into the system by the observer. Defining the message to be transmitted during granitoid formation as the initial composition of the partial melt (Hs), the total information or entropy content (H') preserved in an exposed granitic pluton can be expressed symbolically as:

Syn-collisional granite in the northern part of the Birnin Gwari schist belt consists dominantly of granite and lesser granodiorite and quartzolite. Petrographic and ge¬ochemical data revealed three granite groups: the biotite-hornblende granite (quartzolite-BHG); the biotite granite (BG) and the biotite-muscovite granite (BMG). The rocks generally have calc-alkaline and high-K calc-alkaline affinities, and calc-alkalic to alkali-calcic, peraluminous and ferroan and magnesian geochemistry. They are characterized by LILE enrichment, high LREE fractionation factor [(La/Yb) (6.74 to 45.14] with weak to moderate negative Eu (Eu/Eu* = 0.38 to 0.62) and strong negative Nb, P and Ti anomalies. Variation in the behavior of lithophile elements (Ba, Sr and Rb) revealed diverse granite trend such as "high and low Ba-Sr"; "normal", "anomalous" "strongly differentiated" and "granodiorite and quartz diorite" granite. Their display of similar trace elements and REE patterns suggest they are cogenetic. Major and trace element data indicate differentiation of a mafic magma and partial melting of crustal components inherited from shale-greywacke and quartzose sedimentary protoliths in volcanic arc and post collisional settings. The field and geochemical characteristics of this granite suggest that they are similar to other granites in schist belts in other parts of Nigeria, forming the lateral continuation of the same Pan-African magmatic belt.