http://www.sciencedirect.com/science/article/pii/S1674987112001296

We present field, petrographic, major and trace element data for komatiites and komatiite basalts from Sargur Group Nagamangala greenstone belt, western Dharwar craton. Field evidences such as crude pillow structure indicate their eruption in a marine environment whilst spinifex texture reveals their komatiite nature. Petrographic data suggest that the primary mineralogy has been completely altered during post-magmatic processes associated with metamorphism corresponding to greenschist to lower amphibolite facies conditions. The studied komatiites contain serpentine, talc, tremolite, actinolite and chlorite whilst tremolite, actinolite with minor plagioclase in komatiitic basalts. Based on the published Sm-Nd whole rock isochron ages of adjoining Banasandra komatiites (northern extension of Nagamangala belt) and further northwest in Nuggihalli belt and Kalyadi belt we speculate ca. 3.2–3.15 Ga for komatiite eruption in Nagamangala belt. Trace element characteristics particularly HFSE and REE patterns suggest that most of the primary geochemical characteristics are preserved with minor influence of post-magmatic alteration and/or contamination. About 1/3 of studied komatiites show Al-depletion whilst remaining komatiites and komatiite basalts are Al-undepleted. Several samples despite high MgO, (Gd/Yb)_N ratios show low CaO/Al₂O₃ ratios. Such anomalous values could be related to removal of CaO from komatiites during fluid-driven hydrothermal alteration, thus lowering CaO/Al₂O₃ ratios. The elemental characteristics of Al-depleted komatiites such as higher (Gd/Yb)_N (>1.0), CaO/Al₂O₃ (>1.0), Al₂O₃/TiO₂ (<18) together with lower HREE, Y, Zr and Hf indicate their derivation from deeper upper mantle with minor garnet (majorite?) involvement in residue whereas lower (Gd/Yb)_N (<1.0), CaO/Al₂O₃ (<0.9), higher Al₂O₃/TiO₂ (>18) together with higher HREE, Y, Zr suggest their derivation from shallower upper mantle without garnet involvement in residue. The observed chemical characteristics (CaO/Al₂O₃, Al₂O₃/TiO₂, MgO, Ni, Cr, Nb, Zr, Y, Hf, and REE) indicate derivation of the komatiite and komatiite basalt magmas from heterogeneous mantle (depleted to primitive mantle) at different depths in hot spot environments possibly with a rising plume. The low content of incompatible elements in studied komatiites suggest existence of depleted mantle during ca. 3.2 Ga which in turn imply an earlier episode of mantle differentiation, greenstone volcanism and continental growth probably during ca. 3.6–3.3 Ga which is substantiated by Nd and Pb isotope data of gneisses and komatiites in western Dharwar craton (WDC).     

http://www.sciencedirect.com/science/article/pii/S1674987113000340

Regional surface gravity data and global satellite magnetic data have been utilized to generate a preliminary model of the crustal structure along a southwest-northeast profile （Gadra-Fatehpur） through western Rajasthan.The study area represents the western part of the Indian continental landmass which has undergone several major episodes of repeated subduction/collision,plume traces and rifting from Archaean to recent times.The temporal and spatial relationship between the various geotectonic provinces is quite complex,thereby limiting the emergence of a suitable crustal structure model for this region.Exposures of the Malani Igneous Suite （MIS）,a product of bimodal volcanism （～780 Ma）,and considered to be the third largest felsic magmatic province of the world,is evident along the profile and also to the southwest of the study area.The easternmost part of the profile is close to the DAFB （Delhi Aravalli Fold Belt）,a Proterozoic orogenic belt.This study probes the geometry of the different crustal units in terms of density and susceptibility variations in order to decipher the imprints of the major tectonic processes the region has undergone.In order to decipher the crustal geometry of the Gadra-Fatehpur profile,two NW-SE gravity and magnetic profile vertical sections （A-A＇ in the south and B-B＇ in the north） are modelled on the basis of the constraints provided from previous seismic models.The crustal model of the Gadra-Fatehpur profile is composed of alluvium,Tertiary sediments,MIS,Marwar Supergroup,low-density layers （LDLs） and the middle-lower crustal layers,with a distinct change in configuration from the southwest to northeast.The Moho dips from SW to NE,the MIS in the SW gives way to the thick pile of the Marwar Supergroup to the NE.The evolution of MIS has been suggested to have occurred as a consequence of delamination of the upper mantle.LDLs are incorporated in Gadra-Fatehpur model.In the SW,LDL （2550 kg/m3） lies below the MIS in the NE,another LDL （2604 kg/m3） is depicted below the mid-crustal layer.     

http://www.sciencedirect.com/science/article/pii/S1674987114000681

We present the disaster-forced biological evolution model as a general framework that includes Darwinian "phylogenic gradualism",Eldredge-Gould's "punctuated equilibrium",mass extinctions,and allopatric.parapatric,and sympatric speciation.It describes how reproductive isolation of organisms is established through global disasters due to supernova encounters and local disasters due to radioactive volcanic ash fall-outs by continental alkaline volcanism.Our new evolution model uniquely highlights three major factors of disaster-forced speciation:enhanced mutation rate by higher natural radiation level,smaller population size,and shrunken habitat size(i.e.,isolation among the individual populations).We developed a mathematical model describing speciation of a half-isolated group from a parental group,taking into account the population size(N_e),immigration rate(m),and mutation rate(μ).The model gives a quantitative estimate of the speciation,which is consistent with the observations of speciation speed.For example,the speciation takes at least 10~5 generations,if mutation rate is less than10~(-3) per generation per individual.This result is consistent with the previous studies,in which μ is assumed to be 10~(-3)-10~(-5).On the other hand,the speciation is much faster(less than 10~5 generations)for the case that μ is as large as 0.1 in parapatric conditions(m μ).Even a sympatric(m ~ 1) speciation can occur within 10~3 generations,if mutation rate is very high(μ~1 mutation per individual per generation),and if N_e 20-30.Such a high mutation rate is possible during global disasters due to supernova encounters and local disasters due to radioactive ash fall-outs.They raise natural radiation level by a factor of 100-1000.Such rapid speciation events can also contribute to macro-evolution during mass extinction events,such as observed during the Cambrian explosion of biodiversity.A similar rapid speciation(though in a much smaller scale) also has been undergoing in cichlid fishes and great African apes in the last several tens of thousand years in the current African rift valley,including the origin of humankind due to the radioactive ash fall-outs by continental alkaline volcanism.     

The genesis of the slab window-related Arzular low-sulfidation epithermal gold mineralization （eastern Pontides, NE Turkey）

The Arzular mineralization is one of the best examples of epithermal gold deposits in the eastern Pontides orogenic belt.The mineralization is hosted by the subduction-related basaltic andesites and is mainly controlled by E-W and NE-SW trending fracture zones.The main ore minerals are galena, sphalerite,pyrite.chalcopyrite.tetrahedrite and gold.Homogenization temperatures of fluid inclusions are between 130 and 295℃ for quartz and between 90 and 133℃ for sphalerite.Sulphur isotope values obtained from pyrite,galena and sphalerite vary between 1.2‰ and 3‰.indicating that sulphur belongs to magmatic origin and was derived from the Lutetian non-adakitic granitic intrusions in the region.Oxygen isotope values are between 15.0‰ and 16.7‰ and hydrogen isotope values are between -87‰ and -91‰ The sulphur isotope thermometer yielded temperatures in the range of 244-291℃ for the ore formation.Our results support the hypothesis that the Arzular mineralization is a low-sulfidation epithermal gold deposit associated with non-adakitic subduction- related granitic magmas that were generated by slab window-related processes in a south-dipping subduction zone during the Lutetian.     

http://www.sciencedirect.com/science/article/pii/S1674987112000072

The Abor volcanics outcroping in the core of the Siang window in the Eastern Himalaya comprise voluminous mafic volcanics (47％-56％ w(SiO2)),with subordinate felsic volcanics (67％-75％ w(SiO2)).The felsi...     

http://www.sciencedirect.com/science/article/pii/S1674987114000656

Apatite fission track (AFT) analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma a...     

http://www.sciencedirect.com/science/article/pii/S1674987113000273

1.Introduction The convergence plate margins,where lithospheric plates move each other and collide,are the most intense areas of magmatism, tectonism and metamorphism.The development of slab windows beneath convergent margins,originally defined by Dickinson and Snyder(1979),is one of the essential mechanisms of subduction-related tectonics.A slab window is a gap that forms in a subducting     

http://www.sciencedirect.com/science/article/pii/S1674987113000601

The intrusions of the Panzhihua-Xichang(Panxi) region in southwest China have become well known in the past decade because they host large and rich magmatic oxide deposits that are mined for Fe,Ti and V.These intrusions form part of the Emeishan large igneous province(ELIP),which is commonly believed to be the product of melting in a mantle plume.The ELIP was emplaced about 260 Ma ago,at the same time as the end-Guadalupian mass extinction.The investigation of the Panxi intrusions therefore provides information relevant to three broad areas of the earth sciences:(1)the petrogenesis of mafic magmas, (2) the impact of major magmatic events and global climate and     

http://www.sciencedirect.com/science/article/pii/S1674987114000309

In the early 1980s, evidence that crustal rocks had reached temperatures 〉1000 ℃ at normal lower crustal pressures while others had followed low thermal gradients to record pressures characteristic of mantle conditions began to appear in the literature, and the importance of melting in the tectonic evolution of orogens and metamorphic-metasomatic reworking of the lithospheric mantle was realized. In parallel, new developments in instrumentation, the expansion of in situ analysis of geological ma- terials and increases in computing power opened up new fields of investigation. The robust quantifi- cation of pressure （P）, temperature （T） and time （t） that followed these advances has provided reliable data to benchmark geodynamic models and to investigate secular change in the thermal state of the lithosphere as registered by metamorphism through time. As a result, the last 30 years have seen sig- nificant progress in our understanding of lithospheric evolution, particularly as it relates to Precambrian geodynamics.     

http://www.sciencedirect.com/science/article/pii/S1674987113000881

Granitod batholiths of I-type features(mostly granodiorites and tonalites),and particularly those forming the large plutonic associations of active continental margins and intracontinental collisional belts,represent the most outstanding magmatic episodes occurred in the continental crust.The origin of magmas,however,remains controversial.The application of principles from phase equilibria is crucial to understand the problem of granitoid magma generation.An adequate comparison between rock compositions and experimental liquids has been addressed by using a projected compositional space in the plane F(Fe t Mg)eAnorthiteeOrthoclase.Many calc-alkaline granitoid trends can be considered cotectic liquids.Assimilation of country rocks and other not-cotectic processes are identifed in the projected diagram.The identifcation of cotectic patterns in batholith implies high temperatures of magma segregation and fractionation(or partial melting)from an intermediate(andesitic)source.The comparison of batholiths with lower crust granulites,in terms of major-element geochemistry,yields that both represent liquids and solid residues respectively from a common andesitic system.This is compatible with magmas being formed by melting,and eventual reaction with the peridotite mantle,of subducted mélanges that are fnally relaminated as magmas to the lower crust.Thus,the off-crust generation of granitoids batholiths constitutes a new paradigm in which important geological implications can be satisfactorily explained.Geochemical features of Cordilleran-type batholiths are totally compatible with this new conception.     

http://www.sciencedirect.com/science/article/pii/S1674987113000613

The effective elastic thickness （Te） represents the thickness of the elastic layer or the flexural rigidity of the lithosphere, the equivalent of which can be calculated from the spectral analysis of gravity and topographic data. Studies of Te have profound influence on intracontinental deformation, and coupling of the tectonic blocks. In this paper, we use the multitaper spectral estimation method to calculate the coherence between Bouguer gravity and topography data, and to obtain the Te map of South China. Through the process of correction, we discuss the relationships of Te versus heat flow, and Te versus seismicity. The results show that Te distribution of South China is affected by three factors：the original age, which controls the basic feature;the Mesozoic evolution, which affects the Te distribution;and the neotectonic movement, which shaped the final distribution. The crust age has a positive correlation with the first-order Te distribution;thus the Yangtze Craton has a relatively higher Te （about 50 km） whereas the Te in Cathaysia block is only 10e20 km. By analysis and comparison among the tectonic models of South China, the Te distribution can be well explained using the flat-subduction model. As is typical with neotectonics, the region with a higher heat flow is related with a lower Te. The seismicity does not have a clear relationship with Te, but the strong seismicity could cause a low Te. Seismogenic layer （Ts） has a similar trend as Te in the craton, whereas in other areas the relationship is complex.     

http://www.sciencedirect.com/science/article/pii/S1674987112000060

The Khondalite Belt within the Inner Mongolia Suture Zone（IMSZ） in the North China Craton is a classic example for Paleoproterozoic ultrahigh-temperature（UHT） metamorphism.Here we report new spinel-bearing metapelitic granulites from a new locality at Xumayao within the southern domain of the IMSZ.Petrological studies and thermodynamic modeling of the spinel+quartz-bearing assemblage shows that these rocks experienced extreme metamorphism at UHT conditions.Spinel occurs in two textural settings:（1） high X_Zn（Zn/（Mg+Fe^Ⅱ+Zn）=0.071-0.232） spinel with perthitic K-feld-spar. sillimanite and quartz in the rock matrix;and（2） low X_Zn（0.045—0.070） spinel as inclusions within garnet porphyroblasts in association with quartz and sillimanite. Our phase equilibria modeling indicates two main stages during the metamorphic evolution of these rocks:（1） near-isobaric cooling from 975℃to 875℃around 8 kbar.represented by the formation of garnet porphyroblasts from spinel and quartz;and（2）cooling and decompression from 850℃.8 kbar to below 750℃.6.5 kbar,represented by the break-down of garnet.The spinel+quartz assemblage is considered to have been stable at peak metamorphisni.formed through the break-down of cordierite.indicating a near isothermal compression process.Our study confirms the regional extent of UHT metamorphisni within the IMSZ associated with the Paleoproterozoic subduction-collision process.     

http://www.sciencedirect.com/science/article/pii/S1674987111000582

The Central India Tectonic Zone(CITZ) marks the trace of a major suture zone along which the south Indian and the north Indian continental blocks were assembled through subduction-accretioncollision tectonics in the Mesoproterozoic.The CITZ also witnessed the major,plume-related,late Cretaceous Deccan volcanic activity,covering substantial parts of the region with continental flood basalts and associated magmatic provinces.A number of major fault zones dissect the region,some of which are seismically active.Here we present results from gravity modeling along five regional profiles in the CITZ, and combine these results with magnetotelluric(MT) modeling results to explain the crustal architecture. The models show a resistive(more than 2000Ω·m) and a normal density(2.70 g/cm~3) upper crust suggesting\ dominant tonalite-trondhjemite-granodiorite(TTG) composition.There is a marked correlation between both high-density(2.95 g/cm~3) and low-density(2.65 g/cm~3) regions with high conductive zones (<80Ω·m) in the deep crust.We infer the presence of an interconnected grain boundary network of fluids or fluid-hosted structures,where the conductors are associated with gravity lows.Based on the conductive nature,we propose that the lower crustal rocks are fluid reservoirs,where the fluids occur as trapped phase within minerals,fluid-filled porosity,or as fluid-rich structural conduits.We envisage that substantial volume of fluids were transferred from mantle into the lower crust through the younger plume-related Deccan volcanism,as well as the reactivation,fracturing and expulsion of fluids transported to depth during the Mesoproterozoic subduction tectonics.Migration of the fluids into brittle fault zones such as the Narmada North Fault and the Narmada South Fault resulted in generating high pore pressures and weakening of the faults,as reflected in the seismicity.This inference is also supported by the presence of broad gravity lows near these faults,as well as the low velocity in the lower crust beneath regions of recent major earthquakes within the CITZ.     

http://www.sciencedirect.com/science/article/pii/S1674987111000168

Actual granitoid analytical data of 767 composited samples are presented here.The data source is 6080 samples collected mainly from 750 large- to middle-sized granitoid bodies across China. Data from the composited samples,which includes that of 70 elements,is analyzed according to geological age—Archeozoic(Ar),Proterozoic(Pt),Eopaleozoic(Pz_1),Neopaleozoic(Pz_2),Mesozoic(Mz), and Cenozoic(Cz)—and three major compositional varieties,e.g.alkali-feldspar granite,syenogranite and adamellite.Petrochemical pa...     

http://www.sciencedirect.com/science/article/pii/S1674987115000833

The capabilities of GIS in modeling fault patterns are explored for Irkutsk city in East Siberia with implications for ground stability.The neotectonic structure of the area is visualized in three dimension(3D)taking into account fault dips,using the ArcGIS,GlobalMapper and Paradigm Geophysical packages.The study area is divided into blocks of different size classes according to the length-based ranks of the bounding faults,which are of five classes distinguished with the equal interval method.The blocks show different deformation patterns,with different densities and strikes of crossing and bounding faults.The data are statistically processed using GIS to estimate the deformation degrees of blocks in arbitrary units per square kilometer using the attributes of rank and crossing/bounding position of faults and the size of blocks.The deformation degrees are then compared with available estimates of ground stability measured as a score of points corresponding to destabilizing factors.Although the comparison generally confirms some linkage between the deformation degree of blocks and their ground stability,the correlation is intricate and ambiguous.In order to enhance the advantages of GIS in building and analyzing3 D models of fault patterns for estimating ground stability and mitigating geological hazards,it is expected in the future to proceed from the reported initial step of visualization to more advanced analysis.     

http://www.sciencedirect.com/science/article/pii/S1674987116000037

The rare earth elements are unusual when defining giant-sized ore deposits,as resources are often quoted as total rare earth oxide,but the importance of a deposit may be related to the grade for individual,or a limited group of the elements.Taking the total REE resource,only one currently known deposit(Bayan Obo) would class as giant(1.7×10~7 tonnes contained metal),but a range of others classify as large(1.7×10~6 tonnes).With the exception of unclassified resource estimates from the Olympic Dam 10 CG deposit,all of these deposits are related to alkaline igneous activity- either carbonatites or agpaitic nepheline syenites.The total resource in these deposits must relate to the scale of the primary igneous source,but the grade is a complex function of igneous source,magmatic crystallisation,hydrothermal modification and supergene enrichment during weathering.Isotopic data suggest that the sources conducive to the formation of large REE deposits are developed in subcontinental lithospheric mantle,enriched in trace elements either by plume activity,or by previous subduction.The reactivation of such enriched mantle domains in relatively restricted geographical areas may have played a role in the formation of some of the largest deposits(e.g.Bayan Obo).Hydrothermal activity involving fluids from magmatic to meteoric sources may result in the redistribution of the REE and increases in grade,depending on primary mineralogy and the availability of ligands.Weathering and supergene enrichment of carbonatite has played a role in the formation of the highest grade deposits at Mount Weld(Australia) and Tomtor(Russia).For the individual REE with the current highest economic value(Nd and the HREE),the boundaries for the large and giant size classes are two orders of magnitude lower,and deposits enriched in these metals(agpaitic systems,ion absorption deposits) may have significant economic impact in the near future.     

http://www.sciencedirect.com/science/article/pii/S1674987112000618

The Moyar Shear Zone(MSZ) of the South Indian granulite terrain hosts a prominent syenite pluton (～560 Ma) and associated NW-SE to NE-SW trending mafic dyke swarm(～65 Ma and 95 Ma). Preliminary magnetic fabric studies in the mafic dykes,using Anisotropy of Magnetic Susceptibly(AMS) studies at low-field,indicate successive emplacement and variable magma flow direction.Magnetic lineation and foliation in these dykes are identical to the mesoscopic fabrics in MSZ mylonites,indicating shear zone guided emplacement.Spatial distribution of magnetic lineation in the dykes suggests a common conduit from which the source magma has been migrated.The magnetic foliation trajectories have a sigmoidal shape to the north of the pluton and curve into the MSZ suggesting dextral sense of shear.Identical fabric conditions for magnetic fabrics in the syenite pluton and measured field fabrics in mylonite indicate syntectonic emplacement along the Proterozoic crustal scale dextral shear zone with repeated reactivation history.     

http://www.sciencedirect.com/science/article/pii/S1674987114001583

Detrital zircons from modern sediments display an episodic temporal distribution of U-Pb crystallization ages forming a series of 'peaks' and 'troughs'.The peaks are interpreted to represent either periods of enhanced generation of granitic magma perhaps associated with mantle overturn and superplume events,or preferential preservation of continental crust during global collisional orogenesis.The close association of those peaks with the assembly of supercontinents implies a causal relationship between collisional orogenesis and the presence of zircon age peaks.Here these two end-member models(episodic periodicity of increased magmatism versus selective preservation during collisional orogenesis) are assessed using U-Pb,Hf,and O analysis of detrital zircons from sedimentary successions deposited during the ~ 1.3-1.1Ca accretionary.~1.1-0.9 Ga collisional,and 0.9 Ga extensional collapse phases of the Grenville orogenic cycle in Labrador and Scotland.The pre-collisional,accretionary stage provides a baseline of continental crust present prior to orogenesis and is dominated by Archean and Paleoproterozoic age peaks associated with pre-1300 Ma Laurentian geology.Strata deposited during the Grenville Orogeny display similar Archean and Paleoproterozoic detrital populations along with a series of broad muted peaks from~ 1500 to 1100 Ma.However,post-collisional sedimentary successions display a dominant age peak between 1085 and 985 Ma,similar to that observed in modern North American river sediments.Zircons within the post-orogenic sedimentary successions have progressively lower εHf and higherδ~(18)O values from ~ 1800 to ~ 1200 Ma whereupon they have higher εHf and δ~(18) within the dominant1085-985 Ma age peak.Furthermore,the Lu-Hf isotopic profile of the Grenville-related age peak is consistent with significant assimilation and contamination by older crustal material.The timing of this dominant age peak coincides with the peak of metamorphism and magmatism associated with the Crenville Orogeny,which is a typical collisional orogenic belt.The change from broad muted age peaks in the syn-orogenic strata to a single peak in the post-orogenic sedimentary successions and in the modern river sediments implies a significant shift in provenance following continental collision.This temporal change in provenance highlights that the source(s),from which detrital zircons within syn-orogenic strata were derived,was no longer available during the later stages of the accretionary and collisional stages of the orogenic cycle.This may reflect some combination of tectonic burial,erosion,or possibly recycling into the mantle by tectonic erosion of the source(s).During continental collision,the incorporated continental crust is isolated from crustal recycling processes operative at subduction margins.This tectonic isolation combined with sedimentaiy recycling likely controls the presence of the isotopic signature associated with the Grenville Orogeny in the modern Mississippi and Appalachian river sediments.These results imply that zircon age peaks,which developed in conjunction with supercontinents,are the product of selective crustal preservation resulting from collisional orogenesis.     

http://www.sciencedirect.com/science/article/pii/S1674987112000837

The Venda Nova Pluton(VNP) is a zoned ring structure emplaced in the southern portion of the Neoproterozoic Aracuai Belt,in Espirito Santo.Brazil.It is a slightly westward tilted cylinder-like intrusion,with an almost circular horizontal section.In the center of this structure,an off-centered gabbro-noritic core,surrounded by syeno-monzonitic rocks,intrudes an outer ring of charnockites and norite.These envelop the syeno-monzonitic and gabbro-noritic center,as a narrow discontinuous belt. While,in the core intrusion,mingling and mixing processes are widespread and well documented in the literature,in the outer ring,the norite and charnockite layers show predominantly homogeneous and isotropic internal structures.Nevertheless,smaller interaction zones between charnockites and norite denote a comparatively more restricted mingling process.The norite is a fine-grained rock with hypidiomorphic granular to intergranular texture.The charnockites are medium-grained and made up of: (a) orthopyroxene-tonalite.(b) orthopyroxene-quartz-diorite,and(c) orthopyroxene-granodiorite with hypidiomorphic granular to porphyritic textures.In all lithotypes both ortho- and clinopyroxene are replaced by hornblende and biotite.Two contrasting compositional sequences have been recognized,based on whole rock geochemistry:(1) a basic,with tholeiitic affinities(norite) and,(2) an intermediate. medium-K calc-alkaline,comprising the charnockites.Estimated crystallization temperatures,which have been calculated from micro-probe analysis of pyroxenes,range from 915±25℃to 960±50℃.Re-equilibration temperature(ilmenite-magnetite calibration) is around 600±50℃.This indicates oxygen fugacities four order of magnitude below the FMQ-buffer and a reduced environment. Coeval pressure conditions estimated from the Al-content in hornblende range from 5.5±0.6 kbar.Data obtained for the norite point toward an evolution from the partial melting of an anhydrous tholeiitic mantle magma.The charnockites may correspond to the differentiation of a calc-alkaline parental magma.The later could be the hybrid product from the contamination and mixing between the anhydrous tholeiitic magma with other deeper crustal sources.Further the magmatic system evolved through fractionation of orthopyroxene.clinopyroxene.plagioclase and ilmenite.Our results support the hypothesis for the evolution of the Venda Nova Pluton through a mantle-crust delamination process probably related to the collapse of the Aracuai orogeny.