Magma Mixing Genesis of the Mafic Enclaves and Related Granitoids in the Kan Granite-Gneiss Complex of Central Côte d’Ivoire: Evidence from Geology, Petrology and Geochemistry

The mafic enclaves from Paleoproterozoic domain are considered to be the results of large-scale crust-mantle interaction and magma mixing. In this paper, petrography, mineralogy and geochemistry were jointly used to determine the origin of the mafic enclaves and their relationship with the host granitoids of the Kan granite-gneiss complex. This study also provides new information on crust-mantle interactions. The mafic enclaves of the Kan vary in shape and size and have intermediate chemical compositions. The diagrams used show a number of similarities in the major elements (and often in the trace elements) between the mafic enclaves and the host granitoids. Geochemical show that the Kan rock are metaluminous, enriched in silica, medium to high-K calc-alkaline I-type granite. The similarities reflect a mixing of basic and acid magma. Mafic enclaves have a typical magmatic structure, which is characterized by magma mixing. The genesis of these rocks is associated with the context of subduction. They result from the mixing of a mafic magma originating from the mantle and linked to subduction, and a granitic magma (type I granite) that arises from the partial melting of the crust.

Characteristics:Evidence from the“Enclave Economy”in the PRD Region

Paired assistance is an important means for developed regions to help lessdeveloped regions achieve common prosperity.Despite its advantages,governmentmandated paired assistance tends to be less effective due to the lack of economic incentives for assisting localities.Therefore,local governments in China have explored an incentivecompatible paired assistance model.Based on the paired assistance between cities in the Pearl River Delta(PRD)region and the eastern,western and northern parts of Guangdong Province,this study designed a natural experiment for the network relationship of paired assistance.Empirical results based on industrial and commercial registration data and land transfer data indicate that paired assistance has enhanced bilateral investment linkages,and that the inter-regional benefit sharing mechanism has incentivized assisting localities to provide paired assistance.Our heterogeneity analysis reveals that a shorter distance between assisting and beneficiary localities may lead to better results of paired assistance.This study contributes to the understanding of incentive mechanisms for local government cooperation and offers insights for balancing regional development and achieving common prosperity.

Types of Enclaves and Their Features and Origins in Intermediate-Acid Intrusive Rocks from the Tongling District, Anhui Province, China

Abstract: Enclaves in intermediate-acid plutons from Tongling can be divided into three types: xenoliths, relics and magmatogenic enclaves. The magmatogenic enclaves consist of cumulates, micrograined dioritite mixtite and dioritic chilled border enclaves. Petrologically, relics with eyed and meta-poikilitic texture are characterized by high content of biotite (>80%) and low content of cordierite and grossular. The cumulates with accumulate texture consist of a great amount of pyroxene, hornblende and minor spinel and phlogopite. The micrograined dioritic mixtite is composed of more hornblendes and feldspar and less needle apatites and an ellipsoid basic core included in plagioclase. The chilled border enclaves have the same mineral association, but more dark minerals than the host rocks consisting of plagioclase, quartz, alkaline feldspar, hornblende and biotite. Geochemically, the relics exhibit high REE content (455.8×10?6) and high ratio of LREE/HREE, more obvious Eu negative anomaly and are rich in Cr and Ni, poor in Ba, Nb and Sr. All kinds of magmatogenic enclaves have the same REE pattern without Eu anomaly, and the total REE is 74.9×10?6 for spinel pyroxene cumulate, 179.7×10?6 for hornblende cumulate, 226.9 × 10?6 for hornblende cumulate crystal, 289.9×10?6 for micrograined dioritic mixtite and 131.2×10?6 for chilled border enclaves. Calculation with the thermometer and barometer for minerals shows that the temperature and pressure of formation are 1126 °C and 8.44 kbar (7.15–9.04 kbar) for the spinel pyroxene cumulate, 1065 °C-1029 °C and 8.23 kbar (7.13–9.50 kbar) for the hornblende pyroxene cumulate, 959 °C and 3.40 kbar (2.86–4.09 kbar) for the micrograined dioritic mixtite enclaves, and 951 °C and 0.59 kbar for the dioritic chilled border enclaves, respectively. Thus, the following conclusions can be drawn. Relic enclaves were derived from the crustal partial melting and all cumulate enclaves originated from deep magma chambers near the Moho in the lower crust, which are cumulate fragments formed by fractional crystallization of basic magma; mixtite came from shallow magma chambers in the middle-upper crust, formed by the mixture of mantle-derived magma and acid magma derived from the crustal partial melting; and the chilled border enclaves came from the border fragments of early intrusive bodies.

Geochronology of the Gabbro-mafic Microgranular Enclaves-granite Associations in the Gejiu District, Yunnan Province and Their Geodynamic Significance

Many igneous rocks distribute in Gejiu tin polymetallic ore-field at Yunnan province, rocks including basalt, gabbro, mafic microgranular enclaves, granites （porphyritic granite and equigranular granite） and akaline rocks. The ages of the granites and akaline rocks which are considered to have genetic connecting with the mineralization have been comfirmed, but the gabbro- mafic microgranular enclaves-granite assemblage＇s ages are still unknown. By means of LA-ICP-MS zircon U-Pb dating, the data of Shenxianshui equigranular granite, the mafic microgranular enclave in Jiasha area, the host rock of the mafic microgranular enclaves and the Jiasha gabbro are around ~80 Ma. Besides the above mentioned data, a group of new ages at ~30 Ma were discovered in this study, which is from gabbro and mafic microgranular enclaves. Based on the previous data and the new data gained this time, we suggest the major geochronology framework of the magmatism and mineralization events in Gejiu area is ~80 Ma, which is consistent with the Late Cretaceous magmatism and mineralization events in the whole southeast Yunnan and west Guangxi area and they were suggested to belong to the same geotectonic setting in late Yenshannian. And the new ages of the ~30 Ma obtained in this study is considered to represent a responding to the complicate tectonic evolution history of the Tibetan orogenic events in Cenozoic.

Petrological and Mineralogical Study of Enclaves in Plutons in the Typical Mining Districts of Tongling, Anhui and Its Bearing on the Process of Magmatism Metallogeny

Two types of enclaves occur in magmatic plutons in Tongling, Anhui. Enclaves of the first type are residuals of metamorphic rocks of high amphibolite facies, and those of the other type are magmatic rocks ranging from monzonitic to dioritic in composition. A combined petrological and mineralogical study has been carried out on the two types of enclaves in order to estimate their forming conditions and analyze their relations to their hosts, so as to have an insight into the material sources of magmatic rocks and associated mineral deposits and give a clue to better understanding the mechanism of magmatism metallogeny. This leads us to propose a new metallogenic model for strata bound skarn type ore deposits associated with a syntectic type of magmatic rocks. The new model can be simply summarized as partial melting of old metamorphic basement rocks at depth and accumulating, differentiating and positioning of magmas to form deep level and shallow level magma chambers, followed by mixing of different magmas associated with their crypto explosion, migration of gas bearing ore fluids and precipitation of metals in fluids within the magmas.

LA-ICP-MS Zircon U-Pb Dating of the Huangyangshan Pluton and Its Enclaves from Kalamaili Area Eastern Junggar,and Geological Implications

LA-ICP-MS zircon U-Pb dating has revealed that the Huangyangshan pluton in Eastern Junggar was formed at 311±12 Ma,and that microgranular enclaves were formed at 300±6 Ma;both ages are very consistent within errors.It is the first time that the microgranular enclaves age in Kalamaili area was determined.Petrochemistry and geochemistry research shows the characteristics of host rock as follows:

Discovery of Enclaves from Cenozoic PuluVolcanic Rocks in West Kunlun Mountains and ItsGeological Implications

In this paper, we present the occurrence and mineral components of the enclaves firstly discovered in the Cenozoic Pulu volcanic rocks in west Kunlun Mountains, and propose that the enclave is accumulated by fractional crystallization within high-level magma chamber. In addition, the chemical compositions of its primary magma are calculated. The calculated compositions are similar to those of the Kangxiwa volcanic rocks that belong to the same volcanic belt in the Pulu volcanic region, suggesting their origin from the same source region. However, the temperatures and oxygen fugacity of magmas at high-level magma chamber decreased along with fractional crystallization.

Destruction of the Northern Margin of the North China Craton in Mid-Late Triassic: Evidence from Asthenosphere-derived Mafic Enclaves in the Jiefangyingzi Granitic Pluton from the Chifeng Area, Southern Inner Mongolia

The petrology, geochronology and geochemistry of the mafic enclaves in the Mid-Late Triassic Jiefangyingzi pluton from Chifeng area, southern Inner Mongolia, in China are studied to reveal their petrogenetic relationship with the host pluton. Furthermore, the coeval magmatic assemblage and its petrogenesis on the northern margin of the North China craton(NCC) are studied synthetically to elucidate their tectonic setting and the implications for the destruction of the NCC. Zircon U-Pb dating reveals that the mafic enclaves formed at 230.4 ± 2.2 Ma, which is similar to the age of the host pluton. The most basic mafic enclaves belong to weak alkaline rocks, and they display rare earth element(REE) and trace element normalized patterns and trace element compositions similar to those of ocean island basalt(OIB). In addition, they have positive εNd(t) values(+3.84 to +4.94) similar to those of the Cenozoic basalts on the northern margin of the NCC. All of these geochemical characteristics suggest that the basic mafic rocks originated from the asthenosphere. Petrological and geochemical studies suggest that the Jiefangyingzi pluton and the intermediate mafic enclaves were formed by the mixing of the asthenosphere-derived and crust-derived magmas in different degrees. The Mid-Late Triassic magmatic rocks on the northern margin of the NCC could be classified into three assemblages according to their geochemical compositions: alkaline series, weak alkaline–sub-alkaline series and sub-alkaline series rocks. Petrogenetic analyses suggest that the upwelling of the asthenosphere played an important role in the formation of these Mid-Late Triassic magmatic rocks. Basing on an analysis of regional geological data, we suggest that the northern margin of the NCC underwent destruction due to the upwelling of the asthenosphere during the Mid-Late Triassic, which was induced by the delamination of the root of the collisional orogeny between Sino-Korean and Siberian paleoplates in Late Permian.

Secure Enclave安全体系技术分析与研究

在移动互联网时代,移动智能终端已经成为人们随身携带、随时使用的重要设备。应对移动应用环境中面临的安全威胁,成为业界面临的重要问题。Apple公司设计了一套安全体系,依靠Secure Enclave模块来实现密码运算和敏感数据的存储,在实际的应用中取得了很好的效果。从硬件、系统和通信机制方面分析了Secure Enclave模块的组成结构,进而对系统进行了安全性分析,最后,对模块进行了总结和展望。

Petrogenesis of the ükapili Granitoid and its Mafic Enclaves in Elmal Area (Nigde, Central Anatolia, Turkey)

The Late Cretaceous Uckapth Granitoid including mafic microgranular enclaves intruded into metapelitic and metabasic rocks, and overlain unconformably by Neogene ignimbrites in the Ni^de area of Turkey. It is mostly granite and minor granodiorite in composition, whereas its enclaves are dominantly gabbro with a few diorites in composition. The Uckapdl Granitoid is composed mainly of quartz, K-feldspar, plagioclase, biotite, muscovite and minor amphibole while its enclaves contain mostly plagioclase, amphibole, minor pyroxene and biotite. The Uckapth Granitoid has calcalkaline and peraluminous （AJCNK= 1.0-1.3） geochemical characteristics. It is characterized by high LILE/HFSE and LREE/HREE ratios （（La/Lu）N 3-33）, and has negative Ba, Ta, Nb and Eu anomalies, resembling those of comsion granitoids. The {）fkaplh Granitoid has relatively high STSr/S6Sr0） ratios （0.711189--0.716061） and low eNd（t） values （-5.13 to -7.13）, confirming crustal melting. In contrast, the enclaves are tholeiitic and metaluminous, and slightly enriched in LILEs （K, Rb） and Th, and have negative Ta, Nb and Ti anomalies; propose that they were derived from a subduction-modified mantle source. Based on mineral and whole rock chemistry data, the Uckapth granitoid is H-（hybrid） type, post-collision granitoid developed by mixing/mingllng processes between crustal melts and mantle-derived mafic magmas.

Petrological Significance of Zoned Plagioclase in Eldjurti Granite and Mafic Microgranular Enclaves, North Caucasus, Russia

Plagioclase phenocrysts from mafic enclaves and plagioclase from its host granite possess a pat-tem of complex zonation. A plagioclase phenocryst can generally be divided into three parts : an oscillatory, locally patchy zoned core (An47-19), a ring with dusty, more calcic plagioclase (An64-20) and a normally zoned rim composed of sodic plagioclase (An22-3. 3). Majordiscontinuities in zoning coincide with resorption suffeces that are overgrown by the more calcic plagioclase. The cores of large plagioclase phenocrysts from mafic enclaves and host granite show similar zoning patterns and similar compositions, indicating their crystallization under the same conditions . Steep normal zoning of the rims of plagioclases both from host granite and mafic enclaves illustrates a drastic decrease in An content which is considered to have resulted from the continuous differentiation of hybrid magma and efficient heat loss because of the upward emplacement of the residual magma. Wide rims of plagioclases from the host granite against thc discrete rims of plagioclases from mafic enclaves indicate that differentiation and cooling lasted much longer in the host granite than in the mafic enclaves.

Geological Implications for the Deep-Derived Mafic Enclaves from Cenozoic Shoshonitic Rocks in Jianchuan-Dali Area, West Yunnan

There exist intermediate to intermediate-acid shoshonitic rocks dated at 26.3- 36.7Ma in the Early Tertiary extensional basins along the NE flank of the Dali-Jianchuan section of the Honghe-Ailaoshan left-lateral strike-slip ductile shear zone, where some high- and medium-high grade metamorphosed mafic enclaves have been found. According to the P-T conditions and mineral assemblage characteristics, the enclaves are grouped into three types: type-Ⅰ, garnet diopsidite, formed at lower crust or in the transitional section between the mantle and the crust with the metamorphic condition P=(10.47-11.51)×108 Pa and T=771-932℃; type-Ⅱ, garnet- and diopside-bearing amphibolite, formed at the depth of middle to lower crust with the metamorphic condition: P=(6-10) ×108 Pa and T=780-830℃; type-Ⅲ, metamorphosed gabbro, formed at relatively higher levels than the above 2 types with lower metamorphic condition. Type-Ⅰand type-Ⅱenclaves had experienced a decompressional retrograde metamorphism caused by tectonic elevation associated with the metasomatism of SiO 2, Na 2O-rich fluid phase with the new equilibrated temperature at T=761-778℃. Geochemical evidence indicates that both deep-derived mafic enclaves and host rocks have similar EM Ⅱ properties, which are related to the involvement of subducted materials. The sustaining subduction, compression and strike-slip ductile shearing between the India plate and the Yangtze craton are the main constraints on the subcontinental mantle properties, interaction between crust and mantle, and the formation and evolution of alkali-rich magma.

Recognizing Brazilian Cerrado Enclaves by Modeling Geoenvironmental Parameters

This work focused on the prediction modeling of Cerrado occurrences in the Atlantic Rainforest predominance in the São Paulo Metropolitan Region (SPMR), the fourth largest urban area, in the city of Guarulhos, southeastern Brazil. The methodology was based on the selection of records of occurrence of Cerrado in georeferenced databases, thematic maps of geoenvironmental layers, and modeling of the distribution of species through the MaxEnt tool. Besides that, field research confirmed the presence or not of the species in the areas with a high probability of occurrence of Cerrado (≥0.7). As a result, the model observed a great capacity for the prediction of the occurrence of Cerrado in Ecotonal and anthropic regions (AUC = 0.82), revealing important hotspots such as relics from the past or Cerrado enclaves of high biodiversity. The work also points priority areas for the conservation and preservation of this increasingly endangered biome.

Meaning of Rocks Basic Enclaves in the Eburnean Granitoids of Mako Area (Kédougou-Kéniéba Inlier, Senegal): Petrogenetic Implications

The Mako area, located in eastern Sénégal, constitutes a segment of Paleoproterozoic (Birimian) formations of the Kédougou-Kéniéba Inliers (KKI) in the western part of the West African craton. The basic volcanism of the Birimian formations of the KKI has long been considered to be related to a single magmatic event associated with a Mid Oceanic Ridge Basalts (MORB) setting. The aim of this paper is to demonstrate on the basis of the architectural characteristics of the granitoids dark enclaves, the occurrence of at least two distinct phases of basic Magamtism in the Birimian of the KKI. The methodology consists of a cartography, a petrographic and architectural characterization of the dark enclaves within the Mako granitoids, in order to constrain their spatial and temporal relationships with the granitic magma. The results obtained are compared with those of the bibliography. We have pinpointed two types of enclaves depending on their shapes and the characteristics of their edge with the enclosing rocks: angular enclaves with straight edges (ante-granitoids) and the soft enclaves with uneven edges (syn-granitoids). The enclaves with straight and well-defined rectilinear edges (ante-granitoids) would be linked to a basic magma which is already consolidated before being fragmented, torn and carried away as enclaves in the granitoids. These enclaves would come from enclosing outcrops of metabasalts and metagabbros which are locally cross-cut by the granitoids. The soft enclaves with uneven edges (syn-granitoids) were co-magmatic and not solid during their incorporation into the granitoids. They come from a basic magma which is contemporaneous to the granitic one. Thus, the occurrence of two generations of dark enclaves is related to, at last, two different phases of basic magmatism in the Birimian formations of the KKI.

Progress in Enclave Tourism Study of Overseas:A Literature Review

In response to the "isolated island" phenomenon emerging from the development of tourist resorts in China, this paper reviews the study of enclave tourism overseas, which has similar features to the resort "island". Based on the literatures related to enclave tourism from Tourism Management and Annals of Tourism Research, this paper reviews the study of enclave tour- ism from the following aspects: definition discussion, theories used, causation of enclaves, characteristics and impacts of enclave tourism. The understanding of the overseas researches on enclave tourism would provide instructions for the study on the problems of Chinese resorts, such as enclavity and "island effects", and suggest measures for the sustainable development of resorts in China. This paper is divided into three sections. Section 1 briefly introduces the development of enclave tourism in developing countries and the outline of enclave tourism study. Section 2 elaborates on the contents of enclave tourism research and gives deep insights into the study on concepts, characteristics, causations and effects respectively, which is the key part of this paper; Section 3 concludes the review and proposes suggestions for the enclave tourism study in China.

Deep-derived enclaves (belonging to middle-lower crust metamorphic rocks) in the Liuhe-Xiangduo area, eastern Tibet: Evidence from petrogeochemistry

Petrological and geochemical studies of deep-derived enclaves from the Liuhe-Xiangduo area, eastern Tibet, showed that the enclaves involve five types of rocks, i.e., garnet diopsidite, garnet amphibolite, garnet hornblendite, amphibolite and hornblendite, whose main mineral assemblages are Grt+Di+Hbl, Grt+Pl+Hbl+Di, Grt+Hbl+Pl, Pl+Hbl, and Hbl+Bt, respectively. The enclaves exhibit typical crystalloblastic texture, and growth zones are well developed in garnet (Grt) in the enclaves. In view of major element geochemistry, the deep|derived enclaves are characterized by high MgO and FeO+*, ranging from {12.00%} to {12.30%} and {8.15%} to {10.94%}, respectively. The protolith restoration of metamorphic rocks revealed that the enclaves belong to ortho-metamorphic rocks. The REE abundances vary over a wide range, and ∑REE ranges from {53.39} to {129.04} μg/g. The REE patterns slightly incline toward the HREE side with weak LREE enrichment. The contents of Rb, Sr, and Ba range from {8.34} to 101μg/g, 165 to 1485 μg/g, and 105 to 721 μg/g, respectively. The primitive mantle-normalized spider diagrams of trace elements show obvious negative Nb, Ta, Zr and Hf anomalies. Sr-Nd isotopic compositions of the enclaves indicated that the potential source of deep-derived enclaves is similar to the depleted|mantle, and their {({}+{87}Sr/+{86}Sr)-i} ratios vary from {0.706314} to {0.707198}, {({}+{147}Nd/+{144}Nd)-i} ratios from {0.512947} to {0.513046}, and {ε-{Nd}(T)} values from {+7.0} to {+9.0}, respectively. The potential source of the enclaves is obviously different from the EM2-type mantle from which high-K igneous rocks stemmed (the host rocks), i.e., there is no direct genetic relationship between the enclaves and the host rocks. Deep-derived enclaves in the host rocks belong to mafic xenoliths, and those in the Liuhe-Xiangduo area, eastern Tibet, are some middle-lower crust ortho-metamorphic rocks which were accidentally captured at 20-50 km level by rapidly entrained high-temperature high-K magma, whose source is considered to be located at 50-km depth or so.

Peraluminous A-type granites formed through synchronous fractionation,magma mixing,mingling,and undercooling:evidence from microgranular enclaves and host Mesoproterozoic Kanigiri granite pluton,Nellore Schist Belt,southeast India

The field and microstructural features coupled with mineral chemical data from microgranular enclave(ME)and host Mesoproterozoic Kanigiri granite(KG)pluton of Nellore Schist Belt(NSB),Southeastern India,have been documented in order to infer the likely processes responsible for the origin and evolution of ME and host KG magma.The ME and host KG bear the same mineral assemblages barring the KG which does not contain amphibole;however,they are modally disequilibrated.The ME in KG is originated due to multiple intrusions of ME magmas into the crystallizing host KG magma chamber.Field and textural features indicate the dynamic magma flow,mingling,and undercooling of the ME against a relatively cooler surface of host KG magma.The presence of NSB country rock xenoliths and its diffuse boundaries suggest the intrusive relation and marginal assimilation by the intruding KG magma.The occasional cumulate texture in the ME appears to have formed by the accumulation of early-formed minerals that crystallized rapidly in the ME magma globules.The ME shows the magmatically deform features developed due to the flowage and erosion by the subsequent intrusions of ME magma pulses into the crystallizing host KG magma chamber.The ME amphiboles show unusual composition as ferro-edenitic hornblende to potassian-hastingsitic hornblende,that crystallized in the subalkaline-alkaline transition,low fO_(2)(reducing to mildly oxidizing)magma.The unusual extremely low Mg/Mg+Fe^(t)=0.015(avg.)of ME amphiboles may be related to the changing physico-chemical(P,T,fO_(2),and H_(2)O)condition of the ME magma or they might have crystallized in equilibrium with more evolved KG magma.The KG(FeOt/MgO=37.04,avg.)and ME(FeO~t/MgO=77.72,avg.)biotites are siderophyllite,and buffered between QFM and NNO syn-crystallizing in the water undersaturated(H_(2O)≈3.58 wt.%in KG;≈3.53wt.%in ME),alkaline anorogenic(A-type)host magmas that were emplaced at mid-crustal(4–5 kbar;17 km)depth.Field,microtextural and mineral chemical evidences suggest that the alkaline KG magma originated from crustal source and evolved through synchronous fractionation,mixing,and mingling with coeval ME magmas in the KG magma chamber.

Origin and intraplate tectonic setting of mafic magmatic enclaves from the Ngaoundal area,Adamawa-Cameroon:Insights from petrography and geochemistry

In this contribution,detailed field descriptions together with petrographic and bulk-rock major,trace and rare earth elements(REE)data are used to constrain the origin and geodynamic setting of the mafic magmatic enclaves(MMEs)recently discovered within the Pan-African Ngaoundal pluton,Adamawa area,central Cameroon.The investigated MMEs are dark-colored with chilled margins,and display medium to coarse-grain igneous textures.The mineral assemblage is either dominated by K-feldspar and carbonate(group Ⅰ),or by amphibole and plagioclase(group Ⅱ),though the overall mineral phases made of amphibole,plagioclase,K-feldspar,and biotite are similar to that of their host syenite but in different proportions.The MMEs in Ngaoundal area are foid-gabbro in composition with SiO_(2) contents ranging between 41.52% and 43.74% and are contiguous with their host granitoids of intermediate composition(SiO_(2)=57.52% to 58.98%).The host granitoid rocks are metaluminous,and belong to the shoshonitic series.Petrographic and geochemical data have revealed that the Ngaoundal MMEs derived from rapid cooling of hot injected lithospheric mantle-derived magma within cooler host granitoids magma and were emplaced in the intraplate geodynamic setting.

Petrogenesis and geochemistry of the host monzogranite and mafic enclaves from the Triassic Wulong pluton in South Qinling, central China

The Wulong pluton was emplaced in the metamorphic complex of the Mesoproterozoic Foping Group, South Qinling. A few mafic enclaves which are rounded in shape with sharp boundaries with the host granites in the southern part of the pluton. Based on petrography, geochemistry and chronology data, it is indicated that the Wulong pluton shows some adakitic affinities with depletion in HREE (Yb=0.33–0.96 μg/g, Y=4.77–11.2 μg/g); enrichment in Sr (643–1115 μg/g) and Ba (775–1386 μg/g), high Sr/Y ratios (57.3–160) and Y/Yb ratios (11.0–14.3), and slightly negative Eu anomaly (δEu=0.70–0.83). These patterns suggest a feldspar-poor and garnet±amohibole-rich fractionation mineral assemblage. The mafic enclaves have high concentrations of Mg (MgO=4.15%–8.13%), Cr (14.8–371 μg/g), and Ni (20.0–224 μg/g), and high Nb/Ta ratios (15.42–21.9). It seems that the underplating mantle magma was responsible for the generation of the mafic magma. Companied with the results of investigations for the Qinling Orogenic Belt, it was found that partial melting of the thickened lower crust, which was triggered by the underplated mantle-derived magmas, had generated the felsic magma. The Wulong pluton provided evidence for a mixing and mingling process of two kinds of mamma. Its formation probably represents the oceanic slab breakoff during the late orogenic stage in the Qinling area.

Exchange between Mafic Enclaves and Host Magma： Case of 1991-1995 Mount Unzen Eruption

Recent eruption of Unzen Volcano in 1991-1995 caught attention of scientists all over the world because of disastrous character of previous one in 1792. Intrusion of andesitic magma to the chamber with rhyolitic magma is proposed to be a trigger for these eruptions. T-P-X parameters of two end-member magmas have been estimated several times, but usually estimations are based on phenocrysts assemblages. New results of this research are based on mafic enclaves and groundmass. These results are significant for magma mixing and mingling theory.