Spatiotemporal Characteristics and Future Scenario Simulation of the Trade-offs and Synergies of Mountain Ecosystem Services: A Case Study of the Dabie Mountains Area, China

Mountain ecosystems play an essential role in supporting regional sustainable development and improving local ecological environments. However, economic development in mountainous areas has long been lagging, and multiple conflicts related to resource assurance, ecological protection, and economic development have emerged. An accurate grasp of the current status and evolutionary trends of mountain ecosystems is essential to enhance the overall benefits of ecosystem services and maintain regional ecological security. Based on the In VEST(Integrated Valuation of Ecosystem Services and Trade-offs) model, this study analyzed the spatiotemporal evolution patterns and the trade-offs and synergies among ecosystem services(ES) in the Dabie Mountains Area(DMA) of eastern China. The Markov-PLUS(Patch-generating Land Use Simulation) model was used to conduct a multi-scenario simulation of the area's future development. Water yield(WY) and soil conservation(SC) had overall increasing trends during 2000-2020, carbon storage(CS)decreased overall but slowed with time, and habitat quality(HQ) increased and then decreased. The ecological protection scenario is the best scenario for improving ES in the DMA by 2030;compared to 2020, the total WY would decrease by 3.77 × 10^(8) m^(3), SC would increase by 0.65 × 10^(6) t, CS would increase by 1.33 × 10^(6) t, and HQ would increase by 0.06%. The comprehensive development scenario is the second-most effective scenario for ecological improvement, while the natural development scenario did not have a significant effect. However, as the comprehensive development scenario considers both environmental protection and economic development, which are both vital for the sustainable development of the mountainous areas, this scenario is considered the most suitable path for future development. There are trade-offs between WY, CS, and HQ, while there are synergies between SC, CS, and HQ. Spatially, the DMA's central core district is the main strong synergistic area, the marginal zone is the weak synergistic area, and trade-offs are mainly distributed in the transition zone.

The Key Influence of Fluid in the Preserves, Mineral Assemblages, Compositionsand Structures: Study from High-Pressure Eclogite and Its Amphibolization in the Western Dabie Mountains,Central China

Pseudosection modeling for the garnet amphibolite samples from the Western Dabie Mountains show they have experienced similar HP metamorphic evolution with that of the adjected eclogites.The common assemblage of

The Key Influence of Fluid in Metamorphic Rock Preserves, Mineral Assemblages, Compositions and Structures: Study from High-Pressure Eclogite and Its Amphibolization in the Western Dabie Mountains,Central China

The most of high/ultrahigh-pressure(HP/UHP)terranes of the world are characterized by the occurrence of numerous pods,lenses or layered blocks of eclogite and amphibolites(e.g.O’Brien,1997;Elvevold and Gilotti,2000;Zhang et al.,2003;and references there in).Field and petrological features suggest that amphibolites should

^(207)Pb/^(206)Pb Zircon Dating of the Huangtuling Hypersthene-Garnet-Biotite Gneiss from the Dabie Mountains, Luotian County, Hubei Province, China: New Evidence for Early Precambrian Evolution

The Huangtuling hypersthene-garnet-biotite gneiss at Luotian County, Hubei Provine, is a typicalgranulite-facies rock of the Dabie Group Complex in the Dabie orogenic belt. Investigations on the morphology andoccurrence of zircons and their internal structures shown in the thin sections lead to the recognition of three types ofzircons, which are in good agreement with the types identified on the basis of morphology, colour and external fea-tures from the related zircon concentrates. The observation of zircons in the rock reveals that part of type 1 zirconsshow signs of a double-layered structure. The interval part existed in the protolith prior to the granulite-facies meta-morphism. Type 2, the prismatic zircons which mainly occur in garnet and hypersthene are metamorphic minerals ofthe granulite-facies metamorphism. Type 3, the round multifaceted zircons in felsic minerals and biotite, are proba-bly attributed to a later geological event related to migmatization. The ^(207)Pb/^(206)Pb zircon dating by direct evaporationon (thermal evaporation ion mass spectrometer) yields ages ranging from 2814 Ma to 1992 Ma. The age discrepancyamong these different zircon types is conspicuous. The yellow-brown(type 1) zircons give ages of 2814±29 Ma to2527±6 Ma, the prismatic euhedral zircons (type 2), 2456±7 Ma to 2254±4 Ma, and the round multifaceted zircons(type 3), 1992±10 Ma. The results are geologically interpreted in consideration of the complicated behaviours of zir-cons during Precambrian geological evolution of the Dabie area. (1) If the protolith of the gneiss is a sedimentaryrock, then type 1 zircons are clastic ones and the ages 2814±29 Ma and 2811±27 Ma may reflect the minimum age ofthe rocks of its source region. also the first geological event in the area. Sedimentation of the protolith occurred be-tween 2814 Ma and 2527 Ma, probably close to 2814 Ma. If the protolith is a volcanic rock, then the formation age ofthe supracrustal rocks of the Dabie Group Complex is around 2814 Ma. The age 2456±7 Ma reflects the time whenthe granulite-facies metamorphism took place. The later migmatization event is dated at aboat 1992±10 Ma, and isprobably the latest early Precambrian event in the area. The present work provides geochronological evidence for the existence of the Dabie Archaean craton, whichhad probably experienced 3 or 4 geological events during its early Precambrian evolution.

Role of Water in Deformed Omphacite in UHP Eclogite from the Dabie Mountains,Eastern China

Omphacite grains from UHP eclogite of the Dabie Mountains in eastern China are elongated and show strong lattice preferred orientations (LPOs). Observations by the transmission electron microscopy (TEM) identified not only structures of plastic deformation occurring as free dislocation, dislocation loops and dislocation walls, but also bubbles of water present in the deformed omphacite. The bubbles attach to the dislocation loops which are often connected to one another via a common bubble. Using infrared spectroscopy (IR), two types of hydrous components are identified as hydroxyl and free-water in the omphacite. An analysis of deformation mechanism of microstructure in omphacite suggests that the mineral deformed plastically under UHP metamorphic conditions by dislocation creep through hydrolitic weakening.

Isotopic Geochronology of the Xianghongdian Alkaline Complex, Northern Margin of the Dabie Mountains, China

To the north of the Qinling-Dabie orogen there exists a Mesozoic (K1) granite-syenite belt called the Beihuaiyang granite-syenite belt, in which the Xianghongdian alkaline complex outcrops in the Devonian Foziling schist and also intruded into the slightly earlier volcanic rocks. This alkaline complex is composed of syenite, alkaline syenite and nepheline syenite, but the nepheline syenite occurs inside the alkaline syenite in the pod-like, irregular, lenticular or layered shape. Researches on the petrogenesis of the alkaline complex and the relationship between the alkaline syenite and the nepheline syenite must rely on precise isotopic ages. Previous researches have reported isotopic dating results merely by the 40Ar/39Ar method on hornblende and biotite separated from the alkaline syenite and nepheline syenite. In view of this, the authors have made fairly detailed isotopic geochronological studies of the alkaline syenite and nepheline syenite by using Rb-Sr isochron for the whole rock and minerals, U-Pb for single zircon separate and the 40Ar/39Ar method for hornblende and potash feldspar. The results of this research are completely different from those of previous researches and show that the nepheline syenite was formed far earlier than the alkaline syenite.

A New Species of the Genus Rhacophorus (Anura： Rhacophoridae) from Dabie Mountains in East China

A new species of rhacophorid of the genus Rhacophorus is described from the Dabie Mountains of west Anhui, east China. The new species, Rhacophorus zhoukaiyae sp. nov. is distinguished from its congeners by a combination of the following characters： 1） the ventral surface and front-and-rear of the femur is paler yellowish and decorated with irregular grayish blotching, and without obvious spots on the dorsum of the hand and foot webbing; 2） the outer metatarsal tubercle is small; 3） outer fingers are half-webbed and outer toes two third webbed; 4） the skin on the dorsum is smooth and without compressed warts; 5） the throat, chest and belly are pure paler yellowish; 6） the dorsal part of the fingers and toes are grayish-white; 7） the iris is golden-yellow. In addition, the phylogenetic tree showed that all the individuals of R. zhoukaiyae sp. nov. clustered into one distinct clade which suggested the validity of this species. This results could also be used to the support of species delimitation. Currently, this species is known only from mid-elevation montane evergreen forest in the Dabie Mountains of west Anhui, China.

Tectonic Affinity, T-t Path and Uplift Trajectory of Eclo gites from Northern Dabie Mountains, Central-Eastern China

Petrologic geochemistry and isotopic chronology of the eclogites sug ge st that most of the eclogites in northern Dabie Mountains produced from the Tria ssic Yangtze subducted continental crust (lower crust and formed during the deep subduction) and the metamorphosed mafic untramafic belt with eclogite, marble and meta peridotite blocks around the Mozitan Xiaotian fault zone may represen t the meta tectonic melange produced during the active subduction of an ancient oceanic slab and subsequent collision between the Yangtze and North China conti nental plates. The cooling history of the eclogites from ～900 ℃ to 300 ℃ can b e subdivided into three stages: one isothermal stage and two rapid cooling stage s. The initial stage between (230±6) and 210 Ma was a near isothermal or tempe rature rise process corresponding to the retrograded metamorphism of granulite facies with a rapid uplift of 4 mm/a, then two fast cooling stages occurred with cooling rate of ～10 ℃/Ma during 210 Ma to (172±3) Ma and ～4 ℃/Ma durin g (172±3) Ma to 130 Ma. After the peak metamorphism of eclogite facies, their in itial isothermal stage with slower uplift rate and cooling rate and high T overprinting of granulite facies metamorphism is the major difference between t he eclogites in northern Dabie Mountains from those in southern Dabie Mountains. This may be one of the most important reasons to preserve few evidences of earl ier ultrahigh pressure metamorphism.

U-Pb Dating of Marble Associated With Eclogite from the Dabie Mountains,East China

Marble is associated with ultrahigh pressure eclogite in the Dabie Mountains.East China.U-Pb isotope data for the marble define a 238U-206Pb isochron age of 435±45a with an initial 206Pb/204Pb value of 18.075±0.006,The age of -435 Ma is interpreted to represent the time of limestone diagensis rather than the time of metarmorphic resetting accompanied by the formation of the ultrahigh pressure eclogites at Triassic.The paleontologic and stratigraphic studies also favor a local excursion in the carbon isotopic composition of the latest ordovician water within a sedimentary basin between the Sino-Korean and Yangtze cratos.Becasuse the latest ordovician limestone was involved in the eclogite formation,the continental collision between the Yangtze and Sino-Korean Plates would postdate ordovican.

Orogenic Model of the Eastern Dabie Mountains, Central China

Based on the detailed geological mapping on the scale of 1/50,000 from the eastern Dabie Mountains, central China, an orogenic model of the Dabie belt can be elaborated. The mapping area crosses three litho tectonic belts in the Dabie Mountains including, from south to north, the southern Dabie collisional complex, northern Dabie metamorphic complex and northern Huaiyang metamorphic belts. The southern Dabie metamorphic complex is composed of eclogite blocks, HP metasediments and MP gneisses which have experienced quite different stages of metamorphism. The northern Dabie metamorphic complex and northern Huziyang metamorphic belt are mainly comprised by various supracrustal rocks and gneisses which have been only subjected to the MP metamorphism of amphibolite and epidote amphibolite facies. The central west part of the mapping area is mostly distributed by the Yanshanian magmatics include 4 superunits such as the Yaohe, Huangbai, Penghe and Dahongyan superunits which are closely related to the Dabie orogenic process and recorded an orogenic history from the ending of regional MP metamorphism to the overprinting of the Circum Pacific tectonic domain. The faults in the area include the early stage thrust faults, late stage decollement faults and later stage overprinting strike slip and some thrust faults. Based on these features, the Dabie orogenic process can be divided into 5 stages i.e. the early B type subduction stage, the A type subduction stage, the main collisional stage, the late orogenic uplifting and decollement stage and the post orogenic overprinting stage. Consequently, the Dabie orogenic belt should be a Mesozoic collisional type orogenic belt and has an evolutional history similar to the other typical orogenic belt in the world such as Alps and Himalaya.

TEM and HRTEM Study of Microstructures in Omphacite from UHP Eclogites at Shima,Dabie Mountains,China

Transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) analyses have been performed on omphacite from ultra-high pressure (UHP) eclogites at the locality of Shima, Dabie Mountains, China. TEM reveals that the microstructures consist dominantly of dislocation substructures, including free dislocations, loops, tiltwalls, dislocation tangles and subboundaries. They were produced by high-temperature ductile deformation, of which the main mechanism was dislocation creep. Antiphase domain (APD) boundaries are common planar defects; an age of 470 ± 6 Ma for UHP eclogite formation has been obtained from the equiaxial size of APDs in ordered omphacites from Shima, coincident with ages given by single-zircon U-Pb dating (471 ± 2 Ma). HRTEM reveals C2/c and P2/n space groups in different parts of one single omphacite crystal, and no exsolution is observed in the studied samples, which is attributed to rapid cooling. It is suggested that the UHP eclogites underwent a long period of annealing at high temperatures, followed by relatively rapid cooling. These data provide valuable information for the formation and exhumation mechanism of UHP eclogites in the Dabie high-pressure (HP) and UHP metamorphic belt.

Modern pollen-vegetation relationships along altitudinal vegetation belts in the Leigong Mountain of southwestern China

Understanding the distribution,dispersal,and correlation of modern pollen with vegetation in mountainous regions is essential for establishing accurate modern analogs for fossil pollen records.This study,conducted in Leigong Mountain on the YunnanGuizhou Plateau of southwestern China,involved the collection of 35 surface soil samples from diverse vegetation communities along an elevational gradient ranging from 1210 to 1875 meters.The results reveal a close correspondence between modern pollen assemblages and vegetation zones.Principal Component Analysis(PCA)results indicate that pollen assemblages can effectively distinguish between subtropical montane evergreen broad-leaved forest(SEBF)and subtropical montane deciduous broadleaved forest(SDBF).However,both SEBF and SDBF show significant overlap with subtropical montane evergreen-deciduous broad-leaved mixed forest(SEMF).Detrended Correspondence Analysis(DCA)results clearly distinguish the three vegetation zones,and the first axis of DCA shows a significant positive correlation with elevation(p<0.01,R=0.48).Discriminant Analysis(DA)successfully assigns 94.4%of the modern pollen samples to their respective vegetation zones.Pollen taxa such as Impatiens,Astertype,and Rosaceae exhibit significant indicative capabilities for the SEBF zone,effectively distinguishing this vegetation zone from others.Pinus and Alnus display overrepresentation in the Leigong Mountain region,while Quercus(D,deciduous-type)and Poaceae exhibit high representation in the SEBF zone.In the SEBF zone,both pollen diversity and richness are the lowest.Our study reveals the complex relationship between the richness and diversity of pollen and vegetation.The diversity and richness of tree and shrub pollen are found to be lower than those of the corresponding plants.The pollen-vegetation relationship elucidated in this study serves as a critical reference for reconstructing ancient environments from fossil pollen retrieved in this region.

Dispersal behaviors stimulated by habitat alterations in golden snub-nosed monkeys(Rhinopithecus roxellana)in the Qinling Mountains, China

DEAR EDITOR,Combining location data, species distribution modeling(Max Ent), and major conservation events, we analyzed historical distribution changes in golden snub-nosed monkeys(Rhinopithecus roxellana) in the Qinling Mountains of China.

A BEAUTIFUL CHINA WITH LUCID WATERS AND LUSH MOUNTAINS

Firmly upholding the belief that lucid waters and lush mountains are invaluable asset s, proposed by Chinese President Xi Jinping, China has prioritized eco-environmental protection and green development, making great strides in building a beautiful China.

Raman determination on micro-diamond in eclogite from the Dabie Mountains, Eastern China

THE micro-diamond inclusions in garnet from eclogite in the Dabie Mountains have been reported by the present authors. However, Prof. Liou, J. G. and Dr. Zhang, R. Y. from the Stanford University of USA have expressed their doubts about our discovery of micro-diamond, considering its weak intensity of Raman peak in our determination. Recently, we have determined the micro-diamond inclusion from the same sample 9010574 (fig. 1), tested

SHRIMP Geochronology of Volcanics of the Zhangjiakou and Yixian Formations, Northern Hebei Province, with a Discussion on the Age of the Xing'anling Group of the Great Hinggan Mountains and Volcanic Strata of the Southeastern Coastal Area of China

A zircon U-Pb geochronological study on the volcanic rocks reveals that both of the Zhangjiakou and Yixian Formations, northern Hebei Province, are of the Early Cretaceous, with ages of 135-130 Ma and 129-120 Ma, respectively. It is pointed out that the ages of sedimentary basins and volcanism in the northern Hebei -western Liaoning area become younger from west to east, i. e. the volcanism of the Luanping Basin commenced at c. 135 Ma, the Luotuo Mount area of the Chengde Basin c. 130 Ma, and western Liaoning c. 128 Ma. With a correlation of geochronological stratigraphy and biostratigraphy, we deduce that the Xing'anling Group, which comprises the Great Hinggan Mountains volcanic rock belt in eastern China, is predominantly of the early-middle Early Cretaceous, while the Jiande and Shimaoshan Groups and their equivalents, which form the volcanic rock belt in the southeastern coast area of China, are of the mid-late Early Cretaceous, and both the Jehol and Jiande Biotas are of the Early Cretaceous, not Late Jurassic or Late Jurassic-Early Cretaceous. Combining the characteristics of the volcanic rocks and, in a large area, hiatus in the strata of the Late Jurassic or Late Jurassic-early Early Cretaceous between the formations mentioned above and the underlying sequences, we can make the conclusion that, in the Late Jurassic-early Early Cretaceous, the eastern China region was of high relief or plateau, where widespread post-orogenic volcanic series of the Early Cretaceous obviously became younger from inland in the west to continental margin in the east. This is not the result of an oceanward accretion of the subduction belt between the Paleo-Pacific ocean plate and the Asian continent, but rather reflects the extension feature, i.e. after the closure of the Paleo-Pacific ocean, the Paleo-Pacific ancient continent collided with the Asian continent and reached the peak of orogenesis, and then the compression waned and resulted in the retreating of the post-orogenic extension from outer orogenic zone to inner part (or collision zone). The determination of the eruption age of the volcanics of the Zhangjiakou Formation definitely constrains the switch period, which began in the Indosinian and finished in the Yanshanian, that is, 140-135 Ma. The switch is concretely the change from the approximate E-W Paleo-Asian tectonic system to the NE to NNE Pacific system, and the period is also the apex of a continent-continent collision and orogenesis of subduction, being consumed and eventually disappearing of the Paleo-Pacific ancient continent, and all the processes commenced in the Indosinian. While the following post-orogenic large-scale eruption in the Early Cretaceous marks the final completeness of the Paleo-Pacific structure dynamics system.

Carboniferous Post-collisional Rift Volcanism of the Tianshan Mountains, Northwestern China

The Tianshan Carboniferous post-collisional rift volcanic rocks occur in northwestern China as a large igneous province. Based on petrogeochemical data, the Tianshan Carboniferous post-collisional rift basic lavas can be classified into two major magma types: (1) the low-Ti/Y type situated in the eastern-central Tianshan area, which exhibits low Ti/Y (<500), Ce/Yb (<15) and SiO2 (43-55%), and relatively high Fe2O3T (6.4-11.5%); (2) the high-Ti/Y type situated in the western Tianshan area, which has high Ti/Y (>500), Ce/Yb (>11) and SiO2 (49-55%), and relatively low Fe2O3T (5.8-7.8%). Elemental data suggest that chemical variations of the low-Ti/Y and high-Ti/Y lavas cannot be explained by fractional crystallization from a common parental magma. The Tianshan Carboniferous basic lavas originated most likely from an OIB-like asthenospheric mantle source (87Sr/86Sr(t) ≈ 0.703-0.705, eNd(0 = +4 to +7). The crustal contamination and continental lithospheric mantle have also contributed significantly to the formation of the basic lavas of the Tianshan Carboniferous post-collisional rift. The silicic lavas were probably generated by partial melting of the crust. The data of this study show that spatial petrogeochemical variations exist in the Carboniferous post-collisional rift volcanics province in the Tianshan region. Occurrence of the thickest volcanics dominated by tholeiitic lavas may imply that the center of the mantle-melting anomaly (mantle plume) was in the eastern Tianshan area at that time. The basic volcanic magmas in the eastern Tianshan area were generated by a relatively high degree of partial melting of the mantle source around the spinel-garnet transition zone, whereas the alkaline basaltic lavas are of the dominant magma type in the western Tianshan area, which were generated by a low degree of partial melting of the mantle source within the stable garnet region, thus the basic lavas of the western Tianshan area might have resulted from relatively thick lithosphere and low geothermal gradient.

Petrology, Metamorphic Process and Genesis of The Dabie--Sulu Eclogite Belt, Eastern--Central China

The Qinling-Dabie-Sulu high-pressure and ultra-high pressure metamorphic belt wasformed by subduction and collision between the North China and Yangtze plates. The study ofthe eclogite belt is very important in understanding the evolution of the Qinling Dabie orogen. Inthe present paper the geology, petrology, minerology and chronology of the eclogites in the Dabieand Sulu areas are described. The principal conclusions of this work are as follows: (1) Based up-on the field occurrence and the P-T conditions of the eclogites, two types of eclogite can be dis-tinguished: Type 1—the low-temperature and high-pressure eclogite in the mid-late Proterozoicmetamorphic series, and Type 2—the ultra-high pressure eclogite in the late Archaean to earlyProterozoic metamorphic complex. In the Dabie area, the ultra-high-pressure eclogite,high-pressure eclogite and epidote-blueschist units are nearly parallel to each other and stretchintermittently from north to south. (2) The P-T conditions of the high-pressure eclogites and ul-tra-high pressure eclogites have been estimated. The former are formed at 450-550℃ and1.4-1.6 GPa; while the latter at 650-870℃ and >2.7-2.9 GPa in the Dabie area and at820-1000℃ and >2.8-3.1 GPa in the Sulu area. The metamorphic temperatures of the eclogitesincrease progressively from west to east. (3) The ultra-high pressure eclogites were subjected to 5stages of metamorphism: pre-eclogite epidote amphibolite facies, peak coesite eclogite facies,post-eclogite amphibolite facies, epidote-blueschist facies or epidote amphibolite facies andgreenschist facies. The general features of the PTt path of the ultra-high pressure eclogite are:clockwise pattern, progressive metamorphism being a process of slow increasing temperature andrapid increasing pressure, and the retrogressive section with nearly isothermal decompression atthe early stage, isobaric cooling at the middle stage and nearly isothermal decompression at thelate stage. (4) At least two stages of high-pressure metamorphism occurred in the orogenic belt:the high-pressure eclogite and ultra-high pressure eclogite were formed by the subduction of theoceanic crust northward beneath the North China plate or the Dabie block during theCaledonian; while the epidote-blueschist belt came into being by subdution and collision be-tween the two continental plates during the Indosinian. (5) Due to the continuous sequentialsubduction of the cold plate, the ultra high-presssure metamorphic rocks were uplifted to thecrust by the underplating processes. They can be preserved just because of the 'frozen effect' re-sulting from the continuous subduction of the cold plate. (6) The carbonates, such as magnesite,breunnerite, aragonite and dolomite, and the H_2O-bearing minerals, such as phengite, epidoteand zoisite, were stable during the high-pressure and/or ultra-high pressure metamorphism.

Geochemical Characteristics and Genesis of the Granitic Gneisses from the Southeastern Dabie Mountains

The granitic gneisses from the ultrahigh-pressure (UHP) metamorphic terrain of the southeastern Dabie Mountains encompass two types: monzonitic granitic gneiss and alkali-feldspar granitic gneiss, which are characterized by rich alkalis, poor CaO, high FeO/MgO, particularly high Ba, Rb, Th, Ta, REE (except Eu), Ga, Nb and Zn, and low Sr, Eu, Cr, Co and Ni. The gneisses, particularly the alkali-feldspar granitic gneiss, have typical chemical characteristics of A-type granites. They resulted from partial melting of crustal materials existing in the rift zone along the northern margin of the South China block during the Neoproterozoic. These gneisses might not have undergone UHP metamorphism during the late Triassic, but were involved into UHP rocks by the tectonic mixing process and kept the exhumation message of the UHP rocks from the middle and upper crust.