For the spinel peridotite xenoliths, the precision of the clinopyroxene-orthopyroxene-olivine oxybarometers (Luth and Canil, 1993, Contributions to Mineralogy and Petrology, 113: 236–248) is approximately ±0.52 log units based on very limited experimental data; for the spinel-orthopyroxene-olivine oxybarometers, the Miller et al. (2016, Journal of Petrology, 57: 1199–1222) versions (±0.26–0.42 log units for the three formulations) and the Ballhaus et al. (1991, Contributions to Mineralogy and Petrology, 107: 27–40) version (±0.47 log units) are the most precise. Taking the Ballhaus et al. (1991) oxybarometer as an example, based on the experimental data and natural spinel peridotite xenoliths in which the ferric iron contents of all the minerals have been determined by Mössbauer spectroscopy, numerical simulation of errors suggests that: (a) Errors of input P–T conditions (±70 °C / ±0.3 GPa) may translate to computed logfO2 errors of ±0.48–1.50 log units; (b) Analytical error (±0.01) of Fe3+/ΣFe of spinel can propagate to computed logfO2 errors of ±0.06–0.58 log units; (c) Electron probe microanalysis (EPMA) analytical errors of spinel and olivine may introduce computed logfO2 errors of ±0.19 log units; (d) the total random error of the oxybarometer is ±0.92 log units when simultaneously considering the errors of input P–T conditions, errors of Fe3+/ΣFe of spinel and errors of EPMA analyses of spinel and olivine; and (e) the total error of the oxybarometer is ±1.00 log units, combined with its precision and random error.

The equilibrated metamorphic mineral assemblage hornblende + plagioclase + quartz +/- garnet always appears in either amphibolite, mafic granulite, metapelite, metasemipelite, calcic schist/gneiss or orthogneiss. However, applicability of the present garnet-hornblende (GH) and the plagioclase-hornblende (PH) geothermometers as well as the garnet-hornblende-plagioclase-quartz (GHPQ) and plagioclase-hornblende (PH) geobarometers have seldom been systematically discussed. In this work, we first certified the consistency (+/- 1 kbar) of the empirically calibrated garnet-biotite-plagioclase-quartz (GBPQ) geobarometer with the experimentally calibrated garnetAl2SiO5-plagioclase-quartz (GASP) geobarometer. Then, we applied the GH and PH geothermometers as well as the GHPQ and PH geobarometers to experimental data to check their precision, and afterwards checked their accuracy by applying them to the collated natural diverse metamorphic rocks. It is concluded that: (a) For garnetbearing rocks, the GH geothermometer iterated with the GHPQ geobarometer (Dale et al., 2000, Contributions to Mineralogy and Petrology, 140: 353-362) can be applied to simultaneously yield metamorphic P-T conditions; (2) For garnet-absent rocks, the PH geothermometer (Molina et al., 2021, American Mineralogist, 106: 782-800) combined with the PH geobarometer (Molina et al., 2015, Lithos, 232: 286-305) to obtain metamorphic P-T conditions simultaneously; and (c) Reversed phase equilibrium experiments are quite needed to precisely and accurately calibrate the PH geothermobarometers, adopting accurate activity models of amphibole and plagioclase.

Garnet serves as a key mineral in some granitic rocks, offering unique constraints on melt generation and crustal evolution processes. This study presents an integrated petrological, geochemical, geochronological, and phase equilibrium investigation of garnetbearing granite from the Chengde area of the Trans-North China Orogen. The garnet exhibits homogeneous major element compositions but distinct trace element zoning patterns, characterized by a decrease in yttrium and heavy rare earth element concentrations from core to rim, which is indicative of growth zoning. Textural evidence of garnet-quartz intergrowth, coupled with trace element variations, documents a multistage growth history involving initial metamorphic nucleation followed by rim development under suprasolidus conditions. Phase equilibrium modeling constrains the garnet formation conditions to 10.7-11.1 kbar and 760-775 degrees C, similar to thermometric estimates of 685-757 degrees C. Comprehensive datasets, including whole-rock geochemistry, zircon trace elements, and garnet geochemistry, collectively indicate an S-type granite origin from claypoor metapelitic sources. Magmatic emplacement occurred at 1886-1875 Ma, followed by metamorphic overprinting at 1855-1802 Ma. These findings highlight the utility of garnet as a robust petrogenetic indicator, providing key insights into peritectic phase entrainment during crustal anatexis. The results significantly advance our understanding of granite formation mechanisms in collisional orogens and elucidate the processes of lowercrustal reworking during Paleoproterozoic orogenesis.

Tectono-metamorphic mélanges are critical to understanding orogenic belts, yet their formation processes remain controversial. The Mogutai (MGT) massif in the Dunhuang orogenic belt, NW China, provides an ideal window into this issue. Metamorphic rocks in the MGT mélange belt occur as coherent thrust sheets or exhibit "blocks-in-matrix" fabrics. Petrological, mineral chemical, and geochronological data indicate that granulites in the western part of the belt record peak P-T conditions of 12.8-16.1 kbar and 710-820 °C, with metamorphic ages of 418-419 Ma. Integration with published data reveals that the MGT mélange belt comprises metamorphic rocks formed at various depths and times, and exhumed along different paths. Detailed mapping and structural analysis indicate that rocks in the belt were assembled during two levels of tectonic mixing. First, an imbricated thrust system stacked thrust sheets of different origins of diverse P-T histories. Second, within individual thrust sheets, blocks-in-matrix fabrics developed, incorporating blocks with diverse P-T histories within a shared matrix. The entire system was subsequently overprinted by strike-slip deformation. Field observations and analytical data demonstrate that coherent thrust sheets, blocks, and matrices formed independently and were assembled in the Mogutai mélange belt over a prolonged period from the Ordovician to the Carboniferous. Permian-Triassic sinistral strike-slip further modified the belt. It can be concluded that the tectono-metamorphic mélange belt can undergo a prolonged formation process and assembled progressively by emplacement of rock bodies of various P-T-t conditions (“metamorphism-first” model), instead of a “assembly-first” model that all rock bodies in the mélange belt were assembled first then underwent unified evolutionary history . It suggests that different rock bodies from tectono-metamorphic mélange belt cannot represent a united P-T-t evolutionary history of an orogenic belt. Each rock body may only record its own unique evolution.

The Mogutai block, located in the eastern segment of the Paleozoic Dunhuang Orogenic Belt, northwestern China, represents a typical tectono-metamorphic melange. It exhibits the characteristic block-in-matrix structure, with the matrix being metasedimentary rocks and the tectonic blocks consisting of amphibolite and mafic granulite. Seven representative metamorphic rocks were collected in a limited area with 1.3 km long and 1.2 km wide. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating of metamorphic zircon of these rocks reveals that the metamorphic events occurred at 462-350 Ma. Different mineral assemblages of the metamorphic rocks were formed sequentially in the three distinct metamorphic stages, i.e., the prograde metamorphism (M1), the peak metamorphism (M2), and the retrograde metamorphism (M3). Diverse clockwise metamorphic pressure - temperature (P - T) paths were reconstructed by geothermobarometry, including the P - T paths of the mafic granulite passing from 4.6 - 6.1 kbar/630 - 650 degrees C (M1) through 11.9 - 16.3 kbar/710 - 830 degrees C (M2) and finally to 7.8 - 8.7 kbar/720 - 770 degrees C (M3), as well as from 6.7 kbar/720 degrees C (M1) through 8.0 kbar/750 degrees C (M2) and finally to 4.6 kbar/700 degrees C (M3) for the garnet amphibolite, respectively. Different peak metamorphic P - T conditions of the metapelitic lenses were estimated to be between 3.7 - 11.9 kbar and 610 - 780 degrees C. The significant differences in peak P - T conditions of these metamorphic rocks suggest that they were subducted to varying depths during the subduction process, and finally were amalgamated during exhumation, resulting in formation of the Mogutai tectono-metamorphic melange.

Subduction initiation in hot subduction zones leaves a distinct geological record characterized by forearc basalt−boninite−arc tholeiite assemblages and supra-subduction zone ophiolites. However, cold subduction initiation usually lacks these diagnostic features, complicating its identification in the orogenic record. The Central Asian Orogenic Belt has experienced multiple subduction initiation events, making it a natural laboratory for studying such cases. This study presents a new method for identifying cold subduction initiation in the Anqi accretionary complexes in southern West Junggar, Northwest China. By employing field investigation, large-scale mapping, geochemistry, and geochronology, we divided the target area into five tectonic units. Unit 1 predominantly comprises ca. 410 Ma turbidites that deformed before 314 Ma, indicating Devonian ocean basin rifting and the generation of the newly formed ocean. Unit 2 consists of coherent trench turbidites deposited after 358 Ma and deformed before 342 Ma. Unit 3 is an ocean plate stratigraphy mélange formed after ca. 347 Ma. Together, units 2 and 3 indicate an Early Carboniferous accretionary complex distributed along the Anqi fault. Unit 4 contains ca. 314 Ma coherent turbidites, representing a Late Carboniferous mature accretionary complex. Unit 5 comprises post−327 Ma coarse sediments overlying other units, representing a trench-slope basin. Significantly, the detrital zircon provenance of the Early Carboniferous accretionary complex (units 2 and 3) shows a peak predating any intrusive plutons in the area, indicating an immature initial arc stage with mainly eruptive lavas but lacking intrusive rocks. The Early Carboniferous accretionary complex is the only geological record of this initial subduction in the region, suggesting that it preserves evidence of cold subduction initiation.

The Dongbatu Mountain, located in the northeastern segment of the Paleozoic Dunhuang Orogenic Belt, northwestern China, provides critical constraints in understanding the tectono-thermal evolution of this orogenic belt. The amphibolite exists as tectonic puddings preserved in the metapelite, indicative of tectonic-metamorphic melange. Three different metamorphic mineral assemblages were found in the amphibolite samples, i.e., the prograde assemblage (M1) consisting of tiny inclusion minerals preserved in the garnet interior, the metamorphic peak assemblage (M2) comprising garnet, amphibole, quartz, plagioclase, biotite plus accessary minerals, as well as the retrograde assemblage (M3) consisting of the "white-eye socket" rimming the garnet. Phase equilibrium modeling and conventional geothermobarometry define clockwise pressure-temperature (P-T) trajectories, characteristic of orogenic background. The metamorphic peak P-T conditions (8.1-10.3 kbar and 660-770 degrees C) suggest that the metamorphic event is ascribed to the amphibolite facies and the medium-P/T facies series. Zircon U-Pb ages indicate that the protolith crystallized at-1.60 Ga and the metamorphism occurred at-381- 370 Ma. The petrochemical data suggest that the amphibolite originated in an oceanic-island setting of-1.60 Ga, and was subsequently incorporated into the evolving orogenic system in the Late Devonian, suggesting the tectonic-metamorphic melange formed during the tectonic exhumation.

The late Archean granulite was found as tectonic slices amalgamated with the late Paleoproterozoic metamorphic rocks in the Pingquan area within the Paleoproterozoic Trans-North China Orogen. The late Archean intermediate granulite rocks with distinctive 'red-eye socket' texture record anticlockwise P-T paths and were metamorphosed at similar to 2.5 Ga, whereas the late Paleoproterozoic mafic granulite and amphibolite with "white-eye socket" texture record clockwise P-T paths and were metamorphosed at 1.86-1.80 Ga. The Ar-40/Ar-39 ages (1.81-1.79 Ga) of hornblende further constrain the synchronous exhumation of these disparate metamorphic units, providing critical constraints on the Paleoproterozoic uplifting and cooling process. The juxtaposition of late Archean continental fragments with Paleoproterozoic subduction-related lithologies within a confined orogenic zone highlights the capacity of orogenic systems to preserve both juvenile accreted terranes and reworked more ancient continental fragments, implying remarkable longevity of continental materials through accretionary cycles. This phenomenon suggests that without detailed metamorphic-petrochronological analyses, amalgamated tectonic slices formed at different ages may remain unresolved, potentially leading to erroneous interpretations.

A population of garnet porphyroblasts, spaced apart between c. 6 mm and 40 mm, in a metapelite of the kyanite zone from the Danba dome was investigated to assess the equilibration length scales of major and trace elements in the intergranular medium during garnet crystallization. Garnet crystallization occurred from similar to 525 degrees C /similar to 6.2 kbar to peak conditions of similar to 635 degrees C /similar to 6.2-7.7 kbar. Enrichments in the concentrations of Fe, Nb, Cr, and V, as well as depletions in the contents of Ca, Li, Na, Y, and heavy rare earth elements (HREE) in the early-grown garnet portions indicate that garnet initially pseudomorphed biotite. Results of the statistical analysis of the garnet 3D distribution suggest clustering nucleation mechanisms, providing textural evidence of spatial variations in the distributions of energetically favourable nucleation sites early in the garnet crystallization history. With the exception of the core domains of two early-grown crystals (SC1 and SC8), the distributions of Mg, Ca, Mn, and Fe reflect growth zoning of a garnet population, overprinted by intracrystalline diffusion. The concentrations of Li, Na, Sc, Y, Dy, and Ho in simultaneously grown segments of all garnet crystals are quantitatively comparable, suggesting that the intergranular medium can be considered compositionally homogeneous with regards to these elements, indicative of rapid intergranular chemical transport over a distance of at least c. 40 mm. Differences in the concentrations of Er, Tm, Yb, and Lu are only observed in crystals more than c. 12 mm apart, with the concentrations of these elements decreasing as their atomic masses increase. This systematic trend is interpreted to reflect the possible influence of the relative atomic masses of these elements on the length scales of their diffusion through the intergranular medium during garnet growth. Elements that were heterogeneously distributed across the intergranular medium at the mm-scale during garnet growth include Cr and Zr, reflecting the compositional heterogeneity of the protolith, preserved due to the negligible transport of these elements during the metamorphism. This study emphasizes that the equilibration length scales of trace elements during metamorphism may be larger than previously assumed, presumably depending on the duration of the metamorphism.

Understanding the growth history of metamorphic garnet is crucial for revealing metamorphic evolution and distinguishing thermodynamic and kinetic contributions during metamorphism. Garnet crystals in metapelites from a Barrovian-type metamorphic sequence in the Danba dome (SW China) record microstructural and compositional patterns that provide insights into the petrogenetic evolution of the samples during metamorphism. While sector-zoned garnet in graphite-rich layers and garnet crystals with trace element and microstructural evidence of biotite overgrowth are common in the lower grade garnet-staurolite-kyanite zones, these features are absent in the higher grade sillimanite zone. Reactions associated with accessory phases during garnet growth may explain the yttrium (Y) and heavy rare earth element (HREE) annuli observed in garnet of rocks from the garnet and staurolite zones. The absence of these Y and HREE annuli in garnet of rocks from the sillimanite zone is explained by variations in the bulk-rock composition of the samples, which resulted in different pressure-temperature (P-T) conditions of garnet-forming and accessory phase breakdown reactions (e.g., monazite-allanite transition). Whereas isopleth thermobarometry applied to the cores of the largest garnet crystals demonstrates initial garnet growth close to equilibrium in a rock that was collected very close to the garnet isograd, different degrees of driving force (similar to 1.2-2.3 kJ per mole 12-oxygen garnet) were required for garnet nucleation in other rocks, pointing to varying reaction affinities for initial garnet growth. Garnet crystallization modelling for a rock from the garnet zone also predicts the observed mineral assemblages and garnet growth zoning exceptionally well and yields peak P-T conditions that are identical to the results obtained by conventional thermobarometry. Taken together, these results imply that the growth of metapelitic garnet in the Danba dome was controlled by both thermodynamic (e.g., P-T composition (X) relations) and kinetic (e.g., elemental mobility, protolith heterogeneity, reaction history, and chemical driving force for garnet nucleation) factors. This study underscores the specific impacts of these factors on the growth characteristics of metapelitic garnet in a regional metamorphic context.

The errors in rebuilding the experimental oxygen fugacity (expressed as its common logarithm, logfO(2)) of the Stagno et al. (2013, Nature, 493: 84-88) garnet-orthopyroxene-olivine oxybarometer are within +/- 1.2 log units and this oxybarometer is relatively the most precise one among the six different versions, although experimental data are not sufficient. If we adopt ferric iron contents of the related phases estimated by charge balance method, the computed logfO(2) values were erroneously increased to > + 0.5 log units for all the oxybarometers compared to those determined by direct experimental measuring methods of ferric iron contents. Input pressure-temperature (P-T) errors of +3 kbar/+70 degrees C or - 3 kbar/-70 degrees C may propagate to logfO(2) errors of +0.48 similar to +1.60 log units or - 0.52 similar to -1.31 log units, respectively, for the oxybarometers. Application of the garnet-orthopyroxene-olivine oxybarometers does need direct measurement of ferric contents of the phases, such as M & ouml;ssbauer spectroscopy, synchrotron Fe-edge X-ray absorption near edge structure spectroscopy (XANES) or flank method.

Figure S1: Plot of amphibole and plagioclase compositions. Figure S2: Cathodoluminescence images of the dated zircon grains. Figure S3: Chondrite normalized REE patterns of dated zircon grains. Table S1: Data of standard materials for bulk-rock chemical analyses. Table S2: Representative mineral compositions of the studied samples. Table S3: SHRIMP zircon U-Pb dating results. Table S4: Trace element concentrations of zircon grains of the selected samples. Table S5: SIMS monazite U-Pb dating results for sample 21DB89. Table S6: Matrix-type biotite compositions and temperature results from Ti-in-biotite thermometry. Table S7: Ti contents in zircon and temperatures from Ti-in-zircon thermometry.

The origin of coeval magmatic and metamorphic rock associations is of great significance in tectonic interpretations. In this study, spatially associated cordierite granite (S-type), metapelite and diorite from the Qinghai Nanshan (NW China) area were dated to be coeval at similar to 247-244 Ma. The cordierite granite and metapelite have almost uniform peak pressure-temperature (P-T) conditions of c. 3.8-5.0 kbar / c. 740-790 degrees C, indicating a geothermal gradient of higher than similar to 40 degrees C / km. The zircon crystallization temperature of the diorite pluton is estimated to be c. 760 degrees C by Ti-in-zircon thermometer, putting a lower limit of temperature for dioritic magma. Both cotectic (phenocrysts) and restitic cordierite crystals were identified in the cordierite granite. Similar whole rock compositions of the coarse-grained cordierite granite and the metapelite in the Qinghai Nanshan area as well as the average / median pelite worldwide, imply formation of the granite was from almost complete melting of autochthonous metapelite, followed by in-situ recrystallization with negligible / without melt extraction. These data indicate that the cordierite granite and metapelite are both products of the contact aureole surrounding the diorite pluton. This study presents an example for better understanding the transition from high-grade metapelite to S-type granite.

It is known that different metamorphic rocks may have different abilities in recording metamorphic processes. Here, we report microscopically interlayered garnet amphibolite and metapelite layers in a rock from the Danba dome in eastern Tibetan Plateau, SW China. Both rock types exhibit similar garnet zoning patterns, biotite and plagioclase compositions, as well as peak P-T conditions (7.3-8.0 kbar / 700-725 C-degrees for metapelite and 7.1-8.4 kbar / 690-710 C-degrees for garnet amphibolite, respectively), indicating a global thermodynamic equilibrium state and the same metamorphic record of the two distinct layers. However, medium-sized garnet exhibits homogeneous core compositions and biotite preserves lower Ti and Fe# [= Fe2+ / (Fe2+ + Mg)] at the lithological interface, possibly indicating more intense chemical homogenization at the metamorphic peak and retrograde modification at the interface caused by the possible presence of vast fluid. Sensitive high -resolution ion microprobe (SHRIMP) U-Pb dating of metamorphic zircon show a wide dispersion of ages (c. 200-155 Ma), overlapping previous age data reported for this region. These results indicate that differences in petrochemical compositions may not lead to significant distortion in the metamorphic records, including garnet zoning patterns and peak P-T conditions. This further suggests that metamorphic rocks originating from diverse protoliths, which exhibit varying peak P-T conditions within the same locality, could either be a result of the tectonic juxtaposition of distinct tectonic slices or the influence of varying fluid conditions.

Texturally and chemically sector-zoned garnet crystals in two contiguous metapelitic rocks from the Danba dome, eastern Tibetan Plateau (SW China) were investigated. A petrographic boundary in one of the rocks (sample 21DB103) separates a thin section into two zones. Whereas one zone containing sector-zoned garnet and fined-grained matrix is enriched in graphite and quartz, the other zone encompasses garnets with relatively regular habit in a coarse-grained matrix poor in graphite and quartz. The two zones are distinct with regards to the chemical compositions of biotite and plagioclase, as well as the major and trace element zoning patterns of garnet. Electron back-scattered diffraction analysis shows that all the investigated garnet crystals in this sample are single crystals. Relatively higher P-T conditions are estimated for the initial growth of sector-zoned garnet ( 5.0 kbar / 540 ℃) compared to the regular garnet ( 3.8 kbar / 510 ℃) in this rock, possibly indicating that growth of the sector-zoned garnet postdates growth of the regular garnet. Texturally and chemically radial sectors with garnet-quartz intergrowths and irregular sectors of garnet are preserved in the other graphite-rich rock (sample 21DB104). Isopleth thermobarometry applied to the core of the largest garnet crystal exhibiting sector zoning in this sample reveals P-T conditions of initial garnet crystallization ( 4.4 kbar / 512 ℃) that deviate far ( 0.8 kbar/ 45 ℃) from equilibrium, potentially indicating significant overstepping required for garnet nucleation. Plagioclase inclusions in garnet display varying trace element abundances, indicating their replacements of different preexisting phases. These results suggest that abundant graphite may play a pivotal role in changing fluid conditions and reducing the solubility of SiO2 to grow sector-zoned garnet, as well as impeding matrix coarsening. Development of sector-zoned core and dodecahedral faces of garnet may be related to rapid growth with changes in crystal morphology. Irregular sectors may have developed through fluid infiltration and local chemical adjustments.

Amphibolite- to granulite-facies rocks are widely distributed in the Hengshan Complex, middle Trans-North China Orogen, and the high-pressure (HP) mafic granulite has been recently identified in the southern Hengshan area. The HP mafic granulite and amphibolite occur as rootless tectonic boudins/lenses within the TTG (tonalite-trondhjemite-granodiorite) gneiss/metapelite, indicative of typical "block-in-matrix" texture of metamorphic-tectonic melange. Three to four generations of metamorphic mineral assemblages that correspond to the prograde (M1), peak (M2), and retrograde (M3-M4) stages, are recognized in these rocks. Conventional geothermobarometry and phase equilibrium modeling yield peak P-T conditions of 10.8-13.8 kbar/754-799 degrees C for the HP mafic granulite and 7.3-9.0 kbar/690-725 degrees C for the supracrustal rocks, respectively. A clockwise P-T path with near-isothermal decompression (ITD) and subsequent near-isobaric cooling (IBC) segments is reconstructed for the HP mafic granulite, indicating a dynamic subduction-collision-exhumation process that unfolded during an orogenic event. Secondary ion mass spectrometry (SIMS) U-Pb dating of zircon yields metamorphic ages of ca. 1.91-1.83 Ga, representing the long-lived tectono-metamorphic event caused by collision between the Eastern and Western Blocks along the Trans-North China Orogen. It is hypothesized that the tectono-metamorphic melange in the area originated from the tectonically juxtaposition of metamorphic rocks that had diverse protoliths, different peak P-T conditions and discrepant metamorphic ages. This complexity may be a hallmark of Paleoproterozoic orogens, drawing intriguing parallels with the intricate characteristics observed in Phanerozoic orogenic belts.

The Mesozoic tectono-thermal evolution recorded by metamorphic rocks commonly has been investigated using ubiquitous metapelite that characterizes Barrovian sequences. This study examined the metamorphic histories of both the metabasite slivers or lenses and the host metapelite in the Danba of amphibole + plagioclase + quartz + ilvaried bulk-rock compositions. The peak conditions (similar to 5.4-7.8 kbar/similar to 650-690 degrees C) of the metabasite and metapelite from the sillimanite zone are almost identical. Zircon ages of ca. 192 Ma for the migmatite zone and ca. 188-176 Ma for the sillimanite zone, whereas cooling ages of ca. 169-159 Ma were recorded by most rocks. Combined with the temperatures obtained by Ti-in-zircon thermometry, a relatively slow cooling rate of similar to 4.7 degrees C/m.y. was determined. Zircon ages are consistent for immediately adjacent metabasite and metapelite, and the monazite ages of one metapelite without metamorphic zircon growth also overlap the zircon ages of the neighboring metabasite. These results indicate that the metabasite and metapelite in the Danba dome shared a common metaof peak metamorphism may imply differential burial of rocks in the Danba dome, that is, earlier burial in the northern part (migmatite zone in the metamorphic core) than in the southern part. The younger age tails (after ca. 160 Ma, particularly in the southern part of the Danba dome) may result from later disturbances related to episodic (ca. 149-148 Ma, ca. 139 Ma, and ca. 128 Ma) thermal activations in the eastern Tibetan Plateau. Our data, combined with published data, indicate that the Danba dome and the Longmenshan Thrust Belt in the eastern Tibetan Plateau experienced common Mesozoic tectono-thermal evolution since the Late Triassic-Early Jurassic amphibolite-facies metamorphism.

Metapelite within a similar to 2.5 km-long transect from the southern Neoproterozoic Kang-Dian Orogenic Belt (SW China) was investigated. Metamorphic zircon and monazite of a plagioclase absent sample yielded Permian ages of 268 +/- 4.5 Ma and 265.4 +/- 1.5 Ma, respectively. Metamorphic zircon from the other three samples yielded Neoproterozoic ages of ca. 874-778 Ma but no Permian age, while monazite from one of them yielded both Neoproterozoic (811 +/- 8 Ma) and Permian (259.3 +/- 1.7 Ma) ages. The garnet growth / breakdown and plagioclase consumption / K-feldspar growth might account for the different Y and heavy rare earth element (HREE) content and negative Eu anomaly trend in monazite over time. The garnet was interpreted to be formed in the Neoproterozoic, while the preserved mineral assemblages represent the reworked products during Permian overprint. The synchronous magmatic activities might account for the Permian ages of monazite and zircon and the resorbed and diffused garnet zoning. These data indicate the Permian magmatic-thermal pulse affected the preexisted Neoproterozoic metamorphic rocks differentially. Such phenomenon is important and should be carefully considered in orogenic research.