PETROGENESIS AND RARE METAL MINERALIZATION OF THE ALKALINE GRANITIC MAGMA: A CASE STUDY FROM THE BOZIGUO’ER RARE METAL GRANITIC INTRUSION

The origination and differentiation of rare metalbearing, alkaline granites has attracted extensive interests because of their economic significance.The origination and differentiation of rare metalbearing, alkaline granites has attracted extensive interests because of their economic significance

AN EARLY PERMIAN GARNET-BEATING PERALUMINOUS GRANITIC PLUTON IN THE SOUTH TIANSHAN OROGENIC BELT, NW CHINA: PETROLOGICAL, MINERALOGICAL AND GEOCHEMICAL CONSTRAINTS

The Ku’erchu granitic pluton (283±4 Ma) was exposed in the eastern part of the South Tianshan Orogenic Belt. The granites from the intrusion are mainly composed of orthoclase (~45 vol. %), plagioclase (~15 vol. %), quartz (~20 vol. %), muscovite (~10 vol. %) and biotite (~5 vol. %), with accessory minerals including garnet, zircon and Fe-Ti oxide.The Ku’erchu granitic pluton (283±4 Ma) was exposed in the eastern part of the South Tianshan Orogenic Belt. The granites from the intrusion are mainly composed of orthoclase (~45 vol. %), plagioclase (~15 vol. %), quartz (~20 vol. %), muscovite (~10 vol. %) and biotite (~5 vol. %), with accessory minerals including garnet, zircon and Fe-Ti oxide

Experimental study of liquid immiscibility in the Kiruna-type Vergenoeg iron–fluorine deposit, South Africa

In this study we experimentally assess whether the bulk composition of the Kiruna-type iron–fluorine Vergenoeg deposit, South Africa (17 wt.% SiO2 and 55 wt.% FeOtot) could correspond to an immiscible Fe-rich melt paired with its host rhyolite. Synthetic powder of the host rhyolite was mixed with mafic end-members (ore rocks) in variable proportions. Experimental conditions were 1–2 kbar and 1010 C, with a range of H2O and F contents in the starting compositions. Pairs of distinct immiscible liquids occur in experiments saturated with fluorite, under relatively dry conditions, and at oxygen fugacity conditions corresponding to FMQ 1.4 to FMQ+1.8 (FMQ = fayalite-magnetite-quartz solid buffer). The Si-rich immiscible liquids contain 60.9–73.0 wt.% SiO2, 9.1–12.5 wt.% FeOtot, 2.4–4.2 wt.% F, and are enriched in Na2O, K2O and Al2O3. The paired Fe-rich immiscible melts have 41.0–49.5 wt.% SiO2, 20.6–36.1 wt.% FeOtot and 4.5–6.0 wt.% F, and are enriched in MgO, CaO and TiO2. Immiscibility does not develop in experiments performed under water-rich (aH2O > 0.2; a = activity) and/or oxidized (>FMQ+1.8) conditions. In all experiments, solid phases are magnetite, ±fayalite, fluorite and tridymite. Our results indicate that the rocks from the Vergenoeg pipe crystallized in a magma chamber hosting two immiscible silicate melts. Crystallization of the pipe from the Fe-rich melt explains its extreme enrichment in Ca, F and Fe compared to the host rhyolitic rocks. However, its low bulk silica content compared to experimental Fe-rich melts indicates that the pipe formed by remobilization of a mafic crystal mush dominated by magnetite and fayalite. Segregation of evolved residual liquids as well as the conjugate immiscible Si-rich melt produced the host rhyolite. The huge amount of fluorine in Vergenoeg ores ( 12 wt.% F) can hardly be explained by simple crystallization of fluorite from the Fe-rich silicate melt (up to 6 wt.% F at fluorite saturation). Instead, we confirm a previous hypothesis that the fluorite enrichment is, in part, due to the migration of hydrothermal fluids

TRACKING DEEP ANCIENT CRUSTAL COMPONENTS BY XENOCRYSTIC ZIRCONS OF PALEOZOIC FELSIC IGNEOUS ROCKS FROM THE ALTAI-EAST JUNGGAR TERRANE AND ADJACENT REGIONS AND ITS TECTONIC SIGNIFICANCE

The deep crustal continental components and architecture of the Central Asian Orogenic Belt have long been a matter of debate [Wang et al., 2009; Kröner et al., 2014; Xiao et al., 2015; Yang et al., 2017]. We present an integrated study of geochronological and Hf-inzircon isotopic data for xenocrystic zircons from the Paleozoic granitoid rocks and associated felsic volcanic rocks of the Chinese Altai, East Junggar and nearby regions. The aim is to trace the age spatial distribution of deep old crustal components in these key parts of the western Central Asian Orogenic Belt.The deep crustal continental components and architecture of the Central Asian Orogenic Belt have long been a matter of debate [Wang et al., 2009; Kröner et al., 2014; Xiao et al., 2015; Yang et al., 2017]. We present an integrated study of geochronological and Hf-inzircon isotopic data for xenocrystic zircons from the Paleozoic granitoid rocks and associated felsic volcanic rocks of the Chinese Altai, East Junggar and nearby regions. The aim is to trace the age spatial distribution of deep old crustal components in these key parts of the western Central Asian Orogenic Belt

kNN-CLIP: retrieval enables training-free segmentation on continually expanding large vocabularies

Rapid advancements in continual segmentation have yet to bridge the gap of scaling to large continually expanding vocabularies under compute-constrained scenarios. We discover that traditional continual training leads to catastrophic forgetting under compute constraints, unable to outperform zero-shot segmentation methods. We introduce a novel strategy for semantic and panoptic segmentation with zero forgetting, capable of adapting to continually growing vocabularies without the need for retraining or large memory costs. Our training-free approach, kNN-CLIP, leverages a database of instance embeddings to enable open-vocabulary segmentation approaches to continually expand their vocabulary on any given domain with a single-pass through data, while only storing embeddings minimizing both compute and memory costs. This method achieves state-of-the-art mIoU performance across large-vocabulary semantic and panoptic segmentation datasets. We hope kNN-CLIP represents a step forward in enabling more efficient and adaptable continual segmentation, paving the way for advances in real-world large-vocabulary continual segmentation methods

A snapshot of the transition from monogenetic volcanoes to composite volcanoes: Case study on the Wulanhada Volcanic Field (northern China)

The transition processes from monogenetic volcanoes to composite volcanoes are poorly understood. The Late Pleistocene to Holocene intraplate monogenetic Wulanhada Volcanic Field (WVF) in northern China provides a snapshot of such a transition. Here we present petrographic observations, mineral chemistry, bulk rock major and trace element data, thermobarometry, and a partial melting model for the WVF to evaluate the lithology and partial melting degree of the mantle source, the crystallization conditions, and pre-eruptive magmatic processes occurring within the magma plumbing system. The far-field effect of India-Eurasia collision resulted in a relatively high degree (10 %-20 %) of partial melting of a carbonate-bearing eclogite (~ 3 wt % carbonate; Gt/Cpx ≈ 2 : 8, where Gt denotes garnet and Cpx denotes clinopyroxene) followed by interaction with ambient peridotite. The primary melts ascended to the depth of the Moho (~ 33-36 km depth), crystallized olivine, clinopyroxene and plagioclase at the temperature of 1100-1160 °C with the melt water contents of 1.1 wt %- 2.3 wt %. Part of the primary melt interacted with the lithospheric mantle during ascent, resulting in an increase in the MgO contents and a decrease in the alkaline contents. The modified magma was subsequently directly emplaced into the middle crust (~ 23-26 km depth) and crystallized olivine, clinopyroxene and plagioclase at the temperature of 1100-1160 °C. The primary melts from the same mantle sources migrated upward to the twolevel magma reservoirs to form minerals with complex textures (including reverse and oscillatory zoning and sieve texture). Magma erupted along the NE-SW-striking basement fault and the NW-SE-striking Wulanhada- Gaowusu fault in response to the combined effects of regional tectonic stress and magma replenishment. The crustal magma reservoir in the WVF may represent a snapshot of the transition from monogenetic volcanoes to composite volcanoes. It is possible to form a composite volcano with large magma volumes and complex compositions if the magma is continuously supplied from the source and experiences assimilation and fractional crystallization processes in the magma plumbing system at crustal depth

Measurement and Calibration of Discrete Element Simulation Parameters of Crushed Sugarcane Tail Leaves

Discrete element simulation parameters of the tail stem and tail leaves of crushed sugarcane tail leaves (STL) were calibrated by a combination of physical experiments and simulation optimization design. First, the values or ranges of the basic physical parameters and contact parameters of crushed STL were measured using physical tests, and the results were used as the basis for the selection of the simulation parameters. Plackett-Burman testing was applied for the significance screening of the initial parameters. Then, the error values and significant parameters of stacking angle for the second-order regression models were obtained using the steepest ascent experiment and the Box-Behnken optimization test. An analysis of variance (ANOVA) was also performed. Finally, using 37.52° stacking angle of physical test as the validation target, the optimal combination of parameters was obtained: coefficient of static friction (COSF) for tail stem-tail stem of 0.45, COSF for tail leaf-tail leaf of 0.38, coefficient of rolling friction (CORF) for tail stem-tail stem of 0.14, and CORF for tail stem-tail leaf of 0.12. The error of stacking angle obtained from the simulation and the physical tests was 0.976%, which verifies the reliability of the optimal parameters

PETROGENESIS AND RARE METAL MINERALIZATION OF THE ALKALINE GRANITIC MAGMA: A CASE STUDY FROM THE BOZIGUO’ER RARE METAL GRANITIC INTRUSION

The origination and differentiation of rare metalbearing, alkaline granites has attracted extensive interests because of their economic significance

AN EARLY PERMIAN GARNET-BEATING PERALUMINOUS GRANITIC PLUTON IN THE SOUTH TIANSHAN OROGENIC BELT, NW CHINA: PETROLOGICAL, MINERALOGICAL AND GEOCHEMICAL CONSTRAINTS

The Ku’erchu granitic pluton (283±4 Ma) was exposed in the eastern part of the South Tianshan Orogenic Belt. The granites from the intrusion are mainly composed of orthoclase (~45 vol. %), plagioclase (~15 vol. %), quartz (~20 vol. %), muscovite (~10 vol. %) and biotite (~5 vol. %), with accessory minerals including garnet, zircon and Fe-Ti oxide