Our understanding of the assembly history of Asia depends critically on the tectonic relationships between its major cratons, including Siberia, North China, South China, and Tarim. The intervening ...microcontinents between these cratons can provide insight into the paleogeographic and paleotectonic relationships of the cratons, but there is currently a general lack of knowledge regarding the basement geology of these microcontinents. Here we present results from systematic geologic mapping, U-Pb zircon dating, whole-rock geochemical analysis, and synthesis of existing data to establish the Proterozoic to early Paleozoic evolution of the central Qilian basement to the south of the North China craton in northwest China. Our results indicate that the region underwent three major periods of magmatic activity at 960-880, 877-710, and 550-375 Ma. Our geochemical analysis suggests that the ca. 900 Ma plutons were generated during arc magmatism and/or syncollisional crustal melting, whereas the ca. 820 Ma plutons are A-type granitoids, which are typically associated with extensional tectonism. Igneous zircons from a high- and ultrahigh-pressure eclogite in the north-central Qilian Shan have a U-Pb age of ca. 916 Ma, whereas dating of the recrystallized rims suggests that eclogite facies metamorphism occurred at ca. 485 Ma. Our detrital zircon geochronology also indicates that a widespread metasedimentary unit in the region was deposited between ca. 1200 and ca. 960 Ma, prior to the onset of a rift-drift event at ca. 750 Ma. Based on regional geologic constraints and the magmatic history, we propose the following tectonic history: (1) the paleo-Qilian Ocean bound the combined North Tarim-North China craton to the south (present-day coordinates) in the Mesoproterozoic; (2) the paleo-Qilian Ocean closed between 900 and 820 Ma following the collision of North Tarim-North China craton and the South Tarim-Qaidam-Kunlun continent; (3) the younger Qilian Ocean opened at ca. 775 Ma along the previous suture trace of the paleo-Qilian Ocean as a marginal sea within southern Laurasia; and (4) this ocean closed by ca. 445-440 Ma as a result of collision between the Tarim-North China cratons and the Qaidam-Kunlun continent along a south-dipping subduction system.
Dyslipidemia was present in most of the patients with coronary heart disease. Epidemiological evidence suggests that anthocyanin has some effects on the serum lipid. However, these results are ...controversial. This study aimed at collecting current clinical evidence and evaluating the effects of anthocyanin supplementation on total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in dialysis patients.
The search included PubMed, Web of Science, MEDLINE, Cochrane Library, China National Knowledge Infrastructure, Wanfang Database (up to July 2015) to identify randomized controlled trials (RCTs) on the association between anthocyanin and serum lipids. RevMan (version 5.2) was used for Meta-analysis. Meta-regression analysis, sensitivity analysis and Egger's weighted regression tests were performed by using STATA software (version 12.0; StatCorp, College Station, TX, USA).
Six studies (seven arms) involving 586 subjects were included in this meta-analysis. The results showed that anthocyanin supplementation has significant effects on TC MD = -24.06, 95% CI(-45.58 to -2.64) mg/dL, I2 = 93%, TG MD = -26.14, 95%CI(-40.20 to -3.08) mg/dL, I2 = 66%1, LDL-C MD = -22.10, 95% CI (-34.36 to -9.85) mg/dL, I2 = 61%, and HDL-C(MD = 5.58, 95% CI (1.02 to 10.14) mg/dL;I2 = 90%).
Anthocyanin supplementation significantly reduces serum TC, TG, and LDL-C levels in patients with dyslipidemia, and increases HDL-C. Further rigorously designed RCTs with larger sample sizes are needed to confirm the effectiveness of anthocyanin supplementation for dyslipidemia, especially hypo high density lipoprotein cholesterolemia.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abundant Early Paleozoic magmatism is preserved in northern Tibet and has important implications for continental crustal growth in response to continental collisions. To better constrain the ...evolution of the northern margin of the Tibetan Plateau and the resulting closure of the North Qilian Ocean, we conducted an integrated investigation involving U-Th-Pb zircon geochronology, whole-rock geochemistry, and syntheses of existing data sets across the North Qilian orogenic belt. Zircon U-Pb dating indicates that the Early Paleozoic intrusive rocks in the study area can be divided into two stages: 460-480 Ma and 440 Ma. The 478-480 Ma meta gabbro-diorite samples belong to the calc-alkaline series and show a fractional crystallization trend in the Harker diagrams. These samples have relatively high La/Nb (2.08-3.26) and low La/Ba (0.05-0.06) ratios, indicating a subduction-modified continental-lithospheric mantle source. The 460-480 Ma meta-granite samples are I-type and classified as high-K calc-alkaline series. Both the meta gabbro-diorite and meta-granite samples are characterized by negative Nb, Ta, and Ti anomalies and enriched LILEs, and showing arc signatures that may be related to the southward subduction of the North Qilian oceanic crust. The 441 Ma hornblende syenite samples have high contents of alkalis (K2O + Na2O = 7.80%-12.07%) and belong to the alkaline series, suggesting an extensional geological setting. The 440 Ma syenogranite samples are classified as high Ba-Sr granites and belong to the shoshonitic series. The syenogranite samples were most likely generated by partial melting of lithospheric mantle that had been metasomatized by slab-derived fluids, and mixed by the crust derived granitic magmas during the ascent of the magma. Both the hornblende syenite (441 Ma) and the syenogranite (440 Ma) samples were emplaced in a post-collisional tectonic setting associated with the closure process of the North Qilian Ocean.
The Eastern Kunlun Range in north Tibet, located along the northern margin of the eastern Tethyan orogenic system, records evidence for continental break‐up and ocean development in the ...Neoproterozoic, Paleozoic‐early Mesozoic subduction and continental collision, Mesozoic intracontinental extension, and Cenozoic contractional deformation. The Kunlun region is marked by active left‐lateral strike‐slip deformation of Kunlun fault system, one of the major intracontinental strike‐slip faults in Tibet that developed in response India‐Asia. To better constrain the tectonic evolution of the Eastern Kunlun Range and the closure of the various Kunlun oceans, we conducted detailed investigation integrating new geologic mapping, geochronology, and whole‐rock geochemistry with a synthesis of existing datasets across north Tibet. The Eastern Kunlun Range experienced three major deformation events in the Neoproterozoic, early Paleozoic, and Late Paleozoic‐early Mesozoic, which were associated with collision of the Proto‐, Paleo‐, and Neo‐Kunlun arcs, respectively. Our new detrital zircon analyses from Mesoproterozoic‐Cenozoic strata constrain stratigraphic age and sediment provenance and highlight the importance of three periods of arc activity. Our stratigraphic synthesis, including new field observations, provides new insights into connections between sediment dispersal and changes in tectonism and paleogeography. Miocene‐to‐present strike‐slip activity on the Kunlun fault and the associated strain pattern can be explained by clockwise rotation of the Kunlun fault and its wall rock as a bookshelf‐fault system, which has been proposed for northern Tibet as a result of distributed north‐south right‐lateral shear. The development of this fault system was facilitated by the presence of a Triassic suture that provided a preexisting weakness.
Plain Language Summary
The Eastern Kunlun Range in northern Tibet is located within the interior high‐elevation Tibetan Plateau. Its current morphology and geologic structure reflect Cenozoic faulting related to India‐Asia convergence since the early Cenozoic. Active deformation across the Eastern Kunlun Range reactivates complex older geologic relationships that record prior oceanic subduction and continental collision events. We present field and analytical observations from key sites along the Kunlun and Xiangride Rivers across the Eastern Kunlun Range to establish the pre‐Cenozoic geologic history of this region. Our dating of arc‐related intrusions and sedimentary rocks reveals that three distinct ocean‐closure‐related collisions occurred here over the last billion years. This repeated focused deformation has been reactived most recently in the Cenozoic to for the left‐slip Kunlun fault.
Key Points
The Eastern Kunlun Range, north Tibet, experienced three arc‐collision events in the Proterozoic through Mesozoic
New detrital zircon data from Mesoproterozoic‐Cenozoic better constrain their stratigraphic age and provenance in the Kunlun region
This site of repeated continental collision was reactivated by Cenozoic deformation during India‐Asia convergence
The evolution history of the Hegenshan Ocean is an important part of studying the evolution of the Xingmeng orogenic belt, but it is still controversial. Here we present an integrated study of ...petrology, zircon U-Pb geochronology, whole-rock geochemistry, and Sr-Nd isotopes on a series of intrusive rocks from the Baiyinguole area, Xiwuqi, central Inner Mongolia, NE China. Chronological data indicate that the intrusive rocks can be divided into three stages: 326-317, 297-295, and 259-254 Ma. The 326-317-Ma gabbros and diorites belong to the calc-alkaline series, and are characterized by positive whole-rock ε
Nd
(t) values (+1.1-+6.7), relatively low La/Ba ratios (0.04-0.10), and high La/Nb ratios (1.82-3.18), indicating that the magma source is from a subduction-modified lithospheric mantle. These samples have arc features owing to the southward subduction of the Hegenshan oceanic crust. The 297-295-Ma granodiorites and monzogranites show positive ε
Nd
(t) values (+1.9-+2.4), low
87
Sr/
86
Sr
i
ratios (0.704185-0.705234), and young Nd two-stage model ages (T
DM2
), which is consistent with typical I-type granites. On various tectonic setting discrimination diagrams, the granodiorites and monzogranites are plotted in the syn-collisional field. The 259-254-Ma syenogranites have low abundances of mafic minerals, low contents of Zr/Hf (18.31-31.35) and Nb/Ta (6.80-11.80) values, high SiO
2
(76.36-78.54 wt.%) content, A/CNK (1.08-1.76), and D.I. of 96.8-97.4 (average 97.1), and notable negative Eu anomalies (δEu* = 0.07-0.17) and weakly tetrad-effects in REE pattern, which is affinity to the characteristics of highly differentiated granites. Moreover, they have positive ε
Nd
(t) values (+2.0-+2.1) with scattered T
DM2
of 730-1217 Ma and low Nb/U ratios. This study suggests that the syenogranites are formed in a post-collisional tectonic setting, which is related to the closure of the Hegenshan Ocean. In addition, based on a review of the pre-existing literature data, a model of southward ridge subduction is proposed to explain the tectonic evolution of the Hegenshan Ocean.
The involvement and location of the Neoarchean‐Paleoproterozoic North China craton in the supercontinent Columbia remains enigmatic, and the tectonic history along its margins impacts our ...understanding of connections between North China and other continents. Here we present structural observations from a Paleoproterozoic mélange that is located along its northern margin and that we refer to as the Bayan Obo mélange. It is composed of a structurally complex tectonic mixture of metapelites and metasedimentary rocks mixed with exotic blocks of ultramafic‐mafic rocks, metabasalts, metacarbonate and alkaline rocks, and tonalite‐trondhjemite gneisses. New zircon geochronology of the various constituent blocks suggest that it formed, and was subsequently deformed, at ca. 1.9 Ga. The oldest intramélange blocks are 2.45‐ to 2.54‐Ga tonalite‐trondhjemite‐granodiorite rocks and granitoids that signify the stabilization of the northern North China in the Neoarchean‐Paleoproterozoic. A ca. 2.45‐Ga plagiogranite block probably originated by partial melting of the older tonalite‐trondhjemite‐granodiorite rocks. We suggest that this mélange formed in a sedimentary setting near the subduction trench, on the basis of mixing of upper and lower plate volcanic rocks and textural relationships. The Bayan Obo mélange thus represents one of the oldest documented sedimentary mélanges on Earth, yet its fundamental characteristics strongly resemble Phanerozoic subduction complexes. Based on similar ages and styles of deformation, this zone may represent the ca. 1.9‐Ga collisional zone between North China and the southwestern margin of the Siberia craton. In this context, the North China craton became an integral component of the supercontinent Columbia starting at ca. 1.9 Ga.
Plain Language Summary
The Paleoproterozoic‐Archean North China craton is one of the oldest cratons on Earth. Understanding its tectonic evolution history can provide better constraints on the assembly and tectonic evolution of the Paleoproterozoic‐Mesoproterozoic Columbia supercontinent. In addition, establishing its tectonic evolution will help to affect our current understanding of the Proterozoic‐Phanerozoic formation history of Asia. In a general sense, understanding the formation processes and significance of mélange associated with collision‐accretion in the geological record is significant in documenting the tectonic evolution of orogenic belts. In this study, we report for the first time a new Paleoproterozoic mélange located in the Bayan Obo region on the northernmost margin of the North China craton (present‐day coordinates). This mélange zone was formed and subsequently deformed and metamorphosed at ca. 1.9 Ga. Our observations across this zone are consistent with the proposal that North China collided with the southern margin of the Siberia craton at this time, which has a similar accretionary wedge. It is should be considered that the North China craton was beginning to the context of the Columbia from ca. 1.9 Ga.
Key Points
The Bayan Obo sedimentary mélange formed and deformed along the northern margin of the North China craton at ca. 1.9 Ga
North China collided with the southern margin of the Siberia craton at ca. 1.9 Ga, which has a similar accretionary wedge
The North China craton's involvement in the Columbia supercontinent started at ca. 1.9 Ga
Zircon U–Pb dating and whole-rock geochemical analysis have been performed on Late Jurassic – Early Cretaceous intrusive rocks of the Ulanhot area, NE China, with the aim of constraining the tectonic ...evolution of the central and southern Da Xingan Range. Zircon U–Pb dating indicates that Late Jurassic – Early Cretaceous magmatic events experienced four stages at: c. 155 Ma; c. 144 Ma; 135–130 Ma; and c. 126 Ma. The c. 155 Ma magmatic event consists of quartz diorite and granite-porphyryp with the geochemical characteristic of high Sr and Sr/Y or high A/CNK (1.38), implying the primary magma was derived from partial melting of a thickened lower crust which induced the closure of the Mongol–Okhotsk Ocean. The c. 144 Ma magmatic event consists of quartz monzodiorite with the geochemical characteristics of alkaline series, and indicates the delamination of a thickened crust. The 135–130 Ma magmatic event consists of syenogranite and granite-porphyry with characteristics of both I-type and A-type granites, which induced both the subduction of the Palaeo-Pacific oceanic plate and the post-orogenic extension of the Mongol–Okhotsk Orogenic Belt. The c. 126 Ma magmatic event consisted of highly fractionated I-type biotite granite and alkaline series gabbro, marking the end of the Mongol–Okhotsk Orogen, and implying that the study area was controlled by the circum-Pacific tectonic system during this stage.
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•Gold mineralization in the Daxiyingzi ore distract is associated with quartz veins hosted by volcanic rocks.•Fluid inclusion and stable isotope data suggest magmatic origin of the ...mineralizing fluids.•The mineralization is classified as epithermal-mesothermal gold deposit.•The gold mineralization took place during 149–158 Ma.
The Daxiyingzi gold deposit is located in the Chifeng-Chaoyang gold ore concentration area, toward the northern margin of the North China Craton. The ore bodies of the Daxiyingzi gold deposit are mainly hosted in the Manitu volcanic rocks, which are intruded on by the Mesozoic granite porphyry. The ore formation consists of four main stages: magnetite-hematite (Ⅰ), quartz-metal sulfide (II), gold-bearing polymetallic sulfide-quartz (III), and pyrite-carbonate (IV). The homogenization temperatures of the fluid inclusion range from 189.5 to 310.0 °C, while the salinity ranges from 0.53 to 13.55 wt% NaCl equiv., corresponding to entrapment depths of 0.1–1.0 km below the paleowater table. The quartz from the stage II and III veins from Daxiyingzi have δDV-SMOW values range from −62.1 to −82.8‰, while the δ18OH2O values range from 0.46 to 1.26‰. The samples for galena, sphalerite, and pyrite from the Daxiyingzi veins have approximate S isotopic compositions, with δ34S values ranging from 3.5 to 3.9‰, 3.9 to 4.2‰ and 3.5 to 5.0‰, respectively. The S-H-O isotopic data suggest that the ore-forming fluid had originated from magmatic sources. The zircon U-Pb ages of the volcanic rocks and granite porphyry are ca. 157–158 and 149 Ma, respectively, which suggests that the gold mineralization took place from 149 to 158 Ma. The volcanic rocks are belong to the high-K calc-alkaline to alkaline series, while the granite porphyry is belongs to A-type granite, which suggests an extensional tectonic setting. Our new data indicates that the Daxiyingzi gold deposit is a typical epithermal-mesothermal deposit formed by a Late Jurassic magmatic-hydrothermal system.
One of the ophiolites that record the Proto-Tethys Ocean’s episodic closure is the Munabulake ophiolitic mélange, which is situated in the middle of the Kunlun–Qaidam and Altun–Qilian blocks. ...Detailed field mapping revealed that the Munabulake ophiolitic mélange comprises local (ultramafic rocks, basalts, andesites, gabbros, diorites, and plagiogranites) and exotic (marble, gneiss, schist, and amphibolite) blocks, many of which are in the schist matrix (Qimantage Group). Based on geochronological, geochemical, and petrological observations, the mafic rocks in the Munabulake ophiolitic mélange can be categorized into three categories: 498-Ma OIB-like gabbros, 468-Ma Hawaiian alkaline basalt-like dolerite and pillow basaltic slices, and 428 Ma massive SSZ-like ultramafic rocks. The 501–452 Ma I-type granites exhibit arc affinities due to the oceanic crust subduction. These findings, along with spatial relationships, suggest that the Early Paleozoic ophiolite complex, island arc rocks, and accretionary complex generated as an intra-oceanic arc system as a result of obduction of the south Altun Ocean’s onto the Central Altun block within a north-directed subduction event. A dextral strike–slip was evident throughout the Early Paleozoic oceanic crust subduction based on the whole set of planar and linear structural data, and the subduction polarity was likely to the north. According to the ophiolitic mélange’s youngest rocks and the existence of 413 Ma granite dykes that are widely exposed in the Munabulake ophiolitic mélange, the Munabulake ophiolitic mélange was most likely emplaced during the Middle Silurian. This Munabulake ophiolitic mélange is similar in age and petrochemical characteristics to the other ophiolites in the South Altun subduction–collision belt, indicating that the Manabulak ophiolite mélange is a westward extension of the Apa–Mangya subduction–collision belt, which formed during the northward subduction of the South Altun Ocean slab during the Early Paleozoic. Thus, the final closing time of the South Altun Ocean is between 413 and 428 Ma.
This study investigates the geochemical characteristics and implications of soil gas and geothermal fluids in the fault zone of Xiongan New Area (XNA). Spatial distribution analysis reveals high soil ...gas concentrations along the fault zone, prompting the establishment of measurement lines along specific fault segments, such as Niudong fault, with a vertical burial trend. The measured average Rn flux ranges from 71.44 to 335.35 mBq m−2s−1, while CO2 flux ranges from 25.96 to 78.23 g m−2d−1. Furthermore, the average Rn and CO2 concentration intensities range from 0.91 to 2.30 and 1.13 to 2.61, respectively, indicating significant degassing in the fault zone.
Geothermal well samples are collected from the deep reservoir in XNA, displaying a predominance of Cl–Na composition. Analysis of the Na–K–Mg equilibrium diagram suggests that the chemical characteristics of deep geothermal water are a result of interactions with rocks and mixing with shallow cold water in XNA. Isotopic analysis indicates the atmospheric precipitation origin of the deep geothermal water with extensive lateral recharge from underground runoff, emphasizing strong water-rock interactions. Comparison with other tectonic units in the region reveals that the Niudong Fault Zone serves as a regional geothermal control structure, facilitating deep fluid convection.
In the eastern part of XNA, the geochemical analysis reveals concentrated degassing and a relatively high proportion of mantle-derived sources near the Niudong Fault Zone. This observation suggests the fault zone serves as a primary conduit for deep gases and geothermal fluids. The findings of this research provide valuable scientific references for future urban planning, energy utilization, and geologic hazard monitoring in XNA. Continued monitoring efforts are crucial for understanding the nature of fault activity and resource distribution in the region.
•The fault zone of Xiongan New Area exhibits significant degassing, with concentrations of Rn and CO2 in soil gas showing wide ranges and being most concentrated along buried faults.•Geothermal water in XNA has a Cl–Na composition and exhibits slow runoff characteristics, with an atmospheric precipitation origin and extensive lateral recharge from underground runoff.•The Niudong Fault Zone serves as a regional geothermal control structure, facilitating deep fluid convection and potentially inducing changes in permeability leading to fault movements and earthquakes.•The high values of gas concentration intensity and flux in the RCF in the western part of XNA may be attributed to the intersection of the RCF and the XDF.•The geochemical characteristics of geothermal fluid in XNA can provide valuable insights into the geological processes and fluid dynamics within geothermal systems. The distribution of the geothermal field in XNA is indeed influenced by fault activity.
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