We report here new field and analytical data from Precambrian rocks on Hainan Island of the Cathaysia Block, south China, and examine its probable connection to Laurentia. Granitoids and newly ...discovered felsic volcanic rocks dated at 1433 ± 6 Ma and 1439 ± 9 Ma (SHRIMP U‐Pb zircon) on Hainan Island are coeval with, and isotopically similar to the 1500–1350 Ma trans‐continental granite‐rhyolite province in southern Laurentia. Quartzites unconformably overlying the ca. 1430 Ma volcaniclastic rocks on Hainan Island are interpreted as locally‐sourced Grenvillian foreland basin deposits that can be correlated with the Deer Trail Group of south‐western Laurentia. The detrital provenance of the quartzites contains age populations comparable to the 1610–1490 Ma, westerly‐sourced non‐Laurentian detrital grains reported in the Belt Basin of south‐western Laurentia. Our new data thus make Cathaysia the most likely continental block next to western Laurentia before and during the late Mesoproterozoic assembly of Rodinia.
The Jiaodong super-large gold metallogenic region is located on the eastern margin of the North China craton and the western margin of the Circum-Pacific tectonic belt. Ore-forming chronology ...indicates that these deposits formed at 120 ± 10 Ma. Helium and argon isotope compositions of fluid inclusions in pyrite range in
3
He/
4
He ratios from 0.38 to 2.36 R/Ra (R:
3
He/
4
He ratios of samples; Ra:
3
He/
4
He ratios of Beijing air, 1.4 x 10
-6
) and in
40
Ar/
36
Ar ratios from 310 to 1148. δ
18
O and δD values of fluid inclusions in quartz are -2.16 to +6.28‰ and -65 to -98‰, respectively. A consistent relationship between H-O and He-Ar isotopic systems show that mantle-source fluids were involved in large-scale metallogeny in the Jiaodong region. The fluids were produced accompanying delamination, lithosphere thinning, and crust-mantle interaction that occurred in the eastern North China craton during the Early Cretaceous (140-120 Ma).
Major and trace elements and Sm–Nd isotopic data are presented for metabasites that are present as lenses within Paleozoic metasediments in the Chenxing and Bangxi regions, central Hainan Island, ...Southeast (SE) China. Most metabasites are metamorphosed cumulated gabbroic rocks tholeiitic in nature, and characterized by varying degrees of depletion in Th, Nb, Ta and light rare earth elements (LREE). Moreover, they show high positive ∈Nd(T) values of approximately +7, similar to those of mid‐ocean ridge basalts (MORB). A Sm–Nd isochron age of 333 ± 12 Ma obtained for the metabasites is interpreted as their crystallization age. The combined geochemical and Sm–Nd isotopic data suggest that the metabasites were generated by dynamic partial melting from a MORB‐like mantle source in an oceanic regime. These rocks probably represent remnants of fragmented oceanic crust of the eastern part of Paleo‐Tethys. They were obducted onto the continental crust as part of the ‘Shilu Mélange’ in earliest Mesozoic time when southern Hainan (part of the Indochina block) collided with northern Hainan (part of South China). Alternatively, they could be formed in a volcanic rifted passive margin at the sea‐floor spreading stage as part of MORB‐like seaward‐dipping reflector break‐up packages.
. The Baolun quartz vein type Au deposit, is located at the southwestern Hainan Island. It occurs next to a Triassic ilmenite‐series/S‐type syenogranite complex. A 40Ar/39Ar plateau age for muscovite ...from the master orebody is dated to be 219.4±0.6 Ma, suggesting that the gold deposit genetically related to the granite pluton. In the Baolun mining area, orebodies of auriferous quartz vein and wall rock alteration occur in NNW‐striking fracture zones hosted by weakly metamorphosed turbidite of the Lower Silurian age. Eight fracture zones, 400∼1300 m long and 10∼30 m wide, have been identified. The five fracture zones of them form orebodies. The ores are mainly of quartz vein type. More than 20 orebodies in shapes of vein and lens of 195∼751 m in length and 0.20∼7.49 m in thickness are known, and 14 of them occur in the No. 1 vein belt. Silicification, sericitization and pyritization are closely related to the Au mineralization. The ores exhibit commonly 1.54∼29.48 g/t in Au grade, partially >98 g/t. The master orebody is 720 m long and 2.62 m thick in average, with 9.53∼29.27 g/t Au. Gold reserves of more than 70 t have been proven by geological exploration. More than 20 metallic minerals including native gold and sulfides such as pyrite, pyrrhotite, chalcopyrite, and others are identified to be formed in four ore‐forming stages: (1) Au‐coarse grain quartz stage, (2) Au‐fine grained quartz stage, (3) Au‐bismuthide‐bismuth sulfosalt‐sulfide‐quartz stage, and (4) calcite‐sulfide‐quartz stage. The Au mineralization in this deposit occurred mainly in the first three stages. A variety of Bi‐ and Te‐bearing minerals is closely associated with native gold suggesting that the mineralization may take place in a relatively high temperature.
A number of metamorphosed mafic rocks occurred within the Paleozoic strata in the Chenxing and Bangxi regions at the northern side of the Changjiang-Qionghai Fault in Central Hainan Island. These ...metamorphosed mafic rocks are tholeiites in chemistry. They are characterized by extreme depletion of Th, Nb, Ta and LREEs, resembling the depleted N-type mid-ocean ridge basalts (MORB). Field relations suggest that the protolith of the metamorphosed mafic rocks were likely formed in Paleozoic. These metamorphosed mafic rocks with N-type MORB geochemical features were probably the remnants of the Paleo-Tethys oceanic crust.
Based on an analysis of the fractal structures and mass transport mechanism of typical shear‐fluid‐ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic ...study of the ore formation system. The model of point‐source diffusive illuviation of the shear‐fluid‐ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore‐forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore‐forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore‐forming dynamics is a combination of multi‐processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and fluid‐rock interaction. It changes components and physico‐chemical properties of primary rocks and fluids, favouring deposition and mineralization of ore‐forming materials. (3) Gold ore‐forming processes in different types of shear zones are quite different. (1) In a metallogenic system with inhomogeneous volumetric change and inhomogeneous shear, mineralization occurs in structural barriers in the centre of a shear zone and in geochemical barriers in the shear zone near its boundaries. But there is little possibility of mineralization out of the shear zone. (2) As to a metallogenic system with inhomogeneous volumetric change and simple shear, mineralization may occur only in structural barriers near the centre of the shear zone. (3) In a metallogenic system with homogeneous volumetric change and inhomogeneous shear, mineralization may occur in geochemical barriers both within and out of the shear zone.
The petrological and geochemical features of the bed parallel granitic intrusion in the Pre-Cambrian Baoban group in Hainan Island attest to the anatexis origin of the granites. U-Pb dating analyses ...of zircons from the anatectic granite and the biotite two-feldspar gneiss in the Baoban group, using SHRIMP II in the Beijing Ion-probe Center, acquire 206Pb/238U ages of 368+/-3.5 Ma (of granite, 95% confidence level, MSDW=1.23) and 362.9+/-6.1 Ma (of gneiss, 95% confidence level, MSDW = 2.04) respectively. The two late Devonian ages indicate consistently a tectonic- thermal event experienced in Hainan Island, and are the first discovered record of the Devonian geological process in the district. This event possibly resulted from the deep ther-mal-dynamic process when the Gondwana continent began to break up in the Devonian period.
Obstructive sleep apnea syndrome (OSAS) is associated with many cardiovascular disorders such as heart failure, hypertension, atherosclerosis, and arrhythmia and so on. Of the many associated ...factors, chronic intermittent hypoxia (CIH) in particular is the primary player in OSAS. To assess the effects of CIH on cardiac function secondary to OSAS, we established a model to study the effects of CIH on Wistar rats. Specifically, we examined the possible underlying cellular mechanisms of hypoxic tissue damage and the possible protective role of adiponectin against hypoxic insults. In the first treatment group, rats were exposed to CIH conditions (nadir O2, 5-6%) for 8 hours/day, for 5 weeks. Subsequent CIH-induced cardiac dysfunction was measured by echocardiograph. Compared with the normal control (NC) group, rats in the CIH-exposed group experienced elevated levels of left ventricular end-systolic dimension and left ventricular end-systolic volume and depressed levels of left ventricular ejection fraction and left ventricular fractional shortening (p<0.05). However, when adiponectin (Ad) was added in CIH + Ad group, we saw a rescue in the elevations of the aforementioned left ventricular function (p<0.05). To assess critical cardiac injury, we detected myocardial apoptosis by Terminal deoxynucleotidyl transfer-mediated dUTP nick end-labeling (TUNEL) analysis. It was showed that the apoptosis percentage in CIH group (2.948%) was significantly higher than that in NC group (0.4167%) and CIH + Ad group (1.219%) (p<0.05). Protein expressions of cleaved caspase-3, cleaved caspase-9, and cleaved-caspase-12 validated our TUNEL results (p<0.05). Mechanistically, our results demonstrated that the proteins expressed with endoplasmic reticulum stress and the expression of reactive oxygen species (ROS) were significantly elevated under CIH conditions, whereas Ad supplementation partially decreased them. Overall, our results suggested that Ad augmentation could improve CIH-induced left ventricular dysfunction and associated myocardial apoptosis by inhibition of ROS-dependent ER stress.
Many Chinese breeding pigs are repeatedly vaccinated against classical swine fever virus (CSFV) and porcine epidemic diarrhea virus (PEDV), which cause fatal, highly contagious diseases. To reduce ...their high frequency vaccination-induced immune stress, we constructed a combined vaccine based on the E2 protein of CSFV and the S1 spike protein subunit of PEDV (named E2-S1). In mice, the E2-S1 vaccine elicited higher neutralizing antibody titers and IgG1/IgG2a ratios against CSFV and PEDV than those induced by individual E2 or S1 vaccines. Moreover, it elicited high IL-4 expression, but no IFN-γ expression. The results suggest that good compatibility exists between E2 and S1 antigens, and the E2-S1 vaccine can elicit a strong Th2-type cell-mediated humoral immune response. The E2-S1 recombinant fusion protein provides a novel vaccine candidate against both CSFV and PEDV, laying the foundation for future combination vaccines against swine diseases.
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