Weihai Area Research Articles

Thalassotalea sediminis sp. nov., isolated from coastal sediment.

A novel Gram-stain negative, facultatively anaerobic, rod-shaped and yellowish-white-pigmented marine bacterium, designated strain N211(T), was isolated from marine sediment obtained off the coastal area of Weihai, China. The cells are approximately 0.4-0.9 × 1.8-3.5 μm in size and motile by means of a polar flagellum. The strain grows optimally at 33 °C, pH 7.5-8.5 and in the presence of 3.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences indicated that strain N211(T) fell within the clade comprising the type strains of species of the genus Thalassotalea. Strain N211(T) was most closely related to Thalassotalea ganghwensis DSM 15355(T) (96.4 %) based on the 16S rRNA gene sequence, and shared 94.4-96.4 % similarity with type strains of all members of the genus Thalassotalea. The predominant isoprenoid quinone of strain N211(T) was identified as ubiquinone-8 (Q-8). The major polar lipids were found to be phosphatidylethanolamine, phosphatidylglycerol and an unidentified lipid. C17:1 w8c, summed feature 3 (C16:1 w7c and/or iso-C 15:0 2-OH) and C16:0 were found to be main cellular fatty acids. The G+C content of the genomic DNA is 39.1 mol%. It is evident from phenotypic data and phylogenetic inference that strain N211(T) represents a novel species of the genus Thalassotalea, for which the name T. sediminis sp. nov. is proposed. The type strain is N211(T) (=KCTC 42588(T) = MCCC 1H00116(T)).

Catenovulum maritimus sp. nov., a novel agarolytic gammaproteobacterium isolated from the marine alga Porphyra yezoensis Ueda (AST58-103), and emended description of the genus Catenovulum.

A novel agarolytic, Gram-stain negative, heterotrophic, facultatively anaerobic and pale-white pigmented bacterial strain, designated Q1(T), was isolated from the marine alga Porphyra yezoensis Ueda (AST58-103) collected from the coastal area of Weihai, China. The cells are motile by means of peritrichous flagella. The isolate requires NaCl for growth, while seawater is not necessary, and growth occurs optimally at about 30-33 °C, in 1-3 % (w/v) NaCl and at pH 7-7.5. Strain Q1(T) shows oxidase-positive and catalase-negative activities, and possesses the ability to hydrolyse starch and alginate, but not cellulose, gelatin, urea or Tween-80. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain Q1(T) is affiliated with the family Alteromonadaceae within the class Gammaproteobacteria. The isolate, strain Q1(T), is most closely related to Catenovulum agarivorans YM01(T) (94.85 %), with less than 91.2 % sequence similarity to other close relatives with validly published names. The draft genome sequence of strain Q1(T) consists of 62 contigs (>200 bp) of 4,548,270 bp. The genomes of Q1(T) and YM01(T) have an ANI value of 70.7 %, and the POCP value between the two genomes is 64.4 %. The genomic DNA G+C content of strain Q1(T) is 37.9 mol% as calculated from the draft genome sequence. The main isoprenoid quinone is ubiquinone-8. The predominant cellular fatty acids are summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH), C16:0 and C18:1 ω7c. The major polar lipids are phosphatidylethanolamine and phosphatidylglycerol. Based on data from a polyphasic chemotaxonomic, physiological and biochemical study, strain Q1(T) should be classified as a novel species of the genus Catenovulum, for which the name Catenovulum maritimus sp. nov. is proposed. The type strain is Q1(T) (=CICC 10836(T)=DSM 28813(T)).

Quartz exsolution topotaxy in clinopyroxene from the UHP eclogite of Weihai, China

Abundant oriented silica precipitates of α-quartz (4.0±1.0vol.%), in part coexisting with calcic amphiboles (<0.2vol.%), have been identified in clinopyroxenes of eclogites from the Weihai area, Sulu ultrahigh pressure terrane, eastern China. Electron backscatter diffraction (EBSD) analyses demonstrate that the majority (97%) of quartz precipitates have topotactic relationships with their host clinopyroxenes. Three types of crystallographic topotactic relationship have been identified between quartz and host clinopyroxene: (1) 52% quartz precipitates share the same orientation for the c-axes with [0001]qz//[001]cpx; (2) 34% quartz precipitates share the same orientation for the a-axes with [112¯0]qz//[001]cpx; and (3) 11% quartz precipitates share the same orientation for the s-planes with (112¯1)qz//(100)cpx. Other quartz axes and planes disperse in large or small girdles around the shared axes or planes. Many quartz rods/needles are elongated parallel to the [001]cpx with the long axes of quartz being either [0001]qz or [112¯0]qz. Amphibole precipitates have also a strong crystallographic relationship with host clinopyroxene, i.e., (100)amp//(100)cpx, [010]amp//[010]cpx, and [001]amp//[001]cpx. These results provide quantitative microstructural evidence supporting an exsolution origin for oriented quartz needles/rods in clinopyroxene and demonstrate that the exsolution of quartz from clinopyroxene occurred within the stability field of α-quartz rather than coesite. The oriented precipitates of α-quartz, in part coexisting with calcic amphiboles, in host clinopyroxene are probably promoted by supercritical fluid or partial melting during the early exhumation of eclogites. Our results suggest that oriented quartz precipitates in clinopyroxene cannot be used as an indisputable UHP-indicator.

Paleoproterozoic ultrahigh-temperature pelitic granulites in the northern Sulu orogen: Constraints from petrology and geochronology

Ultrahigh-temperature (UHT) pelitic granulites are reported firstly in Weihai area, the northern segment of Sulu ultrahigh-pressure (UHP) metamorphic belt. The pelitic granulites, together with other metamorphic supracrustal rocks, including gneisses, marbles, quarzites and calc-silicates, occur as blocks within the orthogneisses which formed at Neoproterozoic but underwent Triassic UHP metamorphism. The pelitic granulites have a peak mineral assemblage of garnet+sillimanite+K-feldspar+plagioclase (antiperthite)+quartz+rutile+ilmenite±biotite. The P–T pseudosection and mineral isopleths thermobarometry modeled in the MnNCFKMASHTO system constrain P–T conditions of 11–13kbar and >900°C for the peak stage. In situ LA–ICPMS U–Pb dating and trace element analyses show that zircons from the two granulites have low Th/U ratios, flat HREE patterns with negative Eu anomalies, typical of granulite-facies metamorphic zircon. These zircons yielded 207Pb/206Pb ages of 1818±10Ma to 1854±9Ma, representing the time of the UHT granulite-facies metamorphism. Our result, together with previous investigations, indicates that the Mid-Paleoproterozoic tectonothermal event was widespread in the northern margin of the South China Craton. The Paleoproterozoic UHT granulite-facies metamorphism and associated anatexis, and coeval magmatism possibly derived from accretionary orogeny during the assembly of the supercontinent Columbia.

Experimental Research of Reclamation Performance of Recycled Asphalt Pavement Material at Weihai Area

Based on the recycled asphalt pavement material rooted out during road net reconstruction, this paper uses modified rejuvenating agent technology to study the reclamation performance of recycled asphalt pavement material, the mixture is AC-16 designed with new and old asphalt mixture. The results show that modified rejuvenating agent technology can improve the high temperature stability performance, the low temperature crack resistance performance and the moisture susceptibility performance of recycled asphalt pavement material effectively.

Composite Metallogenic Systems in the Weihai Area of Shandong and Evolution of Continental Dynamic Regimes

Abstract: Based on 9 sheets of l:50,000‐scale regional geological survey and guided by the theory of metallogenic systems and integrated analyses of the structural and metallogenic features, this paper hereby puts forward the composite metallogenic systems of the Weihai area, Shandong Province, aiming at solving the problems on the origins and ore‐controlling structures of the numerous deposits in the area. Its scientific significance is reflected in the following three aspects: (1) The basic features of the composite metallogenic systems can be recognized, which consist of two types: the Proterozoic metamorphic‐hydrothermal metallogenic system and the Mesozoic magmatic‐hydrothermal metallogenic system (i.e. the Indosinian‐early Yanshanian contact metasomatic metallogenic series and the mid‐late Yanshanian magmatic‐hydrothermal metallogenic series). The two series display arcuate and NW‐right lateral arrangements and a N‐S parallel zonal distribution respectively, with the corresponding mineral assemblages being Au+Ag+Pb+Zn, etc.; and Cu+Mo+Fe, Au+Ag+Cu+Pb‐Zn+Mo+Co‐Ni+suIfides+silicides+K‐feldspar, etc. (2) The composite metallogenic systems may be used to interpret the complicated genetic relations of the deposits. Through analyses of the relations between the three main metallogenic intervals and their corresponding source rock series (the Jingshan and Rongcheng groups; the Wendong super‐unit and the early‐middle Yanshanian Weideshan super‐unit; and the mid‐late Yanshanian Weideshan and Laoshan super‐units) as well as a case study of the Fanjiabu gold deposit, we have distinguished the consanguinity between the contact metasomatic (skarn‐type) metallogenic series and the magmatic‐hydrothermal metallogenic series as well as the noncognate superposition between the two and the metamorphic‐hydrothermal metallogenic system. (3) The composite metallogenic systems are easily related to the evolution of continental dynamic regimes. The formation of the metamorphic‐hydrothermal metallogenic system has undergone transformations of three different types of tectono‐dynamic regimes from extensionŕcompressionŕshearing that of the contact metasomatic (skarn‐type) metallogenic system from compressionŕextensionŕcompression; and that of the magmatic‐hydrothermal metallogenic system from extensionŕsubductive compression of the Pacific Plate. The evolutions of the three types are all attributed to the opening‐closing or divergence‐convergence of the paleocontinent, and all their mineralization corresponds to the interval of transformation from the end of convergence to early integration of the Weihai paleocontinent. All these will benefit our deeper study of the dynamics of continental metallogenic processes.

Exhumation tectonics of the ultrahigh‐pressure metamorphic rocks in the Qinling orogen in east China: New petrological‐structural‐radiometric insights from the Shandong Peninsula

In eastern China, the Sulu area is recognized as the eastern extension of the Qinling‐Dabie Belt, which is famous for its ultrahigh‐pressure (UHP) metamorphism. Although numerous petrologic and geochemical works are available, structural data are still rare. This paper provides the first extensive study of bulk geometry and kinematic analysis of the Shandong Peninsula. The study area is divided into three tectonic areas by Cretaceous faults, namely, a southern UHP belt or Sulu area, a northern migmatite area, and an eastern eclogite and migmatite area or Weihai area. Conversely to the deeply entrenched idea that the later area belongs to the North China Belt, and the two others to the South China Block (SCB), we argue that all three areas are parts of the SCB. Structural, petrologic, 40Ar/39Ar, and U/Pb data comply with this new interpretation. In the North Shandong area, mafic granulites enclosed as blocks within gneissic migmatites do not significantly differ from the Sulu and Weihai eclogites which also experienced a granulite facies overprint before migmatization. The circa 210–200 Ma age of the main ductile deformation is related to an extensional event during the Triassic (or Indosinian) orogeny. This date corresponds to the temperature climax, but the time of the pressure peak, i.e., the real age of the UHP metamorphism is discussed.

Ultrahigh-ϵ Nd eclogites from an ultrahigh-pressure metamorphic terrane of China

The SuLu ultrahigh-pressure (UHP) metamorphic terrane is part of the Qinling-Dabie suture zone formed by the collision between the Sino-Korean and Yangtze cratonic blocks. Geochemical and isotopic investigation of the UHP metamorphic rocks has revealed a spectacular history for some eclogitic rocks. Retrograded coesite-bearing eclogites from the Weihai area in the eastern end of the SuLu terrane have recorded an extraordinary Nd isotopic growth with a world-record high ϵ Nd-value of + 264 (range = + 170 to + 264). Such isotopic characteristics are consistent with the observed extreme LREE fractionation and very high Sm/Nd ratios. The SmNd isotopic data allow us to calculate the minimum age of protolith formation at ∼ 1.7 Ga, assuming their evolution from a depleted or a chondritic mantle. Geochemical data indicate that the eclogite protoliths were of basaltic compositions originally, but underwent metasomatism (water-rock interaction) at high pressures and temperatures leading to the present apparent andesitic composition and extreme LREE depletion. This process took place in the Proterozoic (∼ 1.7 Ga) and was not related to the Mesozoic continental collision and ultrahigh-pressure metamorphism at ∼ 210−220 Ma ago. Because of a protracted retrograde metamorphism, garnet SmNd systems were not closed until ∼ 160 Ma ago, ∼ 50 Ma after the peak eclogite metamorphism. This implies that the exhumation history is significantly different in different parts of the Dabie and SuLu UHP metamorphic terranes. From geochemical analyses and isotopic age determinations we argue that at least two ancient tectonic events in the middle and late Proterozoic can be identified prior to the last Mesozoic continental collision and accompanying UHP metamorphism in the SuLu and Dabie terrane.