Preliminary Results of Anthropogenic Seismicity Monitoring in the Region of Song Tranh 2 Reservoir,Central Vietnam

Song Tranh 2 hydropower plant and the reservoir containing backed up water are located in the Quang Nam province (Central Vietnam). The region experiences unusual seismic activity related to the reservoir impoundment, with earthquakes of magnitude up to 4.7. In result of cooperation between the Institute of Geophysics, Vietnam Academy of Sciences and Technology and the Institute of Geophysics, Polish Academy of Sciences a seismic network has been built to facilitate seismic monitoring of the Song Tranh 2 area. The network, operating since August 2013, consists of 10 seismic stations. Here we show that the network is sufficient for advanced data processing. The first results of monitoring of the earthquake activity in Song Tranh 2 area in the period between 2012 and 2014, especially the completeness of catalogs, study and comparisons between water level and the seismic activity suggest direct connection between reservoir exploitation and anthropogenic seismicity.     

Early Carboniferous (Viséan) emplacement of the collisional Kłodzko–Złoty Stok granitoids (Sudetes, SW Poland): constraints from geochemical data and zircon U–Pb ages

Sensitive high-resolution ion microprobe zircon U–Pb dating and geochemical data of igneous rocks from the composite K?odzko–Z?oty Stok (KZS) Granite Pluton, Sudetic Block, indicate that the granitoids represent an Early Carboniferous Viséan phase of Variscan metaluminous, high-K, I-type, syn-collisional granite magmatism within the Saxothuringian Zone of the Central European Variscides. Igneous zircon records hypabyssal magmatism that produced various granitoids and lamprophyre (spessartite) emplaced from ca. 340 to 331 Ma. The KZS granitoids have compositions ranging from granodiorite to monzonite, low A/CNK ratios (<1), and are associated with abundant mafic members. Most of them are alkaline, highly potassic, and moderately evolved. The major and trace element contents of the KZS granitoids suggest geochemical heterogeneity, and the hybrid nature of magmas derived from a range of sources in the middle crust, with a strong input of material from the upper mantle. Mixing of magmas of mantle origin with high-K material from partly melted continental crust was probably a more important factor than fractional crystallization, in controlling the evolution of the magmas. The mean Pb–U ages of the main population of igneous zircon from a quartz monzodiorite (?elazno) and hornblende monzonite (Droszków) are 340.2 ± 2.5 Ma and 339.5 ± 3.1 Ma, respectively. A slightly younger biotite-hornblende granodiorite from Chwalis?aw, 336.7 ± 2.5 Ma, was cut by a spessartite dyke at 333.1 ± 3.1 Ma. This indicates that mafic magmas were immediately intruded into fractured, probably incompletely solidified, granodiorites. The lamprophyric dyke also contains igneous zircon of Neoproterozoic age, 566.3 ± 6.4 Ma, typical of the crust in the Saxothuringian Zone. Tonalite from Ptasznik Hill near Droszków is of similar age to the spessartite, 331.5 ± 2.6 Ma. High REE contents in the tonalite and its igneous zircon indicate advanced differentiation of granitic magma, producing a more leucocratic melt associated with post-magmatic activity including abundant late crosscutting pegmatites and quartz veins, and contact metasomatic mineralization. The KZS granitoids have rather similar petrographic and geochemical characteristics to granitoids from other parts of the Central European Variscides, where a thickened orogenic root caused a substantial rise in crustal temperatures, producing granitoid magmas closely correlated with regional tectonic activity between the Saxothuringian and Brunovistulia Terranes at the NE margin of the Bohemian Massif.     

A Variscan continental collision of the West Sudetes and the Brunovistulian terrane: a contribution from structural and metamorphic record of the Stronie Formation,the Orlica-Śnieżnik Dome,SW Poland

Structural, petrological and geochronological data from marbles and mica schists combined with those from highly disputable gneisses and eclogites of the Orlica-Śnieżnik Dome (OSD), gave new insights into Variscan evolution of eastern borderland of the West Sudetes. It is shown that the Variscan tectonometamorphic evolution of the OSD began with E–W oriented subhorizontal shortening (D1 stage) related to the collision of the West Sudetes terranes and the Brunovistulian terrane. The shortening led to generally upright folding, which resulted in formation of the steep N–S trending metamorphic planar fabric S1, thickening of the lithosphere and burial of the Stronie Formation under greenschist facies conditions. As a consequence of subsequent, near-coaxial gravity-controlled vertical shortening (D2), the S1 foliation was deformed in tight recumbent folds F2. The flattening strain was associated with the progression to amphibolite-facies conditions (from ca. 510 upto ca. 620°C) and uplift from depths corresponding to 9–10 kbar to depths corresponding to 7–8 kbar. On microscale, the flattening strain is documented by rotation of the mineral fabric overgrown by syn-D2 prograde garnet porphyroblasts. The Sm–Nd Grt–WR isochron age, correlated with the D2 event yields 346.5 ± 4.4 Ma. Further deformation and progressive metamorphism led to development of the subhorizontally disposed S2 axial plane schistosity, which terminated at the metamorphic temperature peak. During retrogression but still under ductile conditions of deformation, the S2 planes were reactivated during successive top-to-the-N shear movement of the OSD (D3 stage). Due to the mutual interaction of the OSD with the adjacent terranes the shear deformations were localized within marginal parts of these units. Finally, as a result of the NE–SW and the NW–SE oriented shortenings (D4 stage and D5 stage, respectively), both the structural surfaces and metamorphic isograds were regionally folded with W(NW)-ward plunges. A synthesis of new and existing data shows an overall similarity in sequence of Variscan deformations (D1–D2–D3) in the West Sudetes borderland to that observed in the eastern flank of the Moldanubian domain.     

Decoupled PD set-point controller for underwater vehicles

A set-point controller for autonomous underwater vehicles (AUVs) is proposed in this paper. The controller is expressed in transformed equations of motion with a diagonal inertia matrix. It takes into account the dynamics of the system and it can be applied for fully actuated AUVs. The stability of the designed control law is demonstrated by means of a Lyapunov-based argument. Some advantages arising from the use of the controller are considered too. The performance of the proposed controller is validated via simulation on a 6-DOF underwater vehicle.     

The Use of Stable Sulfur, Oxygen and Hydrogen Isotope Ratios as Geochemical Tracers of Sulfates in the Podwiśniówka Acid Drainage Area (South-Central Poland)

The paper presents the results of determinations of stable S and O isotopes of dissolved sulfates and O and H stable isotopes of waters from three ponds, that is, Marczakowe Do?y acid pond, Marczakowe Do?y fish pond and Podwi?niówka acid pit pond, located in the Holy Cross Mountains (south-central Poland). The δ³⁴S_V-CDT and δ¹⁸O_V-SMOW of SO₄ ^2? in waters of three ponds (n = 14) varied from ?16.2 to ?9.5 ‰ (mean of ?13.6 ‰) and from ?8.1 to ?3.2 ‰ (mean of ?4.8 ‰), respectively. The mean δ³⁴S–SO₄ ^2? values were closer to those of pyrite (mean of ?25.4 ‰) and efflorescent sulfate salts (mean of ?25.6 ‰), recorded previously in the Podwi?niówka quarry, than to sulfates derived from other anthropogenic or soil and bedrock sources. The SO₄ ^2? ions formed by bacterially induced pyrite oxidation combined with bacterial (dissimilatory) dissolved sulfate reduction, and presumably with subordinate mineralization of carbon-bonded sulfur compounds, especially in both Marczakowe Do?y ponds. In addition, the comparison of δ¹⁸O–SO₄ ^2? and δ¹⁸O–H₂O values indicated that 75–100 % of sulfate oxygen was derived from water. Due to the largest size, the Podwi?niówka acid pit pond revealed distinct seasonal variations in both δ¹⁸O–H₂O (?9.2 to ?1.6) and δD–H₂O (?29.7 to ?71.3) values. The strong correlation coefficient (r ² = 0.99) was noted between δ¹⁸O–H₂O and δD–H₂O values, which points to atmospheric precipitation as the only source of water. The sediments of both acid ponds display different mineral inventory: the Marczakowe Do?y acid pond sediment consists of schwertmannite and goethite, whereas Podwi?niówka acid pit pond sediment is composed of quartz, illite, chlorite and kaolinite with some admixture of jarosite reflecting a more acidic environment. Geochemical modeling of two acid ponds indicated that the saturation indices of schwertmannite and nanosized ε-Fe₂O₃ (Fe³⁺ oxide polymorph) were closest to thermodynamic equilibrium state with water, varying from ?1.44 to 3.05 and from ?3.42 to 6.04, respectively. This evidence matches well with the obtained mineralogical results.     

Characteristics of acoustic scattering from a wind-created water surface covered with monomolecular organic films

A spectrum of amplitude fluctuations of the acoustic signal scattered from a wind-driven water surface coated with a monomolecular film of well-defined viscoelastic surface properties was studied under laboratory conditions. The presence of an oil film causes a shift of the peak frequency to higher frequencies and increases the fall-off in the high-frequency band of the spectrum compared with clean surface scattering. The effect turned out to be unequivocally related to rheological parameters of the surface film. Similar features of the scattered signal and wind-generated wave spectra observed for film-covered surfaces can be treated by the Marangoni theory of damping of water surface waves by viscoelastic films.     

Features of Minerogenic Series Related to Continental VolcanicRocks in the Southeastern Coastal Area of China-A Case Study of the Daiyunshan-ShiniushanVolcanic Depression in Fujian

The Daiyunshan-Shiniushan volcanic depression in Fujian Province is situated in a volcanic belt of the southeast coastal area in China along the west Pacific Ocean. A new breakthrough has been made in the exploration of gold and silver ore deposits in recent years. The minerogenic series of the Daiyunshan-Shiniushan volcanic depression is discussed in this paper based on the analysis of major metallogenic types and factors. According to the study of enormous ore deposits and occurrences in the study area, two minerogenic series have been recognized: 1. Late Jurassic Au-Ag-Pb-Zn minerogenic series related to intermediate-acid, acid volcanic formations; 2. nonmetallic minerogenic series (pyrophyllite, alunite pearlite, andalusite, zeolite, corundum and so on) related to intermediate and acid volcanic formations. The division and study of the minerogenic series have revealed metallogenic and time-space distribution characteristics of the ore deposits in the volcanic belt of the southeast coastal area in Ch     

Oil/source rock correlations in the Polish Flysch Carpathians and Mesozoic basement and organic facies of the Oligocene Menilite Shales: insights from hydrous pyrolysis experiments

The Oligocene Menilite Shales in the study area in the Polish Flysch Carpathians are organic-rich and contain varying mixtures of Type-II, Type-IIS and Type-III kerogen. The kerogens are thermally immature to marginally mature based on atomic H/C ratios and Rock-Eval data. This study defined three organic facies, i.e., sedimentary strata with differing hydrocarbon-generation potentials due to varying types and concentrations of organic matter. These facies correspond to the Silesian Unit and the eastern and western portions of the Skole Unit. Analysis of oils generated by hydrous pyrolysis of outcrop samples of Menilite Shales demonstrates that natural crude oils reservoired in the flysch sediments appear to have been generated from the Menilite Shales. Natural oils reservoired in the Mesozoic basement of the Carpathian Foredeep appear to be predominantly derived and migrated from Menilite Shales, with a minor contribution from at least one other source rock most probably within Middle Jurassic strata. Definition of organic facies may have been influenced by the heterogeneous distribution of suitable Menilite Shales outcrops and producing wells, and subsequent sample selection during the analytical phases of the study.