Reconstruction of hydrothermal karst system in Zn-Pb sulphide deposits Upper Silesian region, Poland

PROPERTIES:COMPOSITION, STRUCTURE, DENSITY final phases of regional deformation, and thus, deformation occurred between 1664 and 1654 Ma. -from Authors 946113 Microstructures of ferruginous oolite and their genetic characteristics in the Xuanlong iron deposit, Hebei Province (in Chinese) Zhao Dongxu, Scientia Geologica Sinica, 29(1), 1994, pp 71-77. The ferruginous oolites in the Xuanlogn iron deposit consist of various nuclei and concentric lameUar shells. The mineralogical components of the oolite nuclei area mainly terrigenous quartz sand, hematitic intraclast or clot, a small amount of siderite, etc. The oolite shell is composed of micritic hematites and small amounts of siderites different in their microstmcture and lamellarity. The sheet, flaky and equigranular hematitic micrites forming lamellae were directly precipitated from marine water on oolite surfaces, and inequigranular hematitic micrite was formed by adherence in the process of rolling of oolites. The ferruginous oolite was mainly deposited in a high-energy environment of shallow or deep water zone. -English summary 946114 C a d r e structural dn gite Ag.H.g d ' I m i t e r (Anti Atlas, Maroc); implication metallogenlque (Structural framework of the Ag-Hg deposit o f l m i t e r (Anti-Atlas, Morocco); metallogenic inferences) H. Ouguir, J. Macaudiere, G. Dagallier, A. Qadrouci & J.-M. Leistel, Bulletin - Societe Geologique de France, 165(3), 1994, pp 233-248. Imiter Ag-Hg deposit occurs as fracture infill in black schists regionally associated with greywacke formations which are attributed to Upper Proterozoic (PII). Folding of the series during the main Pan-African orogenic phase developed hecto- to kilometric reclined to recumbent folds with axial plane cleavage. The black schists appear to be situated at the top of the formation and were deposited at the foot of a continental slope. They show a complex faulted contact with the late Precambrian formations (PIII) which are mainly volcanics. Structural analysis shows that the Imiter fault zone started as an extensional fault-zone (NNW-SSE extension) which then evolved toward a simstral-extensive movement (NW-SE extension) during the emplacement of PIII volcanics. Hydrothermal mobilization of sulphides and hydraulic fracturing took place during the activity of this complex wrench and flexure zone. This can be related to the late post collisional stage of the Pan-African orogeny. Cementation which created the native Ag deposit was a later event. There is an extended English abstract. -from English summary 946115 Geology and genesis of the Bajiazi polymetallic sulfide deposits, Liaoning, China Baohong Hou & Dongpu Zhao, International Geology Review, 35(10), 1993, pp 920-943. The Bajiazi deposits of western Liaoning Province, northeastern China, axe aligned approximately west-east in an 8- × 15-krn district. The Zn-Pb-Ag-FeS, sulfide ores are hosted in intensively folded and faulted Early Proterozoic carbonates and minor elastic rocks. The ores are composed of stratabound and stratiform sulfide lenses and layers, are associated with sediments formed in local depressions of a tectonically active, shallow-marine environment, and are limited to dolomitized tidal flat and lagoonal facies with cryptalgal lamination and to adjacent oolitic grainstones of barrier facies. Sulfides are intensely recrystaUized and annealed in the contact metamorphic halo. Isotopes of sul.fur, carbon, oxygen, and lead were examined for genetic interpretation of the sulfides and host rocks. Pb isotope ratios, characterized by a model age of about 1350 Ma, suggest an early Proterozoic, crustal source for the lead in the ores, unrelated to the lead in the Mesozoic granite. -from Authors 946116 Reconstruction of hydrothermal karst system in Zn-Pb sulphide deposits Upper Silesian region, Poland M. Sass-Gustkiewicz, Bulletin - Societe Geographie de Liege, 29, 1993, pp 87-92. In the Upper Silesian district the ore bodies form vertically developed structures at lower levels of the deposits upwarus grading into horizontally disposed structures.

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Both are interpreted as belonging to the same endogenic, hydrothermalkarst system produced by ascending mineralized solutions. All the evidences point out to close genetic relationships between the dissolution of host rocks and the deposition of ores in the evolving karst system. -Author

946117 Synthesizing bulk density for soils with abundant rock fragments K . R . Vincent & O. A. Chadwick, Soil Science Society of America Journal, 58(2), 1994, pp 455-464. Bulk density is a fundamental soil property that is difficult to determine for gravelly to extremely gravelly soils because results vary significantly with sample volume. For such coarse soils, the representative volume (for wholesoil bulk density) should be large, but guidelines for selecting an appropriate sample volume do not exist. The representatave volume for a soil with abundant rock fragments was evaluated, by comparing measured properties of samples ranging in volume from 0.03 to 410 L. For wholesoil bulk density determination, the representative volume is 4 L or larger for a soil horizon containing 34% (vie) gravel and is between 5 and 50 L for a soil horizon containing 54% gravel. Intact samples of that size are prohibitively large, so an alternative approach was develol~ed that starts with measurement of fine-earth bulk density. For fine-earth bulk density, the sample volume needed for representative results is between 0.2 and 1 L for gravelly to extremely gravelly soils. The alternative approach reliably synthesizes whole-soil bulk density using: 1) fine-earth bulk density from modest-sized samples, 2) mass-size distribution from large (>40 kg) representive disturbed samples, and 3) rock fragment bulk densities. The mass and volume of rock fragments that should be in a sample are added to the mass and volume used to calculate fine-eaffh bulk density. This method allows integration of lateral variability in the soil without the consequence of averaging properties across a large depth range. -Authors 946118 Pneumatic conveying of materials at partial gravity T . A . Sullivan, E. Koenig, C. W. Knudsen & M. A. Gibson, Journal of Aerospace Engineering - ASCE, 7(2), 1994, pp 199-208. This project's goal was to evaluate the feasibility of pneumatic transfer for the movement of regolith (lunar soil) at a lunar base. Operation of pneumatic conveying systems at partial (lunar and Mars) gravity conditions on NASA's KC-135 aircraft allowed the determination of some key parameters necessary for the design of an operable system. Both horizontal and vertical transfer were studied. -Authors 946119 Geostatistical characterization of a complex semi-permeable layer M. F. P. Bierkens, H. J. T. Weerts & P. A. Burrough, in: Engineering geology of Quaternary sediments. Proc. symposium, Delft, 1994, ed N. Rengers, (Balkema), 1994, pp 73-92. This paper presents a study to quantify the lithofacies distributlon of a complex semi-permeable layer consisting of fluvial and organic deposits. In a small study area in the central Rhine-Meuse delta a large number of drillings were made in a semi-permeable layer overlying shallow permeable aquifers. Detailed cross sections and semivanogram analysis are used to quantify the spatial variability of fluvial overbank deposits in the semi-permeable layer and to determine minimal drilling distances for detailed mapping of the lithofacies. Conditional indicator simulation is applied to obtain simulated stochastic images of the semipermeable layer. These images may serve as analogues for similar layers found at greater depths. -Authors 946120 Soil physical properties related to soil structure R. Horn, H. Taubner, M. Wuttke & T. Baumgartl, Soil & Tillage Research, 30(2-4), 1994, pp 187-216. The aim of this paper is to clarify the effect of soil aggregation on soft physical and chemical properties of structured soils both on a bulk soil scale, for single aggregates, as well as for homogenized material. Aggregate formation and aggregate strength depend on swelling and shrinkage