Volcanogenic and tectonic features of the Rakkejaur sulfide deposit,Skellefte district,Sweden

The Rakkejaur volcanogenic massive sulfide deposit is conformably situated in a transition zone between Proterozoic pyroclastic and overlying clastic sedimentary rocks. Ore and host rocks are isoclinally folded and slightly overturned. Two distinct types of mineralization occur: Cu-bearing stringers and disseminations, and Zn-rich stratiform banded massive sulfides. Precipitation of stratiform ore was concurrent with late volcanism and continued during the early stages of clastic sedimentation. Pyroclastic debris containing fragments of the underlying stringer-mineralized metavolcanic rocks were deposited in the lower parts of the massive sulfides. Banding of the stratiform massive ore is evidenced by alternating concentrations of pyrite and sphalerite and by interlayered sedimentary strata. Slumping and synsedimentary fragmentation of the massive sulfides took place locally. Epigenetic stringer mineralization was emplaced in two separate conduits located in the footwall metavolcanic rocks. Both mineralized vents are in contact with and beneath the same cap of massive sulfides.Zn, Pb, Ag, and Sb grades are elevated in the banded ore and tend to increase with stratigraphic and lateral distance from the zones of stringer mineralization. Gold occurs in association with arsenic or in amalgam, and each assemblage displays different distribution patterns. Most of the gold is contained in the stratiform ore where distal areas generally show higher Au/As ratios. The Au-As assemblage, however, occurs within one of the conduit zones and in close proximity to the other conduit within the massive sulfides. The ore-forming processes resulted in metasomatic alteration of the footwall rocks, mainly by introduction of Mg and Fe and depletion of Na.     

Impact of satellite observed microwave SST on the simulation of tropical cyclones

The impact of realistic representation of sea surface temperature (SST) on the numerical simulation of track and intensity of tropical cyclones formed over the north Indian Ocean is studied using the Weather Research and Forecast (WRF) model. We have selected two intense tropical cyclones formed over the Bay of Bengal for studying the SST impact. Two different sets of SSTs were used in this study: one from TRMM Microwave Imager (TMI) satellite and other is the weekly averaged Reynold’s SST analysis from National Center for Environmental Prediction (NCEP). WRF simulations were conducted using the Reynold’s and TMI SST as model boundary condition for the two cyclone cases selected. The TMI SST which has a better temporal and spatial resolution showed sharper gradient when compared to the Reynold’s SST. The use of TMI SST improved the WRF cyclone intensity prediction when compared to that using Reynold’s SST for both the cases studied. The improvements in intensity were mainly due to the improved prediction of surface latent and sensible heat fluxes. The use of TMI SST in place of Reynold’s SST improved cyclone track prediction for Orissa super cyclone but slightly degraded track prediction for cyclone Mala. The present modeling study supports the well established notion that the horizontal SST gradient is one of the major driving forces for the intensification and movement of tropical cyclones over the Indian Ocean.     

作为赋存于花岗岩中钨锡矿化勘探指南的流体包裹体异常——前景展望

Studies of the distribution and abundance of fluid inclusions in granitic quartz associated with granite-hosted Sn-W mineralization of the British Isles reveal local and regional scale anomalies.At a sampling interval of c.5～50m,inclusion abundances increase towards zones of vein and stockwork mineralization exemplified by case history examples from exploration prospects in the Mourne Mountains of Northern Ireland and the Carrock Fell mining district of northwestern England.These steam aureoles provide a greater exploration target than the zone of visible alteration and mineralization and the lithogeochemical halo.But it is important to link them to geochemical data on fluid inclusion compositions,such as the semi-quantitative data from decrepitation-linked,ICP-AES (D-ICP)analysis,to optimize their exploration potential.Regional scale fluid inclusion anomalies,based on sampling intervals of c. 2km from the Sn-W mineralized granites of southwest England also broadly correlate with zones of intense mineralization in some areas. Regional-scale D-ICP analyses of quartz from SW England granites did not provide any convincing regional scale anomalies linked to mineralization except for positive boron anomalies around the centrally-mineralized Birch Tor area of the Dartmoor granite.Follow-up D-ICP analysis of quartz from stream sediments from this area,however,could be used to discriminate between samples related to mineralization from those draining unmineralized areas,using multivariate statistical analysis.At the present stage of development, the main contribution of fluid inclusion studies to mineral exploration is mostly limited to the conceptual stage where they continue to contribute to ore genetic theory and models.Costs and lack of knowledge transfer between research scientists and mineral explorationists limit their direct use during regional and target selection stages of exploration.Analysis of steam sediment quartz,using the more sensitive ICP-MS technique as a variant of the D-ICP method,appears to offer the greatest potential for future development as an exploration tool.     

Der Bau der Betischen Kordillere und ihre Stellung im Mediterranen Orogen

Ohne ZusammenfassungÜbersetzung aus dem Holländischen von H.Cloos.Ich will nicht schließen, ohne meinen aufrichtigen Dank Herrn P.de WYKERSLOOTH auszusprechen, der so freundlich war, mir für diesen Artikel verschiedene wertvolle Angaben zu machen.     

MICROSCOPIC STRUCUURE OF TZUHSIEN COALS AND ITS BEARING ON COKING PROPERTY

The samples for microscopic study are all collected from the Hsitsocoal field situated about 50 li northwest of the Tzuhsieh city and 40 li east ofthe Matouchen station of Pinghan Railway.In order to understand the     

ON THE OCCURRENCE OF SPHAEROSIDERITE IN A SUBBITUMINOUS COAL FROM HSIAN COAL MINE,LIAONING PROVINCE

Mr.T.F.Hou,geologist of the National Geological Survey of Chinabrought back in 1931 from Liaoning province,a specimen of subbituminous coalin which are included patches or aggregates of small oolites.This interestingspecimen was given to the writer for microscopical investigation.Both polished     

THINNED POLISHED SECTION OF COAL,A NEW TECHNIQUE IN COAL PETROGRAPHY

Opinions often differ among coal petrographers as to the relative ad-vantages of the thin sections and the polished sections.In reality both of themare useful and they should be used simultaneously in order to get a clear and     

ON THE NEW FINDS OF FOSSIL EGGS OF STRUTHIO ANDERSSONI LOWE IN NORTH CHINA WITH REMARKS ON THE EGG REMAINS FOUND IN SHANSI,SHENSI AND IN CHOUKOUTIEN

In the Museum of the Geological Survey only a single complete speci-men of a fossil egg of Struthio is exhibited.This specimen came from Ssushui(汜水) and it was described briefly by J.G.Andersson in his "Essays on theCenozoic of Northern China."~1 The othe     

THE OCCURRENCE OF CERCIS ASSOCIATED WITH THE REMAINS OF SINANTHROPUS

In a short paper entitled "Evidences of the Use of Fire by Sinanthropus",Dr.Davidson Black has discussed the occurrence of burned bone fragments andcharcoal debris in association with the remains of Sinanthropus at Chou KouTien,and has concluded that Sina