The Julianna peg ma tite vein sys tem at the Pi 3 awa Górna Mine
The newly dis cov ered Julianna peg ma titic sys tem from the Pi3awa Górna Quarry (the Góry Sowie Block, Sudetes, NE mar gin of the Bo he mian Mas sif) is de scribed in terms of geo log i cal set ting, pe trog ra phy and de scrip tive min er al ogy. The sys tem rep re sents the larg est peg ma titic oc cur rence in the Pol ish Sudetes and con sists of a com plex net work of cogenetic rare-el e ment gra nitic pegmatites that in truded into tectonized am phi bo lite as dis cor dant dikes. The pegmatites range from bar ren and weakly zoned to tex tur ally well-dif fer en ti ated ones that are com posed of a fine-grained bor der zone, coarse-grained wall zone, graphic and blocky feld spar in ter me di ate zones and a quartz core. Uni di rec tional and skel e tal so lid i fi ca tion tex tures are well-de vel oped. The Julianna pegmatites con sist of rock-form ing plagioclase (£An39), microcline, quartz and bi o tite ac com pa nied mostly by ac ces sory to mi nor mus co vite, tour ma line, gar net and beryl. They crys tal lised from anatectic melt of hy brid NYF (ni o bium-yt trium-flu o rine) + LCT (lith ium-ce sium-tan ta lum) geo chem i cal char ac ter is tics. Pegmatites with a low to mod er ate de gree of frac tion ation, that dom i nate in the Julianna sys tem, bear NYF-sig na ture ac ces sory min er als, such as al la nite-(Ce), colum bite-, euxeniteand samarskite-group min er als, fergusonite-(Y) and gadolinite-(Y). How ever, rare dikes that at tained a very high de gree of frac tion ation con tain typ i cal min er als of LCT-sig na ture in clud ing tour ma lines of the elbaite-olenite-rossmanite se ries, le pido lite, lithiophilite, spodumene, Cs-rich beryl and pollucite.
Granulitic inliers amidst a gneissic/migmatitic complex of the Owl Mts, Sudetes
In NW part of the Owl Mts, Sudetes, the granulites are characteristically accompanied by serpentinized ultramafic and pyriboIitic rocks, including gametiferous peridotite and websterite of an upper mantle provenance. The ultrabasites display irregular intrusive contacts against the granuIites which pass diaphtoretica1ly into their migmatitic surroundings through a zone of transitional gneissic rock in which the retrogressive replacement of Gr + Ksp by Bio + PIg has been extensively accomplishing. Along the granulite/gneiss contact a belt of strongly recrystallized blastomylonite developed. Both the granulites and serpentinites are foliated and lineated, having received a distinct imprint from the F 2 + M 2 tectonometamorphic episode that affected the gneissic/migmatiti complex. Hence interpretation that the upper mantle ultrabasites had intruded a deep-seated granulitic domain, localized outside the actual Moldanubian Sowie Mts complex, in another level or portion ()f the earth's crust. Then, during the pre- F 2 movements, some indetermined slices were tectonically cut from the parent granulitic domain and after undefined vertical or lateral transport (or both) became upthrust along the ductile shear zones, or otherwise inlaid, into the gneisses just undergoing intense regional folding, metamorphism, and migmatization. Since F 2 + M 2 episode the granulites and accompanying ultramafites have had their further tectonothermal history in common with the Owl Mts gneisses and migmatites.
Evaluation and Control of Collapsible Soils
Some compacted soils wetted under certain conditions of compaction and loading may exhibit additional settlement (collapse). To investigate the effect of the soil type, compaction water content, initial dry unit weight and applied pressure at wetting on collapse potential, 138 single‐oedometer tests were conducted on eight different soils. The results indicate that well‐graded soils tend to collapse more than poorly graded ones under similar conditions. Furthermore, collapse potential decreases with an increase in (1) The difference between the sand and clay percentages; (2) compaction water content; and (3) initial dry unit weight, while it increases with pressure at wetting. A multiple regression analysis was performed on the laboratory results to provide a collapse‐predictive model that was substantiated by data reported by several researchers. A chart is presented to estimate (1) The collapse potential of soils under various conditions; and (2) the critical water content beyond which no collapse is ex...