Eclogites with a short-lived granulite facies overprint in the Moldanubian Zone, Czech Republic: petrology, geochemistry and diffusion modelling of garnet zoning

1995 ◽  
Vol 84 (3) ◽  
Author(s):  
PatrickJ. O'Brien ◽  
Stranislav Vr�na
Keyword(s):  
Czech Republic ◽  
Granulite Facies ◽  
Garnet Zoning ◽  
Moldanubian Zone ◽  
Diffusion Modelling ◽  
And Diffusion

Nutrient convection and diffusion modelling in the intervertebral disc

2011 ◽  
Vol 14 (sup1) ◽  
pp. 145-146 ◽  
Author(s):  
M. Etienne ◽  
O. Boiron ◽  
P. Tropiano ◽  
V. Deplano
Keyword(s):  
Intervertebral Disc ◽  
Diffusion Modelling ◽  
And Diffusion

Apatite with lamellae of sulfide and other phases in ultrahigh-pressure eclogites from Nové Dvory, Moldanubian Zone, Czech Republic

2018 ◽  
Vol 83 (1) ◽  
pp. 95-105
Author(s):  
Shah Wali Faryad ◽  
Radim Jedlicka ◽  
Maria Perraki
Keyword(s):  
Czech Republic ◽  
Surface Charge ◽  
Closed System ◽  
Ultrahigh Pressure ◽  
Temperature Decrease ◽  
Moldanubian Zone ◽  
Sector Zoning ◽  
Growth Plane ◽  
Close Relationship ◽  
Preferential Uptake

AbstractExsolution lamellae of baryte, Fe sulfides, Cu sulfides and Fe oxides were observed in apatite enclosed in garnet and omphacite and their intergranular spaces in ultrahigh-pressure eclogite in the Moldanubian Zone, Czech Republic. Micro-textural relations and compositional mapping of the apatite indicates a close relationship between the density of the exsolution lamellae and compositional domains that are rich in sulfur and iron. No relation between compositional domains and fluorine or chlorine content or any evidence of apatite metasomatisation was observed. On the basis of cathodoluminescence images, the compositional domains reflect sector zoning in apatite crystals by preferential uptake of elements due to differences in surface charge and morphology on the growth plane. It is concluded that the lamellae are products of exsolution in a closed system resulting from temperature decrease during metamorphism.

scholarly journals New evidence for the prograde and retrograde PT-path of high-pressure granulites, Moldanubian Zone, Lower Austria, by Zr-in-rutile thermometry and garnet diffusion modelling

Lithos ◽  
2019 ◽  
Vol 342-343 ◽  
pp. 420-439 ◽  
Author(s):  
Philip Schantl ◽  
Christoph Hauzenberger ◽  
Friedrich Finger ◽  
Thomas Müller ◽  
Manfred Linner
Keyword(s):  
High Pressure ◽  
Moldanubian Zone ◽  
Diffusion Modelling ◽  
Pt Path ◽  
New Evidence ◽  
Garnet Diffusion ◽  
Zr In Rutile

Two Paragenetic Types of Cookeite From the Dolní Bory-Hatě Pegmatites, Moldanubian Zone, Czech Republic: Proximal and Distal Alteration Products of Li-Bearing Sekaninaite

2015 ◽  
Vol 53 (6) ◽  
pp. 1035-1048
Author(s):  
Milan Novák ◽  
Renata Čopjaková ◽  
Marek Dosbaba ◽  
Michaela VAŠINOVÁ Galiová ◽  
Dalibor Všianský ◽  
...  
Keyword(s):  
Czech Republic ◽  
Moldanubian Zone

scholarly journals Deeply subducted continental fragments – Part 1: Fracturing, dissolution–precipitation, and diffusion processes recorded by garnet textures of the central Sesia Zone (western Italian Alps)

Solid Earth ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 167-189 ◽  
Author(s):  
Francesco Giuntoli ◽  
Pierre Lanari ◽  
Martin Engi
Keyword(s):  
High Pressure ◽  
Diffusion Processes ◽  
Shear Zones ◽  
Granulite Facies ◽  
Thermodynamic Modelling ◽  
Italian Alps ◽  
Eclogite Facies ◽  
Compositional Patterns ◽  
And Diffusion ◽  
Insight Into

Abstract. Contiguous continental high-pressure terranes in orogens offer insight into deep recycling and transformation processes that occur in subduction zones. These remain poorly understood, and currently debated ideas need testing. The approach we chose is to investigate, in detail, the record in suitable rock samples that preserve textures and robust mineral assemblages that withstood overprinting during exhumation. We document complex garnet zoning in eclogitic mica schists from the Sesia Zone (western Italian Alps). These retain evidence of two orogenic cycles and provide detailed insight into resorption, growth, and diffusion processes induced by fluid pulses in high-pressure conditions. We analysed local textures and garnet compositional patterns, which turned out remarkably complex. By combining these with thermodynamic modelling, we could unravel and quantify repeated fluid–rock interaction processes. Garnet shows low-Ca porphyroclastic cores that were stable under (Permian) granulite facies conditions. The series of rims that surround these cores provide insight into the subsequent evolution: the first garnet rim that surrounds the pre-Alpine granulite facies core in one sample indicates that pre-Alpine amphibolite facies metamorphism followed the granulite facies event. In all samples documented, cores show lobate edges and preserve inner fractures, which are sealed by high-Ca garnet that reflects high-pressure Alpine conditions. These observations suggest that during early stages of subduction, before hydration of the granulites, brittle failure of garnet occurred, indicating high strain rates that may be due to seismic failure. Several Alpine rims show conspicuous textures indicative of interaction with hydrous fluid: (a) resorption-dominated textures produced lobate edges, at the expense of the outer part of the granulite core; (b) peninsulas and atoll garnet are the result of replacement reactions; and (c) spatially limited resorption and enhanced transport of elements due to the fluid phase are evident along brittle fractures and in their immediate proximity. Thermodynamic modelling shows that all of these Alpine rims formed under eclogite facies conditions. Structurally controlled samples allow these fluid–garnet interaction phenomena to be traced across a portion of the Sesia Zone, with a general decrease in fluid–garnet interaction observed towards the external, structurally lower parts of the terrane. Replacement of the Permian HT assemblages by hydrate-rich Alpine assemblages can reach nearly 100 % of the rock volume. Since we found no clear relationship between discrete deformation structures (e.g. shear zones) observed in the field and the fluid pulses that triggered the transformation to eclogite facies assemblages, we conclude that disperse fluid flow was responsible for the hydration.

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