scholarly journals Phase transitions in the borate minerals from the Kłodawa Salt Dome (Central Poland) as indicators of temperature processes in salt diapirs

2014 ◽  
Vol 58 (3) ◽  
Author(s):  
Jacek WACHOWIAK ◽  
Tomasz TOBOŁA
Keyword(s):  
Phase Transitions ◽  
Salt Dome ◽  
Central Poland ◽  
Borate Minerals

Motukoreaite from the Kłodawa Salt Dome, Central Poland

2016 ◽  
Vol 80 (2) ◽  
pp. 277-289 ◽  
Author(s):  
Jacek Wachowiak ◽  
Adam Pieczka
Keyword(s):  
Layered Double Hydroxide ◽  
Central Europe ◽  
Salt Dome ◽  
Unit Cell ◽  
Central Poland ◽  
The Mean ◽  
Double Hydroxide ◽  
Roof Part

AbstractMotukoreaite, Mg6Al3(OH)18[Na(H2O)6][SO4]2·6H2O, is a poorly-known, rare layered double hydroxide mineral belonging to the wermlandite group in the hydrotalcite supergroup. It was found in abundant quantities (at least hundreds of thousands of Mt) in the roof part the Younger Potash unit of the Leine cyclothem on the Kłodawa Salt Dome in central Poland (Permian–Mesozoic basin of Central Europe), outside its known typical environments like altered basalts and basaltic tuffs, including those deposited in submarine volcanic areas. The mineral displays varying SO2–4, Na+ and H2O contents with negligible CO2–3, corresponding to the mean composition Mg5.75(Al3.20Fe3+0.04)∑3.25(OH)18.00{[Na(H2O)6]0.72□0.28}[(SO4)1.67(CO3)3.03(OH)0.57]·0.72H2O. It can be related to the partly dehydrated, hypothetical end-member Mg6Al3(OH)18[Na(H2O)6][(SO4)2]·6H2O. The Kł odawa motukoreaite represents the hexagonal, 3-layer polytype with the 3 × 3 superstructure in the xy plane, and unit cell a = b = 9.191(2)–9.199(2) Å, i.e. = 3 × 3.064–3.066 Å and c = 33.529(9)–33.562(7) Å, i.e. = 3 × 11.174–11.187 Å. The mineral was formed by alteration of clays delivered to the basin by an aeolian overprint and co-sedimented along with the evaporite sequence, initiated under the influence of Mg2+ - and SO2–4-bearing brines at temperatures not exceeding 160–200°C, released from the evaporites during diagenetic/metamorphic processes.

Hydrocarbon alteration in the bituminous salt of the Kłodawa Salt Dome (Central Poland)

2016 ◽  
Vol 75 ◽  
pp. 325-340 ◽  
Author(s):  
Aleksandra Wesełucha-Birczyńska ◽  
Tomasz Toboła
Keyword(s):  
Salt Dome ◽  
Central Poland

Electron Microscopy of Graphite Intercalation Compounds

1982 ◽  
Vol 40 ◽  
pp. 544-545
Author(s):  
G. Timp ◽  
L. Salamanca-Riba ◽  
L.W. Hobbs ◽  
G. Dresselhaus ◽  
M.S. Dresselhaus
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
Domain Wall ◽  
Intercalation Compounds ◽  
Lattice Plane ◽  
Wall Model ◽  
Graphite Intercalation Compounds ◽  
Fundamental Symmetry ◽  
Graphite Intercalation

Electron microscopy can be used to study structures and phase transitions occurring in graphite intercalations compounds. The fundamental symmetry in graphite intercalation compounds is the staging periodicity whereby each intercalate layer is separated by n graphite layers, n denoting the stage index. The currently accepted model for intercalation proposed by Herold and Daumas assumes that the sample contains equal amounts of intercalant between any two graphite layers and staged regions are confined to domains. Specifically, in a stage 2 compound, the Herold-Daumas domain wall model predicts a pleated lattice plane structure.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

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