326 research outputs found
HYPA-r: Hydrodynamic patterns dataset (raw data)
No full textThe HYPA-r dataset contains raw image data of a variety of gravure printed
patterns. The raw image data is created by high-resolution scanning of printed
samples from industrial gravure printing web-presses. Pattern types, which are
represented in the dataset, are dot patterns, finger patterns and mixed
patterns. The HYPA-r dataset mainly aims at data-driven analysis of
hydrodynamic pattern formation in gravure printing.
HYPA-r stands for **hy** drodynamic **pa** tterns. The suffix -r stands for
**r** aw data.
To get a quick impression of the dataset, two example-images are provided
separately for download, named 'G1-01_WCPvbam_V005_ESA0_L01.tif' and
'G1-01_WCPvbam_V005_ESA0_S01.tif'.
Metadata for the HYPA-r dataset can be found in the dissertation of Pauline
Rothmann-Brumm (2023) and in the provided README-file.
In the related [HYPA-p](https://tudatalib.ulb.tu-
darmstadt.de/handle/tudatalib/3841) dataset, the corresponding processed (-p)
image data can be found
GRAFI-r: Gravure printing finger instability dataset (raw data)
No full textThe GRAFI-r dataset contains high speed videos of finger instabilities during
fluid splitting in gravure printing. The high speed videos were recorded on a
custom-built gravure printing research platform, which enables optical access
to the printing nip. The printing nip is the line of contact between the
engraved printing cylinder and the impression roller. The aim of the dataset
is the in-situ visualization and temporal analysis of hydrodynamic pattern
formation phenomena during fluid transfer. The influence of the engraving
raster on the finger instability can be investigated. The GRAFI-r dataset
comprises raw video data whereas processed video data can be found in the
related [GRAFI-p](https://tudatalib.ulb.tu-darmstadt.de/handle/tudatalib/3848)
dataset.
GRAFI-r dataset stands for **gra** vure printing **f** inger **i** nstability
dataset. The suffix -r stands for **r** aw data.
Metadata for the GRAFI-r dataset can be found in the dissertation of Pauline
Rothmann-Brumm (2023) and in the provided README-file (last item in dataset,
click 'show more')
A crystal chemical re-evaluation of amphibole/melt and amphibole/clinopyroxene D-Ti values in petrogenetic studies
No full textConstraints on the calculation and use of mineral/melt and two-mineral partition coefficients for Ti (D-Ti) have been derived from current knowledge of the distinct crystal-chemical mechanisms for the incorporation of Ti4+ in the amphibole structure as follows: (1) mineral/melt partition coefficients for Ti, and other tetravalent high field-strength elements (HFSE), can be compared only when considering the fraction of Ti4+ that enters the same structural site; (2) accurate two-mineral partition coefficients can be obtained only when considering the fraction of Ti4+ that is involved in the same crystal-chemical mechanism in the two relevant phases (i.e., Ti-M2(4+) and Ti-M1(4+) for amphibole and clinopyroxene, respectively). The complete crystal-chemical characterization of synthetic titanian pargasite and kaersutite and of synthetic richterite tall crystallized under P, T, X, f(O2) conditions of interest for upper-mantle studies) shows that the site preference of Zr and Hf differs between the two amphibole compositions; these elements are essentially ordered at M2 in pargasite and kaersutite, but preferentially enter M1 in richterite. In the latter case, Ti segregates into the split M1' site with distorted coordination and shorter Ti-O3 distances, whereas Zr and Hf most likely prefer the larger and more regular M1 site. The observed site preference is strongly controlled by the relative dimensions of the available sites. The crystal-chemical mechanisms that govern the incorporation of octahedral high-charge cations are the local charge balance of Al-[IV] (by R-3,R-4+ at M2) and of dehydrogenation (by R-3,R-4+ at M1); thus the incorporation of Zr and Hf depends on distinct intensive parameters in the two amphibole compositions. Calculation of partition coefficients and of elastic-site parameters under the assumption that all Ti and other HFSE4+ order at the M2 site in amphibole, as is currently done in geochemical studies, is strongly biased. In the presence of significant dehydrogenation, amphibole/melt D-0 values obtained from modeling based on the elastic-strain theory starting from the more-accurate site populations for Ti may be only 1/4 of those obtained by using the total Ti content, and the derived site parameters E and r(0) are more consistent with octahedral coordination. This result has important consequences for the prediction of D values under P-T conditions different from those of the experimental work. Applying the above concepts to data from natural assemblages, we obtained a significantly narrower (0.3-2.4 vs. 1.5-8.9) and more reasonable range of variation for amphibole/clinopyroxene D-Ti. A relationship between these values for D, and pressure is also now apparent
A crystal chemical re-evaluation of amphibole/melt and amphibole/clinopyroxene D-Ti values in petrogenetic studies
No full textConstraints on the calculation and use of mineral/melt and two-mineral partition coefficients for Ti (D-Ti) have been derived from current knowledge of the distinct crystal-chemical mechanisms for the incorporation of Ti4+ in the amphibole structure as follows: (1) mineral/melt partition coefficients for Ti, and other tetravalent high field-strength elements (HFSE), can be compared only when considering the fraction of Ti4+ that enters the same structural site; (2) accurate two-mineral partition coefficients can be obtained only when considering the fraction of Ti4+ that is involved in the same crystal-chemical mechanism in the two relevant phases (i.e., Ti-M2(4+) and Ti-M1(4+) for amphibole and clinopyroxene, respectively). The complete crystal-chemical characterization of synthetic titanian pargasite and kaersutite and of synthetic richterite tall crystallized under P, T, X, f(O2) conditions of interest for upper-mantle studies) shows that the site preference of Zr and Hf differs between the two amphibole compositions; these elements are essentially ordered at M2 in pargasite and kaersutite, but preferentially enter M1 in richterite. In the latter case, Ti segregates into the split M1' site with distorted coordination and shorter Ti-O3 distances, whereas Zr and Hf most likely prefer the larger and more regular M1 site. The observed site preference is strongly controlled by the relative dimensions of the available sites. The crystal-chemical mechanisms that govern the incorporation of octahedral high-charge cations are the local charge balance of Al-[IV] (by R-3,R-4+ at M2) and of dehydrogenation (by R-3,R-4+ at M1); thus the incorporation of Zr and Hf depends on distinct intensive parameters in the two amphibole compositions. Calculation of partition coefficients and of elastic-site parameters under the assumption that all Ti and other HFSE4+ order at the M2 site in amphibole, as is currently done in geochemical studies, is strongly biased. In the presence of significant dehydrogenation, amphibole/melt D-0 values obtained from modeling based on the elastic-strain theory starting from the more-accurate site populations for Ti may be only 1/4 of those obtained by using the total Ti content, and the derived site parameters E and r(0) are more consistent with octahedral coordination. This result has important consequences for the prediction of D values under P-T conditions different from those of the experimental work. Applying the above concepts to data from natural assemblages, we obtained a significantly narrower (0.3-2.4 vs. 1.5-8.9) and more reasonable range of variation for amphibole/clinopyroxene D-Ti. A relationship between these values for D, and pressure is also now apparent
Trace-element partitioning between synthetic potassic-richterites and silicate melts, and contrasts with the partitioning behaviour of pargasites and kaersutites
No full textSolid/liquid partition coefficients for large ion lithophile elements (Ba, Rb, Sr), high field strength elements (Zr, Hf, Nb, Ta, Ti), rare earth elements (La-Yb), Pb, Th, U and selected transition elements (Sc, V) were determined by means of Secondary Ion Mass Spectrometry on potassic-richterites synthesised at upper mantle conditions (P = 1.4 GPa and T = 850-1020°C) from silica-rich lamproites. Most trace elements display an incompatible behaviour in potassic-richterites; only Sr, Ti, Sc and V show strong positive anomalies in the partitioning pattern. When S/LD for potassic-richterites are compared with those for calcic amphiboles (pargasites and kaersutites) several differences become evident. In general, S/LD are lower in potassic-richterites; also, different partitioning patterns are apparent for RE and LIL elements. These differences are discussed in terms of the distinct crystal-chemical behaviour of the involved amphibole end-members, with particular emphasis to the available charge-balance mechanisms and to the site dimensional constraints ruling incorporation of trace elements in the various sites. The distinct partitioning behaviours of trace elements in potassic-richterites and pargasites and kaersutites imply that melts produced from amphibole-bearing sources may differ markedly depending on the type of amphibole crystallised. Therefore, the new partitioning data are used to discuss the role of potassic-richterite in its principal modes of occurrence, namely in lamproites, in peralkaline ultramafic veins in the lithospheric mantle, and in the deeper parts of subduction zones
Distinct site preferences for heavy and light REE in amphibole and the prediction of Amph/L D REE
No full textNew experimental amphibole/melt partition coefficients from a variety of geologically relevant amphibole (pargasite. kaersutite, and K-richterite) and melt compositions obtained under conditions of interest to upper-mantle studies are combined with the results of X-ray single-crystal structure refinement. The ideal cation radii (r(0)), calculated using the lattice-site elastic-strain model of Blundy and Wood (1994) under the hypothesis of complete REE (rare earth elements) ordering at ([8])M4, mostly differ significantly from those obtained from both the structure refinement and the ionic radius of Ca-[8](2+). Heavier REE may also strongly deviate from the parabolic trends defined by the other REE. On the basis of the crystal-chemical knowledge of major-element site-preference in amphibole and the occurrence of two sites with different co-ordination within the M4 cavity (M4 for Ca and Na, M4' for Fe2+ and Mg), we propose a new model for REE incorporation. LREE order at the ([8])M4 site, whereas HREE prefer the M4' site with lower co-ordination in amphiboles with a significant cummingtonite component, and may also enter the M2 octahedron, at least in richterite. This more complex model is consistent with the observed D-Amph/L, and drops the usual assumption that REE behave as a homogeneous group and order at the M4 site. The availability of multiple crystal-chemical mechanisms for REE3+ incorporation explains why measured and estimated D-Amph/L(HREE) may differ by up to one order of magnitude. When REE enter two different sites within the same cavity, a fit performed on the basis of a single curve may appear correct, but the values obtained for r(0) are biased towards those of the dominant site, and the Young's modulus is underestimated. When REE are incorporated in multiple sites in different cavities, the observed pattern cannot be reduced to a single curve, and the partition coefficients of heavy REE would be strongly underestimated by a single-site fit. The simplistic assumption that REE occupy a single site within the amphibole structure can thus substantially bias predictive models based on the elastic-strain theory. Our combined approach allows linkage between fine-scale site preference and the macroscopic properties of minerals and provides more reliable predictive models for mineral/melt partitioning. After the possible site-assignments have been identified, the shape of the Onuma curves constructed from accurately determined D-Amph/L(REE) now allows the active mechanisms for REE incorporation in amphiboles to be recognised even where site populations are not available. The REE preference for polyhedra with smaller size and lower co-ordination than those occupied by Ca invalidates the general idea that Ca acts as a "carrier" for REE
A crystal chemical re-evaluation of amphibole/melt and amphibole/clinopyroxene D(Ti) values in petrogenetic studies
No full textConstraints on the calculation and use of mineral/melt and two-mineral partition coefficients for Ti (D(Ti)) have been derived from current knowledge of the distinct crystal-chemical mechanisms for the incorporation of Ti4+ in the amphibole structure as follows: (1) mineral/melt partition coefficients for Ti, and other tetravalent high field-strength elements (HFSE), can be compared only when considering the fraction of Ti4+ that enters the same structural site; (2) accurate two-mineral partition coefficients can be obtained only when considering the fraction of Ti4+ that is involved in the same crystal-chemical mechanism in the two relevant phases (i.e., M2Ti4+ and M1Ti4+ for amphibole and clinopyroxene, respectively). The complete crystal-chemical characterization of synthetic titanian pargasite and kaersutite and of synthetic richterite (all crystallized under P,T,X, fo2 conditions of interest for upper-mantle studies) shows that the site preference of Zr and Hf differs between the two amphibole compositions; these elements are essentially ordered at M2 in pargasite and kaersutite, but preferentially enter M1 in richterite. In the latter case, Ti segregates into the split M1' site with distorted coordination and shorter Ti-O3 distances, whereas Zr and Hf most likely prefer the larger and more regular M1 site. The observed site preference is strongly controlled by the relative dimensions of the available sites. The crystal-chemical mechanisms that govern the incorporation of octahedral high-charge cations are the local charge balance of ([IV])A1 (by R3,4+ at M2) and of dehydrogenation (by R3,4+ at M1); thus the incorporation of Zr and Hf depends on distinct intensive parameters in the two amphibole compositions. Calculation of partition coefficients and of elastic-site parameters under the assumption that all Ti and other HFSE4+ order at the M2 site in amphibole, as is currently done in geochemical studies, is strongly biased. In the presence of significant dehydrogenation, amphibole/melt D0 values obtained from modeling based on the elastic-strain theory starting from the more-accurate site populations for Ti may be only 1/4 of those obtained by using the total Ti content, and the derived site parameters E and r0 are more consistent with octahedral coordination. This result has important consequences for the prediction of D values under P-T conditions different from those of the experimental work. Applying the above concepts to data from natural assemblages, we obtained a significantly narrower (0.3-2.4 vs. 1.5-8.9) and more reasonable range of variation for amphibole/clinopyroxene D(Ti). A relationship between these values for D(Ti) and pressure is also now apparent
Cold subduction of oceanic crust: Implications from a lawsonite eclogite from the Dominican Republic
No full textLawsonite eclogite is a rare rock type that has been described from only five natural occurrences. In contrast, laboratory experiments and thermal models predict that lawsonite eclogite should be widespread in subducted oceanic crust deeper than 1.5 GPa. Here we report a new lawsonite eclogite find from the Dominican Republic that provides constraints on the conditions of subducted crust and on its return to the surface. In this sample, lawsonite coexisting with omphacite occurs as both inclusions in garnet and as porphyroblasts, the latter being partly replaced at their margins by epidote and zoisite. Peak pressure conditions estimated from lawsonite-phengite-omphacite-garnet assemblages were ca 1.6 GPa at a temperature of 360degreesC, implying formation under a geotherm of ca. 8degreesC/km. Peak temperature conditions of 410-450degreesC were in the zoisite eclogite field, suggesting that the sample crossed from the stability field of lawsonite eclogite into that of zoisite eclogite as a result of increasing temperature. A comparison with other reported occurrences indicates that most lawsonite eclogite exhumed at the Earth's surface formed in accretionary wedges. The rarity of lawsonite eclogite at the Earth's surface may be principally due to two factors: (i) that in 'normal' subduction settings lawsonite eclogite enters the subduction factory and hence is usually not exhumed; and (ii) that in accretionary wedge settings, where the PT path leaves the stability field of lawsonite eclogite due to heating, lawsonite eclogite is only preserved if the exhumation path is constrained to a narrow window where the terminal stability of lawsonite is not crossed
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