Dehydration of the zeolite merlinoite from the Khibiny massif, Russia: an in situ temperature-dependent single-crystal X-ray study

Dehydration behaviour of the zeolite merlinoite, NaK11[Al12Si20O64]·15H2O, from the Khibiny massif (Russia) was studied by means of single-crystal X-ray diffraction conjoined with step-wise heating to 225 C. At room temperature merlinoite has the space group Immm with a = 14.0312(5), b = 14.2675(6), c = 10.0874(4) Å, and V = 2019.40(14) Å3. At 75 °C the merlinoite structure undergoes pronounced dehydration accompanied by a phase transition to a structure that has the space group P42/nmc and remains consistent at elevated temperature. A fully dehydrated phase occurs at 200 °C (at 225 °C: a = 13.341(4), b = 13.341(4), c = 9.707(4) Å, V = 1727.7(12) Å3). Dehydration-induced framework distortion and symmetry were found to be different from those observed for synthetic potassium merlinoite with the K11.5[Al11.5Si20.5O64]·15H2O composition.

Supramolecular Organization of Dye Molecules in Zeolite L Channels: Synthesis, Properties, and Composite Materials

Sequential insertion of different dyes into the 1D channels of zeolite L (ZL) leads to supramolecular sandwich structures and allows the formation of sophisticated antenna composites for light harvesting, transport, and trapping. The synthesis and properties of dye molecules, host materials, composites, and composites embedded in polymer matrices, including two- and three-color antenna systems, are described. Perylene diimide (PDI) dyes are an important class of chromophores and are of great interest for the synthesis of artificial antenna systems. They are especially well suited to advancing our understanding of the structure–transport relationship in ZL because their core fits tightly through the 12-ring channel opening. The substituents at both ends of the PDIs can be varied to a large extent without influencing their electronic absorption and fluorescence spectra. The intercalation/insertion of 17 PDIs, 2 terrylenes, and 1 quaterrylene into ZL are compared and their interactions with the inner surface of the ZL nanochannels discussed. ZL crystals of about 500 nm in size have been used because they meet the criteria that must be respected for the preparation of antenna composites for light harvesting, transport, and trapping. The photostability of dyes is considerably improved by inserting them into the ZL channels because the guests are protected by being confined. Plugging the channel entrances, so that the guests cannot escape into the environment is a prerequisite for achieving long-term stability of composites embedded in an organic matrix. Successful methods to achieve this goal are described. Finally, the embedding of dye–ZL composites in polymer matrices, while maintaining optical transparency, is reported. These results facilitate the rational design of advanced dye–zeolite composite materials and provide powerful tools for further developing and understanding artificial antenna systems, which are among the most fascinating subjects of current photochemistry and photophysics.

Zeolite and silica diagenesis and sandstone petrography at DSDP Sites 57-438 and 57-439

We detected authigenic clinoptilolites in two core samples of tuffaceous, siliceous mudstone in the lower Miocene section of Hole 439. They occur as prismatic and tabular crystals as long as 0.03 mm in various voids of dissolved glass shards, radiolarian shells, calcareous foraminifers, and calcareous algae. They are high in alkalies, especially Na, and in silica varieties. There is a slight difference in composition among them. The Si : (Al+ Fe3+) ratio is highest (4.65) in radiolarian voids, intermediate (4.34) in dissolved glass voids, and lowest (4.26) in voids of calcareous organisms. This difference corresponds to the association of authigenic silica minerals revealed by the scanning electron microscope: There are abundant opal-CT lepispheres in radiolarian voids, low cristobalite and some lepispheres in dissolved glass voids, and a lack of silica minerals in the voids of calcareous organisms. Although it contains some silica from biogenic opal and alkalies from trapped sea water, clinoptilolite derives principally from dissolved glass. Although they are scattered in core samples of Quaternary through lower Miocene diatomaceous and siliceous deposits, acidic glass fragments react with interstitial water to form clinoptilolite only at a sub-bottom depth of 935 meters at approximately 25°C. Analcimes occur in sand-sized clasts of altered acidic vitric tuff in the uppermost Oligocene sandstones. The analcimic tuff clasts were probably reworked from the Upper Cretaceous terrain adjacent to Site 439. Low cristobalite and opal-CT are found in tuffaceous, siliceous mudstone of the middle and lower Miocene sections at Sites 438 and 439. Low cristobalite derives from acidic volcanic glass and opal-CT from biogenic silica. Both siliceous organic remains and acidic glass fragments occur in sediments from the Quaternary through lower Miocene sections. However, the shallowest occurrence is at 700 meters subbottom in Hole 438A, where temperature is estimated to be 21°C. The d(101) spacing of opal-CT varies from 4.09 to 4.11 Å and that of low cristobalite from 4.04 to 4.06 Å. Some opal-CT lepispheres are precipitated onto clinoptilolites in the voids of radiolarian shells at a sub-bottom depth of 950 meters in Hole 439. Sandstone interlaminated with Upper Cretaceous shale is chlorite- calcite cemented and feldspathic. Sandstones in the uppermost Oligocene section are lithic graywacke and consist of large amounts of lithic clasts grouped into older sedimentary and weakly metamorphosed rocks, younger sedimentary rocks, and acidic volcanic rocks. The acidic volcanic clasts probably originated from the volcanic high, which supplied the basal conglomerate with dacite gravels. The older sedimentary and weakly metamorphosed rocks and green rock correspond to the lithologies of the lower Mesozoic to upper Paleozoic Sorachi Group, including the chert, limestone, and slate in south-central Hokkaido. However, the angular shape and coarseness of the clasts and the abundance of carbonate rock fragments indicate a nearby provenance, which is probably the southern offshore extension of the Sorachi Group. The younger sedimentary rocks, including mudstone, carbonaceous shale, and analcime-bearing tuff, correspond to the lithologies of the Upper Cretaceous strata in south-central Hokkaido. Their clasts were reworked from the southern offshore extension of the strata. Because of the discontinuity of the zeolite zoning due to burial diagenesis, an overburden several kilometers thick must have been denuded before the deposition of sediments in the early Oligocene.

Composition of palygorskite-rich and montmorillonite-rich zeolite-containing sediments from DSDP Sites 164 and 196

Cretaceous, Tertiary, and Quaternary sediments from Deep Sea Drilling Project Sites 164 and 196 (13°12' N, 161°31' W and 30°07' N, 148°34' E, respectively) were analyzed for major chemical elements and mineralogy. Sediments from these sites contain large proportions of authigenic minerals: mainly palygorskite, clinoptilolite and chert in the Cretaceous, and montmorillonite, phillipsite and chert in the Tertiary. The montmorillonite-phillipsite assemblage is thought to be derived from volcanic ash or glass, and the palygorskite-clinoptilolite assemblage is thought to be derived by reaction of biogenic silica with volcanic ash or glass or with montmorillonite and phillipsite. Both assemblages have generally moderate Ti/Al ratios, ranging from 0.026 to 0.047, so most of the palygorskite, clinoptilolite, montmorillonite and phillipsite could not be derived in situ from alteration of basaltic material. Plagioclase compositions suggest that the volcanic precursors were silicic or intermediate, but it is also possible that the sediments have been extensively fractionated by redistribution from nearby seamounts. Available data on other Late Cretaceous sediments in the Pacific were analyzed. Clinoptilolite and chert are present nearly everywhere where palygorskite is abundant; phillipsite is rare where palygorskite is abundant. It is suggested that increased water temperatures during the Cretaceous increased reaction rates and determined the alteration products.

Oxygen and carbon isotope data from late calcite and zeolite pore-fill cements at DSDP Site 445

Oxygen isotopic composition of zeolite pore-fill cements in andesitic volcaniclastic sandstones recovered from DSDP Site 445 ranges from +30.1 to +17.8? (SMOW) downhole. This change is controlled by large heat flow from the basement which caused early diagenetic emplacement of zeolites during early basin rifting. d18O-values of late calcite cements range from +25.1 to +27.4? (SMOW); their petrographic relation and inferred temperature of formation suggest that calcite cements were formed during late stages of diagenesis. Isotopic composition in these sandstones is in agreement with mineral paragenesis determined microscopically.

Análisis de las voladuras realizadas en el centro minero Moró

En este proyecto se analizan seis voladuras realizadas en el Centro Minero Moró (CM Moró) perteneciente a la empresa SIBELCO HISPANIA S.A., situado en la localidad de San Juan de Moró (Castellón). Se analizan las principales diferencias de las voladuras, con respecto a las fases de avance donde se encuentran, el tipo de material volado, la presencia de agua en las mismas, variación de consumo de explosivo y toneladas de roca arrancada. Tomando como base las normas de SIBELCO HISPANIA S.A., el proyecto define la evolución histórica de la empresa, las normativas de seguridad y salud, el ciclo de explotación en el CM Moró, ya que el proceso de arranque tanto de estéril (arenisca y caliza) como de arcillas, se desarrolla por completo mediante voladuras y finalmente un descripción más extensa y concisa de las mismas. ABSTRACT The project presents a comparative study of six blasts realised in the Centro Minero Moró (CM Moró) owned by SIBELCO HISPANIA S.A., located in San Juan de Moró (Castellón). A series of calculations have been conducted and graphs created to observe the main differences between the blasts, with respect to the stage to which it has advanced, the presence of water therein, variation in explosive consumption and tonnes of extracted rocks. Taking the standards of SIBELCO HISPANIA S.A. as a basis, the project defines the historical evolution of the business, the health and safety regulations, the extraction cycle in the CM Moró, since both the sterile (sandstone and limestone) and the clay extraction process are fully achieved by blasts. Ultimately, the aim is to attain a more extensive description of the latter