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The Haymana basin in central Anatolia (Turkey) formed on a Late Cretaceous to Middle Eocene fore-arc accretionary wedge. A sequential model is proposed for the 1-km-thick Lutetian Yamak turbidite complex (YTC) which is the youngest paleotectonic unit of the basin. The YTC represents a prograding submarine fan subdivided into three depositional sequences (DS), each several hundred meters thick. Each depositional sequence consists of a turbidite system (TS), with sandstone and conglomeratic sandstone beds alternating with mudstones, overlain by basin plain mudstones. In each turbidite system, the sandstone and mudstone sequential organization allows the distinction of smaller subdivisions, namely, basic sequences (BS) and basic units (BU), with each basic sequence being composed of several basic units. This subdivision, associated with a two-dimensional geometric reconstruction of the YTC, leads to a better understanding of the evolution in time and space of the submarine fan system. Lower to middle fan depositional lobes, and upper fan and slope channels, are represented. As a whole, the YTC progressed from a sand-poor to a sand-rich system. Depositional sequences (DS) of the YTC may correspond to third-order sea-level cycles of tectonic origin. Accordingly, fourth- and fifth-order cycles might be proposed for the BS and BU, respectively. However, partly because of the limited extent of exposures, the allocyclic origin of these finer subdivisions remains problematic.

Muscovites in metapelites belonging to the Chloritoid, Staurolite, Kyanite, Sillimanite-K feldspar and Sillimanite-K feldspar-Cordierite zones of the Sierra de Guadarrama metamorphic area, have a chemical composition close to the end member Ms (mean value around Ms 92); nevertheless, they show definite variations in Al2O3, K2O and Na2O contents and, to a lesser extent, in FeO and MgO. These chemical variations (i. e., a progressive decrease of celadonite content, a increase followed by a decrease in paragonite solid solution towards compositions close to the endmember muscovite) may be regarded as in a close relationship with metamorphic grade in the upper metamorphic zones (Chloritoid, Staurolite and Kyanite zones), but the corresponding variations in the remaining lower zones (that is, a slight increase in Fe and Mg coupled with a slight increase in AlVI and Ti, and more or less abrupt changes in Na and K contents) can only be explained considering the interference of anatectic phenomena, which modificate the normal trends due to changes in metamorphic grade. As a consequence of these observations, it has been concluded that muscovite composition in metapelites can only be used as an indicator of metamorphic grade in conditions where partial melting phenomena are absent.

A new estimate of the bulk continental crust is reported consisting of 57 percent lower crust (60% felsic and 40% mafic granulites) and 43 percent upper crust. The proportions of crustal units are based on petrological observations (Bohlen &Mezger, 1989). The estimate of a bulk composition is intermediate between andesite and tonalite and is higher in Si, K, Rb, Sr, Zr, Nb, Ba, LREE, Pb, Th concentrations and lower in Mg, Ca, Sc, Mn, Fe than the crustal abundances reported byTaylor &McLennan (1985). Equal chemical composition between the upper crust and the felsic part of the lower crust is attained in balance computations if one restores a fraction of 12.5 percent S-type granite from the upper into the lower crust. An example of water-undersaturated partial melting and separation of a fraction of about 35 percent granitic magma at the conversion from amphibolite-into granulite-facies metasediments has been balanced bySchnetger (1988) in the Ivrea area (N. Italy). The worldwide observed discrepancy between a larger negative Eu anomaly in the upper crust compared with the half as large positive anomaly of the lower crust increasing from the early Precambrian to present has been explained by recycling of Ca-rich restite into the upper mantle. The composition of the Archean crust (example: Greenland) does not differ systematically from the post-Archean crust.

Survenant à relativement faible profondeur d'eau, une éruption basaltique sous-marine est caractéristiquement différente d'une éruption de même nature se produisant à l'air libre: 1. les phénomènes explosifs y sont exceptionnellement violents (hauteur de projection valant plusieurs fois celles des explosions basaltiques subaériennes); 2. leur fréquence est beaucoup plus élevée (20 à 90 explosions par minute contre 0,1 à 10); S. la proportion de produits pyroclastiques est beaucoup plus élevée, celle des coulées se trouvant réduite à moins d'un pour cent parfois; 4. la granulométrie des produits pyroclastiques est beaucoup plus fine, semblable à celle des pyroclastites acides. Ces différences s'expliquent, selon l'auteur, par des séries d'explosions phréatiques, eau de mer brusquement vaporisée, succédant rapidement à chaque manifestation explosive magmatique; par manifestation explosive l'on entend explosion proprement dite d'une poche de gaz sous pression ou brassage violent de la surface de la colonne de lave; la condition sine qua non étant une fragmentation initiale de la lave, mettant en contact l'eau et la matière à très haute température sur une surface suffisante pour provoquer une première explosion de vapeur; cette explosion phréatique brise les fragments engendrés par l'explosion magmatique, mettant ainsi de nouvelles surfaces incandescentes au contact de l'eau et provoquant une 2ème explosion de vapeur avec nouvelle fragmentation plus poussée, et ainsi de suite jusqu'à fragmentation relativement fine. Ce processus permet une transformation très rapide de l'énergie calorifique contenue dans la lave en énergie cinétique. Ceci explique les caractéristiques très particulières observées ainsi que l'absence de ces caractéristiques lorsque les manifestations éruptives sont de type effusif (coulées ou lac de lave) où il n'y a pas de fragmentation explosive initiale.

The Tertiary sedimentary sequence in the Lusatian Brown Coal District is the result of several transgressive pulses with intercalated regressive phases. Regression repeatedly resulted in the formation of large littoral bogs at the transition between brackish and terrestrial palaeoenvironments. In the lithofacies changes of the Lower-Middle Miocene strata (high energy sands, low energy intertidal silts, paralic peats) long-term changes as well as short-term oscillations of sea level are recorded. The rise of sea level in the upper Lower Miocene (Hemmoorian transgression) is proved in numerous localities of the investigation area. After a regression phase with major peat formation events around the Lower-Middle Miocene boundary, a renewed sea-level rise resulted in the widest extension of marine-brackish beds over pre-Tertiary basement in the south of the region (higher Reinbekian transgression, Middle Miocene). Very differentiated, fine-scaled, probably sea-level induced coastline oscillations could probably be traced even into the coal seams by the recognition of successive bogfacial types possibly showing a groundwater level change in the ancient peat bog (change of topogeneous and ombrogeneous bog types). A biostratigraphic calibration of the decalcified Lower-Middle Miocene sequence with its alternating transgressive and regressive trends to the fully marine sediments of the basinal centre, which are dated by calcareous microfossils, is possible by means of dinoflagellate cysts and pollen and spores.

Das mesozoische Profil setzt bei Bande Amir am Südrand des tadschikischen Beckens mit detritogenen, geröllführenden Kalksteinen ein. Es sind marine Bildungen der Oberkreide (Cenoman-Turon), die diskordant eingeebnetes, jungpaläozoisches Grundgebirge (Perm) überlagern. Nach einer neritischen Sedimentationsphase (Santon-Campan) setzten im Verlauf der hohen Oberkreide (Maastricht) Regressionen an der zentralafghanischen Schwelle ein. Diese gehen zurück auf Krustenverstellungen und regionale Aufbiegungen im Hindukusch, die an der Herat-Bruchzone lineamentartig geschient waren. Auf dieser mobilen Zone entstanden im Mitteltertiär intermontane Becken, in denen kontinentale Schuttmassen (Neogen-Konglomerate; Zohak-Schichten) oder lakustrine Sedimente (Ghulghola-Schichten) abgelagert wurden. Im Plio-Pleistozän lebten die Bewegungen an den Schollengrenzen wieder auf. Damit vollzog sich der Anschlu\ an das Amu-Darja-Drainagenetz, was Beckenverlagerungen und canyonartige Einschnitte der Flüsse nach sich zog. Während der quartären Warmzeiten wurde allerdings bei Bande Amir die Tiefenerosion mindestens viermal unterbrochen, weil sich hinter hohen Travertindämmen gro\e Stauseen gebildet hatten.

Attaching himself to his earlier investigations, the author gives a new interpretation of mountain building and associated phenomena on the basis of his earth expansion theory. The geosynclinal phase of mountain building is connected with deep fractures accompanied by deep-sea troughs, isostatic anomalies and andesitic volcanism. On the other hand, the phase of emergence is accompanied by phenomena observable in the graben areas, which in their turn are connected with shallow-focus earthquakes and basaltic volcanism. Folding is brought about in and immediately after the geosynclinal phase by the lateral pressure of the intruding magma masses, and later on by the gliding by gravity of the accumulated sediments.