Geology of South and Southwest part of Uttar Pradesh and its Mineral Significance

The major part of Uttar Pradesh is covered by Gangatic alluvium in the north whereas the southern part is covered by peninsular terrain. This alluvium cover belongs to Holocene age and is mainly dominated by Varanasi older sediments exposed beyond the river basinal areas and Banda younger sediments exposed around the rivers flowing. The older alluvium comprises finer grained, well compacted and more mature sediments occupying extensive stretches at relatively higher elevations. The drainage pattern in region is subdendritic to dendritic type formed by hills and nalas flowing over the soil cover. The Peninsular part of Uttar Pradesh is covered by the rocks of Archean to Mesozoic age. The Bundelkhand craton nuclei mostly composed of Archean granitoids show heterogeneity in texture and composition, intruded by later phase of magmatic activity. The Mahrauni Group of the rocks exposed around Girar, Manpura and Rajaula areas in Madawara block of Lalitpur region. The Bijawar Group is exposed in Sonrai area district Lalitpur of Uttar Pradesh. The rocks of Dudhi Gneissic Complex and Mahakoshal Group are exposed in Sonbhadra and Mirzapur district. Few exposures of Ajabgarh Group rocks are exposed in Mathura district. These Bijawar Group, Mahakoshal Group and Ajabgarh Group rocks are equivalent to Delhi Supergroup. The Bundelkhand craton is capped by the sedimentary units of Vindhyan Supergroup which is exposed mainly in the southern part of Uttar Pradesh and a few exposures are observed in Agra district. The Deccan Trap rocks are also traces in Lalitpur district of Uttar Pradesh.

An upper Miocene hexactinellid sponge from the Puente Shale, Orange County, California

Well-preserved, laterally flattened, farreid hexactinellid sponges of the new species Farrea rugosa have been recently discovered in the upper Miocene Puente Shale in the Peralta Hills in southeastern Anaheim, Orange County, California. This is the first farreid sponge reported from the Miocene of California and is one of the few Miocene sponges reported from North America. The cluster is of upward bifurcating, moderately complex sponges in which branches are regularly rugose and skeletons are each a single layer of dictyid net, with aborted proximal and distal rays in the otherwise laterally fused quadruled skeleton of original silica. The sponges occur in pinkish brown sandy siltstone in the limited exposure beneath older alluvium that blankets much of the local area.

Neotectonics of a Segment of the San Andreas Fault, Southern California (USA)

Die San Andreas-Verwerfung zwischen Valyermo und Wrightwood ist durch eine Hauptverwerfungslinie charakterisiert, die durch Verwerfungskliffe und -senken und tektonische Depressionen mit Alluvionen, Sumpfland, Torfmooren und Teichen gekennzeichnet sind, ferner durch versetzte und verstellte Abflußrinnen, Querriegel und verstellte Hügel, vertonte Zerrüttungszonen, Stufen, Quellen, Vegetationskontraste und durch von Erdbeben verstellte Bäume. Sekundäre Verwerfungslinien divergieren und konvergieren mit der Hauptverwerfungslinie; bezeichnend für sie sind lithologische Kontraste zu unmittelbar benachbarten Schichten, orientierte Täler und vertonte Zerrüttungszonen. Die relative Rechts-Horizontalverschiebung beträgt mindestens 20 m und ist wahrscheinlich zum Teil durch das Fort Tejon-Erdbeben von 1857 verursacht. Die Rechtsverschiebung von verstellten Abflußrinnen variiert zwischen 20 und einigen hundert Metern. Die Verteilung des Older Alluvium (Jungpleistozän?) deutet auf eine kumulative scheinbare Rechtsverschiebung von etwa 3,5 km hin.

Quaternaire et Pliocene du Gurp (Gironde)

The stratigraphy of the Gurp region in Gironde, France, is reviewed in the light of new well data. Thick alluvial deposits underlie the Gurp clay. Pollen analysis indicates that the bed containing Elephas meridionalis is early Pleistocene and that the Gurp clay and older alluvium are Pliocene.

Observations sur la genese des nappes de cailloutis fluviatiles

Discusses the origin of fluvial pebble accumulations. The petrographic composition of such beds depends not only on the nature of outcrops in the drainage basin, but also on reworking of older alluvium in the valley bottom and on the introduction of material from far upstream. These factors vary considerably in relative importance along a watercourse. Different rocks wear differently in transport, so that as distance from the source increases, the proportion of more durable materials also increases.