Application of the Controlled Source Radiomagnetotellurics (CSRMT) in the Study of Rocks Overlying Kimberlite Pipes in Yakutia/Siberia

Тhe task of searching for kimberlite pipes in covered areas of the Yakutia kimberlite province is very difficult due to the significant heterogeneity of the rocks overlying kimberlite pipes. The overlying strata of terrigenous sediments contain rocks of the trap complex (dolerite sills, tuff bodies). We consider the results of the controlled source radiomagnetotelluric (CSRMT) soundings in Yakutia/Siberia. Due to the great thickness of the overlying rocks (near 100 m) and the relatively small horizontal sizes of kimberlite pipes (80–200 m), they cannot confidently be detected directly. An additional difficulty in identifying pipe anomalies is the presence of a layer of conductive carbonaceous siltstones in the overlying strata. Therefore, the main aim of the CSRMT surveys was the study of overlying rocks and the search for indirect indications of the presence of pipes. Possibilities to study the structure of dolerite sills located within overlying sediments and to map the top edge of hosting carbonate rocks are demonstrated using the CSRMT data. The pinching out of dolerite sills above pipes («windows in traps») and the lowering of the top edge of hosting rocks at pipes can be considered as indirect indications of the presence of pipes.

Electron-beam welding of large thickness steels of oil producing platform components

The paper treats problems of reducing the cost of welding and improving the quality and productivity of welding parts of cold-resistant steel of great thickness during the construction of oil platforms. The design of tooling structure, and devices for electron-beam welding have been developed such as welding wire feeder, video observation system, software for controlling the workpiece moving and the electron beam gun travel.

Regularities in variations of the pume volcanics composition in the Southern Atlantic and at the African plate

The action of the African Superplume provided input and accumulation of the volatile, alkaline and some others elements at the base of continental lithosphere. Transformation and interaction of these components with mantle peridotites took place under the African continental plate of the great thickness. Generation of low silica and rich in CO2 melts occurs at the great depth: this is the family of kimberlites, melilitites and carbonatites. At the shallower levels of the lithospheric plate the melts of basalts originated; they are more rich in SiO2 and poor in volatiles. The origin of deep generated volcanics was controlled by the pressure of CO2 in the fluids. The melting of basalts is connected mainly with tectonic position.

The effects of intensive rainfalls (flash floods) on the development on the landforms in the Kőszeg Mountains (Hungary)

The effects of the intensive rainfall episodes in the years 2009 and 2010 in the Kőszeg Mountains were investigated. Channel profiles were constructed at various times during these periods, which were used to describe the channel changes. We measured the length of the incised and filled sections on multiple occasions. We could establish the degree and the direction of the changes using this data. The sediment veneer that developed in the area of Kőszeg town was mapped and its conditions of development were examined. The erosion and accumulation landforms developed during these years were classified and described. These forms are the following: rills, gullies, alluvial fans and sediment veneer. We distinguished and characterised those which had previously formed, but they were changed or increased (the channels). We established the conditions under which the sediment veneer can develop, furthermore those conditions which can increase the chance of the formation of this landform. These conditions are the following: the high density of roads in the catchment areas of valleys leading to settlements, the great thickness of superficial deposit, and the steep slope of the surface of the catchment area. We created theoretical classification of the morphological environment where the development of sediment veneer may happen and identified settlements with structures which promote or prevent the development of the sediment veneer. We determined the probability of the development of the sediment veneer at some settlements in Kőszeg, and suggestions have been given to decrease the chance of the development of this sediment veneer.

The Los Llantenes Formation in the Precordillera of Jagüe (La Rioja Province) and the recognition of a rifting stage in the early evolution of the late Paleozoic basins in western Argentina.

In the northern part of the Argentine Precordillera, northwestern La Rioja, the Upper Paleozoic is over 4,000 m thick. Very coarse conglomerates from the basal section have not been described nor adequately interpreted. This work analyses this unit in the context of a stratigraphic revision of the upper Paleozoic of the region, and interprets the conglomerate as a rift deposit. The thick (>1,000 m) and coarse purple conglomeratic succession, herein named ‘Los Llantenes Formation’, non-conformably rests on the basement rocks of the region and underlies deposits of the first glacial record associated with the Gondwanan glaciation. While its great thickness and restricted areal extent indicate localized subsidence, the crude stratification, poor sorting and abundance of >1-m boulders indicate an origin related to high-gradient, low-efficiency alluvial fans. Their composition and coarse-grained size indicate local provenance, abrupt relief and incipiently developed drainage systems and a highly compartmentalized and abrupt paleogeography. A complex glacial history generated deep ‘U’-shaped paleovalleys in the Los Llantenes Formation, developing paleovalleys that accommodated basal lodgment tills and glacial diamictites with sedimentologic features comparable to the Cerro Tres Condores Formation (Visean in age) exposed to the south. The age of the conglomerates of Los Llantenes Formation, clearly preglacial, can be stratigraphically bracketed between the Middle Devonian substrate cropping out to the south in the sierra de Las Minitas and the Middle Mississippian, age of the Cerro Tres Condores Formation. Consequently, Los Llantenes Formation may partly correlate with the Agua de Lucho Formation (Tournaisian-Vissean) that in the area of Rio del Penon, immediately to the south, underlies the glacigenic Cerro Tres Condores Formation. Mapping relationships with limited areal extent, together with the great thickness of Los Llantenes Formation and the local provenance, allow interpreting accommodation in extensional or pull-apart depocenters, conclusions that are relevant in order to reconstruct the history of the basin.

First fossil gravid turtle provides insight into the evolution of reproductive traits in turtles

Here we report on the first discovery of shelled eggs inside the body cavity of a fossil turtle and on an isolated egg clutch, both referable to the Cretaceous turtle Adocus . These discoveries provide a unique opportunity to gain insight into the reproductive traits of an extinct turtle and to understand the evolution of such traits among living turtles. The gravid adult and egg clutch indicate that Adocus laid large clutches of rigid-shelled spherical eggs and established their nests near rivers, traits that are shared by its closest living relatives, the soft-shelled turtles. Adocus eggshell, however, was probably more rigid than that of living turtles, based on its great thickness and structure, features that may represent unique adaptations to intense predation or to arid nest environments. In light of the reproductive traits observed in Adocus , the distribution of reproductive traits among turtles reveals that large clutches of rigid-shelled eggs are primitive for hidden-necked turtles (cryptodirans) and that spherical eggs may have evolved independently within this group.

Toward the diagnosis of pregnancy in the rudimentary atretic horn of the uterus

Among the numerous variants of uterine abnormalities, expressed in its doubling, the formation of a rudimentary atretic horn is of particular interest. In rare cases, the fetal egg developing in it creates a lethal danger due to the obligatory rupture. The gestational age at which the rupture occurs can vary and depends on the thickness of the myometrium. With low thickness, rupture occurs early and mimics an aborted tubal pregnancy. With great thickness and well developed musculature of the horn there is a termination of pregnancy with a clinical uterine rupture. It is known that the correct diagnosis in such a situation is rarely made - from 6 to 25%.