Micromorphology of solonetzic horizons as related to environmental events in the Caspian Lowland

Micromorphology of solonetz species with special attention to natric horizon was studied in microcatenas at the Dzhanybek Research Station （northwestern Caspian Lowland）. The solonetzic （natric） horizon is easily identified, and it occurs at varying depths, which are the criteria for subdividing solonetzes into 4 species, namely, crusty, shallow, medium and deep. In this sequence, the depth of humus-accumulative horizons increases, and the upper boundary of salinity manifestations goes down. The following micromorphological features are assumed as typical for natric horizons： angular blocky microstructures with partially accommodated aggregates having sharp boundaries and narrow plane-like packing voids; b-fabric speckled in the aggregates＇ centers and monostriated at their peripheries merging into stress coatings; very few interpedal voids; organo-clay coatings; humus- enriched infillings; no calcite and gypsum pedofeatures. A complete set of ＂natric＂ features was found only in the crusty solonetz; the shallow solonetz lacks only illuviation coatings, while the medium and deep species have several modifications of fabric elements： blocky aggregates have a rounded shape and are penetrated by biogenic channels favoring their further biogenic reworking; plant residues became more abundant and diverse, and blackened tissues occur; illuviation clay coatings evolved into papules; stress coatings gave birth to striated bfabrics, thus maintaining a high plasma orientation. The thin sections of natric horizons made 50 and 20 years ago were examined to study the influence of environmental changes （increase in precipitation and rise of ground water table） on micropedofeatures. The following processes took place： （i） in the topsoil： humus accumulation and biogenic structurization; （ii） in the natric horizon - re-arrangement of clay coatings into micromass b-fabrics; and （iii） in the lower part of the natric horizon - development of pseudosand fabric, calcite and gypsum formation. The trends revealed are in good agreement with the environmental events.     

Causes of rockfalls in Al-Huwayshah area,Yemen

According to topography of Yemen,most areas and villages are located at obligated crest,toe of mountain and under cliffs.Therefore Al-Huwayshah consisting of Tawilah sandstone group is characterized by steep slope reach to 90° in some areas.This area is affected by strong tectonic movements and faults that occurred during the geological epochs.This effect enhances to find out fractures and joints as well as the rocks become brittle and ready to slide depending on the position of area.And there are some frac...     

Analysis of petroleum hydrocarbons in mangrove sediments of Red Sea of Yemen

A field work has been carried out to identify the occurrence of oil and oil products pollution in mangrove sediment from Red Sea of Yemen. The concentration of total petroleum hydrocarbons is from 700ng/g at Kamaran Island station to 400 ng/g at Al-Hodiedah station, and the total organic carbon （TOC） in samples ranges from 0. 07% at Dhubab station to 0. 03% at Kamaran Island station. This pollution is as a result of localized oil pollution and/or heavy ship traffic in the Red Sea and Gulf of Aden.     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings have caused many deaths and injuries. The field of earthquake engineering studies     

New observations and transit solutions of the inflated exoplanets HAT-P-40b and HAT-P-51b

We present high-precision photometric observations of the transiting exoplanets HAT-P-40 b and HAT-P-51 b by the Rozhen 2-m telescope.The newly-observed transit of HAT-P-40 b is the first one with a complete curve.The orbital periods of the two targets were improved.We modeled the observed transits and found bigger stellar radii than those derived from the stellar models.The planet radii of HATP-40 b and HAT-P-51 b obtained from our transit solutions are bigger than the values calculated by the empirical relations for Jupiter-mass and Saturn-mass planets respectively.Their values reveal the highlyinflated nature of the two targets,especially that of HAT-P-51 b.We established that the best transit solutions correspond to a quadratic limb-darkening law.The fitted limb-darkening coefficients of HAT-P-40 are close to the theoretical ones while those of HAT-P-51 are a little different.The precise astrometric Gaia distances of the two targets are smaller by 6%–7%than the calculated values from the stellar models.We propose the Gaia distances to be used for improvement of the stellar models as well as for more reliable calculation of the parameters of the known exoplanets.     

原始地核:离子探针为西格陵兰和恩德比地(南极洲)太古宙地区大约4000Ma地壳物质提供的证据

对古老岩区的典型花岗片麻岩中提取单—锆石颗粒内一些直径为15μm的点,用离子探针测量了~(207)pb/~(206)pb的比值表明,这些地方保存一个~(207)pb/~(206)pb比值范围。在含有较高铀含量的锆石内一般可测得~(207)pb/~(206)pb的最低比值,计算的~(207)pb/~(206)pb年龄,一般与反映它们形成后各岩层经受的比较主要地质事件可以对比。似乎可能的是,在年轻事件期间,由于遭受锆石粒高铀区放射性的破坏,使这些地带的放射性铅损失了。在含     

COORDONNEES GEOGRAPHIQUES (LONGITUDE ET LATITUDE) DE PEKIN

INTRODUCTION L'execution des travaux necessites par l'etablissement des cartes au 1/100,000, que nous dressons le long des lignes des chemins de fer chinois, nous a amene a placer certains sites en nous servant de leurs coordonnees geo-     

Membership List for the year 1922

Those who have followed the historical development of the systematicclassification of the old Palaeozoic rocks in Europe would undoubtedly wellremember how the Ordovician became recognized as a well-defined,independ-     

蒙塔那州博耳德地区岩基中的铀矿化

本文介绍了花岗岩类(石英二长岩及花岗闪长岩)岩基型侵入体中矽化带型热液铀矿床的岩体、区域构造、伴生有色金属矿床、铀矿床本身及成矿年代。铀矿化和灰色及黑色微粒石英脉或玉髓脉的关系密切。铀矿化晚于锌铅矿化。铀矿化年代为6000万年。其后有英安岩的侵入。