New age data from the Lesnaya Group: A key to understanding the timing of arc-continent collision, Kamchatka, Russia

Abstract The Lesnaya Group is part of a thick, poorly dated turbidite assemblage that sits in the footwall of a regionally extensive collision zone in which the Cretaceous–Paleocene Olutorsky island arc terrane was obducted onto continental margin basin strata. Nannoplankton from 18 samples from the upper part of the Lesnaya Group yield Paleocene through Middle Eocene assemblages. Detrital zircons from nine sandstone samples have a young population of fission-track ages that range from 43.7 ± 3.4 to 55.5 ± 3.5 Ma (uppermost Paleocene to Middle Eocene). The deformed footwall rocks of the Lesnaya Group and the overlying thrusts of the Olutorsky arc terrane, are unconformably overlain by neoautochthonous deposits which are Lutetian (lower Middle Eocene) and younger. Together, these new data indicate that thrusting, which is inferred to have been driven by collision of the Cretaceous–Paleocene island arc with north-eastern Asia, took place in the mid-Lutetian, at about 45 Ma.     

Impact of treated sewage sludge application on phosphorus release kinetics in some calcareous soils

Treated sewage sludge contains significant amount of phosphorus and is widely used in agriculture. Kinetics of P release in soils is a subject of importance in soil and environmental sciences. There are few studies about P release kinetics in treated sewage sludge amended soils. For this purpose, sludge was mixed with ten soils at a rate equivalent to 100 Mg sludge ha⁻¹, and P desorption was determined by successive extraction using 0.01 M CaCl₂ over a period of 65 days at 25 ± 1°C. Phosphorus release rate was rapid at first (until about first 360 h) and then became slower until equilibrium was approached. Average of P released within 360 h for the unamended and amended soils was about 65 and 73% of the total desorbed P, respectively. Zero-order, first-order, second-order, power function, simplified Elovich and parabolic diffusion law kinetics models were used to describe P release. First-order, Elovich, power function and parabolic diffusion models could well describe P release in the unamended and amended soils. Correlation coefficients between P release rate parameters and selected soil properties showed that in the control soils, calcium carbonate equivalent and Olsen-extractable P; and in the amended soils, calcium carbonate equivalent, cation exchange capacity, organic matter and Olsen-extractable P were significantly correlated with P release parameters. The results of this study showed that application of sewage sludge can change P release characteristics of soils and increase P in runoff.     

Susceptibility analysis for slides and rockfall: an example from the Northern Calcareous Alps (Vorarlberg, Austria)

In this paper a tool for semi-quantitative susceptibility assessment at a regional scale is presented which is applicable at areas with complex geological setting. At a study area within the Northern Calcareous Alps geotechnical mappings were implemented into a Geographical Information System and analysed as grid data with a cell size of 25 m. The susceptibility to sliding and falling processes was considered according to five classes (very low, low, medium, high, very high). Susceptibility to sliding was analysed using an index method. The layers of lithology, bedding conditions, tectonic faults, slope angle, slope aspect, vegetation and erosion were combined iteratively. Dropout zones of rockfall material were determined with help of a Digital Elevation Model. The movement of rolling rock samples was modelled by a cost analysis of all potential rockfall trajectories. These trajectories were also divided into five susceptibility classes. The susceptibility maps are presented in a general way to be used by communities and spatial planners. Conflict areas of susceptibility and landuse were located and can be presented destinctively.     

滇东南喀斯特峰丛地区灰岩土壤的基本性质和综合评价

本文以云南省西畴西部为例,阐述了滇东南喀斯特峰丛地区灰岩土壤的形成、分类和分布规律。从土壤的颜色、结构、机械组成、化学组成、游离碳酸钙、pH值、有机质含量、碳氮比、氮磷钾含量、盐基代换量和盐基饱和度、微量元素含量等方面,对灰岩土壤的基本理化性质进行了分析和评价,提出了合理利用途径。     

斯里兰卡普塔勒姆地区钙质结核的特征及成因

斯里兰卡国普塔勒姆地区滨海沉积物中发育钙质结核,其与我国黄海和东海钙质结核在成分、结构、构造和古生物化石等方面均存在差异。该地区钙质结核含有大量的海相生物化石及其碎屑,CaO的含量＞44.14％, SiO₂的含量＜12.75％,与同地区的碳酸盐软泥相比,结核相对富铁贫硅和富锶贫钡,说明生物对结核的影响大于对碳酸盐软泥的影响。结核的碳、氧同位素值负偏明显,δ¹³C＜-4.54‰,,δ¹⁸O＜-6.37‰,具有轻碳轻氧的特征。结核的矿物成分、古生物化石、主微量元素和碳、氧同位素资料说明其形成于海相环境,后期因海平面下降,受到大气淡水和地下水的影响,元素含量发生变化,形成颇具特色的钙质结核。     

西菲律宾海盆-马里亚纳海槽区柱状岩芯中钙质超微化石分析及地层时代

本文通过对取自西菲律宾海盆及马里亚纳海糟区85kL和77KG,66KG,6lKL,57KL岩芯中钙质超微化石的分析研究,划分了上述岩芯的地层时代。66KG,61KL,57KL地层时代为更新世晚期;77KG0～l0cm和10～20cm地层时代分别为更新世晚、中期;以下(20～30cm)地层时代为早中新世晚期。85kL所处水深位于碳酸盐补偿深度(CCD)以下,岩芯中无化石保存。     

Conodont colour alteration indices: Palaeotemperatures and metamorphism in the Northern Calcareous Alps — a general view

The middle and eastern parts of the Northern Calcareous Alps (NCA) can be subdivided into two distinct units with a lateral boundary marked by abrupt changes in the conodont colour alteration index (CAI-values). The first of these is a northern unit (Tirolikum) with a relatively homogeneous distribution of no or low grade conodont alteration (CAI 1.0–2.0). The thermal overprint is thought to be relatively young and related to a heat flow from the Tauern crystallization. The second unit consists of the Juvavic nappe system (Juvavikum), which is distributed along the southern rim of the NCA but also covers some of the northern parts of the Tirolikum. With respect to its CAI-distribution the Juvavikum is more heterogeneous on a regional and local scale, with some local CAI-inversions. The Juvavikum additionally shows distinctly different sets of CAI-values one with weak (CAI 1.0–1.5) and another with strong alteration (CAI 5.5–7.0) — at present the highest known thermal overprint measured in the NCA. The metamorphism is relatively old as it predates the Late Jurassic—Early Cretaceous gravity tectonic emplacement of the Juvavikum onto the Tirolikum. The high CAI-values of parts of the Juvavic nappe system are though to be related to tectonic burial in an accretionary wedge formed parallel to the closure of the Vardar Ocean. The low CAI values of the Tirolikum apparently exclude a direct juxtaposition of the two units at the time of metamorphism.     

The Bartonian unit stratotype (S. England): Assessment of its correlation problems and potential

The problems of correlation of strata belonging to the unit Bartonian Stage in its type area of the Hampshire Basin, UK, are reviewed. These problems involve not only correlation outside the Hampshire Basin, through biostratigraphy and magnetostratigraphy, but also within the basin in terms of understanding patterns of facies distributions and reliability of local biostratigraphy. On the basis of a combination of calcareous nannoplankton, dinoflagellate cyst and magnetostratigraphic evidence, the base of the type unit Bartonian lies within Chron C18r. However, no reliable biostratigraphic indicators have yet been found to allow a more precise correlation of the base. It is suggested that more detailed microfossil and palaeomagnetic sampling at key sites could resolve these problems in order to help further the quest for an appropriate Global Stratotype Section and Point (GSSP) for the Bartonian Stage.     

钙质砂在三轴剪切中颗粒破碎评价及其能量公式

钙质砂是一种易破碎粒状材料。本文在分析颗粒破碎机理的基础上,提出了颗粒破碎与剪胀耦合作用的破碎功表示式,并用实验证明了相对破碎Br 与1,Wp,WB 之间的关系,从而建立了钙质砂颗粒破碎的评价指标及其能量公式。     

Nannoplankton successions in the northern Red Sea during the last glaciation (60 to 14.5 ka BP): Reactions to climate change

Due to its restricted connection with the Indian Ocean, the desert-enclosed Red Sea is extremely sensitive to global sea level changes and thus ideally suited for paleoceanographic studies of what occurred during the last glaciation. The understanding of its glacial history is, however, still limited. A serious obstacle to obtain satisfactory paleoecological information has been the rarity of microfossil proxy species caused by high salinities. Here, we present a continuous and well-dated calcareous nannoplankton record from the northern Red Sea, covering the interval from 60–14.5 ka BP. Our investigation shows that the composition of the calcareous nannoplankton community varied between  32 ka BP and 14.5 ka BP in response to rapid environmental changes which are closely correlated to climatic fluctuations described from the North Atlantic region. Heinrich events H3, H2 and H1 are dominated by Emiliania huxleyi. Gephyrocapsa oceanica and especially Gephyrocapsa ericsonii are abundant between H3–H2 and H2–H1. A less pronounced response of the calcareous nannoplankton to the high latitudinal climatic oscillations is documented prior to  32 ka BP, suggesting that a strong atmospheric coupling between the northern Red Sea and the North Atlantic realm was established in the late Marine Isotope Stage 3. In contrast to the previously held view of a sea level related salinity increase as the major cause for changes of the plankton communities within the glacial Red Sea, we interpret the documented variations as being caused by local hydrographic changes under the atmospheric control from the extratropics. Temperature changes and especially variations of the water stratification appear to be critical selective factors for the calcareous nannoplankton composition.