The Motion and Range of Landslides According to Their Height

The frequency of catastrophic geological disasters has been increasing significantly, causing tremendous losses of life and property. The study of landslide motion remains incomplete. The variables H/L (ratio of landslide height to length) are often used to describe landslide motion; however, they may also be affected by the height of the landslide itself. To better understand landslide dynamics, this paper aimed to 1) identify the process of landslide motion in relation to height; 2) understand the range of influence of sliding bodies according to height; and 3) construct a formula of landslide disaster range based on the travel distance of the slide center and changes in the center and shape of the sliding body. In this paper, medium-fine quartz sand was used in experiments to observe the movement patterns and sliding body barycenter variations occurring during landslides. We describe the changes that occur during landslides and their deposits’ morphological characteristics and barycenter variations with height. Based on these observations, a landslide model is derived. This paper proposes a new method of estimating the effects of landslides, which can help to mitigate the effects of disasters.

Shear Thickening Polishing of Quartz Glass

Quartz glass is a typical optical material. In this research, colloidal silica (SiO2) and colloidal cerium oxide (CeO2) are used as abrasive grains to polish quartz glass in the shear thickening polishing (STP) process. The STP method employs the shear-thickening mechanism of non-Newtonian power-law fluid to achieve high-efficiency and high-quality polishing. The different performance in material removal and surface roughness between SiO2 and CeO2 slurries was analyzed. The influence of the main factors including polishing speed, abrasive concentration, and pH value on the MRR, workpiece surface roughness, and the surface topography was discussed. Two different slurries can both achieve fine quartz surface in shear thickening polishing with the polishing speed 100 rpm, and pH value 8. The quartz glass surface roughness Ra decreases from 120 ± 10 to 2.3 nm in 14 minutes’ polishing with 8 wt% 80 nm SiO2 slurry, and the MRR reaches 121.6 nm/min. The quartz glass surface roughness Ra decreases from 120 ± 10 to 2.1 nm in 12 minutes polishing by 6 wt% 100 nm CeO2 slurry and the MRR reaches 126.2 nm/min.

A Method to Simulate the Migration and Accumulation of Hydrocarbon with Analogue Modeling

Subsurface migration and accumulation of oil and gas have interested researchers for a long time, but these processes may occur over very long geological periods and are difficult to observe directly, so experimental simulations are warranted. In this study, an experimental method was developed to model hydrocarbon migration in the subsurface structure. Oil migration was simulated in a sandbox model, and industrial CT scanning was used to observe both the internal geometry of the model and the oil migration pathways. In the sandbox model, a NaI solution was used to simulate water, white oil was used to simulate hydrocarbon, and fine quartz sand, glass bead, silica powder, and brown corundum were chosen to represent brittle crust, based on suitable material parameters. A NaI-saturated layered sandbox model was constructed with an along-strike basal discontinuity, which during compression allowed a simple anticline with doubly verging reverse faults to form. Oil was then released continuously at a low rate from an orifice under one limb of the anticline. Initially, the oil migrated vertically through the fault zone until it reached the top of the fault zone; it then migrated laterally along the core of the anticline, saturating a model reservoir by buoyancy and capillary force. This experimental analog helps to explain hydrocarbon migration and accumulation within the Anjihai and Santai anticlines in northwest China.

Roman Wall Paintings: Characterisation of Plaster Coats Made of Clay Mud

This paper reports on the mineralogical characterisation of samples of wall paintings from various Roman sites in Lombardy (Italy), revealing recurrent types of stratigraphy. One of the stratigraphic samples analysed was found to be a particular kind of plaster: a three-coat work featuring two coats made of clay mud, found in the site of Santa Maria alla Porta (area of the Imperial Palace of Milan—first century CE). The fragments were analysed using optical microscopy on thin sections, X-ray diffraction, scanning electron microscopy with an energy-dispersive spectrometer and infrared spectroscopy, also in non-invasive external reflection mode (7500–375 cm−1). The most interesting feature found was the finish coat made of clay mud (illite, chlorite, kaolinite and fine quartz) with a few coarse clasts and linear cavities. This clay coat was the first example ever detected in Roman Lombardy and was used in combination with a thin painted coat made of clay mud with coarse clasts together with a blue pigment (Egyptian blue) and a render coat made of lime associated with lithic clasts (sand). Our findings brought to light a particular construction technique, since in the historical sources clay is only recommended for daubing on reeds and as a render coat.

Chronology of the Huxushan Paleolithic site in south China: Inferred from multiple luminescence dating techniques

The Huxushan archaeological site in northern Hunan Province, China, was recently excavated, from which stone tools including handaxes were unearthed. The deposits of the site are chemically weathered, which makes it difficult to date the site using numerical dating techniques except for optically stimulated luminescence (OSL) method. Here, we used various luminescence procedures including single-aliquot regenerative-dose (SAR), sensitivity-corrected multiple-aliquot regenerative-dose (SMAR) and thermally transferred optically stimulated luminescence (TT-OSL) SAR procedures on fine-grained quartz, and two-step post-infrared infrared stimulated luminescence (pIRIR) and multi-elevated-temperature pIRIR (MET-pIRIR) procedures on fine polymineral fractions. The results show that the fine quartz grains have excellent luminescence properties and the quartz SAR-, SMAR- and TT-OSL ages for the samples agree with each other and in stratigraphical order except for one sample. The fine polymineral fractions exhibited relatively weak pIRIR and MET-pIRIR signals, resulting in difficulty in constructing the dose-response curve for MET-pIRIR signals and the stratigraphically inconsistent pIRIR(100, 275) ages. The seven samples yielded their quartz OSL ages ranging from about 62 ka to 133 ka. The two samples from the cultural layer was dated to 78 to 92 ka using different procedures on fine quartz . However, given the systematically older pIRIR ages obtained with the fine polymineral grains for the two samples, their quartz OSL ages are considered to represent the minimal ages of this layer, and their pIRIR(100, 275) ages of 118 and 110 ka represent the upper age limit, indicating that the site was occupied by hominins during Marine Isotope Stage 5.

Peat-core analysis for tracing the paleoclimate-related changes in aeolian dust deposition in Japan

<p>Aeolian dust coming from arid regions of inland China supplies mineral resources to Japanese Islands. While annual deposition rate is as small as 5~10 g m<sup>-2</sup> yr<sup>-1</sup>, total amount of deposition since the last glacial period can form soil layers with several meters depths. We focused on the mineral fertilization effect of aeolian dust on terrestrial ecosystems in Japan. The deposition and incorporation of dust-derived micaceous mineral into soil through time is our special interest because this mineral has an exceptionally higher ability to retain radiocesium than the others, thereby contributing to reduce soil-to-plant transfer of radiocesium after the Fukushima-Daiichi nuclear power Plant accident. However, little study has focused on aeolian dust as a controlling factor of radiocesium dynamics in soils. In this study, peat-core samples collected from the Kamiyoshi (KMY) basin in Kyoto, Japan was used to obtain the aeolian dust that had been deposited on land during the last glacial period. The KMY core with depth from 9.40 to 8.20 m (corresponding to 75 ka to 68 ka) was horizontally divided into 21 portions. The subdivided samples were treated with H<sub>2</sub>O<sub>2</sub> to decompose organic matters and then size-fractionated to obtain <20 μm particles, i.e., typical size range of the aeolian dust. The <20 μm particles was used to determine mineral composition by X-ray diffraction and selective dissolution analysis. Furthermore, fine-quartz obtained after the selective dissolution analysis was used for oxygen isotopic analysis to determine δ<sup>18</sup>O value. We found that the <20 μm particles occupy more than 90% of total mineral fraction, composed mainly of quartz and micaceous mineral. The fine-quartz in this fraction showed δ<sup>18</sup>O values of 16.8±0.3‰, quite similar to those of loess or aeolian dust previously reported. All these properties strongly indicate the origin of the <20 μm particles is the aeolian dust. Interestingly, the aeolian dust flux between 68 ka and 75 ka ranged widely from 1.9 g m<sup>-2</sup> yr<sup>-1</sup> to 15.7 g m<sup>-2</sup> yr<sup>-1</sup> and highly associated with paleoclimate estimated by the pollen record. Namely, the higher aeolian dust flux was observed at colder and drier paleoclimate as indicated by the higher proportion of pinaceous conifer pollen. We conclude that associative analysis of mineral and pollen record in the peat-core can be a promising method to trace the long term deposition pattern of aeolian dust in terrestrial ecosystems in Japan.             </p>

Single Aliquot Regeneration (SAR) Optically Stimulated Luminescence Dating Protocols Using Different Grain-Sizes of Quartz: Revisiting the Chronology of Mircea Vodă Loess-Paleosol Master Section (Romania)

The loess-paleosol archive from Mircea Vodă (Romania) represents one of the most studied sections in Europe. We are applying here the current state of the art luminescence dating protocols for revisiting the chronology of this section. Analysis were performed on fine (4–11 µm) and coarse (63–90 µm) quartz extracts using the single aliquot regenerative (SAR) optically stimulated luminescence (OSL) dating protocol. Laboratory generated SAR dose response curves in the high dose range (5 kGy for fine quartz and 2 kGy for coarse quartz) were investigated by employing a test dose of either 17 or 170 Gy. The results confirm the previously reported different saturation characteristics of the two quartz fractions, with no evident dependency of the equivalent dose (De) on the size of the test dose. The OSL SAR ages are discussed and compared to the previously obtained results on quartz and feldspars. The previous reports regarding the chronological discrepancy between the two quartz fractions are confirmed. However, while previous investigations on other sites concluded that this discrepancy appears only above equivalent doses of about 100 Gy, here fine grain quartz ages underestimate coarse quartz ages starting with equivalent doses as low as around 50 Gy.