A new type of slumping-induced soft-sediment deformation structure: the envelope structure

The sediments of the Cretaceous Gyeokpori Formation in south-western South Korea accumulated in a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity resulted in unstable lake margins inducing a dominance of gravity-flow deposits. The high sedimentation rate facilitated soft-sediment deformation on the sloping margin. The deposition of numerous gravity-flow deposits resulted in a vertically heterolithic stratification. The slumps are composed of different lithologies, which is expressed in different types of deformation due to the difference in cohesion between sandy and mussy layers within the slumps. Coarser-grained (cohesionless) slumps tend to show more chaotic deformation of their lamination or layering. The difference in slumping behaviour of the cohesive and non-cohesive examples is explained and modelled. A unique soft-sediment deformation structure is recognized. This structure has not been described before, and we call it ‘envelope structure’. It consists of a conglomerate mass that has become entirely embedded in fine-grained sediment because slope failure took place and the fine-grained material slumped down with the conglomerate ‘at its back’. The cohesive laminated mudstone formed locally slump folds that embedded the non-cohesive overlying conglomerate unit, possibly partly due to the bulldozing effect of the latter. This structure presumably can develop when the density contrast with the underlying and overlying deposits is exceptionally high. The envelope structure should be regarded as a special – and rare – type of a slumping-induced deformation structure

Influence of wind speed on optical properties of aerosols in the marine boundary layer measured by ship-borne DePolarization Lidar in the coastal area of Korea

Shipboard measurements of microphysical and optical properties of marine boundary-layer aerosols were performed around the Korean Peninsula from 2 to 5 December 2009. The measurements were conducted aboard the Korean icebreaking research vessel Araon during cruise tracks in the East Sea of Korea near Busan and Pohang. This paper describes the results of optical aerosol measurements acquired with a DePolarization Lidar (DPL) and an Optical Particle Counter (OPC) and data on meteorological parameters. Backward trajectory analyses indicate that two different aerosol characteristics according to different pathways of air mass encountered during the cruise. We find a high correlation between wind speeds across the east coast of Korea and extinction coefficient, depolarization ratio and mass concentration with correlation coefficient (R2) of 0.57, 0.52 and 0.67, respectively. The increase of extinction coefficient, depolarization ratio and number concentration with wind speed may have been caused by the increase of sea-salt aerosol production and transport.Peer reviewe

A new type of slumping-induced soft-sediment deformation structure: the envelope structure

The sediments of the Cretaceous Gyeokpori Formation in south-western South Korea accumulated in a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity resulted in unstable lake margins inducing a dominance of gravity-flow deposits. The high sedimentation rate facilitated soft-sediment deformation on the sloping margin. The deposition of numerous gravity-flow deposits resulted in a vertically heterolithic stratification. The slumps are composed of different lithologies, which is expressed in different types of deformation due to the difference in cohesion between sandy and mussy layers within the slumps. Coarser-grained (cohesionless) slumps tend to show more chaotic deformation of their lamination or layering. The difference in slumping behaviour of the cohesive and non-cohesive examples is explained and modelled. A unique soft-sediment deformation structure is recognized. This structure has not been described before, and we call it ‘envelope structure’. It consists of a conglomerate mass that has become entirely embedded in fine-grained sediment because slope failure took place and the fine-grained material slumped down with the conglomerate ‘at its back’. The cohesive laminated mudstone formed locally slump folds that embedded the non-cohesive overlying conglomerate unit, possibly partly due to the bulldozing effect of the latter. This structure presumably can develop when the density contrast with the underlying and overlying deposits is exceptionally high. The envelope structure should be regarded as a special – and rare – type of a slumping-induced deformation structure

A new type of slumping-induced soft-sediment deformation structure: the envelope structure

The sediments of the Cretaceous Gyeokpori Formation in south-western South Korea accumulated in a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity resulted in unstable lake margins inducing a dominance of gravity-flow deposits. The high sedimentation rate facilitated soft-sediment deformation on the sloping margin. The deposition of numerous gravity-flow deposits resulted in a vertically heterolithic stratification. The slumps are composed of different lithologies, which is expressed in different types of deformation due to the difference in cohesion between sandy and mussy layers within the slumps. Coarser-grained (cohesionless) slumps tend to show more chaotic deformation of their lamination or layering. The difference in slumping behaviour of the cohesive and non-cohesive examples is explained and modelled

Intrastratal flow in the Cretaceous Gyeokpori Formation (SW South Korea)

Intrastratal flow is a process that is still poorly understood, rarely described and difficult to interpret in ancient rocks. Sediments in the Cretaceous lacustrine Gyeokpori Formation of southwestern South Korea contain some chaotically deformed sandstone layers with deformed mudstone clasts that are ascribed to this process. The interpretation is based on the fact that these layers cannot be explained as a result of subaqueous debris flows or mass transport, whereas the sedimentary context, including the presence of other soft-sediment deformation structures, indicates that intrastratal flow must have been physically possible. The sedimentary setting was a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity caused seismic shocks that affected the unstable lake margins resulting in the dominance of gravity-flow deposits, but also in a high sedimentation rate that facilitated soft-sediment deformation partly caused by intrastratal flow. This must have happened fairly frequently during a probably limited time-span, as several layers showing traces of intrastratal flow are present within a succession of only <1 m thick. The combined data on the geological setting and our findings regarding the origin of the various soft-sediment deformation structures may help to recognize the traces left by intrastratal flow elsewhere in the geological record

Understanding luminescence properties of grain boundaries in GaN thin films and their atomistic origin

We report our findings on the optical properties of grain boundaries in GaN films grown on graphene layers and discuss their atomistic origin. We combine electron backscatter diffraction with cathodoluminescence to directly correlate the structural defects with their optical properties, enabling the high-precision local luminescence measurement of the grain boundaries in GaN films. To further understand the atomistic origin of the luminescence properties, we carefully probed atomic core structures of the grain boundaries by exploiting aberration-corrected scanning transmission electron microscopy. The atomic core structures of grain boundaries show different ordering behaviors compared with those observed previously in threading dislocations. Energetics of the grain boundary core structures and their correlation with electronic structures were studied by first principles calculation. Published by AIP Publishing

Predicting prognosis and evaluating the benefits of adjuvant chemotherapy depending on the tumor location in intrahepatic cholangiocarcinoma: focusing on the involvement of below 2nd bile duct confluence

Purpose: Intrahepatic cholangiocarcinoma (ICC) has various characteristics according to anatomical, histologic classifications, and its prognoses are different. This study aimed to compare oncologic outcomes according to tumor location (second bile duct confluence) and evaluate the effect of adjuvant chemotherapy. Methods: Clinical data of 318 patients who underwent curative resection for ICC was reviewed. Central type ICC (C-ICC) and peripheral type ICC (P-ICC) were defined when the tumor invades the intrahepatic secondary biliary confluence and when located more peripherally, respectively. Results: A larger tumor size, higher rate of elevated CA 19-9 level, vascular invasion, R1 resection, advanced T stage, and lymph node metastasis were found in C-ICC. C-ICC had poorer overall survival (median, 33 months vs. 58 months; P = 0.001), and the difference was more prominent in the early stage. C-ICC had a higher recurrence rate (68.7% vs. 55.1%, P = 0.014); otherwise, there was no difference in the recurrence patterns. There were no survival benefits of adjuvant chemotherapy in the entire cohort, but there were benefits in advanced stages (T3-4, N1 stage), especially in C-ICC. Conclusion: C-ICC has more aggressive tumor characteristics and poor survival compared to P-ICC. Adjuvant chemotherapy seems to have survival benefits in the advanced stages, especially in the central type.N