Factors controlling the morphological evolution of the Çanakkale Strait (Dardanelles, Turkey)

Seismic profiling, bathymetric and physical oceanographic data collected from the Çanakkale Strait revealed that the morphological evolution of the strait has been controlled by tectonic activity, and sediment erosion and deposition. Sediments in the strait have been sourced mostly by rivers draining the Biga Peninsula during lowstand periods. In highstand periods, by contrast, deposits in the strait were reworked by currents. The seafloor morphology of the Çanakkale Strait is also controlled by a sequence of factors ranging from tectonics to current erosion and deposition. Channel deposits overlying the basement are being eroded at the narrower, meandering central section of the strait (the Nara Passage) due to high current velocities. The eroded sediments are deposited in the relatively linear and wider, northern and southern sectors of the strait exposed to low current velocities. As a result, the high-energy areas are more deeply incised due to the erosion, whereas deposition elevates the seafloor in the areas exposed to lower current energy. Three strike-slip faults, which possibly relate to the activity of the North Anatolian Fault Zone, are responsible for the irregular shape of the strait and this, in turn, controls the current velocity along the strait. The high-energy conditions probably commenced with the latest invasion of Mediterranean waters some 12 ka b.p., and have continued as a two-layered current system to the present day.     

Assessing Carbon Stock and Sequestration of the Tropical Seagrass Meadows in Indonesia

Ocean Science Journal - Seagrass meadows provide critical ecosystem services for coastal areas, e.g., as nursery habitats for various fish species, help with water filtration of suspended sediment,...     

Geomorphological-geological-geophysical signatures of high-flux fluid flows in the eastern Pearl River Mouth Basin and effects on gas hydrate accumulation

Marine hydrate reservoirs can be divided into focused high-flux and distributed low-flux gas hydrate systems according to free gas migration control mechanisms. In focused high-flux hydrate reservoirs, fluids easily break through the pressure of overlying sediments and reach the shallows, creating a series of geomorphological-geological-geophysical anomalies at and near the seafloor. Based on detailed interpretation of pre-drilling data in the eastern Pearl River Mouth Basin (PRMB), many anomalies related to the high-flux fluid flow are found, including seafloor mounds with intrusive characteristics, bright spot reflections above the bottom-stimulating reflector (BSR), phase reversals in the superficial layer, and an efficient fluid migration and accumulation system composed of fractures and uplifts. The second hydrate drilling expedition was carried out in the eastern PRMB in 2013 to study these anomalies. The acquired data show that high-flux fluid flow occurred in these sites. Gas hydrate pingoes, bright spot reflection above the BSR, and an efficient fluid migration and accumulation system can be used as identification signatures for high-flux fluid migration. The modes of high flux fluid flow are different in deep and shallow sediments during upward migration of fluid. Gas dissolved within migrating water dominates deep fluid migration and upward migration of a separate gas phase dominates the shallow process. This difference in migration models leads to formation of upper and lower concentrated hydrate reservoirs in the drilling area. The discovery of signatures of high-flux fluid flow and their migration modes will help with site selection and reduce risk in gas hydrate drilling.     

基于开挖的增强型地热系统概述

地热能赋存于地球内部岩土体、流体和岩浆体中,是一种永久的、可再生的、储量丰富的清洁能源。地热能的开发,尤其是干热岩的开发利用,有可能成为解决人类未来能源危机的重要途径。目前采用的干热岩开采方法被称为增强型地热系统(EGS)。热储地质环境的复杂性和水力化措施对天然裂隙的依赖性,造成多数的EGS项目存在热储体积和换热面积不足、工质流量小、终端温度低,以及诱发地震风险等局限性,致使干热岩开发始终未能大规模商业化。基于开挖的增强型地热系统(EGS-E)的提出为突破传统EGS的技术弊端和规模局限提供了新思路。文章在其概念模型的基础上,从系统原理、工程构想、技术优势等方面对EGS-E进行了更详尽的阐述。EGS-E采用开挖、爆破、崩落等采矿技术,形成了独特的热储致裂系统和热能交换系统,能够大幅度降低地质环境对热储质量的限制,具备构建定制的热储空间、形成充足的换热面积,维持稳定的工质流量与温度及减少诱发地震风险等优势,为干热岩开发的商业化提供了新的解决方案。     

加权整体最小二乘的验后估计在三维坐标转换中的应用

在求解三维小角度坐标转换EIV模型的过程中,顾及到两套坐标系下点坐标初始单位权方差可能不同导致定权不准确的问题,应用Helmert方差分量估计方法,对加权整体最小二乘的随机模型进行验后估计,从而重新分配观测向量和系数矩阵的权,使得解算模型更加合理。算例证明,利用该方法求解坐标转换参数的精确度有所提高,参数估值更接近真值。     

Estimation of genetic parameters for upper thermal tolerances and growth-related traits in turbot Scophthalmus maximus

An abnormally high temperature produces a stress response in turbot causing large economic losses in the turbot aquaculture industry of China. A genetic improvement of the upper thermal tolerance (UTT) of turbot could allow cultured fi sh to adapt. A genetic evaluation of UTT is required for determining the practicability of including this trait into a breeding program. In this study, data were recorded from a temperature tolerance test conducted on 3 200 individual turbots from 32 full-sib groups. A cross-sectional linear model and a cross-sectional threshold probit model were used to analyze the test-period survival and a cross-sectional threshold logit model was used to analyze the test-day survival. In addition, phenotypic and genetic correlations between body weight and survival data were estimated. The estimated heritability values obtained from the cross-sectional linear model (CSL), the cross-sectional threshold (probit) model (THRp), and the cross-sectional threshold (logit) model (THRl) were 0.247 9±0.108 3, 0.288 3±0.161 2, and 0.106 9±0.045 2, respectively. The correlation coeffi cients among the full-sib family estimated breeding values (EBVs) obtained from the three models were greater than 0.998 6 and all models produced an almost identical family ranking. The accuracies of selection obtained with the CSL, THRp, and THRl model were 0.773 8, 0.775 4, and 0.784 4, respectively, the greatest from the THRl model. The genetic correlations between body weight and survival data EBVs from the CSL, THRp, and THRl models were 0.020 1,-6.201 1×10^-4 , and -3.115 4×10^-4 , respectively, and the phenotypic correlations between the two traits were -0.837 1 and -0.667 1, respectively. The findings of this study provide background information to determine the best strategy of selection for the genetic improvement of UTT in turbot.     

相似像素的Harris角点检测改进算法

针对Harris算法提取的角点对尺度变化较敏感,且运行速度慢的问题,该文提出了一种基于相似像素的Harris角点检测改进算法。受SUSAN算法启发,改进算法首先计算目标像素8邻域内与之相似的像素数目,并据此筛选出候选角点;然后利用候选角点的相似像素数目改进角点响应函数;最后进行局部非极大抑制确定最终角点。实验结果表明,与Harris算法相比,改进算法所提取的角点位置更加准确,重复率较高,且角点检测时间仅为原算法的26.63%。本文所提算法提高了Harris算法的角点检测效率和稳定性。     

A comparative predictive analysis of weighted overlay,weighted sum and fuzzy logic for mineral prospectivity mapping of precious and base metal mineralizations at north-east of Gümüşhane city,NE Turkey

The study area located south of the Eastern Pontide metallogenic belt (NE Turkey) has an important potential for valuable and base metallic minerals. Geological, tectonic, geochemical, hydrothermal alteration, mineralogical and fluid inclusion characteristics of ore formations in the region have been studied in detail. The purpose of this study is to combine and analyse the acquired spatial data layers in a geographic information system (GIS) environment using knowledge-driven approaches and to identify prospective areas in terms of mineralization. Moreover, evaluating the performance of different knowledge-driven mineral probability modelling results comparatively and quantitatively constitutes the other goal of the study. As a result, in addition to the known mineralization locations, a number of new prospective and favourable areas have been identified for future detailed studies. In addition, it has been found that the mineral predictive map generated using fuzzy logic-OR method produces the best and successful results compared to others.     

Late Quaternary evolution of the Çanakkale Strait region (Dardanelles, NW Turkey): implications of a major erosional event for the postglacial Mediterranean-Marmara Sea connection

Seismic and bathymetric data from the Çanakkale Strait and its extensions onto the shelves of the Marmara and Aegean seas indicate that the strait was formed mainly by an erosional event. Four seismic units are observed on seismic profiles. The lower two of these (units 4 and 3) constitute the basement of a regionally widespread erosional unconformity (ravinement), which developed during marine isotope stage 2 (MIS 2). The two upper units (units 2 and 1), which overlie the ravinement surface, form a higher-order sequence. Sequence stratigraphic analysis indicates that units 2 and 1 deposited as lowstand and highstand systems tracts respectively, since the end of MIS 2. The transgressive systems tract is represented by a major erosional event which occurred throughout the Çanakkale sill area when the Mediterranean-Marmara Sea connection and, hence, the Çanakkale Strait was formed. The existence of the erosive ?arköy Canyon along the shelf edge of the southern Marmara Sea demonstrates that the flow direction causing the erosion was from south to north, thus proving that it was produced by Mediterranean water flowing over the sill into the Marmara Sea basin.     

真鲷能量收支和氮与碳收支的初步研究

以真鲷 (起始体重 :1 1 .5～ 1 4.8g)为实验对象 ,在平均水温 2 4.5 7℃下 ,进行饱食状态下的真鲷幼鱼摄食 -生长实验 ,饵料为玉筋鱼 ;对其摄食量、生长及粪便进行直接测定 ,对能量收支、氮和碳收支各组份进行估计和计算。结果表明 ,真鲷幼鱼的能量分配对策是 ,需较多的能量维持其代谢需求 ,同时 ,有较多的氮和碳随代谢产物排出体外 ,从而导致较低的能量生长及物质生长。