Burial fluxes and sources of organic carbon in sediments of the central Yellow Sea mud area over the past 200 years

Long-term changes of composition, sources and burial fluxes of TOC （total organic carbon） in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper. Firstly, similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC （Yellow Sea Warm Current） is prevalent. On this basis, the burial flux of TOC here was considered to be 235.5-488.4 pmol/（cm^2.a） since the first industrial revolution, accounting for about 70%-90% among burial fluxes of TC （total carbon） in the sediments. Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide, we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC （inorganic carbon） are important factors controlling the TOC/TC ratio in sediment. Results of two-end mixed model based on fi13C data indicate that marine-derived organic carbon （OCa） is the main part among total burial organic carbon which accounts for a ratio over 85%. Due to the high TOC/TC ratio in the two cores, TC in the sediments also mainly exists as OCa, and the proportion of OCa is about 60%-80%. Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area. Burial of OC in this mud area is probably mainly influenced by the human activities. Although the economic development during the late 19th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments, the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950s. Otherwise, we also realize that among TC burial fluxes, TIC account for about 10%-30% in sediments of the central Yellow Sea mud area, so its burial could not be simply ignored here. Distinct from TOC burial, long-term TIC burial fluxes variations relate with climate changes more closely： the East Asian summer monsoon may influence the strength of the Huanghe River （Yellow River） flood, which could further affect the transport of terrestrial IC from land to the central Yellow Sea as well as the burial of these IC in the sediments.

Geochemical and Grain-Sized Implications for Provenance Variations of the Central Yellow Sea Muddy Area Since the Middle Holocene

Based on high-resolution analysis to a 280-cm long sediment core obtained from the muddy area in the central Yellow Sea, we examined the provenance of muddy sediments and discussed the changing marine sedimentary environment since the middle Holocene. The results indicated that fine-grained sediments in the muddy area were mainly derived from the Huanghe(Yellow River) and Changjiang(Yangtze River) with considerable stepwise variations during the past 6.6 kyr. The Yellow Sea Warm Current was initiated at 6 kyr when the sea level was high together with the enhanced East Asian Winter Monsoon. These in combination established the framework of shelf circulation in the Yellow Sea that began to trap the river-derived fine-grained sediments. From 4.9 kyr to 2.8 kyr, both the Kushiro Current and East Asian Monsoon were significantly weakened, reducing the delivery of Changjiang sediments to the muddy area. As a result, the sediments were mainly originated from the Huanghe. From 2.8 kyr to 1.5 kyr the continuously weakened East Asian Winter Monsoon and enhanced Yellow Sea Warm Current entrapped more fine-grain sediments. Whereas the enhanced East Asian Winter Monsoon and the human caused increase in sediment load of the Huanghe since 1.5 kyr, and direct delivery of Huanghe sediments to the Yellow Sea during 1128–1855 AD might dominated the sedimentation in the study area. The stepwise variations of the sediment provenance and composition of the Central Yellow Sea muddy sediments are of importance to understanding the formation of muddy deposit in the central Yellow Sea and the associated variations of marine environment since the middle Holocene.

Sedimentary architecture of the Holocene mud deposit off the southern Shandong Peninsula in the Yellow Sea

Newly acquired high-resolution seismic profiles reveal a nearshore and an of fshore mud depocenter of f the southern Shandong Peninsula in the Yellow Sea.The nearshore depocenter is distributed in bands along the south coast of Shandong Peninsula.The of fshore depocenter is part of the distal subaqueous deltaic lobe,which deposited around the southeastern tip of the Shandong Peninsula.Between the two depocenters is a linear depression.The mud deposits directly overlie the postglacial transgressive surface and can be divided into lower and upper units by the Holocene maximum flooding surface.The nearshore and off shore units display different seismic structures.The lower unit of the nearshore deposit exhibits basal onlap,whereas the upper unit is characterized by progradation.The lower and upper units of the off shore deposit display distinct acoustic features.The lower unit has low-angle aggradation with internal reflectors generally dipping seaward and truncated by the Holocene maximum flooding surface,whereas the upper unit is characterized by aggradation and progradation landward rather than seaward.Results of geochemistry analysis of QDZ03 sediments and mineral analysis of WHZK01 sediments suggest that the nearshore deposit and the lower unit of the of fshore deposit are derived from the proximal coastal sediments of the Shandong Peninsula and the Huanghe(Yellow) River sediments.The upper unit of the of fshore deposit is mainly Huanghe River-derived.The lower unit of the mud deposit represents a post-glacial transgressive system tract according to dates of core QDZ03,and the upper unit represents a highstand system tract from middle Holocene to the present.These results will be of great significance to further understanding of the transportation of the Huanghe River sediments into the Yellow Sea and the spatial distribution of the subaqueous delta.

Formation Mechanisms and Geomorphic Evolution of the Erlian Mudflow Fans, Eastern Guide Basin of the Upper Reaches of Yellow River

Several argillaceous platforms lie along the Yellow River（YR） of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using field survey data, sample testing, and high-resolution remote sensing images, the evolution of the Erlian mudflow fans are analyzed. The data show significant differences between fans on either side of the YR. On the right bank, fans are dilute debris flows consisting of sand and gravel. On the left bank, fans are viscosity mudflows consisting of red clay. The composition and formation processes of the left bank platforms indicate a rainfall-induced pluvial landscape. Fan evolution can be divided into two stages： early-stage fans pre-date 16 ka B.P., and formed during the last deglaciation; late-stage fans post-date 8 ka B.P.. Both stages were induced by climate change. The data indicate that during the Last Glacial Maximum, the northeastern Tibetan Plateau experienced a cold and humid climate characterized by high rainfall. From 16–8 ka, the YR cut through the Erlian early mudflow fan, resulting in extensive erosion. Since 8 ka, the river channel has migrated south by at least 1.25 km, and late stage mudflow fan formation has occurred.

贵州青黄泥田重金属元素低积累水稻品种筛选

以贵州中部地区近年主栽的10个水稻品种为试验材料,在中轻度重金属复合污染农田土壤上开展田间原位小区试验,探究不同水稻品种对镉(Cd)、铬(Cr)、铅(Pb)、镍(Ni)、铜(Cu)和锌(Zn)的吸收累积能力差异,并筛选出适宜贵州中部青黄泥田种植的重金属低累积水稻品种。结果表明,不同水稻品种根区土壤重金属含量存在一定的田间异质性,且同一品种的重复之间也具有一定的田间异质性;不同水稻品种糙米对不同重金属元素累积具有显著性差异,参试水稻品种糙米对重金属的富集能力强弱整体表现为Zn>Cd>Cr>Cu>Ni>Pb。水稻品种间对同一典型有害重金属元素的累积存在显著差异,按照糙米中重金属含量进行聚类分析,可以把水稻品种划分为较高值类、中间值类和较低值类3个类别。10个水稻品种糙米综合污染指数(P_(Z))(0.94~3.34)介于无污染至重度污染之间,Cr为主要污染贡献者,其单项污染指数(P_(i))在0.47~1.94之间。供试水稻品种产量在8242.8~13434.0 kg/hm^(2)之间,平均产量为10843.8 kg/hm^(2),极差相差较大,为47.9%。筛选出宜香优800为适宜该地种植的重金属低积累水稻品种。

活性赤泥-聚吡咯复合材料对活性黄-145染料的吸附研究

染料是一种结构复杂、具有剧毒的有机化合物,对人体毒害作用大。本研究制备了一种基于活性赤泥(activated red mud,ARM)和聚合吡咯(polypyrrole,PPy)的吸附剂,并应用于水溶液中染料的吸附脱除。通过吸附实验研究了溶液pH、吸附剂种类、吸附时间、添加量和染料初始浓度对吸附过程的影响,并对ARM-PPy复合材料进行分析表征,阐明了活性黄染料-145(RYD-145)的吸附作用机制。RYD-145在ARM-PPy上的吸附过程与三种吸附等温线关联极好(R2>0.99),其中Langmuir吸附最合适。根据Langmuir吸附模型的拟合结果,RYD-145的最大吸附量是442.5 mg/g。热力学研究表明,RYD-145分子在ARM-PPy的吸附过程中,焓变(ΔH)和熵变(ΔS)均增加,这表明该过程为吸热过程,且表面RYD-145分子排列具有随机性。研究表明,ARM-PPy具有高效处理阴离子和阳离子染料污染废水的能力,且具有较好的成本效益。

南黄海SYS90-1A孔第四纪沉积物磁性地层学研究

可靠的年代地层框架是开展南黄海地区第四纪环境演变研究的基础。目前南黄海南部地区缺乏可靠年代学控制的长序列钻孔。通过对南黄海南部SYS90-1A孔(孔深90.1 m)沉积物开展详细的磁性地层学研究,并结合AMS14C测年结果及区域已有磁性地层学结果,建立南黄海南部地区第四纪沉积物年代地层框架。结果显示,SYS90-1A孔岩芯记录了从布容(Brunhes)正极性时至松山(Matuyama)负极性时上部,包括Kamikatsura和Santa Rosa地磁漂移事件。早、中更新世界线即布容正极性时与松山负极性时界线(B/M界线)深度位于74.2 m,Kamikatsura和Santa Rosa地磁漂移事件深度分别位于79.75~82.47 m和85.25~87.74 m。根据Kamikatsura和Santa Rosa地磁漂移事件的年代控制点和平均沉积速率,推算钻孔底部年龄为0.96 Ma。南黄海SYS90-1A孔早更新世晚期的沉积速率约为8.66 cm/ka,中更新世以来的沉积速率约为9.5 cm/ka,而全新世以来的沉积速率为12.8 cm/ka,沉积速率自早更新世晚期以来呈增加趋势。这一结果不仅为南黄海南部第四纪沉积物研究提供了有效的年代学约束,而且为南黄海地区第四纪地层划分和对比、沉积环境与气候变化、物源示踪等研究提供了重要的时间标尺。

北黄海西部泥质区全新世以来沉积有机碳埋藏特征

北黄海西部泥质区沉积环境稳定、沉积记录连续,是重建过去周边流域变化与黄海海洋环境信息的良好载体。目前围绕北黄海西部泥质区沉积有机碳的研究工作多局限于通过表层沉积物揭示其现代分布特征,对于该泥质区长时间尺度沉积有机碳埋藏过程与机制的研究相对薄弱。通过北黄海西部泥质区W03岩芯的总有机碳指标,重建了全新世以来北黄海西部沉积有机碳的埋藏特征,探讨了气候及海洋环境变化对北黄海西部沉积有机碳埋藏的控制机制。研究表明:海平面上升的停滞期(10.3~9.8 cal.kaBP),发育硬质黏土层,有机碳以陆源输入为主(60.7%),动荡的沉积环境导致总有机碳含量相对较低,平均含量仅为0.22%;海平面上升期(9.8~7.0 cal.kaBP),海源有机碳的贡献增加(47.7%),相对稳定的沉积环境有利于该时期有机碳的埋藏;高海平面以来(7.0 cal.kaBP至今),黄海环流体系逐渐形成,陆源有机碳输入随着东亚冬季风驱动的沿岸流强度变化发生相应的改变,海源有机碳的贡献继续增加(50.0%),总有机碳的含量升高至0.58%。北黄海西部泥质区全新世以来沉积有机碳埋藏主要受控于海平面变化和海洋环流体系的运动。

全新世以来南黄海中部泥质区沉积物的源汇过程及其控制因素

南黄海中部泥质区沉积了大量来自邻近河流的陆源沉积物,是研究沉积物物源的良好区域,但其沉积物的输运过程和控制因素尚不明确。本文利用南黄海中部泥质区岩芯YSCW-1中沉积物的粒度和元素组成特征,查明自全新世以来研究区沉积物的源汇过程及其控制因素。基于^(14)C放射年龄,YSCW-1岩芯沉积物为9.3 ka以来的沉积,泥质沉积中心形成于约6.5 ka。粒度组成表明研究区沉积物主要由砂、粉砂和黏土组成。基于地球化学相关指标,研究区沉积物来源受到黄河和长江的影响。6.7 ka以前,黄河沉积物占据主导地位;6.7 ka之后长江对南黄海中部泥质区的贡献量增加,可能与黄海现代环流体系的形成有关,海洋锋面限制了黄河以及朝鲜河流沉积物向南黄海中部泥质区的输送。

深圳市水土保持智慧监管平台研发及应用

智慧水土保持是智慧水利建设的重要组成部分,针对当前深圳市水土保持监管中信息化和智慧化程度不高的问题,围绕水土保持监管难题,在智慧水务总体框架的基础上,研发并利用水土保持专业模型、黄泥水溯源要素关系模型等关键技术,搭建包含生产建设项目监督管理、水土流失监测、水土保持生态建设、水土保持决策支持、水土保持信息服务、黄泥水防治等六大业务的深圳市水土保持智慧监管平台,实现水土保持业务全覆盖,为水土保持智慧监管提供技术支撑。结果表明:智慧监管平台有效提高深圳市水土保持监管业务中信息处理能力、应用智慧化程度,可为其他城市的智慧水土保持建设提供参考。

浅埋深黄泥顶板工作面围岩稳定性控制

为有效治理晋能控股集团晋城公司七一煤矿9114综采工作面回采期间出现的大面积黄泥冒顶,通过理论分析、微观结构测试和现场实践,揭示了浅埋深黄泥顶板工作面的围岩失稳原因,并提出“留底割顶+短支短护+支架少降快移”的直接顶稳定性控制技术。现场应用表明,该技术有效控制了9114工作面黄泥冒顶事故,顶底板移近量稳定在可控范围内,保证了工作面正常回采,为类似条件下工作面围岩稳定性控制提供一定参考。

复杂地层下钻孔灌注桩护壁泥浆对钻孔灌注桩承载性能影响研究分析

本研究重点考察了护壁泥浆对钻孔灌注桩稳定性的影响,并归纳出如下主要结论:①桩体在初始承受荷重时,沉降主要由于桩内部弹性变形产生,随着荷重增大,桩与土之间发生相对位移,此时桩侧摩擦力成为承载的主力;②泥皮的存在能减弱桩体的承载力,泥皮越厚,桩的承载力下降越显著,与无泥皮桩相比,最大承载力分别降低了 14.8 %、16.4 %、26.6 % 和 33.6 %;③泥皮不仅对桩侧的承载力有显著的削弱作用,且随其厚度增加而损失更多,同时也使得施工效率降低;④桩端的阻力会随泥皮的增厚有所提高,在加载初期,桩端阻力在总承载中占据较大份额,但是随着荷重的持续增加,其比重将趋于一个相对稳定的水平。

不同施肥处理对黄泥田团聚体有机碳固持及其组分的影响

本文旨在研究长期不同施肥处理对南方黄泥田团聚体有机碳固持及其组分分配的影响,为合理培肥及土壤碳库管理提供依据。基于始于1983年的在黄泥田进行的长期定位试验,选择不施肥(CK)、单施化肥(NPK)、化肥+牛粪(NPKM)与化肥+全量稻秸还田(NPKS)4个处理,采集第36年各处理耕层土壤样品并分析各粒级团聚体有机碳固持及其组分变化。结果表明,黄泥田耕层土壤以大团聚体(>2 mm)和中间团聚体(0.25~2 mm)为主,NPKM与NPKS处理的土壤大团聚体质量比重分别比CK显著增加22.0和15.5个百分点(P<0.05)。与CK相比,NPKM与NPKS处理中大团聚体对有机碳固持贡献率分别提高25.0和19.3个百分点(P<0.05)。施肥处理的大团聚体内轻组有机碳(LF-C)含量较CK显著增加,其中NPKS处理后大团聚体中LF-C含量较CK增加32.3%(P<0.05)。大团聚体有机碳含量以及该团聚体内的LF-C含量与水稻产量和有机碳投入量都呈极显著正相关(P<0.01)。以上结果表明,配施牛粪或秸秆还田有利于增加黄泥田大团聚体比例及其有机碳含量,进而提高有机碳固持贡献率,尤其是配施牛粪,而且有机无机肥配施有利于提高大团聚体内轻组有机碳含量与固持贡献,秸秆还田更为明显,可为南方黄泥田施肥管理提供依据。

紫云英还田对黄泥田土壤理化和微生物特性及水稻产量的影响

为探明紫云英连年还田化肥减施单季稻田土壤性质及水稻产量的变化规律,依托位于福建省东部12年黄泥田紫云英-单季稻轮作定位试验,研究了不施肥(C_(0))、单施化肥(C_(100))、紫云英还田(M)、紫云英还田+全量化肥(MC_(100))及紫云英还田+减量20%化肥(MC_(80))处理的土壤理化性状、微生物群落结构和功能及稻谷产量的变化。结果表明:C_(100)、M、MC_(100)、MC_(80)处理土壤有机碳含量比C_(0)分别提高6.97%、15.05%、10.38%、11.15%,全氮分别提高9.52%、18.25%、15.87%、15.87%,硝态氮分别提高6.51%、69.52%、66.87%、78.19%(P<0.05)。冗余分析表明,土壤有机碳、全氮、硝态氮含量对细菌和古菌群落结构和功能有显著的影响。与C_(0)相比,C_(100)、M、MC_(100)和MC_(80)处理土壤慢生根瘤菌属(Bradyrhizobium)丰度分别增加0.52%、24.30%、7.59%、11.93%,其中M处理增加达显著水平(P<0.05);分枝杆菌属(Mycobacterium)分别增加5.51%、21.58%、10.00%、14.74%,其中M处理增加显著(P<0.05);亚硝化杆菌属(Candidatus_Nitrosotalea)分别增加22.93%、17.21%、65.39%、89.89%,其中MC_(100)和MC_(80)处理增加均达显著水平(P<0.05)。相比C_(0),M、MC_(100)和MC_(80)处理土壤链霉菌属(Streptomyces)分别增加6.76%、16.89%、12.16%,其中MC_(100)处理增加显著(P<0.05),而C_(100)却减少2.50%。物种贡献度分析发现,土壤碳代谢和氨基酸合成的主要功能微生物为细菌慢生根瘤菌属(Bradyrhizobium)、分枝杆菌属(Mycobacterium)、链霉菌属(Streptomyces)和古菌亚硝化杆菌属(Candidatus_Nitrosotalea)。M、MC_(100)、MC_(80)处理稻谷产量比C_(0)分别增加9.68%、19.16%、18.72%。阐明紫云英培肥处理能提升单季稻黄泥田土壤肥力水平,调节土壤微生物群落结构,促进土壤碳水化合物和氨基酸代谢。

长期施肥对黄泥田土壤团聚体中氮素积累和有机氮组成的影响

【目的】氮是南方黏瘦型中低产田重要的限制因子。研究长期施肥对黄泥田团聚体中氮素累积及有机氮组成的影响,为合理培肥及土壤氮库管理提供依据。【方法】采集黄泥田36年定位试验中不施肥(CK)、单施化肥(NPK)、化肥+牛粪(NPKM)、化肥+全量稻秸还田(NPKS)4种处理耕层土壤,采用湿筛和Bremner有机氮分级方法,分析团聚体氮素累积与有机氮组分含量及分配的变化。【结果】施肥处理>2 mm团聚体全氮含量较CK显著增加12.7%—51.9%(P<0.05);NPKM与NPKS处理>2 mm团聚体对原土全氮累积贡献率较CK分别显著提高24.7与20.0个百分点(P<0.05)。施肥处理>2 mm团聚体酸解性氮与非酸解性氮含量分别较CK增加10.1%—36.3%与20.7%—100.5%,并相应提高两组分对原土全氮累积贡献率,NPKM与NPKS处理增加尤为明显。对于>2 mm团聚体,施肥处理酸解铵态氮含量较CK显著增加17.2%—40.4%(P<0.05),以NPKM处理增加最为明显;酸解氨基酸态氮与酸解未知态氮含量分别以NPKS与NPKM处理增加最为明显,分别较CK显著提高24.0%与52.1%(P<0.05)。>2 mm与0.25—2 mm团聚体的非酸解性氮及酸解铵态氮与相应粒级团聚体中的碱解氮含量呈显著正相关(P<0.05)。配合稻秸还田较配施牛粪更有利于>2 mm团聚体非酸解性氮的累积。配施牛粪对提高>2 mm团聚体酸解铵态氮、酸解未知态氮含量与对原土全氮累积贡献率最为明显,配合稻秸还田则对提高酸解氨基酸态氮含量及对原土全氮累积贡献最为明显。冗余分析表明,水稻氮吸收量受>2 mm与0.25—2 mm团聚体非酸解性氮组分影响较大,NPKM和NPKS处理水稻氮吸收量受土壤有机氮组分影响高于NPK与CK处理。【结论】长期施肥增加了黄泥田耕层土壤>2 mm团聚体全氮含量及对原土全氮累积贡献率,有机无机肥配施尤为明显。>2 mm团聚体中非酸解性氮、酸解性氮及酸解铵态氮含量与该团聚体中碱解氮含量以及水稻氮吸收量关系密切,是重要的有效氮库。

地域文化视域下的渝东北乡土伦理叙事——论长篇小说《黄泥巴小街》

在立足地域文化和乡土伦理叙事两个学术概念基础上,对长篇小说《黄泥巴小街》从底层叙事、家庭叙事和创伤叙事等方面给予了评论分析。首先,文章从一条小街所展示的渝东北乡土伦理世界,以善恶归一、正邪博弈并借助方言的张力和农耕文明的乡村道德文化背景,窥见社会底层的悲欢;其次,通过描写乡土文化语境下家庭的聚散来关注人的生存境遇、道路抉择、矛盾纷争、私人恩怨和儿女私情等亲情伦理;最后,通过人物的悲剧、人物的命运和社会的变迁,见证了当代中国精神的变迁和身体“症候”,以创伤性成长故事叙写了生命不能承受之重的乡土人生。《黄泥巴小街》是近年来重庆长篇小说的扛鼎之作,小说描写的渝东北黄泥巴小街,构成了中国文学的一个新地标,具有重要的艺术价值和文学史意义。

基于ANSYS的藏式毛石墙体抗压性能研究

藏式毛石墙体普遍抗压性能较差,而改善藏式毛石墙体抗压性能的前提是掌握其在受压状态下的破坏机理。为了提高藏式毛石墙体的抗压性能,利用有限元软件ANSYS,通过一种新的数值模拟方法对藏式毛石墙体受压破坏特征以及薄弱部位进行分析。通过将数值模拟与2片试验墙体的荷载位移曲线进行对比分析,验证了此套数值模拟的可靠性。在此基础上开展了3组不同黄泥含量对藏式毛石墙体受压性能的影响研究。研究结果表明:藏式毛石墙体抗压性能随黄泥含量的增加而提高,当黄泥含量为15%左右时,藏式毛石墙体抗压性能最佳。当黄泥含量超过15%时,藏式毛石墙体抗压性能随黄泥含量增加而降低。

残雪的放逐与坚守:从精神审丑到证伪神明——从《黄泥街》到《茶园》

近四十年的写作生涯中,残雪前期之作《黄泥街》与近期之作《茶园》存在接续性,前者的精神叙事、以丑为美的叛逆和诗性的语言可与后者证伪乌托邦的立场形成互证。在文本细读基础之上,发掘残雪小说写作中深层的现代性价值,能更好地解读残雪创作的精神内核、创作底线和对媚俗自始至终的放逐。

北黄海BS24岩芯稀土元素地球化学与重矿物组成对北黄海晚全新世沉积演化过程的指示意义

北黄海泥质区具有地理位置独特、陆源物质供应丰富、沉积环境复杂等特点,为了更好地理解全球变化背景下对北黄海“源-汇”过程的影响,对北黄海泥质区边缘BS24岩芯沉积物进行了AMS14C测年、粒度、黏土粒级稀土元素和重矿物组成特征分析,以判识沉积物的来源、沉积环境特征,并进一步探讨北黄海的沉积演化过程。研究表明,BS24岩芯轻重稀土元素具有明显分异,稀土元素的球粒陨石标准化配分曲线右倾,轻稀土元素富集,重稀土元素亏损,上陆壳标准化的δEu和δCe无明显异常。稀土元素的变化趋势较为一致,以170 cm为界,上段波动幅度较大,下段含量相对稳定。岩芯中共鉴定出30种重矿物,以黑云母(37.46%)和自生黄铁矿(22.39%)最为常见,辉石和氧化铁矿物及不稳定矿物含量低。黏土粒级及极细砂组分特征指示,BS24岩芯晚全新世以来主要接受黄河物质的沉积。BS24岩芯自生黄铁矿含量的变化可能指示了北黄海冷水团强度的变化。650 cal. a BP以来,北黄海冷水团强度增强,自生黄铁矿含量降低;650~1 560 cal. a BP期间,研究区处于还原环境,北黄海冷水团强度减弱,营造的缺乏对流性环境为自生黄铁矿的富集提供了有利条件。

不同石灰岩顶板厚度下的黄泥顶板变形特性研究

为解决石丘煤业主采煤层顶板黄泥岩的剧烈变形问题,采用FLAC3D数值模拟软件建立下不同石灰岩顶板与黄泥顶板厚度的数值模型,对围岩变形、垂直应力、矢量位移与体积应变进行监测,探究不同厚度石灰岩顶板对不同厚度黄泥顶板变形特性的影响。结果表明,石灰岩厚度小于6 m并且黄泥岩厚度小于3.5 m时,最大顶板下沉量变化较小;石灰岩厚度小于6 m并且黄泥岩厚度大于3.5 m时,顶板最大下沉量随黄泥岩厚度的增加迅速增加;当石灰岩的厚度大于6.0 m,最大离层量随黄泥岩厚度的增加而减小。根据数值模拟结果以及工程现场的顶板实际破碎形态,提出了离层破碎型、离层膨胀型、膨胀蠕变型顶板变形特征以及相应的支护方式。