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在南京六合发现一保存较好的下颌骨化石,保存有5枚完整的臼齿。经刘冠邦教授鉴定,认为与他1993年在江苏北部泗洪地区发现的泗洪泗洪炭兽(Sihongotherium sihongense Liu et zhang)相似,但臼齿相对稍小,且齿冠磨损严重,故仅确定为泗洪炭兽未定种(Sihongotherium sp.),时代属中中新世;其照片经邱占祥院士鉴定也认为属炭兽类无疑。炭兽类始于欧、亚始新世中期,渐新世扩展到非洲和北美,到中新世灭绝。炭兽类在我国过去仅分别发现于内蒙、山西、云南的始新世至渐新世地层中,贵州也曾发现两枚臼齿,但时代不祥。由于化石较重要,经在六合实地调查,化石应产于六合组。六合组和雨花组是归于上新世或中新世,一直有争论,故泗洪炭兽在南京六合的发现,为六合组和雨花台组应为中新世提供了新的重要化石依据。 相似文献
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云南元谋小河及竹棚村考古发现大批化石,牙齿1525枚.古猿臼齿M3＞ M2＞ M1,M3硕大.元谋化石进化,M2＞ M3＞ M1,有的M3退化小于M1.上中门齿成铲形结构,齿釉柱类型由3A型进化成3B型,与现代人相同.小河地层中有钙质胶结砾石,植物孢子花粉稀少,证明气候严寒,与老鸦塘同属龙川冰河时期.龙川组测年447万年～340万年.元谋人起源于距今440万年的小河村. 相似文献
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本文简要回顾了蜀兽类哺乳动物的研究历史,论述了在哺乳动物牙齿演化和中生代陆相地层对比研究中的科学意义。粗壮假碾磨齿兽的发现有力地支持了哺乳动物中“三磨楔齿形臼齿趋同演化”的假设,并再一次以直接的化石证据表明内蒙古宁城道虎沟地区含蜀兽类化石地层的时代为中侏罗世。 相似文献
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中国新近纪的犀科化石有广泛的分布,但以往的研究大多侧重于犀科化石的系统分类,较少涉及到这一重要类别的生态意义。本文试图发现这些犀科化石与环境的密切关系,为恢复这一时期陆地生态系统的演变过程提供新的依据。研究的材料包括中国从早中新世早期直到晚上新世晚期已知的全部犀科化石记录,共2亚科4族25个种。依据新近纪哺乳动物群单位(NMU)标定每个时期犀科的分异度、新记录和绝灭种。中国新近纪犀科化石的分异度变化显著,可划分为5个阶段,包括中中新世和晚中新世2个高分异期以及早中新世、晚中新世初期和上新世3个低分异期。 早中新世(NMU1～5)犀科的分异度非常低,占统治地位的是矮脚犀类。第一次重大的变革发生在中中新世 相似文献
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阿芳托娃戈拉(Afontova Gora)遗址位于俄罗斯西伯利亚叶尼塞河上游右岸的3级阶地,地理坐标北纬55.9°94′83″,东经92.5°08′31″。该遗址出土有晚期智人化石和丰富的打制石器、骨制品、动物化石等,是西伯利亚地区旧石器时代晚期的重要文化遗址之一。遗址剖面第12层约17.0 ka B. P.。从该层出土的哺乳动物化石中,鉴定出4个个体的西伯利亚旱獭(Marmota sibirica)化石材料。西伯利亚旱獭颅骨呈松鼠型,眶上突和矢状嵴发达;腭面宽大,左右颊齿间距在M1处最宽;下颌骨粗壮,水平支较高,冠状突较短而粗壮;颅骨全长113.5 mm,眶间距28.8 mm, P4～M3长27.8 mm。从颅骨、颊齿测量数据上比较发现,西伯利亚旱獭(M.sibirica)明显大于早更新世绝灭种小旱獭(Marmota parva)和现生种草原旱獭(Marmota bobak)。牙齿形态特征上,西伯利亚旱獭具有一定原始性,其下颊齿下中尖粗壮,与早更新世小旱獭有一定相似性;但与小旱獭相比也有明显进步性,如P4臼齿化、下颊齿下后脊高度退化等。遗址动物群生态和地层堆积综合分析显示,阿芳托娃戈... 相似文献
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本文记述了采自甘肃广河石那奴中中新世地层的哺乳动物化石6目10科12属16种类（以小化石为主）,其中新种两个:Alloptox guangheensis sp. nov., Pseudaelurus guangheensis sp. nov.。通过对动物群性质的研究及与其它地区的详细对比,认为下化石层的时代应为中中新世早期,上化石层应为中中新世晚期。二者分别与山旺期、通古尔期大体相当。 广河地区中中新世早期车头沟组和中中新世晚期咸水河组的建立,表示该地区存在着中中新世两个时期的不同环境沉积。 相似文献
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库车坳陷却勒地区新生代盐构造特征、演化及变形控制因素 总被引：3，自引：0，他引：3
本文利用野外地质调查结果、遥感资料、地震资料和钻、测井数据,建立了两条库车坳陷却勒地区的区域大剖面,约束却勒地区盐构造特征和演化,分析东、西段变形差异及差异形成过程,探讨构造变形控制因素。却勒地区发育的盐构造样式主要有盐底辟、盐焊接、盐撤凹陷、大型盐推覆体、外来盐席、盐枕、盐背斜和滑脱褶皱,其中,盐撤凹陷、盐背斜和滑脱褶皱仅发育于东段,造成东、西段构造变形差异。却勒地区盐构造分为3期:①渐新世—中新世吉迪克期为构造平静期,发育盐撤凹陷和盐底辟;②中新世康村期—上新世早期构造挤压微弱,发生早期褶皱作用,却勒盐丘继续发育,北部盐底辟中新世末停止发育;③上新世晚期—现今发生大规模逆冲推覆,是褶皱-冲断带主要形成时期,发育大型盐撤凹陷、外来盐席、盐推覆构造、盐背斜和滑脱褶皱。却勒地区东、西段盐构造变形差异主要形成于上新世晚期—现今(第3期)。喀拉玉尔滚右旋走滑断层为薄皮构造,调节了却勒地区东、西段前缘的变形差异。却勒地区构造变形主要受控于盐岩沉积范围、区域构造应力及强度、上覆层应变强度和差异负载(沉积负载和局部构造负载)。 相似文献
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重庆万州盐井沟是中国南方最经典的第四纪哺乳动物化石产地之一,因化石数量众多、种类多样和完整度极高而著名,但目前重庆万州盐井沟动物群已报道的猪科动物化石仅为野猪(Sus scrofa)和猪属未定种(Sus sp.)。现今可考证的化石点为建国以后发现的4个化石点,即大垭口化石点、平坝上洞、平坝下洞和媒人洞,而四方地化石点是重庆万州盐井沟地区新近发现的第5个化石点,出土了亚成年小猪(Sus xiaozhu)的2件不完整头骨和2件下颌骨化石,代表了迄今发现最完整且时代最晚(晚更新世)的小猪头骨和下颌骨化石,为盐井沟动物群中首次发现。经过与华南第四纪猪属(Sus)其他物种对比,小猪的鉴定特征可归纳为小型猪,面部和腭骨长度远不及李氏野猪(S.lydekkeri)和野猪(S.scrofa),牙齿尺寸小于裴氏猪(S.peii)、李氏野猪(S.lydekkeri)和野猪(S.scrofa),眶前孔位于DP4(P4)与M1界线之上,下颌骨联合部短且厚,终止于P2之前。雄性下犬齿横切面的形状介于“verrucose”型和“scrofa”型之间,属于一种过渡类型,臼齿低冠且呈丘型,结构简单,每个臼齿由4个主尖... 相似文献
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文章报道了云南元谋盆地上中新统小河组芝麻大村小夹巷巷地点的脊棱齿象属(Stegolophodon)的新化石材料:包括一完整的、轻度磨耗的左上第二臼齿,和一不完整的、重度磨耗的右上第三臼齿.第二臼齿和第三臼齿主齿柱中附锥和前中心小尖愈合;后中心小尖很弱小;前二脊发育中沟,且几乎排成一条直线,仅主齿柱的中附锥比主尖略微靠前;第三臼齿的后三脊略向前弯.这些特征与西瓦利克道克派珊组的剑齿象型脊棱齿象(Stegolophodon stegodontoides)形态上十分相似,可归为同一种.元谋盆地小河组此前发现的所谓“Stegolophodon banguoensis”和“Stegolophodon aff.banguoensis”经比较均可以归为此种.小河组的磁性地层年代约为8.3～ 7.2Ma,而相距不远的昭通盆地出产最原始的剑齿象Stegodon zhaotongensis的层位的磁性地层年代约为6.5～6.OMa,因此,剑齿象型脊棱齿象代表了脊棱齿象演化到晚中新世中期的进步类型,此后,脊棱齿象便迅速演化为剑齿象.小河组的剑齿象型脊棱齿象的新材料,能为这一幕演化历史提供生物年代学和形态学的双重证据. 相似文献
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2013年以来在辽宁大连骆驼山金远洞堆积(39°23'59.01"N,121°41'20.28"E)进行的系统发掘出土了大量的哺乳动物化石。最近从偶蹄类化石中鉴定出泥河湾期动物群的典型成员布氏真枝角鹿(Eucladoceros boulei)的头骨等材料。金远洞标本角柄粗短,角柄在额骨上向上、外侧方向生长,角枝长而弯曲;头骨额部宽而平,上颌骨高;颊齿齿冠高度中等偏低,上前臼齿舌侧主尖具釉质褶,P2和P3具明显的内中凹,上臼齿具内附尖(底柱),p4没有臼齿化迹象,下臼齿无古鹿褶,但具下外附尖(底柱)。布氏真枝角鹿的产出层位集中在下更新统,因此是早更新世动物群的代表。布氏真枝角鹿以前主要见于华北,向南可达安徽。大连金远洞标本的发现说明这个种的地理分布范围可以到达东北,但从整体看仍是北方动物群的成员。布氏真枝角鹿与欧洲维拉方期的真枝角鹿在形态上有一定的相似性,说明在早更新世期间欧亚大陆的东西两侧存在过动物群的交流。布氏真枝角鹿高度偏低的齿冠指示其食嫩叶的食性,说明在早更新世期间大连金远洞一带很可能存在一定范围的阔叶林环境。 相似文献
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S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
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E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others. 相似文献
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奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
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Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance. 相似文献
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Alexander E. C. Broberg J. S. Kehren A. R. Graziani M. M. Turri W. L. 《Environmental Geology》1993,22(4):353-361
Bellechester, Minnesota, is a small community of approximately 155 residents located on the county line between Goodhue and Wabasha counties in southeast Minnesota's karst region. Bellechester is served by a 21-year-old wastewater treatment facility (WWTF) consisting of three waste-stabilization ponds. On 28 April 1992 six sinkholes were discovered to have drained cell 2 of the WWTF resulting in the loss of approximately 8.7×106 1 of partially treated effluent and about 600 m3 of soil into previously undetected subsurface voids of unknown dimensions. In the week following the collapse, approximately 200 water wells located within a 5-km radius of the WWTF were sampled in an after-the-fact, emergency sampling program. Twelve samples with elevated fecal coliform levels, 18 samples with nitrate-nitrogen greater than the 10 mg/1 standard, and no samples with elevated chlorides were found. However, the elevated levels could not be unambiguously attributed to the WWTF collapse. This is the third WWTF to fail by sinkhole collapse in southeast Minnesota since 1974. All three collapsed lagoons have been located in similar geomorphic and stratigraphic settings. However, at least two lagoons have collapsed in the adjacent area in northeast Iowa, and these lagoons are located at different stratigraphic positions. Twenty-two WWTFs constructed in southeast Minnesota's karst region in the last 25 years have been identified as subject to potential sinkhole collapse. An unknown but significant number of manure storage lagoons, flood control structures, etc., have also been constructed in the karst region and are at risk. Public agencies are beginning to develop plans to deal with the risk associated with existing and future waste lagoons in this environment. The critical hydrogeologic parameters that can be used to prioritize the risk of collapse at existing facilities include: (1) the lithology of the first bedrock beneath each lagoon, (2) the thickness of surficial materials between the lagoon and the bedrock surface, (3) the presence and construction of liners (seepage rate), and (4) the proximity to existing sinkholes. 相似文献
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岩石密度和超高压岩石折返速率 总被引：1，自引：3，他引：1
在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。 相似文献
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滇东南锡、银、铅、锌多金属矿床主要分布在个旧、白牛厂、都龙3个矿区,而滇东南较大的3个花岗岩体又分别出露在3个矿区或附近.花岗岩体均形成于燕山晚期,岩石化学、矿物成分相似,富含锡、银、铅、锌、钨、铜等成矿元素.矿床主金属元素组合与岩体之间的距离由远而近出现由锡、钨、(铍、铌、钽)→锡、钨、(铁)、铜、铟→锡、铅、锌、银、铟、(锑)有规律的变化.花岗岩浆是成矿物质来源和成矿热源.岩浆侵入初期使上覆地层隆起产生背斜(凹陷部位成向斜);同时使地层产生一系列裂隙、压性断层或层间断裂;岩浆侵入晚期,这些断层再次活动,表现为张性,岩浆产生的含矿热液沿由其活动所造成的断裂迁移、充填、交代、沉淀而形成矿床. 相似文献