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1.
Specimens of fossil wood preserved lignified in Pliocene brown coal and identified as Pinus armandii Francher come from an opencust coalmine at Longling in western Yunnan Province,China. Phytochemical investigation of the fossil wood isolated using liquid column chromatography seven compounds(1-7)including a new fluorene derivative named 11,11-dimethyl-11H-benzo[b]fluorene.A further 28 volatiles were detected by gas chromatography-mass spectrometry(GC-MS).Spectroscopic investigation methods,including MS and 1D and 2D-NMR techniques elucidated the structure of the seven compounds.Two types of natural products,isopimara and stilbene commonly occuring in extant and Plincene fossil P.armandii indicate phytochemical fidelity during burial under certain circumstances in sediments.Discovery of stilbenes that can inhibit the activities of wood-destroying fungi in the Pliocene P.armandii prompts the assumption that the chemical preservation of this Pliocene fossil wood of P.armandii in brown coal might contribute to the presence of inner natural inhibitors against wood-destroying fungi.  相似文献   

2.
云南元谋上新世秋枫化石的首次发现及古气候分析?   总被引:2,自引:0,他引:2       下载免费PDF全文
云南元谋盆地西部物茂盆地的湾堡土林和虎跳滩土林的晚上新世沙沟组地层大戟科秋枫属的秋枫(Bischofia javanica BL.)化石木。化石木木材由导管、纤维、射线组成。生长轮不明显。散孔材。径列复管孔(2~6,多2~4)甚多,单管孔较少,管孔团稀见。导管端壁具单穿孔。管间纹孔式互列。导管内侵填体丰富。轴向薄壁组织未见。木纤维壁薄,分隔。射线组织异形Ⅰ及Ⅱ。射线与导管间纹孔式为横列梯形及大圆形。孢粉分析表明元谋盆地晚上新世可能存在包括大戟科草本植物,而当前秋枫化石木的发现清楚地表明大戟科乔木植物的存在。秋枫为热带和亚热带常绿季雨林中的主要树种。秋枫化石木的发现指示元谋盆地当时的环境较现今湿润。  相似文献   

3.
在云南省腾冲县上新统芒棒组发现了保存较好的被子植物化石密脉鹅耳枥Carpinus m io-fangianaHu et Chaney。该种化石曾在我国山东山旺组有过报道,当前化石在叶形及叶脉特征上都和山旺的标本非常相似。进一步分析了化石叶片的角质层微细构造特征,并结合叶结构分析提高了对化石植物分类鉴定的准确性。基于化石Carpinusm iofangiana与现生植物Carpinus fangiana在生态环境及其结构特征上的相似性,将Carpinus fangiana作为化石的现生对应种进行对比,并统计二者的气孔密度和气孔指数,用气孔比率的方法推测上新世的大气CO2浓度为464×10-6,基本上与Berner全球碳平衡模型GEOCARB III中CO2浓度变化曲线上的数值一致,说明C.m iofangiana叶片可以作为古大气CO2浓度变化的生物指标。最后通过化石和现生叶片角质层的对比分析推断滇西地区上新世时气候比现在温暖湿润。  相似文献   

4.
A new Quercus (Fagaceae) morphospecies is described based on well-preserved fossil leaves.The fossils were collected from Yangyi Formation of the Upper Pliocene at the Yangyi coalmine,Baoshan,western Yunnan,China.Details of the microstructure of mesophyll tissue are preserved because lithification of the fossils was not complete.The fossil laminas possess typical characteristics of Quercus sect.Heterobalanus:quite thick and coriaceous cuticle; secondary veins bifurcating near the margin in the middle and top of the leaf; and upper epidermis with adaxial hypodermis.Based on a detailed morphological and anatomical comparison with all living and fossil species of Quercus sect.Heterobalanus,the fossil leaves prove to be different in their sparse and garland-shaped multicellular trichomes on the lower epidermis,and so it is described as a new species Quercus yangyiensis He,Li et Sun sp.nov.The much sparser trichomes of our fossils compare well with those of living Quercus sect.Heterobalanus and indicate a more humid climate during the deposition of the Yangyi Formation in the Late Pliocene.  相似文献   

5.
石玉若    吴中海  范桃园  仝亚博  杨振宇 《地质通报》2012,31(0203):241-249
报道了应用SHRIMP技术测定云南腾冲地区龙川江河谷附近上新世粗面安山岩和粗面岩的年龄结果。该区粗面安山岩与粗面岩的喷发时代接近,形成时代为2.81Ma±0.11Ma,属上新世。该区火山岩具高钾钙碱性的特点,富集大离子亲石元素、稀土元素和高场强元素(如Zr、Th、Hf)的特征明显不同于典型的岛弧钙碱性火山岩,而与遭受地壳混染的软流圈源大陆玄武岩相类似,是在板内拉张环境下地幔岩浆混染了大量下地壳物质的产物。  相似文献   

6.
报道了应用SHRIMP技术测定云南腾冲地区龙川江河谷附近上新世粗面安山岩和粗面岩的年龄结果。该区粗面安山岩与粗面岩的喷发时代接近,形成时代为2.81Ma±0.11Ma,属上新世。该区火山岩具高钾钙碱性的特点,富集大离子亲石元素、稀土元素和高场强元素(如Zr、Th、Hf)的特征明显不同于典型的岛弧钙碱性火山岩,而与遭受地壳混染的软流圈源大陆玄武岩相类似,是在板内拉张环境下地幔岩浆混染了大量下地壳物质的产物。  相似文献   

7.
报道了应用SHRIMP技术测定云南腾冲地区龙川江河谷附近上新世粗面安山岩和粗面岩的年龄结果。该区粗面安山岩与粗面岩的喷发时代接近,形成时代为2.81Ma±0.11Ma,属上新世。该区火山岩具高钾钙碱性的特点,富集大离子亲石元素、稀土元素和高场强元素(如Zr、Th、Hf)的特征明显不同于典型的岛弧钙碱性火山岩,而与遭受地壳混染的软流圈源大陆玄武岩相类似,是在板内拉张环境下地幔岩浆混染了大量下地壳物质的产物。  相似文献   

8.
In Europe, fossil fruits and seeds of Rhodoleia (Hamamelidaceae) have been described from the Upper Cretaceous to the Miocene, whereas no fossil record of Rhodoleia has been reported in Asia, where the modern species occur. Herein, 21 fossil leaves identified as Rhodoleia tengchongensis sp. nov. are described from the Upper Pliocene of Tengchong County, Yunnan Province, Southwest China. The fossils exhibit elliptic lamina with entire margins, simple brochidodromous major secondary veins, mixed percurrent intercostal tertiary veins, and looped exterior tertiaries. The leaf cuticle is characterized by pentagonal or hexagonal cells, stellate multicellular trichomes, and paracytic stomata. The combination of leaf architecture and cuticular characteristics suggests that the fossil leaves should be classified into the genus Rhodoleia. The fossil distributions indicate that the genus Rhodoleia might originate from Central Europe, and that migrated to Asia prior to the Late Pliocene. Additionally, insect damage is investigated, and different types of damage, such as hole feeding, margin feeding, surface feeding, and galling, are observed on the thirteen fossil leaves. Based on the damage frequencies for the fossil and extant leaves, the specific feeding behavior of insects on Rhodoleia trees appears to have been established as early as the Late Pliocene. The high occurrence of Rhodoleia insect herbivory may attract the insect-foraging birds, thereby increasing the probability of pollination.  相似文献   

9.
在对怒江道街—惠通桥段的考察研究中,不仅重新厘定了河谷中拔河150m以下的多级低阶地,而且在拔河180~380m的高度上发现了多级由磨圆良好、成分复杂的厚层冲积砾石层所组成的高阶地,厚近100m的堰塞湖成因的砂层及其下伏厚约100m的砾石层。冲积层的同位素年龄测定结果表明,6级低阶地形成于中更新世以来。望江楼剖面的磁性地层研究结果显示,组成相当于第九级阶地上部的湖相砂层,上部以正向极性为主,含2次短期的负极性,下部则为负极性。与标准磁性地层柱对比表明,该湖相地层形成于4.2~2.6MaBP的中—晚上新世,湖相地层之下的埋藏阶地与高阶地则应形成于上新世早期至中新世晚期。据此在进一步的区域地层对比后认为:怒江至少在中新世的中晚期已开始形成并下切,至上新世早期已下切至现今河床附近。上述研究结果为更科学地认识青藏高原东缘的强烈隆升过程提供了非常有价值的新线索。  相似文献   

10.
在对怒江道街—惠通桥段的考察研究中,不仅重新厘定了河谷中拔河150m以下的多级低阶地,而且在拔河180~380m的高度上发现了多级由磨圆良好、成分复杂的厚层冲积砾石层所组成的高阶地,厚近100m的堰塞湖成因的砂层及其下伏厚约100m的砾石层。冲积层的同位素年龄测定结果表明,6级低阶地形成于中更新世以来。望江楼剖面的磁性地层研究结果显示,组成相当于第九级阶地上部的湖相砂层,上部以正向极性为主,含2次短期的负极性,下部则为负极性。与标准磁性地层柱对比表明,该湖相地层形成于4.2~2.6MaBP的中—晚上新世,湖相地层之下的埋藏阶地与高阶地则应形成于上新世早期至中新世晚期。据此在进一步的区域地层对比后认为:怒江至少在中新世的中晚期已开始形成并下切,至上新世早期已下切至现今河床附近。上述研究结果为更科学地认识青藏高原东缘的强烈隆升过程提供了非常有价值的新线索。  相似文献   

11.
A Pliocene composite shell concentration from a shallow-marine carbonate succession located in the small, slowly subsiding Novoli graben (Salento peninsula, Puglia, S-Italy) is interpreted as a tsunamite. This interpretation is based on taphonomic, palaeoecological and sedimentologic features. The deposit appears to drape the previous substrate, with thinning on the topographic highs and thickening in the lows, and consists of up to six sub-layers showing repeated grading (normal and reverse), suggesting that deposition occurred during up to six surges. The shell assemblage results from a chaotic mixing of taxa spanning a large spectrum of environments and taphonomic features. Although a fraction of broken shells is present, most shells are integral, suggesting a transport mechanism preventing strong impacts. On the other hand, the high comminution of skeletal remains occurring in the matrix of the deposit is thought to reflect the composition of sea-floor sediment before the inferred high-energy event.The predominance of displaced, but still articulated valves indicates that bivalves were mostly transported while still alive, after having been lifted from the sea bed. Exhumation, displacement, and large-scale transport of large-sized, deep-infaunal organisms (such as Panopea) implies that across relatively large areas the upper few decimetres of the middle–inner shelf floor were eroded by highly turbulent flows of exceptional intensity. A transport as turbulent suspension, very rapid deposition and immediate and permanent burial are strongly suggested by the general integrity of the shells indicating limited effects of physical damage and lack of biological alteration. The variable faunal characteristics of the unit lying below the inferred tsunamite suggest that deposition of the latter took place in settings ranging from a somewhat restricted, relatively low-energy bay, to a more open inner-shelf environment.  相似文献   

12.
The Mission Paléoanthropologique Franco-Tchadienne (MPFT) found a new species of Orycteropodidae (Mammalia, Tubulidentata) in the Kollé fossiliferous sector, northern Chad. After Orycteropus abundulafus [Journal of Vertebrate Paleontology 20 (1) (2000) 205–209; Lehmann, T., Vignaud, P., Likius A., Brunet M., in press. A new Orycteropodidae (Mammalia, Tubulidentata) in the Mio-Pliocene of Northern Chad. Zool. J. Linnean Soc.], this specimen is the second complete skeleton of fossil aardvark found in the Djurab desert. It is the first complete representative of an Orycteropus species found in the Pliocene of Africa. In regard to the Miocene fossil aardvarks, this new taxon, Orycteropus djourabensis nov. sp., shows more affinities with the extant O. afer. The main differences are the larger teeth and the shorter hand in the fossil form. Kossom Bougoudi and Kollé represent a chronological series that gives a unique opportunity for studying the evolution of the African Tubulidentata around the Mio-Pliocene boundary (5.5-4 My). The new species is distinct from the older Chadian Orycteropodid from KB and it embodies the taxonomic turnover that took place within the order Tubulidentata around this boundary in Africa. Moreover, this new species is the oldest known Orycteropus species that clearly belongs to the modern forms including the extant aardvark.  相似文献   

13.
蒋子堃  王永栋  田宁  张武  郑少林 《地质学报》2016,90(8):1669-1678
木化石在陆地生态系统古气候、古环境和古生态研究方面具有重要的意义。辽西北票地区中晚侏罗世髫髻山组保存有数量丰富、类型多样且解剖构造保存完好的木化石。基于北票木化石树木年轮、树桩直径等数据计算了木材早材与晚材的比率(E/L),并推算了松柏类树木古树高。通过已有测量的树木年轮直径,应用Niklas(1994)和Mosbrugger(1994)两种方法恢复了化石森林中松柏类树木的古树高约为25m。推断中晚侏罗世的裸子植物森林树木生长的环境为以火山岩和湖相沉积为主,降水丰富。推断髫髻山组属于温暖、湿润、季节性明显的亚热带到暖温带气候,有利于植物的生长与发育。木化石木材组织中呈现的特殊解剖构造包括假轮、创伤树脂道、年轮扭曲、虫孔等,也能够揭示辽西北票中晚侏罗世植物生长过程中的古气候与古环境状况。表明辽西北票地区中晚侏罗世古气候虽然有利于植物生长,但生长期间受到了火山喷发、虫害、大风、降温等多种不利气候变化的影响与干扰。  相似文献   

14.
基于前人山西榆社盆地张村植物大化石和花粉组合资料,运用分布区叠加分析法,初步重建了山西张村上新世气候参数值和古海拔高度。研究结果表明,由不同数据来源计算的张村古气候参数数值变化范围大多落在今天的暖温带到北亚热带区间;依据原地埋藏的植物大化石组合推出上新世时山西张村地区存在植被垂直分带,周围为山地地形,由此估测的古湖海拔高程范围在400~1 000 m,明显低于今天约1 043 m的海拔高度,表明在上新世之后位于黄土高原东缘的张村地区还有抬升;支持前人关于更新世以来晋东南地区的整体缓慢抬升的推测。  相似文献   

15.
Longling is characterized by a wide distribution of hydrothermal areas, among which the Banglazhang hydrothermal system is the most geothermally active. Banglazhang is marked by intensive hydrothermal activities including hot springs, geysers, fumaroles and hydrothermal explosions. The geothermal waters from the Longling region are mainly HCO_3-Na type with low but comparable SO_4 and Cl concentrations. Calculations based on a variety of chemical geothermometers and a K-Ca geobarometer indicate that the Banglazhang hydrothermal system has much higher subsurface temperature and CO_2 pressure compared to the other systems such as Daheba, Dazhulin and Huangcaoba. However, geothermal water samples collected from all these alternative hydrothermal areas are either partially equilibrated with reservoir minerals or are immature. The silica-enthalpy relationships of Banglazhang geothermal waters indicate the presence of a deep geothermal fluid with an enthalpy value and silica concentration of 945 J/g(up to around 220 °C) and 339 mg/L. Our work indicates the Banglazhang area is a promising source in terms of long-term utilization of hydrothermal resources.  相似文献   

16.
西藏阿里札达盆地上新统鼠兔类牙齿化石的发现   总被引:4,自引:2,他引:4  
首次在西藏阿里札达盆地上新世河湖相沉积地层中发现了鼠兔类牙齿化石,对鼠兔类牙齿化石的基本特征进行了描述,并在同一层位中采集了大量孢粉、古动物和古植物化石。结合区域地质特征,产出鼠兔类牙齿化石地层的古地磁、ESR测年资料,沉积学特征等的简要分析,认为札达盆地鼠兔类的]化迁徙与上新世时气候由温暖湿润向寒冷潮湿—温和干旱的变化有关。显然,这一发现有助于认识青藏高原新近纪上新世的生物]化、气候变化和构造活动,并为研究青藏高原新近纪以来的生物进化、湖泊与河流]化、气候变化、古地理与古环境变迁和古近系、新近系、第四系地层划分等提供了新资料。  相似文献   

17.
孟加拉湾缅甸若开盆地上新统斜坡水道复合体沉积特征   总被引:5,自引:1,他引:5  
斜坡水道复合体是孟加拉湾缅甸海上若开盆地上新统最重要深水沉积结构单元之一。研究工作以地震响应与深水储层之间的对应关系为指导,二、三维地震资料中的强振幅属性用以判断水道复合体内的粗粒沉积。利用多种地震技术,包括相干切片分析、地质异常体处理以及三维可视化,将斜坡水道复合体从背景中区分出来,并从斜坡水道复合体的外部几何形态、...  相似文献   

18.
A new species, Tsuga nanfengensis sp. nov. (Pinaceae), is described on the basis of lignified fossil wood from the late Miocene of the Xianfeng Basin, central Yunnan, southwestern China. Detailed observation of the fossil wood specimens show the following characteristics: distinct growth rings, absence of resin canals, uniseriate bordered pits in the radial wall of tracheids, ray tracheids and piceoid and cupressoid cross-field pits. These features indicate similarities to the wood of extant Tsuga canadensis, T. chinensis, and T. dumosa. According to the fossil record, Tsuga was present in Xundian County during the Miocene. Today Tsuga is drought intolerant, preferring wet conditions with no extant species growing naturally in Xundian County. The presence of Tsuga in the Miocene of Xundian County indicates a humid climate consistent with previous palaeoclimatic reconstructions showing a wetter and probably shorter dry season in the Miocene, relative to the present day. Therefore, the change in the local climate such as increasing aridity through the Miocene might explain the local extinction of Tsuga from central Yunnan.  相似文献   

19.
对发现于浙江省宁海县茶园乡道士桥村附近的上新统嵊县群中的多个化石木材料进行了解剖研究,并对其分类和系统位置进行了讨论。根据解剖特征鉴定出2种化石木。一种为久内枫香树(Liquidambar hisauchi),属于金缕梅科枫香树属,其组合特征为:生长轮明显;散孔材;梯状穿孔板具横隔10~23条;螺纹加厚仅出现在导管末端;导管直径在50~100μm之间;射线宽1~3列。另一种为岛仓栎(Quercus shimakurae),属于壳斗科栎属,其组合特征为:生长轮极明显;环孔材;单管孔;晚材管孔火焰状径列;早材管孔直径最大达300μm,明显比晚材管孔大;单穿孔;轴向薄壁组织星散聚合状和离管带状;射线具单列和极宽2种类型。本研究从大化石角度进一步证明栎属和枫香树属为当时植被的重要组成成分。  相似文献   

20.
A depositional model of the lower Pliocene Hagul formation, which is exposed in the East Cairo district (Egypt), is proposed with more than 10 depositional cycles recognized. Field occurrence, detailed petrographic investigation and geochemical analysis revealed that the sediments within each cycle are the result of three sequential sedimentological processes: (1) alluvial sedimentation, (2) calcretization, and (3) precipitation of palustrine carbonate. It was concluded that Hagul formation has been deposited within the distal part of an alluvial plain during three successive climatic conditions: a humid climate during which alluvial sediments were deposited, a semi-arid climate with episodic precipitation which was favorable for pedogenic calcrete development, and a sub-humid climate during which groundwater level was gradually elevated and groundwater calcrete accumulated. Rising groundwater level continued until shallow wetlands covered the area and palustrine limestone was precipitated. Variations in the thickness and the nature of the host sediment, calcrete and palustrine limestone cycle suggest that each of the sedimentation processes varied from cycle to cycle.  相似文献   

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