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甘肃省宝积山晚三叠世植物群与古地理研究 总被引：1，自引：0，他引：1
阎同生 《地理与地理信息科学》2006,22(1):103-108
晚三叠世地层是我国西北的主要产煤产油地层,对甘肃省宝积山晚三叠世植物群及古地理进行研究,发现植物群31属56种。其中真蕨类植物7属16种,有节类植物4属10种,种子蕨类植物2属2种,苏铁类植物5属7种,银杏类植物6属13种,松柏类植物2属3种,裸子植物种子化石3属3种,分类位置不明化石2属2种,发现了多实拟丹尼蕨和蔡耶贝尔瑙蕨两种北方植物群的典型代表。植物生态类型主要为滨岸、高地和低地。依据纵向分布特点,可将宝积山植物群划分为多实拟丹尼蕨(Danaeopsis fecunda)—周氏似银杏(Ginkgoites chowi)和巨大枝脉蕨(Cladophlebiscf.gigantea)—蟹形新芦木(Neocalamites carcinoides)两个组合带。当时的古气候应为亚热带,通过对沉积物分析确定古环境出现过多次变化,将上三叠统划分为5个古地理演化阶段,可与邻区进行对比。 相似文献
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该文研究河北秦皇岛柳江古植物群 ,共发现植物化石 4 4属 86种 ,主要属种有蕨类、石松、苏铁、银杏、科达等植物 ,华夏植物群特征明显 ,纵向分布可划分为 6个植物组合。其中有少量安加拉植物群混生分子 ,该古植物化石遗迹是宝贵的资源 ,具有较高的科学研究价值 ,同时是科普教育、旅游开发的良好场所。 相似文献
4.
山东淄博四宝山地区灰岩地层出露广泛,本文依托"淄博地质图",经过野外地质勘查、实测地质剖面、化石样品采集与鉴定、室内综合分析等方法对山东淄博四宝山马家沟组的地质状况有了较为详细的认知。研究认为:在四宝山马家沟组地层中发现了大量化石,主要是头足类,还包括腕足类和三叶虫,根据鉴定头足类化石有谭氏阿门角石(Armenocers tani Grabau)、中央阿门角石(Armenoceras central Kobayashi and Matumoto)和三石氏弓珠角石(Cyrtactinoceras mitsuishii Kobayashi)等,三叶虫化石发现有波氏小帝王虫(Basilicus boehmi Lorenz)等,从而根据化石类型可以将四宝山地区进行详细的年代鉴定,经化石组合分析该区域地层具有中奥陶世的特征。该研究为了解中奥陶世生物多样性,完善研究区年代地层格架提高基础地质研究水平,做出应有的贡献。 相似文献
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渤海湾北岸表层沉积中的有孔虫群及其生态环境 总被引：2，自引：0，他引：2
我们对渤海湾北岸177个表层沉积物样品进行了有孔虫分析。经鉴定,未发现浮游有孔虫,底栖有孔虫共计82种,其中包括一新种Jadammina planata He et Li sp.nov.根据不同的环境中沉积物内有孔虫群属种组合不同,大体可归纳为二种组合:一是河口、海滩、泻湖、滨海平原等滨海边缘环境组合,在南堡以东该组合称为厚壁转轮虫——显孔鼓室希望虫组合,南堡以西称为厚壁转轮虫——多变假小九字虫组合,二是分布在水深10米以内的近岸浅海环境组合,称为厚壁转轮虫——缝裂希望虫组合。在不同环境中,有孔虫壳体数量的变化是有规律的,一般在泻湖中有孔虫含量最多,滨岸沙坝处最少,沙坝脊部有时为零,向海方向至近岸浅海共含量又有逐渐增多的趋势。 相似文献
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秦皇岛柳江古植物遗迹研究 总被引：2，自引：0，他引：2
该文研究河北秦皇岛柳江古植物群，共发现植物化石44属86种，主要属种有蕨类，石松，苏铁，银杏，科达等植物，华夏植物群特征明显，纵向分布可划分为6个植物组合，其中有少量安加拉植物群混生分子，该古植物化石遗迹是宝贵的资源，具有较高的科学研究价值，同时是科普教育，旅游开发的良好场所。 相似文献
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摸索沙拐枣属（Calligonum L.）七种植物沙拐枣（Calligonum mongolicum Turcz. ）、泡果沙拐枣（C. junceum (Fisch. et Mey.) Endl.）、无叶沙拐枣（C. aphyllum (Pall.) Gürke）、红果沙拐枣（C. rubicundum Bge.）、心形沙拐枣（C. cordatum E. Kor. ex N. Pavl.）、密刺沙拐枣(C. densum Borszcz.)、乔木状沙拐枣（C. arborescens Litv.）的总DNA提取方法并对DNA样品的纯度和浓度进行鉴定,对传统的CTAB法进行方法和材料的改进,开展与总DNA相关的PCR扩增和其他遗传学分析,并取得满意的结果。其结果对于沙拐枣属植物的有关研究提供了有效的实验手段。 相似文献
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通过对新疆罗布泊地区地层剖面中的介形类分布及其组合特征的分析,在剖面中发现有14属31种介形类化石,划分出两个化石组合层段。第一层段以Limnocythere sanciti-patricii为组合特征,代表沉积环境为湖相,根据14C年龄,此层段的沉积年龄在20 870～14 770 a BP。第二层段以Cyprideis littoralis和Darwinula stevensoni为组合特征,代表咸水-半咸水湖相沉积环境,根据14C测年,地层沉积年龄约30 000 a BP。 相似文献
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《中国沙漠植物志》第1卷中,水毛莨属(Batrachium S.F.Gray)只收载了1种,通过对中国沙区植物标本鉴定和文献考证,认为中国沙区该属植物有6种。 相似文献
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中国荒漠区蒲公英属订正 总被引：1，自引：1，他引：0
《中国沙漠植物志》第3卷中,蒲公英属(TaraxacumF.H.Wigg.)只收载了9种,通过对中国荒漠地区蒲公英属标本鉴定和文献考证,认为中国荒漠地区该属植物有12种,并记载了每个种的产地和生境。 相似文献
11.
LI Lan ZHU Cheng LIN Liugen ZHAO Quanhong SHI Gongyue ZHENG Chaogui FAN Chao 《地理学报》2009,19(6):671-680
Based on archaeological excavations, 217 samples were collected from the Luotuodun Site. Of them 63 samples from the section plane of the site layer were used for identification analysis of foraminifera, plant debris and seed fossils, and four samples were used for 14C dating and relevant analysis. Through many kinds of experiments, we have drawn some conclusions. Firstly, benthic foraminifera, such as Ammonia compressiuscula and Ammonia cff. sobrina, are found in the 10th layer, indicating that between 7500 and 5400 BC, i.e. before the emergence of the Majiabang Culture, Luotuodun Site and its nearby regions had ever experienced a marine transgression event. Secondly, we have found 450 plant fossils in this site, such as Polygonum sp., Scripus sp., Najas sp., Physalis sp., which indicated lacustrine or swamp environment. 相似文献
12.
Based on archaeological excavations, 217 samples were collected from the Luotuodun Site. Of them 63 samples from the section
plane of the site layer were used for identification analysis of foraminifera, plant debris and seed fossils, and four samples
were used for 14C dating and relevant analysis. Through many kinds of experiments, we have drawn some conclusions. Firstly, benthic foraminifera,
such as Ammonia compressiuscula and Ammonia cff. sobrina, are found in the 10th layer, indicating that between 7500 and 5400 BC, i.e. before the emergence of the Majiabang Culture,
Luotuodun Site and its nearby regions had ever experienced a marine transgression event. Secondly, we have found 450 plant
fossils in this site, such as Polygonum sp., Scripus sp., Najas sp., Physalis sp., which indicated lacustrine or swamp environment. 相似文献
13.
Adriana García 《Journal of Paleolimnology》1999,21(3):307-323
Charophyte (Charales, green macroscopic algae) assemblages found in Quaternary shoreline sediments from Salina del Bebedero, Argentina, are described in detail, illustrated, and statistically analysed. Fossil gyrogonites, Late Pleistocene and Holocene in age, of Chara cf. hispida var. major (Hartman) Wood, Chara halina García, Chara hornemannii Wallmann, Chara bulbillifera (Donterberg) García, Lamprothamnium haesseliae Donterberg and Lamprothamnium succinctum (Braun ex Ascherson) Wood were identified. A comparison with extant charophyte species of similar ecological requirements allowed for an accurate systematical determination and provided useful data for complementary palaeoecological and palaeobiogeographical approaches. On this basis, a reconstruction of palaeo-salinities for the Salina del Bebedero lake, represented by eleven palaeo-beaches, is proposed. Also the associations of charophytes with the ostracods Cyprideis sp., Limnocythere sp., Pampacythere sp., Cypridopsis sp., Darwinula sp., Ilyocypris gibba (Randohr) Brady and Norman, and the foraminifers Ammonia sp., Elphidium gunteri Cole, Quinqueloculina sp., and one species of Discorbacea are analysed, since they are present in both the fossil and modern environments. 相似文献
14.
Yan Zhao Carl D. Sayer Hilary H. Birks Michael Hughes Sylvia M. Peglar 《Journal of Paleolimnology》2006,35(2):335-350
We have explored the contemporary spatial relationship between aquatic vegetation and surficial macrofossil and pollen remains
in a small, shallow, English lake. A detailed point-based (n = 87) underwater vegetation survey was undertaken in the middle of the plant-growing season in July 2000. Then following
plant die-back in November 2000, surface sediment samples (upper 1.5 cm) were collected from 30 of these plant survey points
and analysed for plant macro-remains (all 30 samples), and pollen (4 evenly spaced samples). All data were stored as separate
layers in a geographical information system and spatial relationships between the aquatic vegetation and plant remains were
explored. In contrast to pollen types, plant macrofossils were not evenly dispersed across all parts of the lake and, with
the exception of Chara oospores, higher concentrations of remains (particularly for Potamogeton) were found close to areas of source-plant dominance. The spatial pattern of macrophyte–macrofossil relationships revealed
that vegetative remains (particularly leaf fragments) were probably deposited at source, whereas seeds were recovered close
to the shore suggesting slightly wider dispersal. Overall, however, macro-remains best represented local ‘patch-scale’ vegetation
within 20–30 m of the core site. The macro-remains effectively recorded the dominant plants in the lake with 63% of samples
containing a combination of remains of Chara, Elodea, and Potamogeton. However, relationships between macrophytes and fossils were complex. Some species were significantly over-represented by
macrofossils (e.g., Chara spp., Nitella flexilis agg., and Zannichellia palustris), while others were either under-represented (e.g., Potamogeton spp.), or not represented at all (e.g., Lemna trisulca). Pollen represented macrophyte diversity poorly, but some taxa were found (e.g., Myriophyllum spicatum, Ceratophyllum demersum) that were not recorded by macro-remains. We conclude that macrofossil analysis may be very usefully employed to determine
the dominant taxa in past aquatic plant communities of shallow, productive lakes and that the addition of pollen analysis
provides further information on former species richness. 相似文献
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W. Roland Gehrels Simon W.G. Newman 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):97-106
Twenty-seven surface samples were collected from the Kjelst Enge salt marsh in Ho Bugt, Jutland, to investigate the potential use of salt-marsh foraminifera as sea-level indicators in Holocene intertidal deposits. Previous work from many coastlines around the world has shown that the vertical distribution of salt-marsh foraminifera is strongly controlled by the duration of tidal flooding (or height relative to tide level). Concentrations of foraminifera in Kjelst Enge salt marsh are low, especially in the high marsh, but a strong correlation was found between relative abundances of foraminiferal species and tidal elevation for 16 samples containing more than 30 specimens per 5 cc of sediment (r2 = 0.80, root mean square error = 0.16 m). Sediment pH also has a strong influence on the distribution of the foraminifera, but salinity appears to be insignificant. 相似文献
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南极乔治王岛菲尔德斯半岛半三角附近的火山沉积岩,首次发现孢粉、叶化石,显示出晚白垩世的组合面貌。它们表明菲尔德斯半岛存在两个时代不同的植物层,即晚白垩世半三角植物层及始新世化石山植物层;菲尔德斯半岛火山活动始自中生代后期,而不是以前认为的侏罗纪,也非第三纪早期。这也是南设得兰群岛首次发现的晚白垩世陆相古生物证据。 相似文献
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该文探讨河北阳原—蔚县盆地早更新世沉积的泥河湾组所含有孔虫化石是否与海侵有关等问题。通过对河北平原、阳原—蔚县盆地所在地的冀西北山地及北京西山在上新世一晚更新世的地质、构造、地貌等调查、研究与分析,认为阳原—蔚县盆地早更新世时并没有发生海侵,有孔虫来源与海侵无关,属于内陆湖泊非海相有孔虫。 相似文献
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Ramadan H. Abu-Zied Kevin Keatings Roger J. Flower Melanie J. Leng 《Journal of Paleolimnology》2011,45(2):167-182
We studied the sedimentology, benthic foraminifera, molluscs, and δ18O and δ13C of Ammonia tepida tests in two late Holocene sediment cores from Lake Qarun (Egypt). The cores, QARU2 (upper section, 8.2 m) and QARU4 (1.4 m),
span approximately the past 500 years of sedimentation. Benthic foraminifera first appeared in the upper part of QARU2 at
314 cm depth, ca. AD 1550. This depth marks the beginning of colonization of the lake by foraminifera and indicates a change in lake water
salinity, as foraminifera cannot tolerate fresh water. Initially, three species of benthic foraminifera colonized the lake,
Ammonia tepida, Cribroelphidium excavatum and Cribrononion incertum. Relative abundance of these species fluctuated throughout cores QARU2 and QARU4 and highest overall faunal diversity occurred
at the beginning of the twentieth century. High relative abundances of C. incertum and deformed tests are attributed to periods of greater lakewater salinity. Peaks in both δ18O and δ13C indicate times of higher evaporation and reduced fresh water inflow. Inferred salinity was high around AD 1700 and after
AD 1990. Rapid response of climate proxy variables indicates the high sensitivity of Lake Qarun to environmental changes over
the past several 100 years. Increases in lakewater Mg concentration during past evaporative events, associated with less fresh
water inflow, probably provided conditions suitable for C. incertum to build its white or transparent tests. Gradual decrease of C. incertum, until its disappearance at 100 cm depth ca. AD 1890, indicates a more persistent trend in lake water chemistry. Higher concentrations of dissolved sulphates were the
likely cause of this species disappearance. Recent, twentieth-century sediments were deposited under optimal salinity (37‰)
for benthic fauna, but further environmental changes are indicated by the decrease or disappearance of several benthic foraminifera
and mollusc species. Intermittent hypoxia in the lake’s bottom waters, caused by cultural eutrophication, may account for
these most recent changes. 相似文献