贵州台江早、中寒武世凯里组的疑源类*

产凯里生物群的台江八郎剖面凯里组疑源类组合包含 18形态属 ,2 0形态种和 11未定种 ,疑源类化石以无明显附属突起的球形亚类和翼环亚类最多 ,网面和棘剌亚类次之 ,而梭形亚类和对弧亚类很少。具有明显装饰的疑源类类型Micrhystridium ,Retisphaeridium ,Goniophaeridium仅在第 9层、第 2 1— 2 4层出现。在与国内外同期疑源类对比的基础上 ,对下、中寒武统界线进行了划分 ,划分的界线与三叶虫划分的界线位置大体一致 ,并根据疑源类组合特征 ,对沉积环境进行探讨。     

中国贵州东部乌溜-曾家崖剖面早—中寒武世凯里组疑源类(英文)

我国贵州东部乌溜-曾家崖凯里组剖面作为世界早-中寒武世界线层型侯选剖面,产出良好保存的大型无脊椎动物化石(尤其是三叶虫)。因此,更加详细研究该剖面海洋疑源类的生物地层非常重要,将提供围绕界线的生物和环境变化的细微记录。乌溜-曾家崖剖面凯里组的疑源类划分两个组合,它们是凯里组0-52m的Leiomarginata si mplex-Fi mbriaglomerella membranacea组合和52-140m的Cristallinium cambriense-Heliosphaeridiumnodosum-Globosphaeridiumcerinum组合。140-214m仅有很少疑源类标本,可能因为凯里组上部以白云岩为主,不适宜有机壁微体化石的保存。距凯里组底部往上约52m处疑源类组合出现重大变化,无疑为解释沉积环境提供重要资料。两疑源类组合间界线,位于52.3-52.7m,此稍低于被三叶虫Oryctocephalusindicus首现所指示的全球寒武系第5阶潜在层型剖面界线。     

贵州台江凯里动物群中的棘皮动物

早、中寒武世的棘皮动物化石在我国尚属首次报道，贵州台江凯里组中部（中寒武统）的棘皮动物包括海百合亚门（Ｃｒｉｎｏｚｏａ）始海百合纲的１新科、３新属、７新种和海扁果亚门（Ｈｏｍａｌｏｚｏａ）海箭纲的１个未定属种。这些化石个体较小，茎、萼、腕比较发育，萼板较少，缝孔一般发育，普遍具有小瘤突（ｅｐｉｓｐｉｒｅｓ），未见固着器，与北美及东欧波希米亚地区下、中寒武统始海百合纲化石组合特征有明显的差异。     

贵州台江早、中寒武世凯里组的腕足动物

描述贵州台江下、中寒武统凯里组的腕足动物化石６属１０种，其中包括１新种，２比较种和２未定种。该腕足动物组合带有波希米亚及哈萨克斯坦的色彩，对于我国寒武纪腕足动物的分类、演化、古生物地理研究及查清凯里动物群的组成、凯里组的时代，均有重要的意义。     

河北完县中、晚寒武世无铰纲腕足类

研究了河北完县清醒剖面中寒武统张夏组至上寒武统凤山组酸解法所获得的无铰纲腕足类化石5500多件,详细描述了乳孔贝科2新属、16新种、3未定种,圆货贝科1新属、2新种.自张夏组至凤山组建立了8个无铰纲腕足类化石组合.对乳孔贝亚科的幼壳形态进行了分类,并研究幼壳的演化趋向.     

贵州台江八郎下,中寒武统界线及三叶虫动物群

详细记述了贵州台江八郎下、中寒武统界线剖面及所含三叶虫动物群,提出了在过渡区划分下、中寒武统界线新定义：即从三叶虫Ｌａｎｃａｓｔｒｉａ向Ｏｒｙｃｔｏｃｅｐｈａｌｕｓ（或Ｏｒｙｃｔｏｃｅｐｈａｌｉｎａ）的连续演化系列中,以Ｏｒｙｃｔｏｃｅｐｈａｌｕｓ（或Ｏｒｙｃｔｏｃｅｐｈａｌｉｎａ）的首次出现作为中寒武纪的开始。在描述的２８属（亚属）３６种（未定种）三叶虫中,共有７新属（亚属）１７新种。     

贵州早、中寒武世斗篷海绵科(Choiidae)的发现

本文描述了贵州遵义下寒武统牛蹄塘组生物群和台江中寒武世凯里生物群中保存完整的斗篷海绵科(Choiidae)中斗篷海绵(Choia)和小斗篷海绵(Choiaella)化石标本,共计2属2种2未定种：Choia zunyiensis sp.nov.,Choia sp.,Choiaella avata sp.nov.和Choiaella sp.。Choia分布很广．在我国下寒武统澄江生物群及北美中寒武统的四大生物群中均有产出。Choiaella原仅产于我国澄江生物群,凯里生物群中Choiaella的发现使其时代上延至中寒武世。贵州早、中寒武世斗篷海绵科的发现及研究为海绵动物的早期演化及古地理学等方面的研究提供了重要的新材料。     

宜昌峡东地区埃迪卡拉系陡山沱组疑源类化石新材料及其生物地层学意义

在湖北宜昌秭归青林口剖面埃迪卡拉系陡山沱组二段燧石结核中发现大量微体化石,其中包括大型带刺疑源类8属9种(含1个未定种):Appendisphaera?hemisphaerica,A.magnifica,Dicrospinasphaera zhangii,Eotylotopalla dactylos,Mengeosphaera chadianensis,Taedigerasphaera lappacea,Tanariumsp.,Tianzhushania spinosa,以及Variomargosphaeridium lithoschum。同时在宜昌秭归金瓜墩剖面陡山沱组二段发现一些新的具刺疑源类化石材料,结合过去的报道,总结该剖面陡山沱组二段的疑源类化石组成:共7属9种(含3个未定种和1个相似种),及1个不定种,包括Appendisphaera magnifica,Appendisphaera sp.,Dicrospinasphaera zhangii,Knollisphaeridiumsp.,Mengeosphaera chadianensis,Mengeosphaera sp.indet.,Tianzhushania spinosa,Variomargosphaeridium lithoschum,Weissiella cf.brevis,以及Weissiella sp.。在宜昌三斗坪九龙湾剖面陡山沱组二段发现具刺疑源类Variomargosphaeridium lithoschum。这些化石材料丰富了对峡东地区陡山沱组二段具刺疑源类化石组成的认识,表明峡东地区陡山沱组具刺疑源类下组合与上组合在化石组成上的差别或许小于过去的认识。     

黔南三都Etagraptus approximatus笔石带的疑源类化石

本文描述黔南三都ＥＷｔａｇｒａｐｔｕｓ ａｐｐｒｏｘｉｍａｔｕｓ笔石带中的疑源类化石２３属３８种,包括１新种及２未定神。这为建立阿化克期早期笔石带中的疑源类组合,提高疑源类在地层划分对比中的精度提供了依据。     

华北板块南部寒武系底部辛集组遗迹化石及其时代意义

首次详细描述了河南省石门沟、阳坡和山西省水峪等3条剖面寒武系底部辛集组中的遗迹化石。遗迹化石主要产出于辛集组的近底部层位,以水平管状遗迹化石为主,共计8遗迹属,12遗迹种(含3个未定种),包括Arenicolites sp.,Didymaulichnus lyelli,Gordia marina,Helminthopsis abeli,Helminthopsis sp.,Palaeophycus striatus,Palaeophycus tubularis,Phycodes sp.,Planolites beverleyensis,Planolites montanus,Treptichnus pedum与Treptichnus pollardi,此外还有2枚属种未定的遗迹化石。这一遗迹化石组合属非典型的Cruziana遗迹相,形成于盐度正常的潮下带砂质软底环境。通过对寒武纪早期管状遗迹化石Palaeophycus与Planolites直径大小的统计与分析,推测辛集组下部地层的时代不早于沧浪铺期。     

Organic-walled microfossils from Cambrian Stage IV in the Jiaobang section,eastern Guizhou,China

The lower Cambrian succession in the Jiaobang section, Jianhe County, eastern Guizhou, China, includes, in ascending order, the Bianmachong, Balang, and Tsinghsutung formations, with a total thickness of about 645 m. Twenty-six morphological genera (including one new genus) are identified from the Balang and the underlying Bianmachong formations, many of which are common and widely distributed. Six acritarch assemblages are discerned in the Balang Formation. They are, in ascending order, the Adara alea‒Skiagia ornata, the Acrum radiale‒Pterospermella velata, the Comasphaeridium molliculum‒Solisphaeridium baltoscandium, the Corrugasphaera perfecta n. sp.‒Pterospermella vinctusa n. sp., the Acrum novum‒Heliosphaeridium oligum, and the Acrum membranosum‒Adarve diafanum acritarch assemblages. An obvious change of organic-walled microfossil assemblages occurred in the interval between 84 m and 98 m from the bottom of the Balang Formation which roughly corresponds to the boundary between the Oryctacarella duyunensis trilobite Zone and the overlying Arthricocephalus chauveaui trilobite Zone. In addition, organic-walled microfossils are scarce in about 24 m thick from the bottom of the Balang Formation. One new genus and five new species including Plagasphaera balangensis n. gen. n. sp., Asteridium tubulus n. sp., Cymatiosphaera spina n. sp., Corrugasphaera perfecta n. sp., and Pterospermella vinctusa n. sp. are described.     

BASAL CAMBRIAN MICROFOSSILS FROM THE YURTUS AND XISHANBLAQ FORMATIONS (TARIM, NORTH-WEST CHINA): SYSTEMATIC REVISION AND BIOSTRATIGRAPHIC CORRELATION OF MICRHYSTRIDIUM-LIKE ACRITARCHS

Abstract:  Micrhystridium -like acritarchs are widely distributed in basal Cambrian cherts and phosphorites in South China. This paper describes similar acritarchs from the basal Cambrian Yurtus and Xishanblaq formations in Tarim, north-west China. The taxonomy of these acritarchs is revised. The basal Cambrian acritarch assemblage in Tarim and South China is characterized by three genera: Asteridium Moczydłowska, Heliosphaeridium Moczydłowska and Comasphaeridium Staplin, Jansonius and Pocock. This assemblage is named the Asteridium - Heliosphaeridium - Comasphaeridium (AHC) acritarch assemblage. In both South China and Tarim, the AHC acritarch assemblage is associated with the tubular microfossil Megathrix longus Yin L. and the small shelly fossil Kaiyangites novilis Qian and Yin G. This assemblage also occurs in the Lower Tal Formation in the Lesser Himalaya. Correlation with small shelly fossil (SSF) assemblages indicates that the AHC assemblage is restricted to the Meishucunian Stage, and possibly to the lower Meishucunian ( Anabarites trisulcatus - Protohertzina anabarica and Siphogonuchites triangularis - Paragloborilus subglobosus SSF assemblages). The AHC assemblage is broadly similar to the Asteridium tornatum - Comasphaeridium velvetum (acritarch) Zone in the East European Platform, which is considered to be Nemakit-Daldynian (and possibly Tommotian) in age.     

贵州东部下寒武统杷榔组上部的三叶虫

贵州凯里市西北郊瓮岭塘寒武系都匀阶下部(下寒武统)杷榔组顶部和镇远县江古镇杷榔组上部的杷榔动物群,是新近发现的重要动物群。动物群由始海百合与莱德利基虫类三叶虫及多门类的化石组成,表明黔东早寒武世都匀期早期斜坡相生物的多样性。就属种而言,三叶虫类最为丰富,计有4属5种,1亚种和1未定种,包括莱得利基虫类的Redlichia(Pteroredlichia)chinensis,Redlichia(Pteroredlichia)chinensislui,Redlichia(Pteroredlichia)murakamii,耸棒头虫类Arthricocephaluschauveaui,Changaspisplacenta,Changaspismicropyge及褶颊虫类Probowmania(Probowmania)sp.。褶颊虫类Probowmania(Probowmania)的出现,丰富了黔东地区杷榔组上部三叶虫组合,层位明显下延。文章还报道Redlichia(Pteroredlichia)chinensis分节末期到成虫早期个体发育特征。     

湖北宜昌奥陶系庙坡组疑源类

湖北宜昌地区庙坡组是达瑞威尔阶/桑比阶界线附近的地层,该段地层产出分异度较高,丰度适中的疑源类组合。该组合包括16属,28种,其中7个未定命名种,可与国内、外同期疑源类组合进行对比。庙坡组疑源类组合既产出晚奥陶世特征分子,也产出阿伦尼格期(弗洛阶上部—达瑞威尔阶底部)的特征分子,显示出一定的过渡特色。组合以Baltisphaeridium(17%—52%),Leiosphaeridia(6%—78%)占优势;反映了其沉积环境为离岸较远的外陆棚环境。     

Palynomorphs from the Cambrian Series 3, Parahio valley (Spiti), Northwest Himalaya

We present low-diversity acritarch assemblages, including Alliumella baltica, Bavlinella faveolata, Brocholaminaria nigrita, Brocholaminaria sp., Eliasum sp., Leiosphaeridia minutissima, Leiosphaeridia spp., Lophosphaeridium sp., Pterospermella solida, Satka colonialica, Siphonophycus sp., and Synsphaeridium sp., as well as filamentous algae and cryptospore-like microfossils recorded from 45 rock samples around the Oryctocephalus indicus Zone (Cambrian Series 3) in the Cambrian Kunzam La (Parahio) Formation at the Kaltarbo locality in the Parahio valley, Northwest Himalaya. One new species Synsphaeridium parahioense was established. The acritarch assemblages at the basal part of the Cambrian Series 3 in the Kunzam La (Parahio) Formation were dependent on the local marine environment. The new discovery of cryptospore-like microfossils from the Cambrian Kunzam La (Parahio) Formation supports the extensive distribution of possible cryptospores in the Cambrian stratigraphic sequences.     

新疆哈密地区晚泥盆世疑源类化石的发现及地质意义

从新疆哈密地区石城子北剖面7件样品获得分异度较高、有机质壁显著炭化保存的疑源类化石,根据其形态特征,共鉴定出14个形态属和15个形态种(其中8个未定种,3个比较种)。结合国内外古生代晚泥盆世已知疑源类组合进行比较,清楚表明当前获得的疑源类组合代表了晚泥盆世海洋微体浮游植物群面貌。我国涉及晚古生代疑源类生物地层的调查研究相对薄弱,而有关晚泥盆世疑源类化石的发现和报道更为匮乏,当前疑源类化石的发现,填补和丰富了新疆乃至国内晚泥盆世疑源类化石研究资料。该发现佐证了关于卡拉麦里洋在早石炭世闭合的认识;作为基础食物链的海洋微体浮游植物是重要成烃生物,晚泥盆世疑源类的保存预示研究区域具有石油、天然气勘察的前景。     

中国湖北秭归县庙河村早寒武世天竺山段的硅化微体化石

描述了湖北秭归县庙河村寒武系最底部(天竺山段)硅化微体化石13属16种,并论述了其地层意义.所有微体化石皆见于燧石切片中,此组合含大量小个体的具刺凝源类,以Micrhystridium ampliatum Wang为主,并与Paracymatiosphaera spp.,其它球形分子Lelosphaeridia,Favososphaeridium,Eoaperturilites及丝状体Obruchevella 和Megathrix共生,此地真正的陡山沱组是以含大量的和形态复杂的疑源类及简单的丝状体和球状化石为特征,这两个可靠的微体化石组合的发现和区分对本区及邻区震旦系-寒武系过渡层的划分和地层对比有重要意义.     

Palynostratigraphy of Middle Cambrian to lowermost Ordovician stratal sequences in the High Zagros Mountains, southern Iran: Regional stratigraphic implications, and palaeobiogeographic significance

A palynological investigation of Cambro-Ordovician stratal sequences in the High Zagros Mountains of southern Iran permits the definition of a series of successive acritarch assemblage zones of chronostratigraphic significance, much improving the current knowledge of the Lower Palaeozoic stratigraphy of this important area for oil exploration. The five acritarch assemblage zones can be readily correlated with previously established palynostratigraphic schemes constrained by co-occurrence of independent age evidence, confirming the utility of organic-walled microfossils for the detailed biostratigraphic characterization of sedimentary units. The proposed biozonation will facilitate accurate dating of the southern Iranian Cambrian sequences during future drilling of deep test oil wells. Acritarch assemblage zone I (Middle Cambrian), occurs at the base of Member C of the Mila Formation; assemblages zone II (late Middle to earliest Late Cambrian) extends through the middle and upper part of the same lithostratigraphic unit; zone III (early Late Cambrian in age) characterizes the lower part of the Ilebeyk Formation; zone IV (middle Late Cambrian up to Cambrian/Ordovician transitional levels) occurs in the middle and upper part of the Ilebeyk Formation; finally, acritarch assemblage zone V ranges through the basal part of the Zardkuh Formation and proves an early Tremadocian age for the latter unit. The Mid-Late Cambrian acritarch associations show a marked Avalonian palaeobiogeographical affinity, also sharing a high proportion of taxa with typical Baltican and North Africa–Gondwanan assemblages; on the other hand, they are clearly different from known Laurentian (North America) fossil microphytoplankton suites. These results are in general agreement with current palaeogeographical models which place Avalonia, Baltica, and the North African part of Gondwana, all at relatively high southern palaeolatitudes, in contrast with the sub-equatorial position of Laurentia. However, the presence of many typical “Avalonian” taxa in the Iranian Mid-Late Cambrian assemblages would suggest a closer position of Iran to Avalonia than currently envisaged. The observed breakdown of acritarch biogeographic differentiation in earliest Ordovician times possibly represents a major disruption of oceanic current patterns and a lessened palaeolatitudinal thermal gradient.