Early Carboniferous Radiolarian Fauna from Heiyingshan South of the Tianshan Mountains and Its Geotectonic Significance

Abundant and well-preserved fossil radiolarians found from the Artencasher Formation, Heiyingshan of Baicheng County, Xinjiang Uygur Autonomous Region, are identified, including 15 species and 2 unnamed species in 9 genera. The fauna is dominated by the Family Entactiniidae of Spumellaria. According to the faunal characteristics, the radiolarians may be divided into five assemblages, namely, the Triaenosphaera sicarius, Entatinosphaera palimbola, Entactinia vulgaris, Belowea cf. variabilis and Archocyrtium sp assemblages. The fauna may be correlated with that from the Early Carboniferous of Frankenwald and Rein in Germany. Thus, ophiolite was formed in the Carboniferous, while the age of collision between the ***Ili plate and the Tarim plate is Early Carboniferous.

Permo-Carboniferous Radiolarians from the Wupata'erkan Group,Western South Tianshan, Xinjiang, China

The Wupata'erkan Group, also called Wupata'erkan Formation, distributed in the South Tianshan, Xinjiang, China, mainly consists of gray and dark gray fine-grained clastic rocks, interlayered with volcanic rocks, carbonates and cherts. Some ultra-basic rocks (blocks) punctuate the formation. The formation was variously assigned to Silurian-Middle Devonian, Silurian-Lower Devonian, and pre-Devonian, mainly based on Atrypa bodini Mansuy, Hypothyridina parallelepipedia (Brour.) and Prismatophyllum hexagonum Yoh collected from the limestone interlayers, respectively. However, radiolarian fossils obtained from 24 chert specimens of the Wupata'erkan Group, mainly include Albaillella sp. cf. A. undulata Deflandre, Albaillella sp. cf. A. paradoxa Deflandre, Albaillella cf. A. deflandrei Gourmelon, Albaillella sp. cf. A. indensis Won, Albaillella sp. cf. A. excelsa Ishiga, Kito and Imoto, Albaillella sp. and Latentifistulidae gen. et. sp. indet., are earliest Carboniferous and Late Permian. The earliest Carboniferous assemblage is characterized by Albaillella sp. cf. A. undulata Deflandre, Albaillella sp. cf. A. paradoxa Deflandre, Albaillella cf. A. deflandrei Gourmelon and Albaillella sp. cf. A. indensis Won, and the Late Permian assemblage by Albaillella sp. cf. A. excelsa Ishiga, Kito and Imoto. This new stratigraphic evidence indicates that the Wupata'erkan Group is possibly composed of rocks with different ages from Silurian to Permian, and therefore, it is probably an ophiolite melange. The discovery of Late Permian Albaillella sp. cf. A. excelsa provides more reliable evidence supporting the existence of a Permian relic ancient oceanic basin in the western part of Xinjiang South Tianshan.

Uppermost Permian Radiolaria from Southwestern China

The uppermost Permian radiolarian fauna of Southwestern China described here includes 11 genera and 17 species, of which 2 species are new. Preliminary geochemistry research indicates that the sediments yielding the fauna are with anoxic feature. This study contributes to a better understanding on the evolution of Permian radiolarias and the cause of end Permian radiolarian extinction.

Discovery of Radiolaria from the Zongzhuo Formation in Tianba,Kangmar,Tibet and its Age Implication

There is a group of variegated marine deposits, including the red beds widespread in the area of Tianba, Kangmar, southern Tibet, which previous works have contributed to Cretaceous Zongzhuo Formation by lithologic associations only, but with poor fossil evidence. Due to the absence of age dating fossils, the red bed age is obscure. Abundant Cretaceous radiolaria were discovered from the Zongzhuo Formation in the present study. In spite of the poor general preservation of some radiolarian specimens as recrystallized quartz infillings, 58 species from 46 genera of radiolaria, extracted from chert and silicous limestone of the Zongzhuo Formation in Kangmar, were identified on the basis of their shape and ornamentation. Based on the radiolaria, the age of the Zongzhuo Formation of this area has been referred to as Late Cretaceous. The new radiolarian data from the Zongzhuo Formation of Tianba area provide a local basis to correlate these deposits with other regions of the Tethyan Himalaya.

Permian and Triassic Radiolarian Biostratigraphy in South and Southwest China

The study of Permian radiolarias in South and Southwest China has been advanced in recent years . A well-preserved radiolarian fauna of Triassic is recently found in Southwest China . Eight radiolarian assemblage zones are recognized as follows in ascending order: Pseudoalbaillella rhombothoracata assemblage zone (Qixian ), Pseudoalbaillella fusiformis assemblage zone (early-middle Maokouan ), Follicucullus assemblage zone (late Maokouan-Wujiapingian ), Cangyuanella assemblage zone (early-middle Changxingian ), Clavata assemblage zone (latest Permian), Triassocampe yini assemblage zone (early Early Triassic ), Pseudoeucyrtis liui assemblage zone (late Early Triassic )and Triassocampe dew even assemblage zone (Middle Triassic ). The Permo -Triassic boundary in chert mono -facial sequence of the Muyinhe Formation is discussed .

OCEANIC DEPOSITS IN THE YARLUNG—TSANGPO SUTURE ZONE: STRUCTURAL SETTING, RADIOLARIAN AGES AND THEIR TECTONIC IMPLICATIONS

The Yarlung—Tsangpo Suture Zone, the youngest in Tibet, marks a site of collision of the Eurasia continent and Indian subcontinent. It is characterised by a discontinuous line of ophiolitic bodies in southern Tibet and beyond. Fragments of Tethyan oceanic pelagic and hemipelagic deposits are distributed along the suture. These oceanic deposits occur in two distinctive tectonic settings: (1) above the ophiolite and (2) in fragments of an accretionary wedge that lies to the south of the ophiolite.Supra\|ophiolite sequences, examined at several localities, are mostly made up of chert and siliceous mudstones and display varied lithostratigraphy. Sections are thin, have different degrees of completeness and are truncated at their tops. Most of them are in undisturbed stratigraphic contact with underlying pillow lava or pillow breccia. Previously the cherts above the ophiolite in this area were dated as late Albian\|possibly early Cenomanian (Marcoux et al., 1982) or early Cenomanian (Wu, 1986). Our investigation reveals Aptian radiolarian fossils in the cherts and siliceous mudstones. The oldest radiolarians, late Barremian, occur in chert at the base of the Qunrang section. This allows reassessment of the timing of eruption of Xigaze ophiolite basalts to during, or before, the late Barremian—early Aptian.

YAMDROK MELANGE,SOUTH TIBET

Yamdrok melange occurs south of, and parallel to, the Yarlung—Zangbo ophiolites, extending several hundreds of kilometres with a width of several to tens of kilometres. Areas near Baisa and Rilang in the Gyangze district were chosen for detailed investigation in this study. Three months of field mapping (1∶1000 and 1∶50000) has been followed by laboratory investigation to extract radiolarians from cherty blocks and matrix material. Laboratory work is continuing..Field investigations in the Baisa area near Gyangze indicate the presence of three melange facies:broken formation, matrix\|rich facies, and block\|in\|matrix melange. Broken formation is characterized by disruption of layering by means of boudinage and pinching\|and\|swelling and dispersal of blocks within the finer\|grained shales due to layer\|parallel extension. Broken formation occurs mostly as dispersed but more\|or\|less traceable lenses within a foliated matrix. A transition from broken formation to typical block\|in\|matrix melange is observed in the field. Further disruption of broken formation leads to the formation of typical block\|in\|matrix melange either, by later shearing, or by suspected mud diapirism. Matrix\|rich facies is characterized by a dominance of shale matrix containing small granules of sandstone and other lithologies. This facies commonly is subject to later deformation, with disruption of the primary foliation into sigmoidal structures. Block\|in\|matrix facies is the most common melange facies and is characterized by blocks of different sizes, shapes and lithologies either encased in, or floating on, relatively finer\|grained arenaceous\|argillaceous matrix. Blocks range in size from several centimeters to several hundreds of meters, and have various shapes from phacoidal, elongate, to irregular. The blocks are mainly composed of varicolored cherts, greywacke and limestone as well as igneous rocks including serpentinite and basalt breccia. The matrix is mainly composed of dark argillaceous shales and siliceous shales, and partly of yellowish green greywacke. The injection or intrusion of mud matrix into blocks is quite common in this melange facies.

Late Olenekian Radiolarians from Bedded Chert of Ashio Terrane, Northeast Japan, and Faunal Turnovers in Western Panthalassa during Early Triassic

Late Olenekian assemblages in the western Panthalassa have been recovered from bedded radiolarian chert sequences of an accretionary complex, the Ashio belt. These faunas are documented and considered in terms of radiolarian diversity and faunal turnover during the latest Permian to Middle Triassic time. The fauna includes 30 radiolarians belonging to Spumellaria or Entactinaria, with two relicts from the Late Permian. This late Olenekian fauna is markedly different from Permian and Anisian faunas, respectively, and is herein named the Minowa fauna. Study of the literature indicates that radiolarian provinces were significantly disconnected between the western Panthalassa and eastern Tethys during late Olenekian time. Furthermore, 121 of 143 species disappeared during late Olenekian time, and in turn 118 new species appeared in the western Panthalassa around the Olenekian Anisian boundary. It is concluded that faunal turnover occurred at least three times between the latest Permian and Middle Triassic. The first turnover is the Paleozoic type radiolarian extinction at the Permian Triassic boundary, the second is the diversification of spheroidal Spumellaria and Entactinaria between early and late Olenekian time, and the third is a faunal turnover from the Minowa fauna to the true Mesozoic type radiolarian faunas that are characterized by multi segmented Nassellaria.

Discovery of Radiolaria from the Zongzhuo Formation in Tianba,Kangmar and Its Age Implication

There is a group of variegated marine deposits including red beds widespread in the area of Tianba, Kangmar,southern Tibet.Previous works grouped the red beds into Cretaceous Zongzhuo Formation simply by lithologic associations but with poor fossil evidence.Due to the absence of age dating fossils,the age of the red bed has been obscure.Abundant Cretaceous radiolaria were discovered by the present author firstly from the Zongzhuo Formation.In spite of the poor general preservation of some radiolarian specimens as recrystallized quartz infillings,fifty eight species from forty six genera of radiolaria,

THE MONSOON IN THE ARABIAN SEA:IMPLICATIONS FROM RADIOLARIAN FLUXES TO THE DEEP SEA

Evolution of Monsoon climate can be attributed to high altitude topography of the Himalaya—Tibetan Plateau. It is important to decipher the modern Monsoon processes in the Indian Ocean so that we will have a better understanding of global evolution of paleoclimate. An international collaborative effort has been expended since 1986 to collect marine particle fluxes in the Arabian Sea where significant amount of organic carbon is fixed annually. Such high biological productivity is mainly due to monsoonal upwelling that occurs twice a year in the region. The southwest (SW) Monsoon occurs in June to September and the northeastern (NE) Monsoon occurs in November to February with a varying degree depending on the regions. PARFLUX sediment traps were deployed in the bathypelagic zone (2800～3000m) at three locations (Western[16°20′N, 60°30′E], Central[14°31′N, 64°46′E], and Eastern[15°31′N, 68 43′E] Stations) representing different patterns and degrees of the Arabian Sea particle fluxes.

Uneven Distribution of Pseudotormentus De Wever et Caridroit(Radiolaria,Protozoa):Provincialism of a Permian Planktonic Microorganism

The Permian planktonic distribution is not well known,in contrast to other fossil distributions of nekton and benthos.Radiolaria are representative microfossils of plankton in the Permian palaeocean.This study compares both correlated radiolarian occurrences（Pseudotormentus De Wever et Caridroit and Quadriremis Nazarov et Ormiston） in literature data from the Pacific Rim and quantitative data from the Liuhuang and Gujingling sections in South China.Pseudotormentus distributions are concentrated in the Panthalassa,whereas Quadriremis occurrences are distributed over both the Panthalassa and the Palaeotethys.The uneven distribution of Pseudotormentus seems to have been controlled by a difference in the oceanic basins,indicating the presence of faunal differences in Permian planktonic microorganisms between the Panthalassa and the Palaeotethys.In other words,this study infers the provincialism of Permian planktonic microorganisms.The uneven distribution is explainable by a hypothesis that Pseudotormentus was strongly affected by a Panthalassan equatorial current.

Integrated Radiolarian and Conodont Biostratigraphy of the Middle to Late Permian Linghao Formation in Northwestern Guangxi, South China

The Permian radiolarian zones and their correlations with conodont zones or other chronostratigraphic schemes are still under debate. In this study, four genera, 21 species and two subspecies of radiolarians together with one genus and six species of conodonts were recovered from the Linghao Formation cropping out at the Longwangpo(LWP) section, northwestern Guangxi, South China. Six radiolarian interval zones and one abundance zone are recognized in the section, namely in ascending order, the Follicucullus scholasticus, Albaillella cavitata, A. protolevis, A. levis, A. excelsa, A. triangularis Interval zones and A. yaoi Abundance Zone. They are correlated with the Clarkina dukouensis, C. guangyuanensis and C. orientalis conodont zones recognized at the same section. Based on our data, the F. scholasticus Interval Zone and the lowermost part of A. cavitata Interval Zone are recognized to be upper Capitanian age, whereas the four Albaillella Interval zones are of Lopingian age(Wuchiapingian to the late Changhsingian). Two previously known Changhsingian radiolarian zones, namely the A. triangularis and A. yaoi Interval zones, should be extended down to the uppermost Wuchiapingian in this studied section.

New Evidence for Eastward Extension of Late Hercynian－Early Indosinian Qinling Sea

The problem of the eastward extension of Qinling sea of Late Hercynian -Early Indosinian has always been in suspension. The present paper makes an assumption that the Qinling rock-group should be a tectonic complex consisting of complicated structural slices of different ages according to the new discovery of radiolarias and other faunas in the Yanlinggou rock-formation in the area around eastern Qinling-Toughai Mountains. The discovery of the Early Triassic radiolarias in Tongbai Mountain and the analysis of the paleogeography of the Yangtze and North China plate margins indicate the existence of eastern Qinling-Tongbai-Dabie sea of Late Hercynian-Early Indosinian, which is considered to be the eastward extension of the western Qinling rift trough. The rift trough was closed by the convergent collision between the Yangtze and North China plates in Middle to Late Triassic.

A new radiolarian species Clathrocorys gracilis from northern South China Sea

A new species, Clathrocorys gracilis nov. spec., of Tripocyrtidae (Radiolarians: Nassellaria) from surface water in northern South China Sea, is described in this paper. The new species has four radial beams arising from the cephalic base centre, each foot with cup-shaped structure and ramified bar in the proximal section (near cephalic base), and each wing with a large mesh in the middle, a medium mesh and a small mesh on each side respectively.

Study of Radiolaria in the surface sediments from the area east of Taiwan Island

The species and characteristics of Radiolaria in the surface sediments were systematcally investigated in the sea east of Taiwan Island. One hundred and seventy-eight species of Radiolaria (including 21 unidentified species) have been identified in the surface sediments, and they belong to 2 orders, 34 families and 101 genera. Among them there are 19 families, 70 genera, 134 species of Spumellaria and 15 families, 31 genera, 44 species of Nassellaria. Of the 178 species of Radiolaria, the individual number of Spumellaria amounts to 88.1 % of the total individual number, and that of Nassellaria amounts to 11.9% of the total individual number. It is shown that most of the dominant species belong to the tropical and subtropical dominant species and are brought into the area mainly by the Kuroshio, and some affecting factors including the submarine topography, submarine sediments, upwelling current east of Taiwan Island and carbonate dissolution play a secondary role in forming the Radiolaria distributions.

Pleistocene Radiolaria from Leg 119 Site 738B (Sections 1H1-1H2): Systematics and Biostratigraphy

This paper presents a record of radiolarian species from the sections (1H1-1H2) Leg 119 Site 738B of Southern Ocean region. Well diversified taxa of typical Antarctic assemblage are present in the sections. Thirty species were identified and illustrated from twenty-nine samples. On the basis of appearance, disappearance and abundance of taxa, viz. Omega and Psi zones are established and systematics of stratigraphically important species is described. These zones are equivalent to NR1 and NR2 of Upper Quaternary.

Radiolaria fossils in the surface sediments and sedimentary environment in the Bering Sea

Totally 2472 grains of Radiolaria belonging to 36 Genera and 45 species are distinguished from 12 surface sediments in the Bering Sea. The distribution characteristics of Radiolaria fossils in the surface sediments are as follows: (1) From the shelf of shallow water to the upper of continental slope, there are a few Radiolaria fossils and monotonous genus and species; (2) In the lower of continental slope, Radiolaria fossils are poor in the volcanic cinders and turbidite; (3) The abundance and diversity of Radiolaria fossils are high in clay of the basin. The dominant species of Radiolaria is Spongotrochus glacialis on the continental shelf. Current, topography, water depth, and temperature etc. are key factors influencing Radiolaria distribution. The sources of sediments mainly are terrigenous, biogenic and volcanic sediments in the survey area and they are mostly from the Kamchatka peninsula in the east of Russia and the Aleutian Islands.

Radiolarian and Planktic Foraminifera Biostratigraphy of the Early Albian Organic Rich Beds of Fahdene Formation,Northern Tunisia

The lower part of Fahdene Formation outcropping in northeastern Tunisia is repre- sented by pelagic sequences and characterized by an important siliciclastic fraction that includes ra- diolarian and organic-rich beds of Allam Member. Litho-biostratigraphic analysis based on planktic foraminifera and radiolaria shows that deposition of organic-rich beds of Allam Member is confined to the Microhedbergella rischi Zone through the lower part of Ticinella primula Zone. Age diagnostic radiolaria recovered from these beds has been identified to constrain a direct age of black shale depo- sition. The assemblages can be correlated with the radiolarian biochronozone U.A.10-11 indicating an Early Albian to early Middle Albian in age. Radiolarian assemblages composed of species characteris- tic of U.A.10 biochronozone （A. montisserei, D. gracilis） are associated with radiolarian taxa belonging to Costata Zone （U.A.9 Pseudoeucyrtis hanni and Thanarla pseudodecora）, which can be correlated with Dercourt Member in the Ionian Zone and Paquier level of the Vocontian Basin （southeast of France）. Biostratigraphic and abundance curves analysis has demonstrated significant diversification of cryptocephalic Nassellaria and Archaeodictyomitrae, probably adapted to eutrophic conditions that characterized the Aptian-Albian transition. Ecological conditions may have governed the stratigraphic range of many cosmopolitan taxa （i.e., Pseudodictyomitrae lodogaensis） compared with stratigraphic distributions schemes reported from other domains. The timing of black shales deposition was dia- chronic due to local geodynamic conditions and upwelling currents distribution. The Allam black shales are correlative with the oceanic anoxic event OAElb which is characterized by the widespread of supraregionnally organic-rich beds in the Mediterranean Tethys basins across the Aptian-Albian transition.

Radiolarian fauna from the Chiungchussuan Shuijingtuo Formation(Cambrian Series 2) in Western Hubei Province, South China

Little is known regarding characteristics and evolution of radiolarian fossils in the early Cambrian due to its rarity and poor preservation. Here we report a new radiolarian fauna from the Cambrian Shuijingtuo Formation corresponding to the Chiungchussuan Stage(Cambrian Series 2) in western Hubei, China. It contains over 300 radiolarian tests and these fossils belong to 4 morphotypes, including Paraantygopora porosa gen.et sp. nov., Braunosphaera sinensis gen.et sp. nov., Tetrasphaera? sp. and incertae spherical radiolarians. In taxonomy, Spumellaria predominates in the fauna and comprises 92% of the total. In shell structure, about 73% of all specimens are similar to the early Ordovician radiolarian fossils, with the shell walls characterized by perforated plate structures. The spherical radiolarians with latticed shells constitute another feature of the early Cambrian radiolarian fauna. The radiolarian fauna reported here contains many fossil specimens and covers different taxonomical taxa. These specimens usually consist of distinctive concentric multi-layers with complex structure. These characteristics indicate that Radiolaria had already thrived during the Cambrian Chiungchussuan Stage(Series 2, Stage 3), which may have occurred synchronously with the explosion and prosperity of macrobiota recorded in the strata deposited in shallower water condition.

A New Early Devonian Radiolarian Genus From Western Yunnan

A new radiolarian genus, Eoalbaillella belonging to Albaillellidae Deflandre emend. Holdsworth, is proposed from the Early Devonian in Western Yunnan, Southwestern China. Its test is composed of an imperforate lamellar shell and an elongate triangular framework, of which the upper part is enclosed by the lamellar shell and the lower part, without the shell, has the shape of the letter X. The relations between new genus and other radiolarian genera are studied and the type species of the genus is described.