Abstract A diverse, well-preserved radiolarian assemblage is reported from the Sandbian age Climacograptus bicornis Graptolite Biozone. This new assemblage, recovered from the Pingliang Formation in the Guanzhuang section, China, includes six new species along with 13 other previously described taxa. Geminusphaera new genus incorporates G . grandis n. sp. and G . kongtongensis n. sp. and is proposed for inaniguttids constructed from two distinct porous spheres bearing seven or more primary spines. Protopylentonema new genus is introduced to incorporate pylomate entactinarians with five-rayed initial spicules. It includes P . ordosensis n. sp. as well as P . aperta , P . rimata , and P . insueta that were formerly assigned to Kalimnasphaera . Micro-computed tomography investigation of skeletal microstructure supports establishment of the new genera together with other new spumellarian species: Haplotaeniatum implexa n. sp., Inanigutta quadrispinosa n. sp., and Kalimnasphaera pingliangensis n. sp. It also indicates that family-level reassignment of Etymalbaillella from the Proventocitidae to the Ceratoikiscidae is appropriate. Global distribution of Late Ordovician radiolarian occurrences highlights a strong preference for areas with equatorial to tropical sea surface temperatures. This must have led to ecological stress among radiolarian communities in adapting to global cooling in the Hirnantian. UUID: http://zoobank.org/3d3f55b8-0e70-4f9f-9738-265750d8ec3a .
The Bohemian Massif in the eastern Variscan Orogen is the host of globally significant ultrahigh-pressure metamorphic rock suites that experienced enigmatic unroofing processes. In the eastern Bohemian Massif, the Moravosilesian Culm Basin (The Czech Republic) with ≤ 7.5 km thick Lower Carboniferous siliciclastic turbidities has recorded crustal unroofing associated with the late Paleozoic amalgamation of Gondwana and Laurussia. This study presents data from sandstone petrography, heavy mineral assemblages, and detrital zircon U-Pb geochronology from Moravosilesian Culm sediments. Sandstone modal compositions imply continental/recycled orogen affinities. High-grade metamorphic lithic fragments and high garnet contents in upper Culm sediments indicate the exhumation of the middle to lower crustal materials, consistent with those of the Bohemian Massif. Detrital zircon U-Pb data constrain maximum depositional ages of sediments in the Drahany Upland to 335–326 Ma (late Viséan–middle Serpukhovian). Detrital, igneous and metamorphic zircon U-Pb data compiled from surrounding regions support that source regions for lower Culm sediments (Moldanubian Unit and Sudetes) remained the same. Whereas, upper Myslejovice sediments might have derived from exhumation and erosion of the root of the Moldanubian Unit and/or Moravosilesian Nappes. Rapid exhumation of the Moldanubian Unit within the Bohemian Massif during the deposition of upper Culm sediments is inferred.
Rugose and tabulate corals were recovered from two localities in the Anaiwan terrane. Fossils from locality A include Tryplasma sp. aff. T. columnare ETHERIDGE, 1907, Tabulophyllum sp., Heliolites sp., and unidentified favositids and syringoporoids, indicating an Emsian age. The only fossil collected from locality B was Thamnophyllum sp., giving a possible Lower to Middle Devonian age for this site. These are the first reported Lower to Middle Devonian fossils from the Anaiwan terrane and provide constraints on the timing of the development of its southern edge.
Radiolarians occur at five Leg 126 sites.Well-preserved radiolarians were recovered from Miocene and Pliocene through Holocene sections.The results of this study may help to fill the informational gap on Quaternary radiolarian distribution at mid-latitudes in the western Pacific.Radiolarian preservation is discontinuous, and, although present in Oligocene sections, specimens are poorly preserved.
Timing of the accretion of an intra‐oceanic island arc sequence (Gamilaroi Terrane) to the eastern margin of Gondwana is constrained by the appearance of Lachlan Fold Belt‐derived quartzarenite clasts in the marine clastic sequence which unconformably overlies the island arc sequence. The oldest formation containing quartzarenite clasts is the Late Devonian (Famennian) Keepit Conglomerate. As a consequence of this accretion event the Gamilaroi Terrane became contiguous with the continental margin of Gondwana. This finding indicates that docking occurred some 30 Ma earlier than the Visean‐Namurian event suggested by other researchers.
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