The Experts below are selected from a list of 6 Experts worldwide ranked by ideXlab platform

Jell, Peter A. - One of the best experts on this subject based on the ideXlab platform.

  • Carboniferous platyceratid gastropods from Western Australia and a possible alternative lifestyle adaptation
    2016
    Co-Authors: Cook, Alex G., Jell, Peter A.
    Abstract:

    Cook, A.G. & Jell, P.A., September 2015. Carboniferous platyceratid gastropods from Western Australia and a possible alternative lifestyle adaptation. Alcheringa 40, XX–XX. ISSN 0311-5518 Platyceratid gastropods, common and in many cases abundant as elements of middle Palaeozoic gastropod faunas worldwide, are rare or absent in Australian Devonian faunas. In Australia, the earliest abundant platyceratids occur in the Lower Carboniferous (Tournaisian) echinoderm-rich Septimus Limestone and Enga Sandstone in the Bonaparte Gulf Basin, Western Australia. Four taxa, each with significant morphological plasticity, are recognized. In Platyceras (Platyceras) tubulosus (de Koninck, 1883), three rows of long radially arranged spines and common pentameral symmetry of re-entrants on the aperture suggest an alternative possibility that a relationship between echinoderms and platyceratids developed, and that this may be with archaeocidaroids that are commonly preserved with the gastropods. Similarly in the singly spinose Platyceras (Platyceras) emmemmjae sp. nov., re-entrants suggest an echinoderm relationship. It is proposed that an echinoderm–Platyceras relationship possibly developed in Australia only after a suitable echinoid host had evolved allowing an alternative way for a gameto- or coprophagous habit to be exploited fully

Cook, Alex G. - One of the best experts on this subject based on the ideXlab platform.

  • Carboniferous platyceratid gastropods from Western Australia and a possible alternative lifestyle adaptation
    2016
    Co-Authors: Cook, Alex G., Jell, Peter A.
    Abstract:

    Cook, A.G. & Jell, P.A., September 2015. Carboniferous platyceratid gastropods from Western Australia and a possible alternative lifestyle adaptation. Alcheringa 40, XX–XX. ISSN 0311-5518 Platyceratid gastropods, common and in many cases abundant as elements of middle Palaeozoic gastropod faunas worldwide, are rare or absent in Australian Devonian faunas. In Australia, the earliest abundant platyceratids occur in the Lower Carboniferous (Tournaisian) echinoderm-rich Septimus Limestone and Enga Sandstone in the Bonaparte Gulf Basin, Western Australia. Four taxa, each with significant morphological plasticity, are recognized. In Platyceras (Platyceras) tubulosus (de Koninck, 1883), three rows of long radially arranged spines and common pentameral symmetry of re-entrants on the aperture suggest an alternative possibility that a relationship between echinoderms and platyceratids developed, and that this may be with archaeocidaroids that are commonly preserved with the gastropods. Similarly in the singly spinose Platyceras (Platyceras) emmemmjae sp. nov., re-entrants suggest an echinoderm relationship. It is proposed that an echinoderm–Platyceras relationship possibly developed in Australia only after a suitable echinoid host had evolved allowing an alternative way for a gameto- or coprophagous habit to be exploited fully

West Yunnan - One of the best experts on this subject based on the ideXlab platform.

  • HELMUT WOPFNER
    2016
    Co-Authors: West Yunnan
    Abstract:

    Abstract: Upper Palaeozoic glaciomarine deposits combined with the presence of cold-water faunas and Glossopteris indicate aGondwana provenance ofthe Baoshan and Tengchong Blocks in western Yunnan. The glacial origin of these Permo-Carboniferous deposits is verified by a three-fold subdivision of the basal sequence comprising, in ascending order: diamictites with faceted and striated clasts, laminites with dropstones, and a black anaerobic de-glaciation facies. The succeeding carbonates of the upper Permian and Lower Triassic originated during a post-glacial phase of a much warmer climate. Although the two blocks are adjacent to each other their Upper Palaeozoic sequences show significant differences. The glacigene successions of the Baoshan Block are comparatively thin and are overlain by thick basalts and red beds. On the Tengchong Block the glacigene marine deposits exceed 1000 m and are followed by thick reefal limestones of Lower Permian age. An active volcanic rift setting is suggested for the Baoshan Block and a proximal passive margin environment at a somewhat lower latitude for the Tengchong Block. The succession of the latter is comparable with Permo-Carboniferous sections in NW Australia, especially that of the Bonaparte Gulf Basin, and it is assigned to the Sibumasu tectono-stratigraphic unit. The Baoshan sequence shows similarities to sequences of Tibet and NE India and is therefore assigned to the Tibetan realm. Both terranes separated from Gondwana in the late Early Permian. Docking commenced in the Late Triassic concomitant with the closure of the Changning-Menglian Belt. Lateral displacements in the course of the Himalayan orogeny moved the Tengchong Block north, bringing it into juxtaposition with the western margin of the Baoshan Block. This tectonic ontact is now the Nujiang Line. In southwest China the east-west tectonic trends of the Himalaya turn sharply into a north-south direction. This direction is maintained essentiall