Porifera-microbialites of the Lower Liassic (Northern Calcareous ...

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6. Fossil Record of Sponges ................................................................................................................ 75 6.1. Preservation and Classification .............................................................................................. 75 6.2. Paleogeographical Extension ................................................................................................. 80 7. Comparison with other Spiculites ................................................................................................... 83 8. Geochemical Analyses ...................................................................................................................... 87 8.1. Stable Isotopes ....................................................................................................................... 87 8.2. Major and Trace Elements ..................................................................................................... 94 8.3. Biomarkers .............................................................................................................................. 97 9. Triassic-Jurassic Boundary Event ................................................................................................... 99 10. Conclusions ..................................................................................................................................... 101 References .............................................................................................................................................. 103 Plates 1-22 Supplements 1. Stable isotopes (δ 13 C, δ 18 O) 2. X-ray fluorescence (XRF) 3. Inductively coupled plasma mass spectrometry (Laser-/Liquid- ICP-MS) 4. Energy dispersive x-ray detection (EDX) 5. Biomarker analyses 6. Register of localities and samples Publications Acknowledgements Curriculum Vitae
Introduction 9 1. Introduction In Upper Rhaetian time, reef evolution culminated in highly diverse ecosystems that notably flourished along the northern shelf of the former Tethys ocean. Several of these buildups constructed by branching corals and coralline sponges (Demospongiae with secondary basal skeletons) are presently exposed in the Northern Calcareous Alps, where they are found both at the northern and southern margins of the Upper Triassic Carbonate Platform (Flügel and Kiessling 2002; Stanley 1988). Furthermore, the record of capping Lower Liassic sediments show that all of the reefs abruptly disappeared at the Triassic-Jurassic boundary, when one of the five most severe mass extinction occurred (Hallam 1990). The reasons for their sudden demise are still under discussion and less is known yet about its effects on subsequent Liassic benthic faunas. While it is postulated that faunal turnover took place also on land, the most severe extinction rates are known from the marine realm, where they affected mainly invertebrate groups like cephalopods, bivalves, brachiopods and corals (Hallam 1981; Benton 1991; Hallam and Wignall 1997). In contrast to the concurrent demise of Rhaetian buildups that served as “carbonate factories” less is known about the biodiversity in adjacent basins, where low sedimentation rates prevailed. Since sea-level changes are discussed as playing the most important role for the decease of many taxa, the fossil record of grey cherty deep water limestones suggests widely spread populations of siliceous sponges persisting through the Triassic-Jurassic boundary. As investigations by Mostler (1989a,b; 1990a,b) and Krainer and Mostler (1997) have shown so far, these sponge faunas were dominated by taxa of the Hexactinellida and non-lithistid Demospongiae. Further they have shown that the faunal composition in these settings was hardly effected by the Triassic-Jurassic extinction event and the total number of hexactinellid sponges continuously increased. Most of the skeletal remains belong to collapsed non-rigid species, and Mostler had to determine nearly all taxa by solitary spicules, especially by microscleres that were etched out of the limestones. Hence, the density of sponge settlement could only be estimated, growth forms are mostly unknown, and collected material could have been contaminated by dislocated spicules. In Liassic time, after the Rhaetian reefs drowned, the rise of the sea level apparently triggered a diversification of sponges mainly in the deep water realm south of the Upper Triassic Carbonate Platform. North of the platform, sponge faunas occur in distal settings as well (e.g. Krainer and Mostler 1997), but they are also known from Hettangian red limestones that onlapped the former reef slopes. There the abundance of sponge spicules indicates that environmental changes and the lack of competition by corals led to a radiation of sponges from deep water environments onto some of the drowned buildups. Böhm (1992) already assumed that Liassic sponge diversity in the alpine region was strongly influenced by the extant Triassic paleorelief.
Page 1 and 2: Porifera-microbialites of the Lower
Page 3 and 4: Abstract In the aftermath of the Tr
Page 5 and 6: Zusammenfassung Nach dem Aussterbee
Page 7: Content 1. Introduction ...........
Page 11 and 12: Geological Setting 11 2. Geological
Page 13 and 14: Geological Setting 13 Fig. 2. Locat
Page 15 and 16: Methods 15 3. Methods In the Rot-Gr
Page 17 and 18: Localities (Facies and Sponge Analy
Page 51: Localities (Facies and Sponge Analy
Page 54 and 55: 54 and ferromanganese crusts. The b
Page 56 and 57: 56 5.1.1. The Sponge Fauna of the S
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58 Skeleton: Lyssacinosid type with
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60 Fig. 29a. Skeleton types and ass
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62 new data from recent species to
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64 sheltered by the adjacent sand d
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66 In addition to the episodic sedi
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68 found in the most condensed sect
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70 5.2.1. The Sponge Fauna of the S
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72 5.2.2. Diagenesis Sponge-dominat
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Fossil Record of Sponges 75 6. Foss
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Fossil Record of Sponges 77 Fig. 35
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Comparison with other Spiculites 83
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Comparison with other Spiculites 85
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88 Hallam 1996; Hallam and Goodfell
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90 From the Lower Liassic Kendlbach
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92 At Steinplatte/Plattenkogel loca
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94 8.2. Major and Trace Elements We
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96 sediments. Due to this “contam
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98 significance of microbial involv
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100
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102 � The Lower Liassic sediments
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104 Böhm F (1992) Mikrofazies und
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106 Garrison RE, Fischer AG (1969)
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108 Krause FF, Scotese CR, Nieto C,
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110 Olsen PE, Kent DV, Sues H-D, Ko
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112 Schulze FE (1904) Hexactinellid
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114 Wendt J (1969) Stratigraphie un
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Plate 1 Glasenbachklamm - Lower Lia
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Plate 2 Mühlstein-South - Hornstei
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Plate 3 Sonntagkendlgraben - Flecke
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Plate 4 Hochgern - Liassic sediment
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Plate 5 Scheibelberg - Type locatio
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Plate 6 Luegwinkel - Liassic sedime
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Plate 7 Moosbergalm - Slope and bas
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Plate 8 Tannhauser Berg - Liassic s
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Plate 9 Adnet / Rot-Grau-Schnöll Q
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Plate 10 Adnet / Rot-Grau-Schnöll
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Plate 15 Adnet / Lienbacher Quarry
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Plate 16 Adnet / Eisenmann Quarry -
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Plate 17 Steinplatte / Plattenkogel
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Plate 21 Diapir of Murguia / Spain
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Plate 22 Arctic Vesterisbanken Seam
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Supplement 1.1 (datas to Fig. 42) -
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Supplement 1.2 (datas to Fig. 43 +
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Supplement 2. (datas to Fig. 47) -
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Supplement 3.2 (datas to Fig. 46) -
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Supplement 4. - Energy Dispersive X
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Supplement 6. - Register of Localit
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Steinplatte/Fischer’s Coral Garde
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Publications Parts of this study ar
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Curriculum Vitae Geboren in Bremerh
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Porifera-microbialites of the Lower Liassic (Northern Calcareous ...

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