Radiolarians and Tethyan Radiolarites from Primary Production to their Paleogeography

Wever, Patrick De; Baudin, François; Azéma, Jacques; Fourcade, Éric

doi:10.1007/978-1-4899-1558-0_9

Cited by 12 publications

(15 citation statements)

References 99 publications

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“…Other mechanisms interpreting bedded chert formation such as turbiditic re-deposition of siliceous sediments and significant silica redistribution during diagenesis (e.g., Nisbet and Price, 1974;Murray et al, 1992b) are less likely in the present case. The present alternation of chert and shale parting is believed to reflect original cyclic sedimentation of siliceous and relatively clay-rich materials, though probably biased and exaggerated by later diagenetic redistribution of Si (De Wever et al, 1995;Tada, 1991).…”

Section: Implications Of Depositional Environment and Origin Of Beddementioning

confidence: 92%

“…In the case of radiolarian bedded cherts now concerned, on the other hand, blooming of radiolaria in the ocean surface may have directly resulted in increase in accumulation and burial of biogenic silica. This could be explained by assumed high productivity during the chert formation, like Tethyan radiolarites and by less dissolution susceptibility of radiolarian tests relative to diatoms dominant siliceous organisms in post-Cretaceous Ocean (De Wever and Baudin, 1996;De Wever et al, 1995;Nelson et al, 1996). De Wever et al (1995) noted that in the zone of higher productivity, higher proportion of primarily produced silica could reach the sediments, and that high accumulation of biogenic silica could result in less dissolution at the sediment-water interface due to rapid burial.…”

Section: Implications Of Depositional Environment and Origin Of Beddementioning

confidence: 99%

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Biogeochemical signatures preserved in ancient siliceous sediments; new perspectives to Triassic radiolarian bedded chert compositions

et al. 2006

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Major and minor elements of successively collected 70 Middle Triassic radiolarian bedded cherts from the Mino Belt in central Japan were studied. In order to reveal pre-diagenetic, primary geochemical signatures related to marine biogeochemical cycles, composite data of chert-shale couplets in addition to raw data were examined. The results show that Mn, Cu, Sr, Ba and P were supplied significantly by non-lithogenic excess fractions. Positive correlation with SiO 2 / TiO 2 suggests that accumulations of Ba, Sr, Mn and Cu were closely related to sedimentation of biogenic silica; Mn and Cu were probably incorporated into oxides, whereas Ba into barite. Relationship between SiO 2 /TiO 2 and excess-Ba, proxy for surface productivity implies that regeneration of silica from sinking radiolarian tests was not significant. This may have been caused by an expected relatively short travel time of radiolarian tests from the ocean surface to the bottom, reflecting their large size compared with diatoms. Positive correlations between CaO and P 2 O 5 imply that apatite species are host phases for P and Ca. Although conodont composed of apatite is abundant in both chert and shale, their CaO/P 2 O 5 ratio differs markedly from those of cherts and shales. Other apatite species, possibly carbonate apatite of diagenetic origin, are present in the bedded cherts and contribute to excess-P accumulation. Early diagenesis is believed to have modified only slightly primary geochemical features of the studied bedded cherts. This suggests relatively oxic depositional environment for the bedded cherts, under which regeneration of redox sensitive elements were not active.

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Section: Implications Of Depositional Environment and Origin Of Beddementioning

confidence: 92%

Section: Implications Of Depositional Environment and Origin Of Beddementioning

confidence: 99%

Biogeochemical signatures preserved in ancient siliceous sediments; new perspectives to Triassic radiolarian bedded chert compositions

et al. 2006

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“…Moreover, higher productivity beyond a critical threshold results in higher proportions of biosiliceous surface production reaching the seafloor (Dewever et al, 1994). After death, the mineral skeletons are exposed to seawater, and dissolution is more pronounced in surface seawater.…”

Section: The Katsuyama T-oae Record: Global Carbon Cycle Signals and mentioning

confidence: 99%

An open ocean record of the Toarcian oceanic anoxic event

et al. 2011

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Abstract. Oceanic anoxic events were time intervals in the Mesozoic characterized by widespread distribution of marine organic matter-rich sediments (black shales) and significant perturbations in the global carbon cycle. These perturbations are globally recorded in sediments as carbon isotope excursions irrespective of lithology and depositional environment. During the early Toarcian, black shales were deposited on the epi-and pericontinental shelves of Pangaea, and these sedimentary rocks are associated with a pronounced (ca. 7 ‰) negative (organic) carbon isotope excursion (CIE) which is thought to be the result of a major perturbation in the global carbon cycle. For this reason, the lower Toarcian is thought to represent an oceanic anoxic event (the T-OAE). If the T-OAE was indeed a global event, an isotopic expression of this event should be found beyond the epi-and pericontinental Pangaean localities. To address this issue, the carbon isotope composition of organic matter (δ 13 C org ) of lower Toarcian organic matter-rich cherts from Japan, deposited in the open Panthalassa Ocean, was analysed. The results show the presence of a major (>6 ‰) negative excursion in δ 13 C org that, based on radiolarian biostratigraphy, is a correlative of the lower Toarcian negative CIE known from Pangaean epiand pericontinental strata. A smaller negative excursion in δ 13 C org (ca. 2 ‰) is recognized lower in the studied succession. This excursion may, within the current biostratigraphic resolution, represent the excursion recorded in European epicontinental successions close to the Pliensbachian/Toarcian boundary. These results from the open ocean realm suggest, in conjunction with other previously published datasets, that these Early Jurassic carbon cycle perturbations affected the active global reservoirs of the exchangeable carbon cycle (deep marine, shallow marine, atmospheric).

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“…Thus the abundance and diversity of the radiolarians suggests that the Mae Hong Son assemblages represent an open pelagic-basin environment. Furthermore, the presence of radiolarite and phosphatic nodules suggests that the basin was located in a region of upwelling (De Wever et al 1995). Modern radiolarians accumulate in abundance in periequatorial zones, polar belts and some continental margins where upwelling is active (De Wever et al 1995), and radiolarian oozes are deposited on oceanic floors in periequatorial zones (Renz, 1976).…”

Section: S T R a T I G R A P H I C I M P L I C A T I O N Smentioning

confidence: 99%

“…Furthermore, the presence of radiolarite and phosphatic nodules suggests that the basin was located in a region of upwelling (De Wever et al 1995). Modern radiolarians accumulate in abundance in periequatorial zones, polar belts and some continental margins where upwelling is active (De Wever et al 1995), and radiolarian oozes are deposited on oceanic floors in periequatorial zones (Renz, 1976). Globally Early Carboniferous radiolarian localities are generally situated between latitudes 308S and 308N.…”

Section: S T R a T I G R A P H I C I M P L I C A T I O N Smentioning

confidence: 99%

Early Carboniferous radiolarians from north‐west Thailand: palaeogeographical implications

et al. 2004

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ABSTRACT. Moderately well-preserved radiolarian assemblages are described from bedded cherts south of Mae Hong Son, north-west Thailand. Twenty species and subspecies are identified, including one new species (Archocyrtium sashidai Feng sp. nov.). The assemblages belong to the middle Early Carboniferous Albaillella indensis and Eostylodictya rota zones. The new data suggest that there was a pelagic basin between the Shan-Thai terrane and Gondwana during the Early Carboniferous. This implies, contrary to previous interpretations, that the Shan-Thai terrane had already rifted apart from Gondwana during the Early Carboniferous.

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Radiolarians and Tethyan Radiolarites from Primary Production to their Paleogeography

Cited by 12 publications

References 99 publications

Biogeochemical signatures preserved in ancient siliceous sediments; new perspectives to Triassic radiolarian bedded chert compositions

Biogeochemical signatures preserved in ancient siliceous sediments; new perspectives to Triassic radiolarian bedded chert compositions

An open ocean record of the Toarcian oceanic anoxic event

Early Carboniferous radiolarians from north‐west Thailand: palaeogeographical implications

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