Nd isotope composition of early Cambrian discrete basins

Felitsyn, S. B.; Gubanov, Alexander P.

doi:10.1017/s0016756801006252

Cited by 7 publications

(9 citation statements)

References 41 publications

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“…Pratt & James 1986; McKie 1990a; Holmden et al . 1998; Felitsyn & Gubanov 2002). In such settings, including northwest Scotland (part of the Laurentian margin of the Iapetus Ocean), the very low gradient of the shoreface and shelf (McKie 1993) would have played a significant role in controlling the presence and diversity of bioturbating organisms, especially during periods of low relative sea level.…”

Section: Discussionmentioning

confidence: 99%

Controls on trace fossil diversity in an Early Cambrian epeiric sea: new perspectives from northwest Scotland

Davies

Herringshaw

Raine

2009

LET

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The Lower Cambrian Eriboll Formation of northwest Scotland is renowned for the high density, low diversity trace fossils ( Skolithos ichnofacies) found in its upper Pipe Rock Member. Ichnofabric analysis of the member indicates that relatively small examples of Skolithos terminating at the same foreset boundary were formed during a brief colonization window after a single depositional event, that particularly long Skolithos specimens are equilibrichnia, and that palimpsests of Skolithos represent the marginal, slightly deeper water fringes of the Pipe Rock Member depositional environment. Nearest neighbour analysis, however, suggests that such palimpsests were uncommon. A much more diverse trace fossil assemblage is present in the overlying Fucoid Member

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Section: Discussionmentioning

confidence: 99%

Controls on trace fossil diversity in an Early Cambrian epeiric sea: new perspectives from northwest Scotland

Davies

Herringshaw

Raine

2009

LET

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“…This observation also suggests a more congruent weathering for mafic rock than felsic rock. (B) Compilations of potential seawater εNd(t) records derived from shallow carbonates (this study), sedimentary phosphorites (Yang et al, 1997) and phosphatic Small Shelly Fossils (Felitsyn and Gubanov, 2002). Shaded area is the estimated εNd(t) range for paleo-pacific (Panthalassa) seawater (Keto and Jacobsen, 1988).…”

Section: Discussionmentioning

confidence: 95%

“…To better understand holistic εNd(t) variations of shallow seawater, εNd(t) record derived from shallow-marine carbonates in this study is combined with more εNd(t) records from phosphoric rocks (Yang et al, 1997;Felitsyn and Gubanov, 2002) in different regions from the Ediacaran to early Cambrian (Fig. 6B).…”

Section: Long-term Evolution Of εNd(t) In Continental Shelf Seawater:mentioning

confidence: 99%

Long-term evolution of terrestrial inputs from the Ediacaran to early Cambrian: Clues from Nd isotopes in shallow-marine carbonates, South China

Wei

Shields

Chen

et al. 2019

Palaeogeography, Palaeoclimatology, Palaeoecology

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The emergence and radiation of metazoans have been widely attributed to a progressively more oxidizing surface environment through the Ediacaran-Cambrian transition interval. However, the root causes for atmospheric and oceanic oxygenation are still disputed. Long-term tectonic changes could possibly have led to atmospheric oxygenation but geochemical evidence for this linkage remains elusive. In this study, we analyzed the radiogenic Nd isotopic compositions (εNd) of shallow-marine carbonates from South China in order to track secular variations in terrestrial inputs from Ediacaran to early Cambrian time. Compared with most other geochemical indices, the Nd isotope system in carbonates is less susceptible to early diagenetic exchange and can thus act as a robust proxy for continental materials undergoing weathering. We interpret an abrupt excursion to lower εNd values during the middle Ediacaran as due to rapid exchange of different water masses. However, the more gradual trend towards lower εNd values from the Ediacaran to 2 early Cambrian, accompanied by increasing 87 Sr/ Sr ratios of the studied carbonates, likely indicates the enhanced weathering of old continental rock following the assembly of Gondwana. Increased net accumulation of atmospheric oxygen as a result of enhanced organic carbon burial may have benefited from intense continental denudation.

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“…Reference data for Vendian to Lower Cambrian sediments were obtained from argillites and phosphorites (Felitsyn & Gubanov, 2002; see Appendix, Table 1). Reference data for Vendian to Lower Cambrian sediments were obtained from argillites and phosphorites (Felitsyn & Gubanov, 2002; see Appendix, Table 1).…”

Section: Geochemistrymentioning

confidence: 99%

“…Thus, analyses of the Nd isotopic ratio (expressed as ε Nd (t), which represents deviations of the initial 143 Nd/ 144 Nd ratio in parts per 10 4 from the chondritic uniform reservoir) in fossil biogenic apatites can be used for provenance analysis, reflecting the proportion of radiogenic Nd in the sediment source area. Such analyses can then also be applied to the reconstruction of water mass circulation patterns and exchange between discrete oceanic reservoirs, as demonstrated elsewhere in the Phanerozoic, including the earliest Cambrian (Keto & Jacobsen, 1987;Stille, 1992;Stille, Steinmann & Riggs, 1996;Felitsyn & Gubanov, 2002).…”

Section: Introductionmentioning

confidence: 99%

Neodymium isotopic composition of Cambrian–Ordovician biogenic apatite in the Baltoscandian Basin: implications for palaeogeographical evolution and patterns of biodiversity

et al. 2005

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Biogenic apatite preserved in 148 samples of conodonts and organophosphatic-shelled brachiopods from Cambrian through Ordovician successions of the Baltoscandian Basin (Baltica Plate) preserves a sensitive record of early Palaeozoic sea-water chemistry interpreted via neodymium isotope ratios. Consistent ε Nd (t) values of −9.6 to −8.3 for Lower to Middle Cambrian samples suggest no significant lateral or temporal variation across the region. Average Upper Cambrian values are −7.2 to −7.7. Sedimentary analysis suggests that the influence of continental weathering from Baltica as a major source of radiogenic Nd was negligible. Ordovician samples show a rise to −5 to −6 in the early Arenig, early-mid Llanvirn and late Caradoc. Sea-water mixing from the southeast Iapetus Ocean was a constant factor throughout Cambrian-Ordovician times. The rise reflects erosion of obducted volcanic arc complexes along the Caledonian margin, and probably also relates to pollution of the Baltica sector of Iapetus from the approaching Avalonia Plate. Patterns of evolutionary biodiversity and palaeobiogeographical linkages support the geochemical signatures in interpreting the tectonic history of the region. Extinction of lingulate brachiopod faunas in the Tremadoc, followed by subsequent recovery and emergence of benthic assemblages typical of the Ordovician Evolutionary Fauna in the Billingen-early Volkhov regional stages coincide with significant changes in geochemical characteristics of water masses across the Baltoscandian basin. The early and mid Ordovician (Arenig to Llandeilo) brachiopod faunas of the North Estonian Confacies Belt are characterized by high endemism and low turnover rates, whereas increased immigration resulted in the extinction of a number of local lineages in the late Llanvirn. From the mid Caradoc to mid Ashgill, when Baltica was drifting on a course to collide eventually with Avalonia and gradually approach Laurentia, brachiopod assemblages were characterized by higher turnover rates. At the same time they gradually became more cosmopolitan and less influenced by the invasion of new faunas.

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Nd isotope composition of early Cambrian discrete basins

Cited by 7 publications

References 41 publications

Controls on trace fossil diversity in an Early Cambrian epeiric sea: new perspectives from northwest Scotland

Controls on trace fossil diversity in an Early Cambrian epeiric sea: new perspectives from northwest Scotland

Long-term evolution of terrestrial inputs from the Ediacaran to early Cambrian: Clues from Nd isotopes in shallow-marine carbonates, South China

Neodymium isotopic composition of Cambrian–Ordovician biogenic apatite in the Baltoscandian Basin: implications for palaeogeographical evolution and patterns of biodiversity

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