Duration of the Early Cambrian: U-Pb ages of volcanic ashes from Avalon and Gondwana

Landing, Ed; Bowring, Samuel A.; Davidek, Kathleen L.; Westrop, Stephen R.; Geyer, Gerd; Heldmaier, Wolfram

doi:10.1139/cjes-35-4-329

Cited by 39 publications

(68 citation statements)

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“…Johnson and McLeod 1996). This paper reports the results of new and previous mapping in the New River belt combined with recently published geochronological data and sequence stratigraphy for the Avalonian cover sequence (e.g., Isachsen et al 1994;Landing 1996;Landing and Westrop 1998;. These data suggest that the differences exhibited by the Pocologan River segment do not necessarily imply a non-Avalonian origin for these rocks.…”

Section: Introductionmentioning

confidence: 60%

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Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

Johnson¹

2001

atgeol

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The Pocologan River and Long Reach areas are situated in the New River belt, which comprises the westernmost exposures of Neoproterozoic rocks in southern New Brunswick. Previous mapping in the southwestern part of the New River belt indicated that Neoproterozoic and Cambrian rocks in the Pocologan River area are different from coeval strata in the Caledonia belt (Avalon /one sensu stracto) in the Saint John area. Recent mapping in the Long Reach area has shown that there are significant lithological changes across the Robin Hood Lake fault, which bisects the New River belt into northeastern (Long Reach) and southwestern (Pocologan River) segments. Neoproterozoic and Cambrian rocks in the Long Reach area are directly comparable to those in the Caledonia belt, demonstrating that the New River belt is composite. Recent data have also shown that Early Cambrian volcanic activity in the Pocologan River area is broadly contemporaneous with epeirogenic events related to a major sequence boundary in the Avalonian cover sequence. This suggests that the northeastern and southwestern segments of the composite New River belt may have experienced a similar tectonic event, possibly as separate but adjacent continental fragments or as geographically isolated parts of one Gondwanan terrane. The lithological similarity of late Early to (?) Middle Cambrian quartzose sedimentary strata in the Pocologan River area to Middle Cambrian rocks in the St. Croix belt in Maine also supports the suggestion that the St. Croix belt is part of this composite terrane. RÉSUMÉ Les secteurs de la riviére Pocologan et de Long Reach sont situes dans la ceinture de New River, qui englobe les affleurements les plus à I'ouest des roches du Protérozoique supéricur du Sud du Nouveau-Brunswick. Des travaux de cartographic antérieurs dans Ie sud-ouest de la ceinture de New River ont révé;lé que les roches du Protérozoique supeérieur et du Cambrien du secteur de la riviére Pocologan constituaient des exemplaires uniques de stretcs contemporaines de la ceinture de Caledonia (zone d'Avalon au sens strict) dans la région de Saint-Jean. Des travaux de cartographic recents dans le secteur de Long Reach ont révélé des changements lithologiques marqués a travers la faille du lac Robin Hood, qui subdivise la ceinture de New River en deux segments : les segments nord-est (Long Reach) et sud-ouest (riviere Pocologan). Les roches du Protérozoique supérieur et du Cambrien du secteur de Long Reach sont directement comparable? à celles de la ceinture de Caledonia, ce qui démontre que la ceinture de New River constitue unc ceinture composite. Des donées récentes ont également rétvélé que I'activitié volcanique du Cambrien inférieur dans le secteur de la riviére Pocologan a en gros été contemporaine aux phénomenes épirogéniques apparentés à une Iimite de séquence importante dans la séquence de couverture avalonnienne. Cela laisse supposer que les segments nord-est et sud-ouest de la ceinture composite de New River pourraient avoir été soumis a un phénomene tectonique analogue, possiblement en tant que fragments continentaux distincts mais adjacents ou de parties géographiquement isolées d'un terrane du Gondwana. La similarity lithologique des strates seédimentaires quartzeuses de la fin du Cambrien précoce au Cambrien moyen (?) dans le secteur de la riviére Pocologan avec les roches du Cambrien moyen de la ceinture de St. Croix au Maine appuie par ailleurs l’hypothése que la ceinture de St. Croix fail partie de ce terrane composite. Traduit par la rédaction

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Section: Introductionmentioning

confidence: 60%

“…Formational nomenclature for the Saint John Group employed herein follows Tanoli (1987) and Tanoli and Pickerill (1988), however, boundary revisions and significant disconformities as outlined in Landing (1996) and Landing and Westrop (1998) are taken into consideration (Fig. 6).…”

Section: Saint John Groupmentioning

confidence: 99%

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

Johnson¹

2001

atgeol

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“…2). R. insolutum is also reported from the Camenella baltica Zone of Avalonia (SE Newfoundland, Brasier 1984Brasier , 1986Brasier , 1989aLanding 1988;Landing et al 1998;and Britain, Brasier 1986) and Schmidtiellus mickwitzi Zone of Baltica (Bornholm, Poulsen 1967;Brasier 1989a Remarks.-By contrast with other species of "protoconodonts" herein (see also Kouchinsky et al 2011 Amphigeisina danica (Poulsen, 1966) (Kouchinsky et al 2011). The species is also known from the upper part of Series 2 of Kazakhstan (Gridina 1991), Avalonia, Britain (Hinz 1987), and Laurentia (Landing 1974;John S. Peel, personal communication 2010) and from Series 3 of Baltica (Poulsen 1966;Bengtson 1976) and South and North China (Qian et al 2004;Steiner et al 2007).…”

Section: Rhombocorniculum Insolutum Missarzhevsky Inmentioning

confidence: 80%

A bradoriid and brachiopod dominated shelly fauna from the Furongian (Cambrian) of Västergötland, Sweden

et al. 2013

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A small assemblage of shelly fossils, dominated by the brachiopod Treptotreta jucunda and the bradoriid arthropod Mongolitubulus aspermachaera new species is described from a Furongian limestone of Västergötland, south-central Sweden. Mongolitubulus aspermachaera is represented in the assemblage by individual valves and numerous, ornamented spines. Valves and spines share identical ornament and microstructure leaving no doubt that the isolated spines were once attached to the bradoriid valves. Mongolitubulus aspermachaera adds to the increasing list of spinose Cambrian bradoriid arthropods, and Mongolitubulidae new family is erected here to incorporate the genera Mongolitubulus, Tubuterium and Spinospitella. Mongolitubulus aspermachaera represents the youngest member of the new family and supplements the biodiversity of bradoriids in the Furongian, an interval when bradoriid diversity is considered to be very much on the decline. The brachiopod Treptotreta jucunda described predominantly from the ‘middle' to ‘late' Cambrian of Australia is here documented for the first time from outside Gondwana, dramatically extending the biogeographical range of the species. Other elements of the faunal assemblage include typical Baltic Furongian representatives, such as the trilobite Parabolina, the agnostoid Agnostus and the phosphatocopids Hesslandona and Vestrogothia.

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“…Thus, chemostratigraphy corroborates biostratigraphic assignment of the Pedroche Formation to the lower part of Cambrian Series 2, Stage 3. Moreover, correlation of the Pedroche δ 13 C carb values to a radiometrically calibrated Cambrian Terreneuvian-Series 2 δ 13 C carb curve suggests an absolute depositional age between 520.93 ± 0.14 Ma and 517.0 ± 1.5 Ma (Maloof et al, 2010b;Landing et al, 1998).…”

Section: Carbon Isotopic Chemostratigraphymentioning

confidence: 90%

Geobiology of a lower Cambrian carbonate platform, Pedroche Formation, Ossa Morena Zone, Spain

Creveling

Fernández-Remolar

Rodríguez-Martínez

et al. 2013

Palaeogeography, Palaeoclimatology, Palaeoecology

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The Cambrian Pedroche Formation comprises a mixed siliciclastic–carbonate succession recording subtidal deposition on a marine platform. Carbonate carbon isotope chemostratigraphy confirms previous biostratigraphic assignment of the Pedroche Formation to the Atdabanian regional stage of Siberia, correlative to Cambrian Series 2. At the outcrop scale, thrombolitic facies comprise ~60% of carbonate-normalized stratigraphy and coated-grains another ~10%. Petrographic point counts reveal that skeletons contribute at most 20% to thrombolitic inter-reef and reef-flank lithologies; on average, archaeocyath clasts make up 68% of skeletal materials. In contrast, petrographic point counts show that skeletons comprise a negligible volume of biohermal and biostromal thrombolite, associated nodular carbonate facies, and ooid, oncoid and peloid grainstone facies. As such, archaeocyathan reefal bioconstructions represent a specific and limited locus of skeletal carbonate production and deposition. Consistent with data from coeval, globally dispersed lower Cambrian successions, our analysis of the Pedroche Formation supports the view that lower Cambrian carbonates have more in common with earlier, Neoproterozoic deposits than with younger carbonates dominated by skeletal production and accumulatio

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Duration of the Early Cambrian: U-Pb ages of volcanic ashes from Avalon and Gondwana

Cited by 39 publications

References 0 publications

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

A bradoriid and brachiopod dominated shelly fauna from the Furongian (Cambrian) of Västergötland, Sweden

Geobiology of a lower Cambrian carbonate platform, Pedroche Formation, Ossa Morena Zone, Spain

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