scholarly journals The SPICE carbon isotope excursion in Siberia: a combined study of the upper Middle Cambrian–lowermost Ordovician Kulyumbe River section, northwestern Siberian Platform

2008 ◽  
Vol 145 (5) ◽  
pp. 609-622 ◽  
Author(s):  
ARTEM KOUCHINSKY ◽  
STEFAN BENGTSON ◽  
YVES GALLET ◽  
IGOR KOROVNIKOV ◽  
VLADIMIR PAVLOV ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Siberian Platform ◽  
Total Duration ◽  
Local Maximum ◽  
Magnetic Polarity ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
Carbon Isotopic ◽  
Reversal Frequency ◽  
Northwestern Margin

AbstractAn integrated, high-resolution chemostratigraphic (C, O and Sr isotopes) and magnetostratigraphic study through the upper Middle Cambrian–lowermost Ordovician shallow-marine carbonates of the northwestern margin of the Siberian Platform is reported. The interval was analysed at the Kulyumbe section, which is exposed along the Kulyumbe River, an eastern tributary of the Enisej River. It comprises the upper Ust'-Brus, Labaz, Orakta, Kulyumbe, Ujgur and lower Iltyk formations and includes the Steptoean positive carbon isotopic excursion (SPICE) studied here in detail from upper Cambrian carbonates of the Siberian Platform for the first time. The peak of the excursion, showing δ13C positive values as high as +4.6‰ and least-altered87Sr/86Sr ratios of 0.70909, is reported herein from the Yurakhian Horizon of the Kulyumbe Formation. The stratigraphic position of the SPICE excursion does not support traditional correlation of the boundary between the Orakta and Labaz formations at the Kulyumbe River with its supposedly equivalent level in Australia, Laurentia, South China and Kazakhstan, where theGlyptagnostus stolidotusandG. reticulatusbiozones are known to immediately precede the SPICE excursion and span the Middle–Upper Cambrian boundary. The Cambrian–Ordovician boundary is probably situated in the middle Nyajan Horizon of the Iltyk Formation, in which carbon isotope values show a local maximum below a decrease in the upper part of the Nyajan Horizon, attributed herein to the Tremadocian Stage. A refined magnetic polarity sequence confirms that the geomagnetic reversal frequency was very high during Middle Cambrian times at 7–10 reversals per Ma, assuming a total duration of about 10 Ma and up to 100 magnetic intervals in the Middle Cambrian. By contrast, the sequence attributed herein to the Upper Cambrian on chemostratigraphic grounds contains only 10–11 magnetic intervals.

Carbon isotope stratigraphy and the problem of a pre-Tommotian Stage in Siberia

2001 ◽  
Vol 138 (4) ◽  
pp. 387-396 ◽  
Author(s):  
ARTEM KOUCHINSKY ◽  
STEFAN BENGTSON ◽  
VLADIMIR V. MISSARZHEVSKY ◽  
SHANE PELECHATY ◽  
PETER TORSSANDER ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Siberian Platform ◽  
Lower Cambrian ◽  
Isotopic Data ◽  
Sequence Stratigraphic ◽  
Anabar Uplift ◽  
Carbon Isotopic ◽  
The North ◽  
Isotope Stratigraphy ◽  
Isotopic Variations

Carbon isotopic oscillations are useful to elucidate the stratigraphy and biogeochemical events around the Precambrian–Cambrian transition. New isotopic data from the Manykaj and Emyaksin formations of the eastern Anabar Uplift (Siberia) help to correlate the Lower Cambrian and Neoproterozoic–Cambrian transitional beds across the Siberian Platform. The similarity of trends and amplitudes of the carbon isotopic curves, together with biostratigraphic and sequence-stratigraphic markers from the Anabar Uplift, provide a precise correlation with the southern part of the Siberian Platform. Diagenesis of argillaceous limestones of the Emyaksin Formation has apparently not affected the primary isotopic variations. The resulting curve is nearly identical in sections about 100 km apart in the Tommotian–Atdabanian portion of the formation. Relatively frequent and pronounced isotopic oscillations in the lower beds of the Emyaksin Formation fit between features I and II of the southern Siberian isotopic reference scale but are undetected therein owing to the depositional hiatus at the base of the Tommotian Stage in its type section. This confirms the transgressive onlap from the north suggested by previous studies, and makes the appearance of the Cambrian skeletal fossils on the Siberian Platform less abrupt. The hiatus in the south appears to embrace at least two biostratigraphic zones as recognized in the north. The case is strengthened for a pre-Tommotian Cambrian Stage in Siberia, the biostratigraphic framework for which has been elaborated earlier.

scholarly journals Carbon isotopes, stratigraphy, and environmental change: the Middle–Upper Cambrian Positive Excursion (SPICE) in Port au Port Group, western Newfoundland, Canada

2018 ◽  
Vol 55 (11) ◽  
pp. 1209-1222 ◽  
Author(s):  
Rosalia Barili ◽  
Joyce Elaine Neilson ◽  
Alexander Thomas Brasier ◽  
Karin Goldberg ◽  
Tatiana Pastro Bardola ◽  
...  
Keyword(s):  
North America ◽  
Environmental Change ◽  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Carbonate Rocks ◽  
Isotopic Signature ◽  
Upper Cambrian ◽  
Carbon Isotopic ◽  
Carbon Isotope Excursion ◽  
Diagenetic Environment

In many basins, Upper Cambrian carbonate successions display intervals with a positive carbon isotope excursion (CIE) of up to +5‰. In North America, this marks the boundary between the Sauk II–III super-sequences. A Steptoean positive carbon isotope excursion (SPICE) locality previously identified in the Port au Port peninsula, western Newfoundland, has been revisited and an additional potential SPICE locality found. In both locations, a CIE is found to be associated with a prominent bioherm and sandstone layer within a sequence of carbonate rocks. At March Point columnar stromatolites occur, whereas at Felix Cove thrombolites can be seen. In the latter, the sandstone immediately overlies the thrombolites coincident with the CIE, whereas at March Point a dolomitized grainstone occurs above the stromatolites. The sandstone at this locality post-dates the CIE. Although lower than the SPICE in some localities, a positive CIE is present in both sections: March Point (+1.1‰) and Felix Cove (+1.8‰). Additionally, δ13Corg rises from −30.0‰ to −22.0‰ at March Point and from −27‰ to −24.0‰ at Felix Cove and, in accordance with previously published work, we suggest that this could be the SPICE. Comparison of the stratigraphy and petrography between the two localities suggest that both depositional and diagenetic factors could have influenced the nature of the interpreted SPICE in Newfoundland. It is also possible that the local carbon isotopic signature may have been influenced by a semi-restricted depositional and early diagenetic environment related to the paleogeographic configuration rather than the global marine excursion.

Evolution of trilobite biofacies in Cambrian basins of the Siberian Platform

2000 ◽  
Vol 74 (6) ◽  
pp. 1000-1019 ◽  
Author(s):  
Tatyana V. Pegel
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Siberian Platform ◽  
Global Scale ◽  
Depositional Environments ◽  
Sign Reversal ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
Sea Level Fluctuations ◽  
Stratigraphic Succession

Cambrian biotic zonation on the Siberian Platform reflects differentiation of the depositional environments (inner shelf, outer shelf and open basin). The combination of the chart of trilobite biofacies replacement and the curve of sea-level fluctuations shows that trilobite biofacies replacement occurs as a rule at times of sign reversal and distinct change in the rates of sea-level rise or fall. The boundaries of major Siberian platform Cambrian chronostratigraphic units, such a stages and series, frequently coincide with the boundaries of biofacies in stratigraphic succession related to sea-level fluctuations. If these fluctuations are gradual and restricted, then the boundaries of the Cambrian stages and series cannot be isochronous levels at a global scale. The known levels for intercontinental correlation on the Siberian Platform include boundaries of the adjacent Triplagnostus gibbus and Tomagnostus fissus Zones from the uppermost Amganian Stage (Middle Cambrian) and the Glyptagnostus stolidotus and Glyptagnostus reticulatus Zones of the lower Upper Cambrian. Both levels correspond to boundaries between highstands and lowstands on the Siberian Platform and appear to serve as boundaries of high rank. Evolution of the trilobite biofacies zonation is illustrated by genera typical for each of the various Cambrian paleogeographic environments on the Siberian Platform.

Carbon isotope stratigraphy of the Precambrian–Cambrian Sukharikha River section, northwestern Siberian platform

2007 ◽  
Vol 144 (4) ◽  
pp. 609-618 ◽  
Author(s):  
ARTEM KOUCHINSKY ◽  
STEFAN BENGTSON ◽  
VLADIMIR PAVLOV ◽  
BRUCE RUNNEGAR ◽  
PETER TORSSANDER ◽  
...  
Keyword(s):  
High Resolution ◽  
Carbon Isotope ◽  
Siberian Platform ◽  
Lower Cambrian ◽  
River Section ◽  
Carbon Isotope Stratigraphy ◽  
Reference Profile ◽  
Northwestern Margin ◽  
Isotope Profile ◽  
Isotope Stratigraphy

A high-resolution carbon isotope profile through the uppermost Neoproterozoic–Lower Cambrian part of the Sukharikha section at the northwestern margin of the Siberian platform shows prominent secular oscillations of δ13C with peak-to-peak range of 6–10 ‰. There are six minima, 1n–6n, and seven maxima 1p–7p, in the Sukharikha Formation and a rising trend of δ13C from the minimum 1n of − 8.6 ‰ to maximum 6p of + 6.4 ‰. The trough 1n probably coincides with the isotopic minimum at the Precambrian–Cambrian boundary worldwide. Highly positive δ13C values of peaks 5p and 6p are typical of the upper portion of the Precambrian–Cambrian transitional beds just beneath the Tommotian Stage in Siberia. A second rising trend of δ13C is observed through the Krasnoporog and lower Shumny formations. It consists of four excursions with four major maxima that can be correlated with Tommotian–Botomian peaks II, IV, V, and VII of the reference profile from the southeastern Siberian platform. According to the chemostratigraphic correlation, the first appearances of the index forms of archaeocyaths are earlier in the Sukharikha section than in the Lena–Aldan region.

A Vendian–Cambrian boundary succession from the northwestern margin of the Siberian Platform: stratigraphy, palaeontology, chemostratigraphy and correlation

1998 ◽  
Vol 135 (4) ◽  
pp. 473-494 ◽  
Author(s):  
JULIE K. BARTLEY ◽  
MICHAEL POPE ◽  
ANDREW H. KNOLL ◽  
MIKHAIL A. SEMIKHATOV ◽  
PETER YU. PETROV
Keyword(s):  
Siberian Platform ◽  
Western Siberia ◽  
World Ocean ◽  
Environmental Evolution ◽  
Carbon Isotopic ◽  
Reference Sections ◽  
The World ◽  
Northwestern Margin

Siberia contains several key reference sections for studies of biological and environmental evolution across the Proterozoic–Phanerozoic transition. The Platonovskaya Formation, exposed in the Turukhansk region of western Siberia, is an uppermost Proterozoic to Cambrian succession whose trace and body fossils place broad limits on the age of deposition, but do not permit detailed correlation with boundary successions elsewhere. In contrast, a striking negative carbon isotopic excursion in the lower part of the Platonovskaya Formation permits precise chemostratigraphic correlation with uppermost Yudomian successions in Siberia, and possibly worldwide. In addition to providing a tool for correlation, the isotopic excursion preserved in the Platonovskaya and contemporaneous successions documents a major biogeochemical event, likely involving the world ocean. The excursion coincides with the palaeontological breakpoint between Ediacaran- and Cambrian-style assemblages, suggesting a role for biogeochemical change in evolutionary events near the Proterozoic–Cambrian boundary.

Carbonate carbon isotope evolution of seawater across the Ediacaran–Cambrian transition: evidence from the Keping area, Tarim Basin, NW China

2017 ◽  
Vol 154 (6) ◽  
pp. 1244-1256 ◽  
Author(s):  
QINGJUN GUO ◽  
YINAN DENG ◽  
JIAN HU ◽  
LIYUAN WANG
Keyword(s):  
Carbon Isotope ◽  
Tarim Basin ◽  
Sedimentary Rocks ◽  
Absolute Minimum ◽  
Nw China ◽  
Upper Cambrian ◽  
Carbon Isotopic ◽  
Carbonate Carbon ◽  
The World ◽  
Good Agreement

AbstractSedimentary rocks from the Ediacaran–Cambrian boundary record important biological, climatic and geotectonic changes during this time. To date, only few geochemical investigations on the upper Ediacaran – upper Cambrian rocks in the Tarim Basin have been carried out. Here, we report high-resolution δ13Ccarb records from the Penglaiba, the Wushi phosphorite and the Dongergou sections from Ediacaran–Cambrian Series 3 in the Keping area of the Tarim Basin. The sections display several obvious δ13Ccarb shifts; δ13Ccarb values increased from 3‰ to 6.7‰ across the Qigebulage Formation. Moreover, a negative δ13Ccarb shift across the Ediacaran–Cambrian boundary is apparent; δ13Ccarb values decreased to a minimum of −9.8‰ in the Wushi phosphorite section (−7.7‰ in Dongergou section and −5.4‰ in Penglaiba section), followed by a positive carbonate carbon isotopic excursion across the Yuertusi Formation into the middle of the overlying Xiaoerbulak Formation. Furthermore, more or less invariable positive δ13Ccarb values characterize the middle and upper Xiaoerbulak Formation. The most negative δ13Ccarb value (−14.3‰) occurred near the base of the Shayilik Formation, which is the absolute minimum value among the studied sections of the Cambrian Series 2 to Cambrian Series 3 transition in the world. The δ13C data from Keping, Tarim Basin are in good agreement with carbon isotope profiles recorded in South China, and these events may reflect the perturbation of the carbon cycle in the Tarim Basin during the Ediacaran–Cambrian and the Cambrian Series 2 – Cambrian Series 3 transitions.

Early Paleozoic Hyolitha from North America: reexamination of Walcott's and Resser's type specimens

1988 ◽  
Vol 62 (2) ◽  
pp. 218-233 ◽  
Author(s):  
John Mark Malinky
Keyword(s):  
North America ◽  
Lower Cambrian ◽  
Type Species ◽  
New Genus ◽  
Early Paleozoic ◽  
Type Specimens ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
New Family ◽  
The Family

Concepts of the family Hyolithidae Nicholson fide Fisher and the genera Hyolithes Eichwald and Orthotheca Novak have been expanded through time to encompass a variety of morphologically dissimilar shells. The Hyolithidae is here considered to include only those hyolithid species which have a rounded (convex) dorsum; slopes on the dorsum are inflated, and the venter may be flat or slightly inflated. Hyolithes encompasses species which possess a low dorsum and a prominent longitudinal sulcus along each edge of the dorsum; the ligula is short and the apertural rim is flared. The emended concept of Orthotheca includes only those species of orthothecid hyoliths which have a subtriangular transverse outline and longitudinal lirae covering the shell on both dorsum and venter.Eighteen species of Hyolithes and one species of Orthotheca from the Appalachian region and Western Interior were reexamined in light of more modern taxonomic concepts and standards of quality for type material. Reexamination of type specimens of H. similis Walcott from the Lower Cambrian of Newfoundland, H. whitei Resser from the Lower Cambrian of Nevada, H. billingsi Walcott from the Lower Cambrian of Nevada, H. gallatinensis Resser from the Upper Cambrian of Wyoming, and H. partitus Resser from the Middle Cambrian of Alabama indicates that none of these species represents Hyolithes. Hyolithes similis is here included under the new genus Similotheca, in the new family Similothecidae. Hyolithes whitei is designated as the type species of the new genus Nevadotheca, to which H. billingsi may also belong. Hyolithes gallatinensis is referred to Burithes Missarzhevsky with question, and H. partitus may represent Joachimilites Marek. The type or types of H. attenuatus Walcott, H. cecrops Walcott, H. comptus Howell, H. cowanensis Resser, H. curticei Resser, H. idahoensis Resser, H. prolixus Resser, H. resseri Howell, H. shaleri Walcott, H. terranovicus Walcott, and H. wanneri Resser and Howell lack shells and/or other taxonomically important features such as a complete aperture, rendering the diagnoses of these species incomplete. Their names should only be used for the type specimens until better preserved topotypes become available for study. Morphology of the types of H.? corrugatus Walcott and “Orthotheca” sola Resser does not support placement in the Hyolitha; the affinities of these species are uncertain.

The Middle–Upper Cambrian Transition in Southeastern Newfoundland, Canada

1975 ◽  
Vol 12 (12) ◽  
pp. 2065-2079 ◽  
Author(s):  
Valdemar Poulsen ◽  
Michael M. Anderson
Keyword(s):  
Basal Part ◽  
Eastern Canada ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
First Time

The Middle-Upper Cambrian transition in southeastern Newfoundland is shown to be very similar to the transition in Scandinavia and in the English Midlands. The late Middle Cambrian Lejopyge laevigata Zone, which is recorded for the first time from eastern Canada, is contained in the basal part of the Elliott Cove Formation and is conformably overlain by the Upper Cambrian Agnostus pisiformis Zone. The following trilobite species from the Lejopyge laevigata Zone at Manuels River and on Random Island are described: Andrarina costata (Angelin), Paradoxides sp., Lejopyge laevigata (Dalman), and Peronopsis insignis (Wallerius).

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