Lower Cambrian acritarchs from northern Spain: the Precambrian-Cambrian boundary and biostratigraphic implications

1992 ◽  
Vol 129 (4) ◽  
pp. 421-436 ◽  
Author(s):  
Teodoro Palacios ◽  
Gonzalo Vidal
Keyword(s):  
Lower Cambrian ◽  
East European Platform ◽  
Early Cambrian ◽  
Eastern Siberia ◽  
Western North America ◽  
Northern Spain ◽  
East European ◽  
Cantabrian Region ◽  
Biostratigraphic Correlation ◽  
Cambrian Trilobite

AbstractAcritarchs are reported from basal Cambrian rock units inthe Cantabrian region of northern Spain that are known to contain archaeocyathan and trilobite faunas. Biostratigraphic correlation of the Iberian sequences with other regions has been hampered by the strong provincialism of these faunas. However, this report of evidently cosmopolitan acritarch taxaestablishes the time equivalence of early Cambrian trilobite faunas from Iberia, Baltoscandia and the East European Platform (EEP). Our data suggest that the detrital deposition of the Lower Cambrian Herreria Formation embraces at least three (and possibly four) Lower Cambrian acritarch zones previously identified in the EEP, eastern Siberia, Baltoscandia, Scotland, Greenland, Svalbard and western North America. The early Cambrian transgression in northern Spain was probably initiated in Talsy times (Schmidtiellus mickwitzi trilobite Zone in Baltoscandia and the EEP), in part corresponding to the Dokidocyathus regularis archaeocyathian Zone of the Middle Tommotian in Siberia.

Micropaleontology across the Precambrian—Cambrian boundary in Spitsbergen

1987 ◽  
Vol 61 (5) ◽  
pp. 898-926 ◽  
Author(s):  
Andrew H. Knoll ◽  
Keene Swett
Keyword(s):  
Eastern Europe ◽  
Lower Cambrian ◽  
East European Platform ◽  
Trace Fossils ◽  
Early Cambrian ◽  
East Greenland ◽  
East European ◽  
Stratigraphic Subdivision ◽  
Biostratigraphic Correlation ◽  
Early Metazoan

Paleobiological studies of early metazoan evolution are critically dependent on the accurate stratigraphic subdivision and correlation of uppermost Proterozoic and Lower Cambrian sequences. Planktonic microfossils evolved rapidly during this period and are widely distributed and abundant in Vendian and Lower Cambrian rocks; therefore, they provide what is potentially one of the best means of correlating successions of this age. In Ny Friesland, Spitsbergen, tillite-bearing detrital rocks of the uppermost Proterozoic Polarisbreen Group are overlain without apparent unconformity by the Tokammane Formation, a tripartite lithologic sequence consisting of quartzarenites (Blårevbreen Member) overlain by dark shales with subordinate sandstone (Topiggane Member) and dolomites (Ditlovtoppen Member).Salterella, hyoliths, and other invertebrate remains occur in the upper part of the Tokammane succession; trace fossils are found in the Tokammane quartzarenites and shales, as well as in the uppermost few meters of the Polarisbreen sequence. Planktonic microfossils occur throughout the succession. They indicate that the Polarisbreen Group is Vendian in age and that a hiatus corresponding in time to the latest Vendian and (perhaps) earliest Cambrian coincides with the Polarisbreen/Tokammane boundary. Lower Topiggane shale samples contain acritarchs comparable to those found in the sub-HolmiaLontova Beds of Eastern Europe. Upper Topiggane samples contain diverse acritarch assemblages that indicate a lateHolmiaorProtolenusage, suggesting the presence of a second hiatus within the Tokammane Formation. Planktonic microfossils allow biostratigraphic correlation with other sequences both within (East Greenland) and between (East European Platform) paleocontinents. Like those from other areas, diversity trends exhibited by late Proterozoic and Early Cambrian acritarchs from Spitsbergen indicate a major Vendian episode of extinction followed by Early Cambrian rediversification of planktonic microfossils.

Low-temperature diagenetic illite-smectite in Lower Cambrian clays in North Estonia

Clay Minerals ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 151-163 ◽  
Author(s):  
K. Kirsimäe ◽  
P. Jøgensen ◽  
V. Kalm
Keyword(s):  
Lower Cambrian ◽  
East European Platform ◽  
Clay Fraction ◽  
High Water ◽  
Early Cambrian ◽  
Important Process ◽  
X Ray ◽  
East European ◽  
Ray Methods ◽  
Water Contents

AbstractEarly Cambrian sediments on the East European platform in North Estonia, represented mostly by clays and silty clays, were deposited under normal marine conditions. The sediments were never affected by significant tectonic or thermal events after sedimentation 530 Ma ago, and the clays still have high water contents. The clay fraction, divided into four sub-fractions, was studied using X-ray methods and Rb/Sr dating. Decomposition of the XRD curves was used to quantify the amounts of illitic minerals in the sub-fractions. Dating by Rb/Sr showed that the finest fraction (<0.06 µm) was formed 50–150 Ma after sedimentation. The coarser fractions also contain considerable amounts of diagenetically formed minerals. This shows that neoformation of illitic minerals in marine sediments with high water/sediment ratios is a very important process even at temperatures <35°C.

Nd isotope composition of the Ediacaran and earliest Cambrian phosphorite nodules and Fe sulphide from the East European Platform

2020 ◽  
Vol 157 (12) ◽  
pp. 2081-2088
Author(s):  
Sergey B Felitsyn ◽  
Eugeny S. Bogomolov
Keyword(s):  
East European Platform ◽  
Isotope Composition ◽  
Water Reservoir ◽  
Secular Change ◽  
Early Cambrian ◽  
Iron Sulphide ◽  
Nd Isotope ◽  
East European ◽  
Moscow Syneclise ◽  
Nd Isotope Composition

AbstractAn enhanced concentration of phosphorus has been found at the stratigraphic level of the disappearance of Ediacaran taxa in two areas, the Cis-Dniester region and the Moscow syneclise, on the East European Platform (EEP). The isotope composition of neodymium was determined in Fe sulphide and phosphorite in the same beds. Measured εNd(t) values in diagenetic phosphate nodules are similar to those in iron sulphide from the same layer. During the Ediacaran − Early Cambrian, accumulation of radiogenic Nd in the epeiric basins on the EEP increased progressively from −17.9 and −19.4 in pyrite from the sequence bottom to −7.9 and −8.5 in the Early Cambrian pyrite of the central part of the EEP. The Ediacaran phosphate nodules show εNd(t) ranging from −12.9 to −15.0, while that in the Early Cambrian nodules is typically c. −9.0. These data indicate the secular change in Nd isotope composition of the water reservoir on the EEP from Ediacaran to Cambrian.

The Early Cambrian worm tube Onuphionella from California and Nevada

1988 ◽  
Vol 62 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Philip W. Signor ◽  
Mark A. S. Mcmenamin
Keyword(s):  
New Species ◽  
North America ◽  
Lower Cambrian ◽  
Early Cambrian ◽  
Western North America ◽  
Baltic Region ◽  
Two New Species ◽  
Modern Genus ◽  
The Baltic ◽  
Middle Member

Two new species of worm tubes referable to the genus Onuphionella occur in Lower Cambrian strata in eastern California and western Nevada. Onuphionella durhami n. sp. is found in the Campito Formation (in pre-trilobite strata, in the Fallotaspis and, possibly, the Nevadella Zones) and O. claytonensis n. sp. occurs in the Middle Member of the Poleta Formation (Nevadella Zone). The unusual tubes are armored with an imbricated coat of mica flakes, reminiscent of the modern genus Owenia. The lowest occurrence of Onuphionella in western North America corresponds closely with the lowest occurrence of the genus in the Baltic region, indicating that correlations between the two regions are not greatly in error.

Early Cambrian trilobite larvae and ontogeny of Ichangia ichangensis Chang, 1957 (Protolenidae) from Henan, China

1999 ◽  
Vol 73 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Xi-Guang Zhang ◽  
Brian R. Pratt
Keyword(s):  
Lower Cambrian ◽  
Henan Province ◽  
The Other ◽  
Early Cambrian ◽  
Structural Variations ◽  
Simple Body ◽  
Cambrian Trilobite

The Lower Cambrian Shuigoukou Formation of Xichuan, Henan province, China, yielded phosphatized instars belonging to the protolenid Ichangia ichangensis Chang, 1957, and two undetermined taxa. With relatively simple body plans, the three larval forms resemble each other to some extent, and protaspides of I. ichangensis show general similarities to those of the ellipsocephalid Palaeolenus lantenoisi Mansuy. However, their early ontogenetic processes exhibit subtle yet distinct differences. One group of unassigned protaspides possesses a sagittal glabellar furrow and protomarginal spines with branching extremities. The other unassigned protaspides bear especially long genal and protomarginal spines. The detailed preservation of these larvae reveals delicate structural variations that help provide a framework for evaluating relationships among Early Cambrian trilobites.

Stratigraphical characteristics and development of Vendian–Cambrian boundary beds on the East European Platform

1986 ◽  
Vol 123 (4) ◽  
pp. 357-360 ◽  
Author(s):  
K. Mens ◽  
E. Pirrus
Keyword(s):  
East European Platform ◽  
Sedimentary Environment ◽  
Lower Boundary ◽  
Climatic Conditions ◽  
Northwestern Part ◽  
Early Cambrian ◽  
East European ◽  
Clastic Rocks ◽  
Continuous Sedimentation ◽  
The Baltic

AbstractThe present paper serves as a review on the stratigraphy and lithological characteristics of the Cambrian–Vendian boundary beds in the northwestern part of the East European Platform. This transition interval is represented by clastic rocks accumulated in humid climatic conditions. According to the lithological and palaeontological data the corresponding (transition) interval comprises two regional series: the Valdai Regional Series and the Baltic one. They both are divided into two regional stages (from below to top): Redkino, Kotlin, Rovno and Lontova.The Redkino–Kotlin and Kotlin–Rovno boundaries are characterized by distinct contacts reflecting various changes in the sedimentary environment whereas the boundary between the Rovno and Lontova regional stages drawn on the basis of the palaeontological data only falls within the interval of continuous sedimentation.Proceeding from the study of the fossil distribution and their living conditions during late Vendian and early Cambrian on the East European Platform the lower boundary of the Cambrian is most likely situated at the base of the Baltic Series.

Carbon isotope geochemistry and palaeontology of Neoproterozoic to early Cambrian siliciclastic successions in the East European Platform, Poland

1997 ◽  
Vol 134 (1) ◽  
pp. 1-16 ◽  
Author(s):  
HARALD STRAUSS ◽  
GONZALO VIDAL ◽  
MAŁGORZATA MOCZYDŁOWSKA ◽  
JOLANTA PACZEŚNA
Keyword(s):  
Organic Carbon ◽  
East European Platform ◽  
Carbonate Platform ◽  
Isotope Geochemistry ◽  
Carbon Isotopic Composition ◽  
Early Cambrian ◽  
East European ◽  
Carbon Isotopic ◽  
Radiation Extinction ◽  
Extinction Events

A well-preserved stratigraphic record of the organic carbon isotopic composition across the Precambrian–Cambrian transition has been obtained from a sequence of entirely detrital rocks underlying the Lublin Slope, East European Platform, Poland. The observed δ13C pattern for organic carbon is comparable to isotope data determined for coeval carbonate platform sequences elsewhere. These results underline the truly global nature of these secular variations within the carbon cycle during the terminal Proterozoic and early Cambrian, largely independent of host lithology and facies. The direct combination of micropalaeontological and geochemical results from sedimentary organic matter allows a detailed interpretation of the isotope record as probably caused by secular changes in the net balance of burial and erosion rates of repositories of organic carbon. Furthermore, these variations appear to be directly correlatable with changes in the diversity and abundance of the biota and radiation/extinction events.

scholarly journals Early Cambrian syenite and monzonite magmatism in the southeast of the East European Platform: petrogenesis and tectonic setting

2019 ◽  
Vol 27 (4) ◽  
pp. 357-400
Author(s):  
A. A. Nosova ◽  
A. A. Voznyak ◽  
S. V. Bogdanova ◽  
K. A. Savko ◽  
N. M. Lebedeva ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
East European Platform ◽  
Tectonic Setting ◽  
Geochemical Data ◽  
Early Cambrian ◽  
Southeastern Part ◽  
East European ◽  
Isotopic Compositions ◽  
Time Period ◽  
Feature Negative

The paper reports new geochronological, petrological, and isotope-geochemical data on the syenites and alkali syenites of the Artyushki massif, and the monzonites of the Gusikha massif. These massifs are located along the southwestern and northeastern margins of the Pachelma aulacogen, in the southeastern part of the East European Platform (EEP). They have Early Cambrian ages of 524 ± 3 (Artyushki) and 514 ± 2 Ma (Gusikha) obtained by the U-Pb zircon method and similar ages of amphibole and K-feldspar by the 40Ar/39Ar method. This time period has previously been regarded as amagmatic in the EEP evolution. The Artyushki massif is made up of Amp-Cpx syenite porphyries and Grt-Cpx alkali syenite porphyries and their fenitized varieties. As compared to the Amp-Cpx varieties the Grt-Cpx rocks are more peralkaline (A/NK > 0.9) and have higher LREE and HFSE, and fractionated HREE patterns. The metasomatized (fenitized) varieties are more potassic and bear geochemical evidence of fluid reworking (high Y/Ho ratios, significant Zn variations, and etc.). Bulk samples have weakly radiogenic Sr isotopic compositions: (87Sr/86Sr)520 are within 0.703066–0.703615. The values of εNd(520) vary from –0.69 to +1.64. The Grt-Cpx syenite porphyries have the positive εNd(520), while the Amp-Cpx and fenitized syenite porphyries feature negative εNd. The Gusikha massif consists of biotite-amphibole and biotite monzonites. Similar to the Artyushki syenites in SiO2 contents, the Gusikha monzonites have higher Mg# (0.22–0.54 and 0.34–0.71 for the Artyushki and Gusikha massifs, respectively). They are also characterized by a negative Nb-Ta anomaly (Nb/Nb* = 0.5), high Ва/Sr ratio, and highly radiogenic (87Sr/86Sr)520 = 0.705204 and 0.705320. Their Nd-isotopic compositions correspond to εNd(520) = –6.7 and –7.0. Two melts contributed to the formation of the Artyushki massif. One was a strongly contaminated melt (Amp-Cpx syenite porphyries, the other was weakly contaminated (Grt-Cpx syenite porphyries). The main contribution was phonolitic melt derived from the melting of a moderately metasomatized (carbonate- and amphibole-bearing) shallow lithospheric mantle. The earliest and deepest melt portions were carbonate-silicate in composition. The geochemical, as well as the Sr and Nd isotopic compositions of the Gusikha monzonites indicate a predominant crustal contribution and pervasive reworking of the lithospheric mantle beneath southeastern Volgo-Uralia of the EEP in the Mesoproterozoic. Both massifs feature the geochemistry of within-plate and supra-subduction derivatives, which suggests a postorogenic tectonic setting of the magmatism. The presence of the Early Cambrian postorogenic magmatism within the East European Platform/Baltica is direct evidence for the involvement of Baltica in the collisional and/or accretionary events during the terminal Neoproterozoic – the beginning of the Paleozoic. This suggests reworking of the lithospheric mantle of Baltica during its collision with Timanian and East Avalonian/Cadomian terranes, including Scythia.

Early Cambrian Syenite and Monzonite Magmatism in the Southeast of the East European Platform: Petrogenesis and Tectonic Setting

Petrology ◽  
2019 ◽  
Vol 27 (4) ◽  
pp. 329-369 ◽  
Author(s):  
A. A. Nosova ◽  
A. A. Voznyak ◽  
S. V. Bogdanova ◽  
K. A. Savko ◽  
N. M. Lebedeva ◽  
...  
Keyword(s):  
East European Platform ◽  
Tectonic Setting ◽  
Early Cambrian ◽  
East European
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