Wyniki wyszukiwania - Biblioteka Nauki

1

Slope failure on a Cambrian carbonate platform, mass-flow transitions and resulting complex deposit

100%

Wang Z. , Liu J. , Van Loon A. J. T. , Zhu D. , Qin P. , Han Z.

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tom Vol. 64, No. 1

3--15

EN

The quiet environment of the carbonate platform in the epeiric sea that existed during the Cambrian between present-day China and Korea was occasionally affected by processes that have hitherto not been described from such a setting. A conglomerate was found in the Middle Cambrian Gushan Formation near Chengouwan (Shandong Province, E China), eroded into the underlying sediments. The conglomerate is explained as a deposit consisting of material that was eroded up-slope when slope-failure took place, resulting in a slump that passed into a high-density debris flow with erosive power that passed, in turn, again into a slump. The slump came to rest when it lost its momentum on a less inclined part of the basin slope. Immediately after deposition, fluidization occurred in the lower part of the slump deposit, as proven by a funnel-shaped water-escape structure and a lateral injection of some metres long of brecciated material.

2

The Burges Shale animal Oesia is not a chaetognath: A reply to Szaniawski [2005]

86%

Morris S. C.

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nr 1

175-179

EN

The Middle Cambrian Oesia disjuncta, a monospecific genus, is known only from the celebrated Burgess Shale of British Columbia. It has been re−interpreted by Szaniawski (Acta Palaeontologica Polonica 50:1–8; 2005) as a chaetognath, a distinctive phylum whose exact position in the protostomes is still controversial. Unequivocal chaetognaths, that have no similarity to Oesia, are already known to occur in the Chengjiang Lagerstätte (Lower Cambrian, S.W. China), and here I describe the first example of a chaetognath from the Burgess Shale itself. Comparisons between Oesia and chaetognaths fail to find any significant homologies. Whilst the phyletic position of Oesia is very uncertain, a place in the hemichordates may be worth exploring.

3

Perspektywiczne obszary poszukiwań węglowodorów w kambrze polskiej części platformy wschodnioeuropejskiej

72%

Stolarczyk F. , Stolarczyk J. , Wysocka H.

Przegląd Geologiczny

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2004

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tom Vol. 52, nr 5

403-–412

EN

Perspectives of prospecting for hydrocarbons in the Platform Cambrian strata of NE Poland are evaluated. The evaluation includes previous studies on type and distribution of sedimentary facies, possibilities of generating, accumulating and retention of hydrocarbons, reservoir properties of rocks, and presence of local structures. The results of their analysis presented herein allowed to delineate the optimum zone of occurrence of hydrocarbons, and to indicate primary areas within that zone to be prospected first. According to these criteria, the perspective zone for hydrocarbon prospecting in the Cambrian strata occurs on theWestern slope of the East European Platform and in its regional depressions, where the Cambrian occurs at depth 1500–3000 metres. A detailed analysis of geological data permits to pinpoint the following especially promising areas within that zone (fig. 7), best suited for hydrocarbon accumulation and deserving special attention: the Siedlce palaeoelevation; the Olsztyn palaeoelevation; an area near the Polish state border near Braniewo, Górowo Iławeckie and Bartoszyce; peri-Baltic part of the Łeba Elevation.

4

Bentonit środkowokambryjski z otworu Borcz-1 z basenu bałtyckiego

72%

Kowalska S. , Zagórska U. , Mikołajewski Z.

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2016

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tom R. 72, nr 12

1043--1048

PL

Nie odnotowano dotąd obecności śladów aktywności wulkanicznej w utworach kambryjskich występujących na obszarze polskiej części skłonu platformy wschodnioeuropejskiej. Dzięki nowym wierceniom prowadzonym przez PGNiG SA podczas poszukiwania gazu w pokładach łupków w otworze Borcz-1 udało się znaleźć cienką 3-centymetrową wkładkę bentonitową w obrębie utworów kambru środkowego. W prezentowanym artykule przedstawione zostaną pierwsze wyniki badań wykonanych w celu przeprowadzenia charakterystyki mineralogicznej powyższej skały. Analiza pierwiastków śladowych pozwoliła na określenie przybliżonego składu pierwotnego materiału wulkanicznego, wskazując na obojętny, trachyandezytowy charakter magmy macierzystej. Materiał wulkaniczny pochodził najprawdopodobniej z rejonu aktywnej krawędzi kontynentu.

EN

Traces of volcanic activity in the Cambrian rocks occurring within the Polish part of the East European Platform slope has not been recorded to date. Thanks to new shale gas exploration conducted by PGNiG SA a thin, 3 cm thick, bentonite layer was found within the Middle Cambrian strata in the Borcz-1 borehole. This article presents the first results of studies carried out, in order to perform mineralogical characteristics of the above rock. Analysis of trace elements composition, allowed us to determine the approximate initial composition of original volcanic material pointing to an intermediate, trachyandesitic parent magma. Volcanic material probably came from an active continental margin.

5

Soft-part preservation in two species of the arthropod Isoxys from the middle Cambrian Burgess Shale of British Columbia, Canada

58%

Garcia-Bellido D. C. , Vannier J. , Collins D.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 4

EN

More than forty specimens from the middle Cambrian Burgess Shale reveal the detailed anatomy of Isoxys, a worldwide distributed bivalved arthropod represented here by two species, namely Isoxys acutangulus and Isoxys longissimus. I. acutangulus had a non−mineralized headshield with lateral pleural folds (= “valves” of previous authors) that covered the animal’s body almost entirely, large frontal spherical eyes and a pair of uniramous prehensile appendages bearing stout spiny outgrowths along their anterior margins. The 13 following appendages had a uniform biramous design—i.e., a short endopod and a paddle−like exopod fringed with marginal setae with a probable natatory function. The trunk ended with a flap−like telson that protruded beyond the posterior margin of the headshield. The gut of I. acutangulus was tube−like, running from mouth to telson, and was flanked with numerous 3D−preserved bulbous, paired features interpreted as digestive glands. The appendage design of I. acutangulus indicates that the animal was a swimmer and a visual predator living off−bottom. The general anatomy of Isoxys longissimus was similar to that of I. acutangulus although less information is available on the exact shape of its appendages and visual organs. I. longissimus is characterized by extremely long anterior and posterior spines. There are now seven Isoxys species known with soft−part preservation, I. acutangulus, I. longissimus from the Burgess Shale, I. auritus and I. curvirostratus from the Maotianshan Shale of China, I. communis and I. glaessneri from the Emu Bay Shale of Australia and I. volucrisfrom Sirius Passet in Greenland. The frontal appendages of Isoxys strongly resemble those of other Cambrian arthropods, characterized by a single pair of “great appendages” with a shared prehensile function yet some variability in length and shape.

6

Morphology and relationships of the enigmatic stenothecoid pan-brachiopod Stenothecoides - new data from the middle Cambrian Burgess Shale Formation

58%

Johnston P. A. , Streng M.

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nr 4

7

Fossil chaetognaths from the Burgess Shale: A reply to Conway Morris [2009]

58%

Szaniawski H.

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nr 2

361-364

EN

Walcott (1911) erected the new genus and species Oesia disjuncta and assigned them to the polychaete annelids, based on a small collection of similar fossils from the famous Middle Cambrian Burgess Shale. In 2002 I suggested that the species is “possibly related to chaetognaths” (Szaniawski 2002: 405). Later, after obtaining new photos of the specimens and making comparative investigations with the extant chaetognaths, I was able to describe many significant similarities, and came to the conclusion that O. disjuncta indeed is an ancestral chaetognath (Szaniawski 2005). This interpretation already has been accepted in several publications (Vannier et al. 2005; Ball and Miller 2006; Hu et al. 2007. Giribet 2008). Ball and Miller (2006: 594) confirmed not only its “... remarkable resemblance to modern chaetognaths” but also correctness of recognition of all its organs. They even reproduced a part of my illustration showing them (Ball and Miller 2006: fig. 2). Vannier et al. (2006: 629) combined the problem with the open question of the systematic position of another Burgess Shale fossil Amiskwia sagittiformis Walcott, 1911, and expressed their reservation based on “...the lack of clear evidence of a grasping apparatus...”. Only Conway Morris (2009) firmly disagreed with this diagnosis and even devoted a special “discussion” article addressing the issue. However, that article contains several ambiguities and misunderstandings which need clarification.

8

Burgess Shale-type microfossils from the middle Cambrian Kaili Formation, Guizhou Province, China

58%

Harvey T. H. P. , Ortega-Hernandez J. , Lin J.-P. , Yuanlong Z. , Butterfield N. J.

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nr 2

EN

Diverse carbonaceous microfossils, including exceptionally preserved remains of non−biomineralizing metazoans, are reported from a basal middle Cambrian interval of the Kaili Formation (Guizhou Province, China). The application of a gentle acid maceration technique complements previous palynological studies by revealing a larger size−class of acritarchs, a richer assemblage of filamentous microfossils, and a variety of previously unrecovered forms. Metazoan fossils include Wiwaxia sclerites and elements derived from biomineralizing taxa, including chancelloriids, brachiopods and hyolithids, in common with previously studied assemblages from the early and middle Cambrian of Canada. In addition, the Kaili Formation has yielded pterobranch remains and an assemblage of cuticle fragments representing “soft−bodied” worms, including a priapulid−like scalidophoran. Our results demonstrate the wide distribution and palaeobiological importance of microscopic “Burgess Shale−type” fossils, and provide insights into the limitations and potential of this largely untapped preservational mode.

9

Middle Cambrian gogiid echinoderms from Northeast Spain: Taxonomy, palaeoecology, and palaeogeographic implications

58%

Zamora S. , Gozalo R. , Linan E.

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nr 2

253-265

EN

Gogia parsleyi Zamora sp. nov. and Gogia sp. are described from two different echinoderm assemblages, both from the middle Cambrian of the Murero Formation (Iberian Chains, NE Spain). Gogia parsleyi is reconstructed and described on the basis of fifteen complete or partial specimens and numerous isolated plates. It is characterised by spiralled brachioles, simple epispires, sometimes covered by stereomic domes or tiny cover plates, and by thecal plates arranged in subregular circlets. This gogiid population comprises juveniles, advanced juveniles and mature individuals. The material was found in the upper part of the Murero Formation (upper Caesaraugustian–lower Languedocian). Gogia sp. is represented by two almost complete specimens and several isolated plates from the lower part of the Murero Formation (lower Caesaraugustian). The genus Gogia was first described in Western Gondwana from the Languedocian (upper middle Cambrian) of France, but the material from Spain is older and represents the oldest record of this genus in Gondwana, suggesting an early migration from Laurentia. The gogiids are well preserved in two echinoderm Lagerstätten, which, together with other echinoderms, comprise the majority of the fossil fauna. Both levels are derived from obrution deposits produced in calm and open marine conditions, sometimes affected by sporadic storms. Their holdfast morphology suggests that these gogiids were low−tier suspension feeders, living attached to trilobite fragments in a soft, muddy environment.

10

Rugosa and Scleractinia - a commentary on some methods of phylogenetic reconstructions

58%

Fedorowski J.

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1997

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tom 42

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nr 3

EN

The origin of the Rugosa and relationships between the Rugosa and Scleractinia are debated. In the present account I comment on some recently published phylogenetic reconstructions, which in my opinion, are based on inadequate data.

11

A new Middle Cambrian stem-group echinoderm from Spain: Palaeobiological implications of a highly asymmetric cinctan

58%

Zamora S. , Smith A. B.

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2008

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tom 53

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nr 2

EN

A new exquisitely preserved stem group echinoderm (cinctan), Lignanicystis barriosensis gen. et sp. nov., is described from the Middle Cambrian of Los Barrios de Luna, North Spain. This displays a unique asymmetrical body plan with ventral projecting nodes that raised the lower surface above the substratum. There are four openings through the body wall: mouth, anus, atrium, and an aligned row of sutural pores of uncertain function. Unlike other cinctans, Lignanicystis has a strongly asymmetrical shape convergent with that of some cornute carpoids. Like cornutes, the test is also elevated above the substratum to allow water flow beneath the theca. In both cases this is probably an adaptation to life in higher water flow regimes.