A Lower Palaeozoic shallow water sequence in the eastern European Variscides (SW Poland): provenance and depositional history

1994 ◽  
Vol 83 (1) ◽  
pp. 5-19 ◽  
Author(s):  
Ryszard Kryza ◽  
Krzysztof Turniak ◽  
Andrzej Muszyński ◽  
Jan A. Zalasiewicz
2016 ◽  
Vol 154 (2) ◽  
pp. 305-333 ◽  
Author(s):  
C. N. WATERS ◽  
P. CÓZAR ◽  
I. D. SOMERVILLE ◽  
R. B. HASLAM ◽  
D. MILLWARD ◽  
...  

AbstractA rationalized lithostratigraphy for the Great Scar Limestone Group of the southeast Askrigg Block is established. The basal Chapel House Limestone Formation, assessed from boreholes, comprises shallow-marine to supratidal carbonates that thin rapidly northwards across the Craven Fault System, onlapping a palaeotopographical high of Lower Palaeozoic strata. The formation is of late Arundian age in the Silverdale Borehole, its northernmost development. The overlying Kilnsey Formation represents a southward-thickening and upward-shoaling carbonate development on a S-facing carbonate ramp. Foraminiferal/algal assemblages suggest a late Holkerian and early Asbian age, respectively, for the uppermost parts of the lower Scaleber Force Limestone and upper Scaleber Quarry Limestone members, significantly younger than previously interpreted. The succeeding Malham Formation comprises the lower Cove Limestone and upper Gordale Limestone members. Foraminiferal/algal assemblages indicate a late Asbian age for the formation, contrasting with the Holkerian age previously attributed to the Cove Limestone. The members reflect a change from a partially shallow-water lagoon (Cove Limestone) to more open-marine shelf (Gordale Limestone), coincident with the onset of marked sea-level fluctuations and formation of palaeokarstic surfaces with palaeosoils in the latter. Facies variations along the southern flank of the Askrigg Block, including an absence of fenestral lime-mudstone in the upper part of the Cove Limestone and presence of dark grey cherty grainstone/packstone in the upper part the Gordale Limestone are related to enhanced subsidence during late Asbian movement on the Craven Fault System. This accounts for the marked thickening of both members towards the Greenhow Inlier.


1979 ◽  
Vol 8 (1) ◽  
pp. 533-544 ◽  
Author(s):  
P. M. Brück ◽  
P. R. R. Gardiner ◽  
T. J. Reeves ◽  
P. M. Shannon ◽  
J. R. J. Colthurst ◽  
...  

2019 ◽  
Vol 157 (4) ◽  
pp. 539-550
Author(s):  
Gabriela Torre ◽  
Guillermo L. Albanesi

AbstractThe presence of a carbonate platform that interfingers towards the west with slope facies allows for the identification of an ancient lower Palaeozoic continental margin in the Western Precordillera of Argentina. The Los Sombreros Formation is essential for the interpretation of the continental slope of the Precordillera, which accreted to Gondwana as part of the Cuyania Terrane in the early Palaeozoic. The age of these slope deposits is controversial; therefore, a precise biostratigraphic scheme is critical to reveal the evolution of the South American continental margin of Gondwana. The study of lithic deposits of two sections of the Los Sombreros Formation, the El Salto and Los Túneles sections, provides important information for further understanding the depositional history of the slope. At El Salto section, the conodonts recovered from an allochthonous block refer to the Cordylodus proavus Zone (upper Furongian). The conodonts recovered from the matrix of a calclithite bed of the Los Sombreros Formation in the Los Túneles section are assigned to the Lenodus variabilis Zone (early Darriwilian), providing a minimum age for this stratigraphic unit. In addition, clasts from this sample yielded conodonts from the Paltodus deltifer − Macerodus dianae zones (upper Tremadocian). The contrasting conodont colour alterations and preservation states from the elements of two latter records, coming from the same sample, argue the reworked clasts originated in the carbonate platform and later transported to the slope during the accretion process of the Precordilleran Terrane to the South American Gondwanan margin during the Middle–Late Ordovician.


1937 ◽  
Vol 74 (11) ◽  
pp. 481-495 ◽  
Author(s):  
G. L. Elles

The classification of the British Ordovician Rocks has gone through many phases of instability in the past, and at the present time seems to be passing through another such phase. There are probably many causes contributing to this state of things, two of which seem to be fundamental; the first, the differentfacies of development exhibited in different districts by the formations making up the system; the second, the varied elements entering into the composition of the shallow water faunas apart from the considerations of facies; these would seem to be governed largely by possibilities of migration into the British region of the Lower Palaeozoic geosyncline from different directions, i.e. from America, from Northern Europe, and from Central Europe, so that a different type of “shelly” fauna characterizes the north-west and south-east margins.


1992 ◽  
Vol 6 ◽  
pp. 77-77
Author(s):  
T. Peter Crimes ◽  
N. Chris Hunt

There was a dramatic increase in abundance and diversity of trace fossils in Upper Precambrian and Lower Cambrian shallow water seas. The trace-producing animals rapidly filled all the available niches and in low energy, muddy, environments they evolved winding, meandering and patterned habits. Traces such as Taphrhelminthopsis, Helminthoida, Nereites, Paleodictyon and Squamodictyon had all evolved in clastic shelf seas during the pre-trilobite Lower Cambrian.Significant colonisation of the deep oceans seems to have mostly been delayed until the Ordovician. A recently described suite of trace fossils from a flysch sequence in Eire includes such deep water types as: Glockerichnus, Helminthopsis, Lorenzinia, Paleodictyon and Taphrhelminthopsis. This migration into the deep sea is accompanied by a virtual absence of such traces from shallow water sequences after the Cambrian.Deep water trace fossils therefore seem to have evolved initially in shallow water clastic seas and then migrated in to the deep ocean, thereby providing an exciting example of an onshore-offshore pattern. This may be of particular significance in that it is presumably mimicked by body fossil migrations in these early seas.


2007 ◽  
Vol 145 (1) ◽  
pp. 85-93 ◽  
Author(s):  
RAFAŁ TYSZKA ◽  
RYSZARD KRYZA ◽  
JAN A. ZALASIEWICZ ◽  
ALEXANDER N. LARIONOV

AbstractSIMS dating of detrital zircons from the stratigraphically enigmatic Radzimowice Slates of the Kaczawa Mountains (Sudetes, SW Poland), near the eastern termination of the European Variscides, has yielded age populations of: (1) 493–512 Ma, corresponding to late Cambrian to early Ordovician magmatism and constraining a maximum depositional age; (2) between 550 and 650 Ma, reflecting input from diverse Cadomian sources; and (3) older inherited components ranging to c. 3.3 Ga, with age spectra similar to those from Gondwanan North Africa. The new data show that the Radzimowice Slates cannot form a Proterozoic base to the Kaczawa Mountains succession, as suggested by earlier models, but was deposited, at the earliest, as an extensional basin-fill, during a relatively late stage of the break-up of this part of northern Gondwana.


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