Late Carboniferous to Recent, Geodynamic Evolution of the West Gondwanian, Cratonic, Tethyan Margins

1995 ◽  
pp. 101-124 ◽  
Author(s):  
René Guiraud ◽  
Yves Bellion
Keyword(s):  
Late Carboniferous ◽  
Geodynamic Evolution ◽  
The West

Outflow ignimbrite sheets from Late Carboniferous calderas, Currabubula Formation, New South Wales, Australia

1983 ◽  
Vol 120 (5) ◽  
pp. 487-503 ◽  
Author(s):  
J. McPhie
Keyword(s):  
New South ◽  
Sedimentary Facies ◽  
Late Carboniferous ◽  
The West ◽  
Pyroclastic Deposits ◽  
Flow Units ◽  
South Wales ◽  
Accretionary Lapilli ◽  
North Eastern ◽  
Thickness Variations

SummaryRegionally mappable, silicic, outflow ignimbrite sheets are interbedded with fluvial volcanogenic conglomerates and sandstones of the Late Carboniferous Currabubula Formation of north-eastern N.S.W. Four of the most widespread of these ignimbrites are described and defined as members. The oldest member is comprised of many thin, originally non-welded flow units. Interbedded accretionary lapilli horizons may indicate phreatomagmatic activity at vent during the eruption in addition to local rain-flushing of co-ignimbrite ash clouds. Of the three other members, two are multiple flow-unit sheets, 160–180 m in aggregate thickness. Substantial portions of these sheets were originally welded. The remaining member is a simple welded ignimbrite characterized by abundant spherulites and lithophysae. Irregular pre-eruption topography and contemporaneous erosion were responsible for thickness variations of the ignimbrite sheets. Some palaeovalleys, now delineated by the ignimbrites, persisted in spite of repeated pyroclastic influxes. Relic pumice, shards and crystal fragments are ubiquitous components of the sedimentary facies of the Currabubula Formation, and were probably derived from originally poorly consolidated pyroclastic deposits such as airfall ash layers and non-welded ignimbrites. No surface trace of the sources of these ignimbrites exists. However, internal facies, thickness variations and volumes of the ignimbrites indicate that they periodically emanated from a multiple-caldera terrain which was continuously active during the Late Carboniferous, and located several kilometres to the west of present exposures.

Kinematic data on major Variscan strike-slip faults and shear zones in the Polish Sudetes, northeast Bohemian Massif

1997 ◽  
Vol 134 (5) ◽  
pp. 727-739 ◽  
Author(s):  
P. ALEKSANDROWSKI ◽  
R. KRYZA ◽  
S. MAZUR ◽  
J. ŻABA
Keyword(s):  
Shear Zone ◽  
Fault Zone ◽  
Bohemian Massif ◽  
Early Carboniferous ◽  
Shear Zones ◽  
Strike Slip ◽  
Late Carboniferous ◽  
Late Devonian ◽  
The West ◽  
West Sudetes

The still highly disputable terrane boundaries in the Sudetic segment of the Variscan belt mostly seem to follow major strike-slip faults and shear zones. Their kinematics, expected to place important constraints on the regional structural models, is discussed in some detail. The most conspicuous is the WNW–ESE Intra-Sudetic Fault Zone, separating several different structural units of the West Sudetes. It showed ductile dextral activity and, probably, displacement magnitude of the order of tens to hundreds kilometres, during late Devonian(?) to early Carboniferous times. In the late Carboniferous (to early Permian?), the sense of motion on the Intra-Sudetic Fault was reversed in a semi-brittle to brittle regime, with the left-lateral offset on the fault amounting to single kilometres. The north–south trending Niemcza and north-east–southwest Skrzynka shear zones are left-lateral, ductile features in the eastern part of the West Sudetes. Similarly oriented (northeast–southwest to NNE–SSW) regional size shear zones of as yet undetermined kinematics were discovered in boreholes under Cenozoic cover in the eastern part of the Sudetic foreland (the Niedźwiedź and Nysa-Brzeg shear zones). One of these is expected to represent the northern continuation of the major Stare Mesto Shear Zone in the Czech Republic, separating the geologically different units of the West and East Sudetes. The Rudawy Janowickie Metamorphic Unit, assumed in some reconstructions to comprise a mostly strike-slip terrane boundary, is characterized by ductile fabric developed in a thrusting regime, modified by a superimposed normal-slip extensional deformation. Thrusting-related deformational fabric was locally reoriented prior to the extensional event and shows present-day strike-slip kinematics in one of the sub-units. The Sudetic Boundary Fault, although prominent in the recent structure and topography of the region, was not active as a Variscan strike-slip fault zone. The reported data emphasize the importance of syn-orogenic strike-slip tectonics in the Sudetes. The recognized shear sense is compatible with a strike-slip model of the northeast margin of the Bohemian Massif, in which the Kaczawa and Góry Sowie Units underwent late Devonian–early Carboniferous southeastward long-distance displacement along the Intra-Sudetic Fault Zone from their hypothetical original position within the Northern Phyllite Zone and the Mid-German Crystalline High of the German Variscides, respectively, and were juxtaposed with units of different provenance southwest of the fault. The Intra-Sudetic Fault Zone, together with the Elbe Fault Zone further south, were subsequently cut in the east and their eastern segments were displaced and removed by the younger, early to late Carboniferous, NNE–SSW trending, transpressional Moldanubian–Stare Mesto Shear Zone.

scholarly journals Observations Concerning the Thickness of Rocks Eroded Between the Cambrian and Bolsovian (= Westphalian C) in Central and Western Bohemia

2012 ◽  
Vol 46 (1-2) ◽  
pp. 1-14 ◽  
Author(s):  
Jiří Pešek ◽  
Karel Martínek
Keyword(s):  
Late Carboniferous ◽  
The Other ◽  
The West ◽  
Lower Paleozoic ◽  
Upper Carboniferous ◽  
Western Bohemia ◽  
Volcaniclastic Rocks

Abstract Carboniferous outliers are found west of the late Carboniferous West Bohemian basins and also south of the West and Central Bohemian basins. The West Bohemian group is Asturian (= Westphalian D) or younger and is notably coal-bearing, the other group of outliers consists mostly of coal-bearing upper Carboniferous volcaniclastic rocks of Bolsovian (= Westphalian C) and/or Asturian age. They form a discontinuous belt extending through the area between and around the towns of Merklín and Beroun. These rocks are underlain chiefly by rocks of ages varying from the Neoproterozoic or Cambrian up to the Ordovician. If the nappe structure of the Barrandian Lower Paleozoic proposed by Melichar and Hladil (e.g. 1999) is not widely present, then it can be assumed that as much as 1850 m of Lower Paleozoic sediments and volcanics could have been eroded prior to the onset of sedimentation of the Bolsovian rocks. In the upper Carboniferous outliers near Mirošov, Skořice and Kamenný Újezd, where sedimentation began as late as in the Asturian, the thickness of eroded deposits might have been even greater, reaching as much as 3150 m.

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