Successive Paleocene and Eocene infillings of polyphase paleokarsts within the Cretaceous limestones of the Empordà thrust sheets (Catalan Pyrenees, Spain) : relationships between tectonics and karstification

2007 ◽  
Vol 178 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Bernard Peybernès ◽  
Marie-José Fondecave-Wallez ◽  
Pierre-Jean Combes ◽  
Michel Seranne
Keyword(s):  
Late Cretaceous ◽  
Root Zone ◽  
Planktonic Foraminifera ◽  
Thrust Sheet ◽  
Tectonic Events ◽  
Karst Formation ◽  
Early Paleocene ◽  
Thrust Sheets

Abstract The Mesozoic series of the southern units of the Pyrenean Empordà thrust sheets (Montgrí and Figueres nappes, Catalonia, Spain) were finally emplaced over the autochthonous basement and its Cenozoic cover during Eocene times. However, they have originally been folded by the “Laramian” compressional event (Late Cretaceous/Early Paleocene), while they were still in their root zone more than 50 km to the N-NE. Postdating the Santonian, the emersion of the Cretaceous tectorogen induced karst formation at the expense of Berriasian to Santonian limestone sequences. Karst cavities of this paleokarst 1 (lapiaz and canyons) were subsequently coated with a fine, red or black, Microcodium-bearing, continental silt, and infilled with marine chaotic breccias. Following a new episode of emersion then erosion, the original paleokarst 1 was cross-cut by newly formed cavities of the paleokarst 2, filled with Lutetian-Bartonian marine breccias. Both types of marine breccias (Paleocene then Eocene in age) are now relatively well dated by means of planktonic foraminifera (Globigerinacea) occurring within the argillaceous-sandy matrix, and for the older ones, within the argillaceous-sandy or carbonate, finely laminated, interbedded hemipelagites, that mark the top of marine sequences tens of centimetres thick. The relationships of the “Laramian” and “Pyrenean” compressional tectonic events, occurring from latest Cretaceous to Bartonian, with the development of paleokarsts 1 and 2 are analysed in the perspective of the progressive southwards emplacement of the Montgrí thrust sheet, during Eocene time.

The crucial boundaries in the development of the late cretaceous biota of plankton foraminifers in the southern part of the Indian ocean

2019 ◽  
Vol 59 (6) ◽  
pp. 1074-1085
Author(s):  
E. A. Sokolova
Keyword(s):  
Indian Ocean ◽  
Species Composition ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Planktonic Foraminifera ◽  
The Indian Ocean ◽  
Systematic Composition ◽  
Climatic Series

The article analyzes own data on the species composition of shells of planktonic foraminifera from the Upper Cretaceous sediments of the Indian Oceans, as well as from the sections of the offshore seas of Australia. The species of planktonic foraminifera are grouped and arranged in a climatic series. An analysis of the change in the systematic composition of foraminifers made it possible to distinguish periods of extreme and intermediate climatic states in the Late Cretaceous.

Structural analysis of Bic fault, a thrust-related strike-slip fault of the external domain of the Taconic Orogen, Appalachians, Quebec, and metallogenic implications

1991 ◽  
Vol 28 (5) ◽  
pp. 788-799 ◽  
Author(s):  
P. Rhéaume ◽  
K. Schrijver
Keyword(s):  
Strike Slip ◽  
Strike Slip Fault ◽  
Thrust Sheet ◽  
Kink Bands ◽  
Strain Ellipsoid ◽  
Adjacent Part ◽  
External Domain ◽  
Dextral Strike Slip Fault ◽  
Thrust Sheets ◽  
Stage 1

The Bic fault is exposed along the shoreline of the St. Lawrence River, 21 km southwest of Rimouski, for 210 m at Cap à l'Orignal and for 100 m at Cap Enragé. The fault brings in contact two major thrust sheets, the Des Seigneuries and the Des Iles, Cambrian lithologies of the former overlying Ordovician rocks of the latter. In the Taconic Orogen, such contacts are normally thrust faults, but the Bic fault is a dextral strike-slip fault, striking east–west and dipping southward. A study of a narrow zone straddling the fault and an adjacent part of the Des Seigneuries thrust sheet has led to the recognition of four successive stages of deformation, all compatible with a northeast–southwest-trending strain ellipsoid. The two first stages are most important: stage 1 brought about regional folding and faulting, whereas stage 2 was characterized by the development of various structural elements (C–S fabrics, stretching lineation, Riedel shears, and kink bands) exclusive to the fault zone. We infer that (i) in the study area, the Bic fault constituted a lateral ramp along which the Des Seigneuries thrust sheet slid horizontally westward; and (ii) emplacement of Ba–Pb–Zn deposits took place slightly after this movement, probably during regional uplift of the orogen in Late Ordovician to Early Silurian time. The latter hypothesis tends to be corroborated by model lead ages of galena in two deposits.

The Ecological Balance of Nature: Identifying Stasis and Growth in Late Cretaceous Planktonic Foraminifera from ODP Hole 690C (Weddell Sea)

2020 ◽  
Vol 50 (3) ◽  
pp. 313-317
Author(s):  
Martin A. Buzas ◽  
Lee-Ann C. Hayek ◽  
Brian T. Huber
Keyword(s):  
Species Richness ◽  
Late Cretaceous ◽  
Planktonic Foraminifera ◽  
Sampling Time ◽  
Weddell Sea ◽  
Species Evenness ◽  
Data Set ◽  
Balance Of Nature ◽  
Ecological Balance ◽  
Do So

ABSTRACT The ecological balance of nature is defined as an equilibrium between species richness (S) and species evenness (E) such that diversity (H) remains constant with time. Based on this definition, our approach identifies growth or decline in communities as perturbations from stasis and has successfully done so for benthic foraminiferal communities. Here, we examine whether this approach is appropriate for planktonic foraminifera. To do so, we utilized planktonic foraminiferal counts (39 samples, 66% recovery) from Maastrichtian sediments in the Weddell Sea from ODP Hole 690C. A total of 24 species were observed and both >63-µm and >150-µm fractions were counted. In the >63-µm fraction, nine communities were recognized while in the >150-µm fraction, there were 12. In both fractions at 70.45 Ma, a boundary was recognized and immediately after this boundary, a community in growth was identified. A trend of increasing diversity upcore was substantiated by regression on individual samples. For our purposes, the >150-µm fraction in this data set is sufficient to recognize community trends. The >150-µm fraction in Hole 690C has 82% of the sampling time in stasis and an average time per community is 0.85 Ma. The >63-µm fraction has 73% of the sampling time in stasis and an average time per community of 1.02 Ma.

Revised age constraints for Late Cretaceous to early Paleocene terrestrial strata from the Dawson Creek section, Big Bend National Park, west Texas

2018 ◽  
Vol 130 (7-8) ◽  
pp. 1143-1163 ◽  
Author(s):  
Caitlin E. Leslie ◽  
Daniel J. Peppe ◽  
Thomas E. Williamson ◽  
Matthew Heizler ◽  
Mike Jackson ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
National Park ◽  
Big Bend National Park ◽  
West Texas ◽  
Big Bend ◽  
Early Paleocene ◽  
Age Constraints

scholarly journals The Cretaceous-Paleogene boundary in turbiditic deposits identified to the bed: a case study from the Skole Nappe (Outer Carpathians, southern Poland)

2011 ◽  
Vol 62 (4) ◽  
pp. 333-343 ◽  
Author(s):  
M. Gasiński ◽  
Alfred Uchman
Keyword(s):  
Precise Determination ◽  
Thrust Sheet ◽  
Southern Poland ◽  
The Carpathians ◽  
Early Paleocene ◽  
Outer Carpathians ◽  
First Time

The Cretaceous-Paleogene boundary in turbiditic deposits identified to the bed: a case study from the Skole Nappe (Outer Carpathians, southern Poland)The Cretaceous-Paleogene (K-T) boundary has been recognized in turbiditic sediments of the Ropianka Formation in the Skole Nappe (Bąkowiec section) on the basis of planktonic foraminiferids with an accuracy of 40 cm. Such precise determination of the K-T boundary for the first time in the Carpathians and in turbiditic flysch sediments in general was possible due to the successive occurrence of the Early Paleocene planktonic taxa of the P1 Zone above the latest MaastrichtianAbathomphalus mayaroensisZone with theRacemiguembelina fructicosaSubzone. The trends in composition of the latest Maastrichtian foraminiferal assemblages are similar to the Gaj section from the adjacent thrust sheet, probably due to the influence of the same paleoenvironmental factors.

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