Block tilting of the North Provence early Cretaceous carbonate margin: stratigraphic, sedimentologic and tectonic data

2009 ◽  
Vol 180 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Jean-Pierre Masse ◽  
Michel Villeneuve ◽  
Emmanuelle Leonforte ◽  
Jean Nizou
Keyword(s):  
Early Cretaceous ◽  
Biological Diversity ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Structural Elements ◽  
The North ◽  
Subaerial Exposure ◽  
Tectonic Events ◽  
Complete Series ◽  
Structural Architecture

Abstract In the western part of the Castellane tectonic arc, the so-called “ Provence platform area “, corresponding to the foreland of the Alpine nappes (figs. 1–2), is marked by Tithonian-Berriasian shallow water carbonates capped by hemipelagic sediments deposited from the Valanginian up to the Aptian-Albian. A detailed biostratigraphic study of the Berriasian succession, based on calcareous algae and foraminifera, allows us to distinguish a Lower to Middle Berriasian, with Clypeina sulcata, Clypeina isabellae and Holosporella sarda, from an Upper Berriasian with Pfenderina neocomiensis, Danubiella cernavodensis, Falsolikanella campanensis and Macroporella praturloni (fig. 3). We performed a field survey of 30 sites located from Quinson to the west, and Escragnolles to the east (figs. 4–5) including the study of measured stratigraphic sections and the collection of samples for biostratigraphic interpretations. These stratigraphic investigations show that below the Valanginian beds, the Berriasian platfom carbonate succession, is locally incomplete, i.e. Upper Berriasian beds are frequently absent. During the Early and Middle Berriasian, depositional environments are marked by a strong bathymetric instability, with frequent subaerial exposure events, and a significant marine restriction; by contrast, during the Late Berriasian, the overall biological diversity increases and water agitation as well, which means a significant marine opening towards the basin. The Upper Berriasian hiatus is consequently regarded as the result of a Berriasian/Valanginian and/or a lowermost Valanginian erosion (fig. 6). The spatial distribution of complete or truncated Berriasian successions identifies east-west bands, in each band truncated series are located northward and complete series are located southward. Bands are limited by thrust or strip faults interpreted as palaeofaults reactivated during the Alpine orogeny (fig. 7). These fault-bounded blocks, 3 to 10 km in width, known as the Aiguine, La Palud-sur-Verdon, Carajuan-Audibergue and Peyroulles-La Foux blocks, are southerly rotated by 1 to 2o. We regard this structural architecture as the result of basinward tilting of blocks. Due to their rotation, the uplifted parts were eroded whereas the depressed parts were protected against erosion (fig. 8). Such a dynamic behavior reflects a distensive tectonic regime, which has been active at least during the Valanginian, that is after the drowning of the North-Provence carbonate platform. These structural events are considered as the regional expression of the Neocimmerian tectonic phase coupled with an enhancement of the Atlantic rifting. The orientation of the major Alpine structural elements (folds and faults) of the Castellane arc, is mostly inherited from these early Cretaceous tectonic events.

scholarly journals Biothems: sequence stratigraphic units and their implications for regional tectono-stratigraphic interpretations

1992 ◽  
Vol 6 ◽  
pp. 176-176
Author(s):  
H. R. Lane ◽  
M. W. Frye ◽  
G. D. Couples
Keyword(s):  
North American ◽  
Regional Distribution ◽  
Depositional Environments ◽  
Mississippi Valley ◽  
Basin And Range Province ◽  
Anadarko Basin ◽  
Sequence Stratigraphic ◽  
The North ◽  
Tectonic Events ◽  
Stratigraphic Framework

Biothems are regional wedge- or lens-shaped bodies of strata that are: bounded shelfward or cratonward by paleontologically recognizable unconformities; generally thicken on marine shelves, where they are typically conformable with underlying and overlying biothems; are commonly thinner or represent “starved” sequences further basinward; and in their most basinward extent, are either bounded by biostratigraphically recognizable unconformities or are conformable with underlying and overlying biothems. Biothems are practical units whose definition and degree of refinement are dependent on the quality and availability of biostratigraphic control. As recognized to date, biothems have a logical distribution of faunal and floral components, as well as facies groupings that represent internally consistent and logical sequences of depositional environments. The use of biothems as primary sequence stratigraphic units places the emphasis on relative time in a stratigraphic framework.A west-to-east transect within the North American Mississippian System, which extends from the Basin and Range Province, across the Transcontinental Arch (TA) and into the Anadarko Basin, was constructed to demonstrate the regional distribution and tectono-stratigraphic significance of biothems relative to the axis of the TA. The relationships portrayed on the transect, tied to an understanding of North American Mississippian paleogeography, imply that biothems deposited during relative highstand events on one flank of the TA are time-equivalent to biothems deposited during relative lowstand events on the opposite flank of the TA. This distribution is interpreted to have been controlled by intraplate tectonic events that formed “piano-key” basins along the flanks of the TA. The spatial patterns of these basins are not consistent with published models of basin evolution. A further conclusion is that the lack of transgressive or regressive coincident Mississippian biothems on either flank of the TA suggests that it is inadvisable to impose the Mississippi Valley-derived eustasy curve on western flank depositional sequences.

Deciphering the geodynamic evolution of the Dinaric orogen through the study of the ‘overstepping’ Cretaceous successions

2020 ◽  
Vol 157 (8) ◽  
pp. 1238-1264
Author(s):  
Giuseppe Nirta ◽  
Martin Aberhan ◽  
Valerio Bortolotti ◽  
Nicolaos Carras ◽  
Francesco Menna ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Continental Margin ◽  
Late Jurassic ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Small Scale ◽  
Large Area ◽  
Geodynamic Evolution ◽  
Sedimentary Evolution ◽  
Platform System

AbstractAlong the Dinaric–Hellenic orogen, the Late Jurassic – Early Cretaceous ophiolite obduction over the Adria continental margin was sealed by sedimentation of clastic terrestrial deposits rapidly followed by a widespread carbonate platform system since the Early Cretaceous period. These Cretaceous sediments presently crop out over areas of varying extension, from several hundred kilometre wide undeformed continuous covers to small-scale tectonic slivers involved in the tectonic stack following the latest Cretaceous–Palaeogene collision. These deposits are unconformably sedimented above the units formed by the Late Jurassic to Early Cretaceous nappe stacking above the eastern Adria continental margin. We studied these deposits in a large area between western Serbia and eastern Bosnia. In the studied area, these deposits are divided into three lithostratigraphic groups according to their age, depositional environment and type of underlying basement. The Mokra Gora Group sediments (upper Aptian–Maastrichtian) were deposited on top of previously obducted and weathered ophiolites, the Kosjerić Group (Cenomanian–Campanian) overlies composite tectonic units comprising obducted ophiolites and their underlying continental basement portions, while the Guča Group (Campanian–Maastrichtian) exclusively rests on top of continental basement. The reconstructed sedimentary evolution of these groups, together with the comparison with the syn- and post-obduction deposits at the front of the ophiolitic nappe(s) in a wider area of the internal Dinarides (e.g. Pogari Group and Bosnian flysch), allowed us to clarify the obduction mechanisms, including their tectonic context, the changes in depositional environments and the timing of depositional and tectonic events, and, in a wider view, shed light on the geodynamic evolution of the Dinaric belt.

scholarly journals Spatiotemporal evolution of the Jehol Biota: Responses to the North China craton destruction in the Early Cretaceous

2021 ◽  
Vol 118 (34) ◽  
pp. e2107859118
Author(s):  
Zhonghe Zhou ◽  
Qingren Meng ◽  
Rixiang Zhu ◽  
Min Wang
Keyword(s):  
Early Cretaceous ◽  
North China Craton ◽  
North China ◽  
Depositional Environments ◽  
Rift Basins ◽  
Spatiotemporal Evolution ◽  
Jehol Biota ◽  
The North ◽  
Terrestrial Biota ◽  
Craton Destruction

The Early Cretaceous Jehol Biota is a terrestrial lagerstätte that contains exceptionally well-preserved fossils indicating the origin and early evolution of Mesozoic life, such as birds, dinosaurs, pterosaurs, mammals, insects, and flowering plants. New geochronologic studies have further constrained the ages of the fossil-bearing beds, and recent investigations on Early Cretaceous tectonic settings have provided much new information for understanding the spatiotemporal distribution of the biota and dispersal pattern of its members. Notably, the occurrence of the Jehol Biota coincides with the initial and peak stages of the North China craton destruction in the Early Cretaceous, and thus the biotic evolution is related to the North China craton destruction. However, it remains largely unknown how the tectonic activities impacted the development of the Jehol Biota in northeast China and other contemporaneous biotas in neighboring areas in East and Central Asia. It is proposed that the Early Cretaceous rift basins migrated eastward in the northern margin of the North China craton and the Great Xing’an Range, and the migration is regarded to have resulted from eastward retreat of the subducting paleo-Pacific plate. The diachronous development of the rift basins led to the lateral variations of stratigraphic sequences and depositional environments, which in turn influenced the spatiotemporal evolution of the Jehol Biota. This study represents an effort to explore the linkage between terrestrial biota evolution and regional tectonics and how plate tectonics constrained the evolution of a terrestrial biota through various surface geological processes.

scholarly journals Triassic and Jurassic transtension along part of the Sorgenfrei–Tornquist Zone in the Danish Kattegat

2003 ◽  
Vol 1 ◽  
pp. 437-458 ◽  
Author(s):  
Tommy Egebjerg Mogensen ◽  
John A. Korstgård
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Strike Slip ◽  
Early Permian ◽  
North East ◽  
The North ◽  
Tectonic Events ◽  
Weakness Zone ◽  
Surrounding Areas

In the Kattegat area, Denmark, the Sorgenfrei–Tornquist Zone, an old crustal weakness zone, was repeatedly reactivated during Triassic, Jurassic and Early Cretaceous times with dextral transtensional movements along the major boundary faults. These tectonic events were minor compared to the tectonic events of the Late Carboniferous – Early Permian and the Late Cretaceous – Early Tertiary, although a dynamic structural and stratigraphic analysis indicates that the Sorgenfrei–Tornquist Zone was active compared to the surrounding areas. At the end of the Palaeozoic, the area was a peneplain. Regional Triassic subsidence caused onlap towards the north-east, where the youngest Triassic sediments overlie Precambrian crystalline basement. During the Early Triassic, several of the major Early Permian faults were reactivated, probably with dextral strike-slip along the Børglum Fault. Jurassic – Early Cretaceous subsidence was restricted primarily to the area between the two main faults in the Sorgenfrei–Tornquist Zone, the Grenå–Helsingborg Fault and the Børglum Fault. This restriction of basin development indicates a change in the regional stress field at the Triassic–Jurassic transition. Middle Jurassic and Late Jurassic – Early Cretaceous subsidence followed the Early Jurassic pattern with local subsidence in the Sorgenfrei–Tornquist Zone, but now even more restricted to within the zone. The subsidence showed a decrease in the Middle Jurassic, and increased again during Late Jurassic – Early Cretaceous times. Small faults were generated internally in the Sorgenfrei–Tornquist Zone during the Mesozoic with a pattern that indicates a broad transfer of strike-slip/oblique-slip motion from the Grenå–Helsingborg Fault to the Børglum Fault.

Palaeoecology of Cenomanian oysters of the northern margin of the Aquitaine Basin

2007 ◽  
Vol 178 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Blaise Videt ◽  
Didier Néraudeau
Keyword(s):  
Brackish Water ◽  
Carbonate Platform ◽  
Sand Dunes ◽  
Marine Species ◽  
Depositional Environments ◽  
Time Interval ◽  
Northern Margin ◽  
The North ◽  
Shallow Subtidal ◽  
Aquitaine Basin

Abstract The purpose of this paper is to understand which parameters control the palaeoenvironmental distribution of Middle Cretaceous oysters. To reach this objective, the following two step analysis has been carried out. First, ten major Upper Albian to Lower Turonian outcrops from the northern part of the Aquitain Basin (SW France) (fig. 1) were analysed with respect to their sedimentological and palaeontological features (see fig. 2 for oyster distribution). They represent a time interval corresponding to a 2nd order transgression [Hardenbol et al., 1997; Néraudeau et al., 1997], characterised in the Charentes (North Aquitaine Basin) by a great variety of depositional environments and very rich in oyster assemblages [Videt, 2004]. According to previous authors [Moreau, 1993; Néraudeau et al., 1997; Platel, 1989, 1996], this series can be divided into seven lithological units, A to G, four units (A, B, C and G) being subdivided into two or three subunits (A1 and A2, B1 to B3, C1 to C4, G1 and G2). Apart from the sub-units A1 and Tu, which correspond to the Late Albian and Early Turonian respectively, all the lithological sub-units A2 to G2 correspond to the Cenomanian series. A and B belong to the lower Cenomanian, C1 to C3 to the middle Cenomanian, and C4 to G2 to the Upper Cenomanian. In terms of palaeoenvironments, unit A is considered as deposits of a sandy estuary (with local lignite layers) [Néraudeau et al., 2002, 2003; Perrichot, 2003], and unit B as shallow subtidal sand dunes [Vullo et al., 2003]. Unit C corresponds to the optimal development of a carbonate platform with rudists [Chéreau et al., 1997], unit D to a marly open shelf marly facies, unit E to an oyster bank mainly composed of Pycnodonte biauriculata [Dhondt, 1984], unit F to a moderately deep bioclastic facies colonised by rudist Ichthyosarcolites triangularis and, unit G, which forms progressively marly up-section, to progressive platform flooding at the Cenomanian-Turonian boundary. From the analysis of these different lithological units and subunits, the North Aquitaine Basin can be considered as a mixed siliciclastic-carbonate platform. Two main depositional systems have been identified, namely an open one and a closed one. The synthetic distribution of twelve kinds of oysters biofacies (bf1 to bf12) described in these units and subunits is summed up in figure 3 according to depositional type, lithology and depth. Based on the palaeoenvironmental distribution of Middle Cretaceous oysters in the northern part of the Aquitain Basin, the palaeoecological affinities of the nine marine species are discussed regarding seven main parameters i.e., oxygenation, water turbulence, salinity, turbidity, bathymetry, grain size, and substrate consistency (i.e. “hardground” VS “softground”) (fig. 4). Acutostrea aff. incurva (Nilson, 1827) (figs 4, 5h) and Curvostrea rouvillei (Coquand, 1862) (figs 4, 5i) are very rare species with a distribution that is still ambiguous. Apparently they preferred soft substrates and seem to have tolerated lowered oxygen levels. In addition, they are encountered in quiet, deep environments, i.e., the lower infralittoral to circalittoral zones sensu Néraudeau et al. [2001]. Ceratostreon flabellatum (Goldfuss, 1833) (figs 4, 5e) is not a prolific species but was widely distributed all over the carbonate platform. Nevertheless it is mainly marine and located in the infralittoral zone [sensu Néraudeau et al., 2001]. Gyrostrea delettrei (Coquand, 1862) (figs 4, 5g) might have been very widespread but is very rare. It was most abundant in marginal marine environments where it was the sole oyster that tolerated brackish water conditions. Pycnodonte biauriculata (Lamarck, 1819) (figs 4, 5d), in spite of its very short stratigraphic range (Naviculare Ammonite Zone), colonised a wide variety of environments. It is mainly a relatively medium water species (regarding to other species) [Stenzel, 1971; Harry, 1985; Freneix and Viaud, 1986], from the lower infralittoral zone [sensu Néraudeau et al., 2001] but it needed food-laden currents. Pycnodonte vesicularis (Lamarck, 1819) (figs 4, 5f) is also an ubiquitous species. However, in contrast to Pycnodonte biauriculata, it preferred deep, soft substrates (circalittoral and deeper ones? [Néraudeau and Villier, 1997]). Rastellum carinatum (Lamarck, 1806) (figs 4, 5c) and Rastellum diluvianum (Linne, 1767) (figs 4, 5b) exhibit an identical distribution pattern in spite of the fact that R. diluvianum is more selective than Rastellum carinatum. Carter [1968], Jablonsky and Lutz [1980] and Freneix and Viaud [1986] have already demonstrate that these species do not tolerate turbulent conditions but are particularly adapted to quiet water and soft substrates. The two species also do not tolerate salinity variations. Rhynchostreon suborbiculatum (Lamarck, 1801) (figs 4, 5a) is the most ubiquitous species in the Cenomanian of the Aquitain Basin. Videt and Néraudeau [2003] and Videt [2004] have already defined the parameters that affected its shape and its abundance. As the species does not occur in brackish water deposits, salinity seems to have been a major factor limiting its distribution.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

Illegal rattan extraction trends in the Ankasa Conservation Area in Ghana

2018 ◽  
Vol 2 (3) ◽  
pp. 84-92
Author(s):  
R. Obour, D. Amankwaa, A. Asare
Keyword(s):  
Protected Areas ◽  
Biological Diversity ◽  
Forest Products ◽  
Simple Random Sampling ◽  
Sampling Techniques ◽  
Snowball Sampling ◽  
Conservation Area ◽  
Forest Reserve ◽  
The North ◽  
Non Timber Forest Products

Protected Areas (PAs) are created for the protection and maintenance of biological diversity, but many of Ghana’s PAs are subjectto severe pressures and threats, the main pressures being the illegal extraction of natural resources. Rattans are indisputablyone of the most important Non-Timber Forest Products (NTFPs) in Ghana’s Protected Areas that is without doubt one of thereasons for which it has drawn the attention of researchers. In this study the illegal rattan extraction patterns in the AnkasaConservation Area (ACA) in Ghana was inspected. Simple random sampling and Snowball sampling techniques were used. Datacollection employed the use of semi-structured questionnaires, interviews and field enumeration of rattans as well as an analysisof Effective Patrol Man-days (EPMDS) from 2004 to 2012. The results showed a significant positive correlation (r = 0.75, p<0.05, r2 = 0.557) between patrol effort and rattan extraction encounters. In addition, there was a general reduction in illegalrattan extraction encounters from 2004 to 2012 at a rate of 4.3 per year. The highest illegal rattan extraction incidences wererecorded in 2006 (76 encounters), 2005 (35 encounters), 2008 (22 encounters), 2004 (18 encounters) and the least incidencewere recorded in both 2010 (3 encounters) and 2011 (3 encounters).The research also revealed that Eremospatha macrocarpawas the most extracted rattan species followed by Laccosperma secundiflorum. The major rattan extraction and trade routesoriginate in the northern parts and in the area east of the reserve and also south of Draw River Forest Reserve. Generally, rattanpoaching in Ankasa Conservation Area has declined, but there are still human incursions in the northern part of the reserve. Thestudy recommended an intensification of patrols in the north of the reserve. Also, enrichment planting and Agroforestry practicesof inter-cropping rattans with seasonal crops should be pursued vigorously for the local communities.

ЗУБРЫ НА СЕВЕРЕ РОССИИ — НАСТОЯЩЕЕ И БУДУЩЕЕ

2019 ◽  
pp. 42-44
Author(s):  
I.V. GUSAROV ◽  
V.A. OSTAPENKO ◽  
T.V. NOVIKOVА
Keyword(s):  
Biological Diversity ◽  
Climatic Conditions ◽  
Economic Consequences ◽  
European Bison ◽  
Rare And Endangered Species ◽  
The North ◽  
Rare And Endangered ◽  
Relationship Of ◽  
First Time ◽  
The Relationship

Впервые в мире создана популяция зубров на территории 60 градусов северной широты. В новых климатических условиях разведения и сохранения зубров определены и проанализированы факторы существования вида на севере Европейской части РФ. Выявлены признаки, динамика численности, которые являются составной частью системы, предназначенной для управления биоразнообразием. Интродукция, являясь процессом введения в экосистему нехарактерных для нее видов, может усиливать изменения биоценозов как положительно, так и отрицательно. Насколько быстро и успешно проходит процесс адаптации заселенного вида, и усматривается его влияние на окружающую среду зависит дальнейшее существование зубров и в целом биоразнообразия. В статье обсуждаются вопросы взаимоотношения зубров с другими видами копытных и хозяйственной деятельностью человека, а также дальнейшим использованием зубров в сельскохозяйственном производстве. Пластичность зубров, выявление изменений и их анализ при вселении видов в новые условия обитания необходимы не только для определения развития или деградации биоценозов и в целом экосистемы, но и прогноза социально-экономических последствий интродукции как одного из методов сохранения редких и исчезающих видов фауны.For the first time in the world, a bison population has been created in an area of 60 degrees north latitude. In the new climatic conditions of breeding and preservation of bison, the factors of the species existence in the north of the European part of the Russian Federation are identified and analyzed. The signs, dynamics of abundance, which are an integral part of the system designed to manage biodiversity are identified, since the preservation of biological diversity on the planet is one of the main problems of our time. Introduction, being the process of introducing non-typical species into an ecosystem, can enhance changes in biocenoses, both positively and negatively. The question posing sounds especially when it comes to such a large hoofed animal as the European bison. How quickly and successfully the process of adaptation of the universe takes place and its environmental impact is seen depends on the continued existence of bison and biodiversity in general. The article discusses the relationship of bison with other types of ungulates and human activities, as well as the further use of bison in agricultural production. How these issues will be resolved positively depends on the future of these animals. Thus, the plasticity of bison, the identification of changes and their analysis, with the introduction of species into new habitat conditions is necessary not only to determine the development or degradation of biocenoses and the ecosystem as a whole, but also to predict the socio-economic consequences due to the introduction as one of the methods of preserving rare and endangered species of fauna.

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