Relationships between tectonics and sedimentation on the northeastern margin of the Subpyrenean trough during the late Santonian

2005 ◽  
Vol 176 (5) ◽  
pp. 443-455 ◽  
Author(s):  
Michel Bilotte ◽  
Laurent Koess ◽  
Elie-Jean Debroas
Keyword(s):  
Debris Flows ◽  
Major Change ◽  
Sediment Supply ◽  
Coarse Grained ◽  
Fault System ◽  
The South ◽  
Delta Front ◽  
Eastern Area ◽  
The North ◽  
Sedimentary Evolution

Abstract In the eastern part of the Aquitaine Basin and to the south of the Toulouse high, the Subpyrenean trough is a narrow trench oriented N110°E to N130° E. The deposits on the northeastern side of this depression are preserved in the autochthonous Mesozoic cover of the Variscan Mouthoumet Massif, but also in the parautochthonous or allochthonous tectonic units that fringe to the north (Camps – Peyrepertuse slice, fig. 2) the North Pyrenean frontal thrust. From the Middle Cenomanian to the Lower Santonian included (96 to 85 Ma ago), the sedimentation in the Mouthoumet Massif indicates shallow marine carbonate or mixed (carbonate to terrigenous) conditions. The different facies depend mainly on two parameters : the variations of the accommodation space for sedimentation and the location of the numerous rudist buildups. The deposits are first organized in a homoclinal ramp until the Turonian. From the Coniacian up to the early Santonian, drowned platform patterns prevail. During the late Santonian and more precisely around 85 Ma with an other event around 84 Ma, the Mouthoumet Massif and its cover broke up under tectonic stresses. Positive and negative topographies reactivate the Variscan fault system. Platform – slope/basin morphologies substituted the preceeding ramp and drowned platform morphology. Looking to the south and in the direction N120°E, the distal slope received gravitational and turbiditic sediments called the Grès de Labastide (fig. 7). The sediment supply shifted from north to south and from east to west. To the north of this slope, the platform itself broke up into a mosaic of rhomboedric blocks, leading to a graben and horst morphology. Those units are clearly different according to the character of their sedimentary facies, deltaic or reefal (Montagne des Cornes, Calcaires de Camps – Peyrepertuse). The detailed stratigraphic and sedimentologic studies of some of these systems reveal a tectono-sedimentary evolution involving two successive cycles Ss1 (lower Upper Santonian) and Ss2 (Uppermost Santonian). In the western part of the Mouthoumet Massif this cyclic evolution is recorded from south to north, on the Parahou slope, the Rennes-les-Bains graben and the Bugarach horst. The lower cycle Ss1, located on the Rennes-les-Bains graben, is approximatively 85 Ma to 84 Ma in age. It starts with reworked deposits (lowstand systems tract) made up of sometimes several m3 elements derived from former sedimentary deposits (from Turonian up to Lower Santonian) even when the same deposits are in place on the adjacent horsts (e.g. the eastern horst of Bugarach). Those reworked deposits fill the bottom of the graben, principally in the transit zones (debris-flows of the Conglomerat de la Ferrière), or in the Parahou slope (slumps and debris-flows of the Cascade des Mathieux); then the deltaic complex of Rennes-les-Bains covers the older chaotic deposits; the blue marls and the overlying sandy facies (transgressive and highstand systems tracts) related to prodelta and deltafront deposits represent the infilling of the Rennes-les Bains graben. The upper cycle Ss2 developed probably between 84 Ma to 83,5 Ma; its geographical extension overlaps the limits of the lower cycle (e.g. the Bugarach horst), but its sedimentary organisation is still the same including: on the Parahou slope debris-flow and intrabasinal reworking (Conglomérat des Gascous: lowstand systems tract); on the northern platform transgressive and highstand systems tracts, present in the Montagne des Cornes delta where the Marnes bleues de Sougraigne represent the prodelta deposits, and the terrigenous and rudist buildups of the delta front deposits (fig.7). The final infilling results from the spreading from NE to SW, of the (estuarine ? to) fluvial deposits of the Grès d’Alet Formation at around 83 Ma. In the eastern part of the Mouthoumet Massif, sedimentary development is punctuated by tectonic events. Nevertheless, it is possible to identify in some outcrops the main elements of the two tectono-sedimentary cycles. – The cycle Ss1 is partly preserved in the genetic sequence which links the Calcaires de Camps-Peyrepertuse (shelf margin wedge systems tract) and the Marnes du Pla de Sagnes (transgressive systems tract). The cycle Ss2 is only known through different facies of the Grès de Labastide Formation: reworked deposits on the slope; coarse-grained silicoclastic deposits on the transit zones. – In the cycle Ss1 differences appear between the western and the eastern parts of the Mouthoumet massif. When in the western area deltaic conditions prevailed, in the eastern area a shallow carbonate and buildup facies developed. Such differences disappear in the cycle Ss2 by the general establishment of fore slope deltaic deposits. The geodynamic reconstruction resulting from plate kinematics indicates a major change between the early Coniacian (89 Ma) and the Middle Campanian (79 Ma), when the sinistral/divergent motion of Iberia with respect to stable Europe turned to a dextral/convergent movement. The tectono-sedimentary events presented here took place during this period (85 Ma to 83 Ma). The tectono-sedimentary evolution of the subpyrenean trough and the shift of the European and Iberian plates are thought to be intimately linked. The new chronological and geodynamical data proposed herein show that the genesis and the evolution of the subpyrenean sedimentary processes related to the northern Aquitanian margin of the Subpyrenean trough allow to draw some basic conclusions: – the opening of the Subpyrenean trough occurred in two steps, the first around 85 Ma and the second around 84 Ma; – this caused a change in the sedimentary setting with platform environments replacing the earlier ramp geometry; – the Subpyrenean trough formed and evolved under transtensive tectonic conditions; – during the late Santonian two tectono-eustatic sequences marked the former stages of the eastward opening and infilling of this basin; – the diachronous infilling which began here around 83,5 Ma prograded to the western Plantaurel and Petites-Pyrénées area; – no significant northward shifting of the depositional-axis of the Senonian basins occurred; – only a gradual westward shift of the depositional centers, along the subpyrenean direction of the slope area (N110°E to N130°E) was noticed.

The Paleoproterozoic upper Gowganda Formation, Whitefish Falls area, Ontario, Canada: subaqueous deposits of a braid delta

1995 ◽  
Vol 32 (2) ◽  
pp. 197-209 ◽  
Author(s):  
R. M. Junnila ◽  
G. M. Young
Keyword(s):  
Sediment Supply ◽  
Coarse Grained ◽  
Fold Belt ◽  
Delta Front ◽  
North Shore ◽  
The North ◽  
Tectonically Active ◽  
Sediment Deformation ◽  
Sand Sheets ◽  
Marine Basin

The upper Gowganda Formation is part of the Paleoproterozoic Huronian Supergroup (ca. 2.5–2.2 Ga) of the north shore of Lake Huron. The upper Gowganda Formation rests with sharp conformable contact on glaciogenic rocks of the lower Gowganda Formation and is gradational with cross-bedded sandstones of the overlying Lorrain Formation. At the southern margin of the Huronian fold belt, in the Whitefish Falls area, the upper Gowganda Formation is 380–750 m thick, and consists of four coarsening-upward cycles from 30 to 300 m in thickness. Each is comprised of the succession (a) laminated argillite deposited from suspension on the prodelta, (b) argillite and cross-laminated sandstone laid down on the delta front by normal fluvial input and flood episodes, (c) fine-to coarse-grained, cross-bedded sandstone formed as distributary-mouth sand sheets influenced by shallow marine processes. Abundant soft-sediment deformation indicates rapid sedimentation and (or) contemporaneous fault-related seismicity. Erosional contacts between cycles resulted from marine reworking as sediment supply diminished. Each coarsening-upward cycle is interpreted as the subaqueous deposits of a braid delta that prograded into a moderately wave-influenced, tectonically active marine basin. In some respects, the succession of the deltaic deposits is comparable to those formed during the postglacial evolution of the Mississippi delta, but it is likely that the fluvial regime at the time of deposition of the Gowganda Formation was dominantly braided.

Palaeoenvironmental analysis of a Miocene basin in the high Taurus Mountains (southern Turkey) and its palaeogeographical and structural significance

2002 ◽  
Vol 139 (4) ◽  
pp. 473-487 ◽  
Author(s):  
F. OCAKOĞLU
Keyword(s):  
Depositional Environments ◽  
Coarse Grained ◽  
Fault System ◽  
Small Scale ◽  
The South ◽  
Taurus Mountains ◽  
The North ◽  
South Central ◽  
Southern Turkey ◽  
Basin Fill

Determination of the relationships between the southern, marine-dominated Miocene basins of south central Turkey and their continental hinterland in southern Turkey has traditionally been frustrated by the apparent absence of basin remnants within the Taurus Mountains. The Dikme basin, which seems to be an enclave of basin remnants within the Aladağ Mountains (Eastern Taurides), consists mainly of coarse-grained continental sediments of various facies. These mostly early–middle Miocene sediments were studied to determine the depositional environments and the factors controlling the basin formation and basin fill architecture, to attempt to close the information gap between the Adana Basin to the south and central Anatolian Miocene further to the north. A generally southwest-flowing axial fluvial system and interfingering coarse-grained marginal alluvial clastics derived from northwest and southeast were identified. The marginal facies to the northwest is bounded by a N 55° E-running structural lineament, that starts from the Ecemiş Fault Zone and in digital elevation models extends toward the north of the study area. Along this lineament, Miocene sediments onlap steep fault-line escarpments. Certain Miocene levels are tectonically disrupted, and an intraformational unconformity and boulder conglomerates are also well-developed in the Miocene sequence. The southeast boundary is similarly defined by a NE-trending fault that periodically elevated the adjacent Tufanbeyli autochthon, producing coarse clastics from this area. This boundary fault also induced fining-upwards vertical patterns and synsedimentary deformation in the marginal facies. Additionally, the central part of the basin exhibits a distinct fault-defined morphology characterized by small-scale (tens of metres to 150 m high) valley-and-sill topography. A thin marine interval was also encountered in the southernmost part of the basin, indicating that the clastic system originating around this area debouched into a Miocene sea situated further to the south. The proposed palaeogeography and basin fill model suggests that the Dikme basin and similar Miocene remnants, all controlled mainly by a northeast-running extensional or transtensional fault system, may have been parts of the terrestrial hinterland that supplied sediment to rapidly subsiding marine areas further south, such as the Adana Basin.

Mechanism of Carboniferous-Permian transgression/regression in the east Ordos basin and associated paleoecological variability: Insight from detrital geochronology and palaeontology data

2020 ◽  
Author(s):  
Chao Fu ◽  
Xinghe Yu ◽  
Marc Jolivet ◽  
Shunli Li ◽  
Zixiao Peng ◽  
...  
Keyword(s):  
North China ◽  
Ordos Basin ◽  
Second Order ◽  
Sediment Supply ◽  
Late Carboniferous ◽  
Coarse Grained ◽  
Early Permian ◽  
The South ◽  
The North ◽  
Facies Associations

<p>Developed on the North China Craton, the intra-cratonic Ordos basin contains a complete Paleozoic to Cenozoic sediment record allowing long-term paleo-environmental and climate change investigation. During the Carboniferous-the early Permian period, convergence between the North China block and the paleo-Yangtze plate to the south lead to a general marine regression characterised by a series of second-order transgression/regression cycles diachronous along the eastern margin of the Ordos. However, the detailed mechanisms that induced these cycles, as well as the associated paleoecological changes, are still unknown. In this study, we integrated the description of numerous core samples with electric-log data and 2-D seismic data to reconstruct the sediment facies associations across the first-order regression from the Carboniferous tidal flat depositional system to the early Permian prograding fluvial delta system. δ<sup>18</sup>O, δ<sup>13</sup>C and clay content (w(Illite + Kaolinite)/w(smectite) ratio) stratigraphic variations were then used to reconstruct the paleo-sea level from the late Carboniferous to the early Permian. We conclude that the direction of second-order transgression/regression mainly stroke to the east during the late Carboniferous and switched clockwise towards the north during the early Permian. We suggest that the variability of the second-order cycles, diachronous in space and time was mainly linked to local variations in sediment supply and regional uplift.  Using detrital zircon U-Pb data, major and trace elements content and heavy minerals assemblages (HMA), we estimated the sediment provenance area. The sediment volumes deposited in the basin through time were obtained using 3Dseismic data. During the Carboniferous, the coarse-grained sediments deposited in the eastern Ordos were derived from the uplifting Helan Mountain. By the early Permian, the detrital material became multi-sourced issuing from both the Yinshan range to the north and the Qinling range to the south. During the first stage, regression was controlled by regional uplift, while the sediment supply controlled the second stage. Indeed, based on sediment dispersal volume calculation, we can infer that the sediment supply during the early Permian was more extensive than during the Late Carboniferous – early Permian. We correlate this observation to a more humid climate during the early Permian: multi- paleoecological indexes, including the sporopollenin content and microsomal type assemblage, suggest that glaciation prevailed during the Late Carboniferous – early Permian shallow-marine stage. In contrast, the early Permian alluvial and deltaic series were deposited under a warmer, interglacial climate (Sakmarian). Finally, the typical interglacial coal accumulation pattern occurs earlier than the Pennsylvanian–Permian transition it characterises around the world (Artinskian).</p>

scholarly journals Heavy minerals in the Wajid Sandstone from Abha-Khamis Mushayt area, southwestern Saudi Arabia: implications on provenance and regional tectonic setting

GeoArabia ◽  
2004 ◽  
Vol 9 (4) ◽  
pp. 77-102 ◽  
Author(s):  
Mahbub Hussain ◽  
Lameed O. Babalola ◽  
Mustafa M. Hariri
Keyword(s):  
Saudi Arabia ◽  
Tectonic Setting ◽  
Principal Component ◽  
Heavy Mineral ◽  
Heavy Minerals ◽  
Coarse Grained ◽  
Distribution Data ◽  
The South ◽  
Quartz Content ◽  
The North

ABSTRACT The Wajid Sandstone (Ordovician-Permian) as exposed along the road-cut sections of the Abha and Khamis Mushayt areas in southwestern Saudi Arabia, is a mediun to coarse-grained, mineralogically mature quartz arenite with an average quartz content of over 95%. Monocrystalline quartz is the dominant framework grain followed by polycrystalline quartz, feldspar and micas. The non-opaque heavy mineral assemblage of the sandstone is dominated by zircon, tourmaline and rutile (ZTR). Additional heavy minerals, constituting a very minor fraction of the heavies, include epidote, hornblende, and kyanite. Statistical analysis showed significant correlations between zircon, tourmaline, rutile, epidote and hornblende. Principal component R-mode varimax factor analysis of the heavy mineral distribution data shows two strong associations: (1) tourmaline, zircon, rutile, and (2) epidote and hornblende suggesting several likely provenances including igneous, recycled sedimentary and metamorphic rocks. However, an abundance of the ZTR minerals favors a recycled sedimentary source over other possibilities. Mineralogical maturity coupled with characteristic heavy mineral associations, consistent north-directed paleoflow evidence, and the tectonic evolutionary history of the region indicate a provenance south of the study area. The most likely provenances of the lower part (Dibsiyah and Khusayyan members) of the Wajid Sandstone are the Neoproterozoic Afif, Abas, Al-Bayda, Al-Mahfid, and Al-Mukalla terranes, and older recycled sediments of the infra-Cambrian Ghabar Group in Yemen to the south. Because Neoproterozic (650-542 Ma) rocks are not widespread in Somalia, Eritrea and Ethiopia, a significant source further to the south is not likely. The dominance of the ultrastable minerals zircon, tourmaline and rutile and apparent absence of metastable, labile minerals in the heavy mineral suite preclude the exposed arc-derived oceanic terrains of the Arabian Shield in the west and north as a significant contributor of the sandstone. An abundance of finer-grained siliciclastic sequences of the same age in the north, is consistent with a northerly transport direction and the existence of a deeper basin (Tabuk Basin?) to the north. The tectonic and depositional model presented in this paper differs from the existing model that envisages sediment transportation and gradual basin filling from west to east during the Paleozoic.

The discovery of a new sedimentary basin: offshore Raukumara, East Coast, North Island, New Zealand

2008 ◽  
Vol 48 (1) ◽  
pp. 53 ◽  
Author(s):  
Chris Uruski ◽  
Callum Kennedy ◽  
Rupert Sutherland ◽  
Vaughan Stagpoole ◽  
Stuart Henrys
Keyword(s):  
New Zealand ◽  
Oil And Gas ◽  
East Coast ◽  
Plate Boundary ◽  
Source Rocks ◽  
Fault System ◽  
Northern Coast ◽  
The South ◽  
Petroleum Potential ◽  
The North

The East Coast of North Island, New Zealand, is the site of subduction of the Pacific below the Australian plate, and, consequently, much of the basin is highly deformed. An exception is the Raukumara Sub-basin, which forms the northern end of the East Coast Basin and is relatively undeformed. It occupies a marine plain that extends to the north-northeast from the northern coast of the Raukumara Peninsula, reaching water depths of about 3,000 m, although much of the sub-basin lies within the 2,000 m isobath. The sub-basin is about 100 km across and has a roughly triangular plan, bounded by an east-west fault system in the south. It extends about 300 km to the northeast and is bounded to the east by the East Cape subduction ridge and to the west by the volcanic Kermadec Ridge. The northern seismic lines reveal a thickness of around 8 km increasing to 12–13 km in the south. Its stratigraphy consists of a fairly uniformly bedded basal section and an upper, more variable unit separated by a wedge of chaotically bedded material. In the absence of direct evidence from wells and samples, analogies are drawn with onshore geology, where older marine Cretaceous and Paleogene units are separated from a Neogene succession by an allochthonous series of thrust slices emplaced around the time of initiation of the modern plate boundary. The Raukumara Sub-basin is not easily classified. Its location is apparently that of a fore-arc basin along an ocean-to-ocean collision zone, although its sedimentary fill must have been derived chiefly from erosion of the New Zealand land mass. Its relative lack of deformation introduces questions about basin formation and petroleum potential. Although no commercial discoveries have been made in the East Coast Basin, known source rocks are of marine origin and are commonly oil prone, so there is good potential for oil as well as gas in the basin. New seismic data confirm the extent of the sub-basin and its considerable sedimentary thickness. The presence of potential trapping structures and direct hydrocarbon indicators suggest that the Raukumara Sub-basin may contain large volumes of oil and gas.

Origin of glacial ridges (OIS 6) in the Kaskaskia Sublobe, southwestern Illinois, USA

2012 ◽  
Vol 78 (2) ◽  
pp. 341-352 ◽  
Author(s):  
Nathan D. Webb ◽  
David A. Grimley ◽  
Andrew C. Phillips ◽  
Bruce W. Fouke
Keyword(s):  
Debris Flows ◽  
Spatial Arrangement ◽  
Coarse Grained ◽  
Ice Flow ◽  
Glacial Ice ◽  
Distinctive Features ◽  
Fine Grained ◽  
The North ◽  
Till Fabric ◽  
Glacial Landforms

AbstractThe origin of Illinois Episode (OIS 6) glacial ridges (formerly: ‘Ridged Drift’) in the Kaskaskia Basin of southwestern Illinois is controversial despite a century of research. Two studied ridges, containing mostly fluvial sand (OSL ages: ~ 150 ± 19 ka), with associated debris flows and high-angle reverse faults, are interpreted as ice-walled channels. A third studied ridge, containing mostly fine-grained till, is arcuate and morainal. The spatial arrangement of various ridge types can be explained by a glacial sublobe in the Kaskaskia Basin, with mainly fine-grained ridges along the sublobe margins and coarse-grained glaciofluvial ridges in a paleodrainage network within the sublobe interior. Illinois Episode till fabric and striation data demonstrate southwesterly ice flow that may diverge near the sublobe terminus. The sublobe likely formed as glacial ice thinned and receded from its maximum extent. The Kaskaskia Basin contains some of the best-preserved Illinois Episode constructional glacial landforms in the North American midcontinent. Such distinctive features probably result from ice flow and sedimentation into this former lowland, in addition to minimal postglacial erosion. Other similar OIS 6 glacial landforms may exist in association with previously unrecognized sublobes in the midcontinent, where paleo-lowlands might also have focused glacial sedimentation.

scholarly journals THE BRANCHING CHANNEL NETWORK IN THE YANGTZE ESTUARY

2012 ◽  
Vol 1 (33) ◽  
pp. 69
Author(s):  
Zheng Bing Wang ◽  
Pingxing Ding
Keyword(s):  
Yangtze Estuary ◽  
River Delta ◽  
Sediment Supply ◽  
Channel Structure ◽  
The South ◽  
Channel Network ◽  
The Yangtze Estuary ◽  
The North ◽  
Navigation Channel ◽  
The Impact

The channels in the Yangtze Estuary have an ordered-branching structure: The estuary is first divided by the Chongming Island into the North Branch and the South Branch. Then the South Branch is divided into the North Channel and South Channel by the Islands Changxing and Hengsha. The South Channel is again divided into the North and South Passage by the Jiuduansha Shoal. This three-level bifurcation and four-outlet configuration appears to be a natural character of the estuary, also in the past (Chen et al., 1982), although the whole system has been extending into the East China Sea in the southeast direction due to the abundant sediment supply from the Yangtze River. Recently, the natural development of the system seems to be substantially disturbed by human interferences, especially the Deep Navigation Channel Project. For the understanding of the behaviour of the bifurcating channel system in the estuary we present analysis on two aspects: (1) the equilibrium configuration of river delta distributary networks, and (2) influence of tidal flow on the morphological equilibrium of rivers. Based on the analyses we conclude that the branching channel structure of the Yangtze Estuary can be classified as tide-influenced river delta distributary networks. Its basic structure is the same as in case of river dominated delta. The empirical relations describing the basic features of the river-dominated distributary delta networks can be explained by theoretical analysis, although they are not fully satisfied by the Yangtze Estuary because of the influence of the tide. Two major influences of the tide are identified, viz. increasing the resistance to the river flow into the sea and increasing the sediment transport capacity. As consequence of these two influences the cross-sectional area of the river/estuary increases in the seawards direction and the bed slope decreases. The insights from the analyses are helpful for the understanding of the impact of the Deep Navigation Channel Project on the large scale morphological development of the estuary.

scholarly journals The Jurassic of the Netherlands

2003 ◽  
Vol 1 ◽  
pp. 217-230 ◽  
Author(s):  
G.F. Waldemar Herngreen ◽  
Wim F.P. Kouwe ◽  
Theo E. Wong
Keyword(s):  
The Netherlands ◽  
Structural Complexity ◽  
Coarse Grained ◽  
The South ◽  
Lower Saxony ◽  
Central System ◽  
Sequence Stratigraphic ◽  
The North ◽  
Roer Valley Graben ◽  
Middle Callovian

A recent revision of the lithostratigraphy of the Netherlands has triggered an extensive re-evaluation of existing ideas on the Jurassic structural and depositional history. Significant advances can be attributed to the incorporation of sequence stratigraphic concepts. In the course of the Triassic and Jurassic, structural complexity increased progressively. The Jurassic sedimentary succession can be subdivided into three depositional megasequences. Megasequence I (Rhaetian– Aalenian) reflects the period between the so-called early and mid-Cimmerian tectonic phases. Megasequence II (Aalenian – Middle Callovian) covers the period of activity of the mid-Cimmerian phase. Megasequence III (Middle Callovian – Ryazanian) corresponds with the period between the mid-Cimmerian and late Cimmerian phases (particularly after pulse II). In this latter megasequence, six stages (IIIa–f) are recognised. Sediments deposited during the Rhaetian and Ryazanian bear a stronger affinity with the Jurassic succession than with Triassic and Cretaceous sediments respectively. These stages are thus treated here as an integral part of the Jurassic succession. During the Rhaetian–Bajocian the area subsided relatively uniformly. A sheet of predominantly fine-grained marine sediments of great lateral uniformity was deposited. During the Toarcian, in particular, basin circulation was largely restricted. The cooling that followed the thermal Central North Sea dome uplift triggered an important extensional phase during the Aalenian–Callovian. The rift phase resulted in the formation of several smaller basins, each with its own characteristic depositional succession. The basins fall into three structural provinces: the eastern province (Lower Saxony Basin, E–W-striking); the northern province (Central Graben, N–S-striking); and the southern–central system (Roer Valley Graben – Broad Fourteens, with a strong NW–SE strike). The mid-Cimmerian event started to affect the Dutch basins during the Bajocian. Sedimentation ceased in the Dutch Central Graben while it persisted in a predominantly coarse-grained, shallow marine facies in the southern basins (Roer Valley Graben, West Netherlands Basin). Extensional tectonics in the Central Graben were initiated during the Middle Callovian, with the deposition of continental sediments. During the Oxfordian–Kimmeridgian, marine incursions gradually became more frequent. Marine deposition in the other basins in the south persisted into the Oxfordian, at which time deposition became predominantly continental. Marine conditions gradually returned in the south during the Ryazanian–Barremian, with a series of advancing partial transgressions from the north. The present- day distribution of Jurassic strata in the Netherlands was determined largely by erosion associated with Late Cretaceous – Paleocene uplift.

Strain partitioning around an indenter during oroclinal bending: kinematics of the Circum-Moesian fault system of the Carpatho-Balkanides

2021 ◽  
Author(s):  
Nemanja Krstekanic ◽  
Liviu Matenco ◽  
Uros Stojadinovic ◽  
Ernst Willingshofer ◽  
Marinko Toljić ◽  
...  
Keyword(s):  
Large Scale ◽  
Strike Slip ◽  
Fault System ◽  
Normal Faults ◽  
Strain Partitioning ◽  
The South ◽  
The Carpathians ◽  
The North ◽  
Moesian Platform ◽  
Parallel Extension

<p>The Carpatho-Balkanides of south-eastern Europe is a double 180° curved orogenic system. It is comprised of a foreland-convex orocline, situated in the north and east and a backarc-convex orocline situated in the south and west. The southern orocline of the Carpatho-Balkanides orogen formed during the Cretaceous closure of the Alpine Tethys Ocean and collision of the Dacia mega-unit with the Moesian Platform. Following the main orogen-building processes, the Carpathians subduction and Miocene slab retreat in the West and East Carpathians have driven the formation of the backarc-convex oroclinal bending in the south and west. The orocline formed during clockwise rotation of the Dacia mega-unit and coeval docking against the Moesian indenter. This oroclinal bending was associated with a Paleocene-Eocene orogen-parallel extension that exhumed the Danubian nappes of the South Carpathians and with a large late Oligocene – middle Miocene Circum-Moesian fault system that affected the orogenic system surrounding the Moesian Platform along its southern, western and northern margins. This fault system is composed of various segments that have different and contrasting types of kinematics, which often formed coevally, indicating a large degree of strain partitioning during oroclinal bending. It includes the curved Cerna and Timok faults that cumulate up to 100 km of dextral offset, the lower offset Sokobanja-Zvonce and Rtanj-Pirot dextral strike-slip faults, associated with orogen parallel extension that controls numerous intra-montane basins and thrusting of the western Balkans units over the Moesian Platform. We have performed a field structural study in order to understand the mechanisms of deformation transfer and strain partitioning around the Moesian indenter during oroclinal bending by focusing on kinematics and geometry of large-scale faults within the Circum-Moesian fault system.</p><p>Our structural analysis shows that the major strike-slip faults are composed of multi-strand geometries associated with significant strain partitioning within tens to hundreds of metres wide deformation zones. Kinematics of the Circum-Moesian fault system changes from transtensional in the north, where the formation of numerous basins is controlled by the Cerna or Timok faults, to strike-slip and transpression in the south, where transcurrent offsets are gradually transferred to thrusting in the Balkanides. The characteristic feature of the whole system is splaying of major faults to facilitate movements around the Moesian indenter. Splaying towards the east connects the Circum-Moesian fault system with deformation observed in the Getic Depression in front of the South Carpathians, while in the south-west the Sokobanja-Zvonce and Rtanj-Pirot faults splay off the Timok Fault. These two faults are connected by coeval E-W oriented normal faults that control several intra-montane basins and accommodate orogen-parallel extension. We infer that all these deformations are driven by the roll-back of the Carpathians slab that exerts a northward pull on the upper Dacia plate in the Serbian Carpathians. However, the variability in deformation styles is controlled by geometry of the Moesian indenter and the distance to Moesia, as the rotation and northward displacements increase gradually to the north and west.</p>

IV.—The Carrara, Massa, and Versilia Marble District

1915 ◽  
Vol 2 (12) ◽  
pp. 554-565
Author(s):  
C. S. Du Riche Preller
Keyword(s):  
Sea Level ◽  
Coarse Grained ◽  
Maximum Height ◽  
The South ◽  
The North ◽  
The Mediterranean ◽  
Apuan Alps ◽  
Marble Industry

The range of the Apuan Alps, commonly called the Carrara Mountains, is an offshoot of the Apennines, trending N.N.W. to S.S.E., parallel to the Mediterranean littoral, from which it rises within a distance of barely four miles to a maximum height of 6,000 feet above sea-level. Exclusive of the outer belt of the more recent strata, the Triassic formation, within which the saccharoidal marble beds are situated, covers about 25 by 13 kilometres or about 130 square miles, of which the marble zone proper represents 64 square miles or about half. The range is bounded on the north by the Aullela valley in the Lunigiana district; on the east by the Serchio valley in the Garfagnana district; and on the south by the Serchio valley in the Province of Lucca. The marble district, whose western part faces the Mediterranean, comprises the three divisions of Carrara, Massa, and the Versilia in the corresponding parallel valleys of the Carrione, Frigido, and Serravezza Rivers. The Versilia division, which forms part of the Province of Lucca, is composed of the Seravezza, Stazzema, and Arni subdivisions, of which the last-named lies on the eastern watershed of the Apuan range. The Versilia division also includes Pietrasanta, Camajore, Massarosa, and the wellknown watering-place of Viareggio, near the last-named of which are situated extensive subaqueous deposits of a peculiarly coarse-grained, sharp macigno sand. These deposits, formed as a delta in a lacustrine expanse by the River Serchio, constitute an important and indispensable adjunct of the marble industry as grinding material for the numerous marble saw-mills in the three parallel valleys already referred to.

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