scholarly journals Large-scale vertical movements in Cenomanian to Santonian carbonate platform in Iberia: Indicators of a Coniacian pre-orogenic compressive stress

Author(s):  
Simon Andrieu ◽  
Nicolas Saspiturry ◽  
Marine Lartigau ◽  
Benoit Issautier ◽  
Paul Angrand ◽  
...  

The Cenomanian to early Santonian interval is usually considered a time of postrifting tectonic quiescence around the northern margins of Iberia that preceded the onset of the Pyrenean convergence by crustal thrusting in the latest Santonian. However, plate kinematic models of the Mesozoic evolution of Iberia poorly constrain the Turonian-Santonian position of Iberia relative to Eurasia. This study reconstructs changes in the sedimentary facies and architecture of the Iberian carbonate platform throughout the Late Cretaceous and sheds new light on the geodynamic evolution of the Iberia-Eurasia relationship at that time. Sixteen outcrop sections were described and 24 sedimentary facies identified that define 5 depositional environments ranging from the basin to the continental setting. From these and previously published field data we reconstruct the evolution of the Pyrenean carbonate platform, on an east-west transect nearly 400 km long, on the basis of 11 short-term depositional sequences and 5 long-term systems tracts. In our interpretation, the Cenomanian and Turonian correspond to a postrift stage during which the European and Iberian margins, together with the deep basin between them, subside gently, as shown by accommodation rates varying from ~15 to 30 m/My in the margins and ~100 to 150 m/My in the basin. The Coniacian and early Santonian are characterized by a large-scale flexural response consisting of (1) uplift of the southern Iberian margin, with negative accommodation rates, karstified surfaces and paleosols, and (2) increasing subsidence rates in the basin and its edges (the northern Iberian margin and eastern Aquitaine platform), with accommodation rates several times greater than during the Turonian. We propose that far-field stress associated with slight northward motion of the Iberia plate led to the incipient large-scale flexural deformation in the Pyrenean domain. The late Santonian and Campanian are an early orogenic stage marked by rapid subsidence throughout the Pyrenean domain, except at its western end. We argue that the initiation of the Pyrenean convergence, usually considered to occur during the latest Santonian, occurred in the Coniacian.

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin

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.


1988 ◽  
Vol 62 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin

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.


Author(s):  
Nicolas Saspiturry ◽  
Benoit Issautier ◽  
Philippe Razin ◽  
Simon Andrieu ◽  
Eric Lasseur ◽  
...  

Abstract — The Mauléon basin, in the northwestern Pyrenean belt, is related to Early Cretaceous rifting and continental breakup. Here we review the evolution of depositional environments in the hyperextended Mauléon rift basin during Albian and Cenomanian time. This review includes the lithostratigraphy, regional distribution, boundaries, age and facies sedimentology of the basin’s syn-rift formations and their members. We construct paleogeographic maps to elucidate (1) the 3D distribution of sedimentary facies and depositional environments during the Albian and Cenomanian from the Iberian proximal margin to the hyperextended domain and (2) the link between major extensional structures and sedimentation during rifting and continental breakup. The Mauléon rift was supplied during most of the Albian by sediments from the Iberian proximal margin. The southern margin had a steep and abrupt topographic boundary related to a northward crustal rollover along the south-dipping Saint-Palais detachment. This feature controlled the deposition of base-of-slope conglomerates at the base of the margin that abruptly gave way to low-density turbidites, then hemipelagic deposits in the hyperextended domain. During latest Albian to Early Cenomanian time, continental breakup occurred in the eastern Mauléon basin and the vergence of the detachment systems reversed. Minor debris-flow deposits formed at the foot of fault scarps associated with the newly formed north-dipping detachments. Elsewhere, sediment from deltaic systems to the west in the Saint-Jean-de-Luz area deposited low-density turbidites in the hyperextended domain. During the post-rift stage, the flux of coarse sediment from the detachment footwall gradually declined as deformation waned, and low-density turbidites expanded onto the hyperextended domain from the European Late Cretaceous carbonate platform. These paleogeographic reconstructions, in addition to offering a synthetic view of the evolution of sedimentary environments during rifting, offer new insight into the post-rifting exhumation of the lower crust and mantle.


1999 ◽  
Vol 18 (1) ◽  
pp. 45-65 ◽  
Author(s):  
Esam O. Abdulsamad ◽  
Roberto Barbieri

Abstract. In the coastal area of northeastern Cyrenaica (Libya), the excellent exposures of Cenozoic limestone sequences of Al Jabal al Akhdar average around 1000 m in thickness and allow detailed stratigraphic investigations to be undertaken. This study of the biostratigraphy and depositional environments has been augmented by an analysis of the microfacies and of matrix-free foraminiferal assemblages. The biotic contents of the microfacies provide a good tool for correlation with the Letter classification developed from the Indo-Pacific region. The palaeoecological significance of the biota has been evaluated by comparison with the ecological requirements of their present day counterparts. Limitations for the palaeoecological interpretations are mainly due to the inadequate relationships with existing ecological data sets and to some local bias in fossil recovery because of some unfavourable lithologies. In the investigated Eocene to Miocene shallow marine carbonate succession nine different microfacies and sub-microfacies were distinguished through depositional texture and biotic components. Wilson’s standard carbonate facies belts, integrated with present day foraminiferal distribution models, have been used for reference in microfacies analysis and description. Most of the microfossils present are foraminifera and a total of 150 taxa, including larger, small and planktonic foraminifera, have been recognized and their stratigraphic and palaeaeocological distribution reported. Physiographically, the rock sequences investigated are referred to a shelf–carbonate platform complex, in which the depositional environments range from open shelf to restricted platform conditions. The nature and distribution of the foraminiferal assemblages and related biota, in association with sedimentological evidence, indicate a generalized shallowing upward trend in which several bathymetric oscillations, especially in the Oligocene, are reported. These reflect the interplay between local tectonics and large-scale eustatic changes.


2021 ◽  
Author(s):  
Larissa Hansen ◽  
Rachel Healy ◽  
Luz Gomis Cartesio ◽  
David Lee ◽  
David Hodgson ◽  
...  

Scours, and scour fields, are common features on the modern seafloor of deep-marine systems, particularly downstream of submarine channels, and in channel-lobe-transitions-zones. High-resolution images of the seafloor have improved the documentation of the large scale, coalescence, and distribution of these scours in deep-marine systems. However, their scale and high aspect ratio mean they can be challenging to identify in outcrop. Here, we document a large-scale, composite erosion surface from the exhumed deep-marine stratigraphy of Unit 5 from the Permian Karoo Basin succession in South Africa, which is interpreted to be present at the end of a submarine channel.This study utilizes 24 sedimentary logs, 2 cored boreholes, and extensive palaeocurrent and thickness data across a 126 km2 study area. Sedimentary facies analysis, thickness variations and correlation panels allowed identification of a lower heterolithic-dominated part (up to 70 m thick) and an upper sandstone-dominated part (10-40 m thick) separated by an extensive erosion surface. The lower part comprises heterolithics with abundant current and sinusoidal ripples, which due to palaeocurrents, thickness trends and adjacent depositional environments is interpreted as the aggradational lobe complex fringes. The base of the upper part comprises 2-3 medium-bedded sandstone beds interpreted as precursor lobes cut by a 3-4 km wide, 1-2 km long, and up to 28 m deep, high aspect ratio (1:100) composite scour surface. The abrupt change from heterolithics to thick-bedded sandstones marks the establishment of a new sediment delivery system, which may have been triggered by an updip channel avulsion. The composite scour and subsequent sandstone fill support a change from erosion- and bypass-dominated flows to depositional flows, which might reflect increasingly sand-rich flows as a new sediment route matured. This study provides a unique outcrop example with 3D stratigraphic control of the record of a new sediment conduit, and development and fill of a large-scale composite scour surface at the channel mouth, providing a rare insight into how scours imaged on seafloor data can be preserved in the rock record.


2021 ◽  
Vol 9 ◽  
Author(s):  
L. A. S. Hansen ◽  
R. S. Healy ◽  
L. Gomis-Cartesio ◽  
D. R. Lee ◽  
D. M. Hodgson ◽  
...  

Scours, and scour fields, are common features on the modern seafloor of deep-marine systems, particularly downstream of submarine channels, and in channel-lobe-transition-zones. High-resolution images of the seafloor have improved the documentation of the large scale, coalescence, and distribution of these scours in deep-marine systems. However, their scale and high aspect ratio mean they can be challenging to identify in outcrop. Here, we document a large-scale, composite erosion surface from the exhumed deep-marine stratigraphy of Unit 5 from the Permian Karoo Basin succession in South Africa, which is interpreted to be present at the end of a submarine channel. This study utilizes 24 sedimentary logs, 2 cored boreholes, and extensive palaeocurrent and thickness data across a 126 km2 study area. Sedimentary facies analysis, thickness variations and correlation panels allowed identification of a lower heterolithic-dominated part (up to 70 m thick) and an upper sandstone-dominated part (10–40 m thick) separated by an extensive erosion surface. The lower part comprises heterolithics with abundant current and sinusoidal ripples, which due to palaeocurrents, thickness trends and adjacent depositional environments is interpreted as the aggradational lobe complex fringes. The base of the upper part comprises 2-3 medium-bedded sandstone beds interpreted as precursor lobes cut by a 3–4 km wide, 1–2 km long, and up to 28 m deep, high aspect ratio (1:100) composite scour surface. The abrupt change from heterolithics to thick-bedded sandstones marks the establishment of a new sediment delivery system, which may have been triggered by an updip channel avulsion. The composite scour and subsequent sandstone fill support a change from erosion- and bypass-dominated flows to depositional flows, which might reflect increasingly sand-rich flows as a new sediment route matured. This study provides a unique outcrop example with 3D stratigraphic control of the record of a new sediment conduit, and development and fill of a large-scale composite scour surface at a channel mouth transition zone, providing a rare insight into how scours imaged on seafloor data can be filled and preserved in the rock record.


2020 ◽  
Vol 295 (1) ◽  
pp. 61-89
Author(s):  
Mohammad Safaei ◽  
Asadollah Mahboubi ◽  
Soroush Modabberi ◽  
Reza Moussavi-Harami

Four Lower Cretaceous sections in the southern Yazd Block were measured and studied to interpret the palaeoenvironments, synsedimentary tectonics, and sequence stratigraphy. The Early Cretaceous sedimentary record of this block, consisting of the Sangestan, Taft, Abkuh, and Darreh Zanjir formations, was mainly influenced by synsedimentary tectonic activities in a tectonically unstable basin. Field observations and laboratory studies were used to identify lithofacies and microfacies, based on which six depositional environments were identified: upper coastal plain (alluvial fans), shore, tidal flat, lagoon, shoal, and open marine. A carbonate-siliciclastic shallow platform including an alluvial-coastal plain and an inner platform is suggested for the depositional environment of the Sangestan Formation. The depth of the overall shallow sedimentary basin of Sangestan Formation increases from west to east and deposition was controlled by long- term sea-level changes. A carbonate platform consisting of inner and outer parts, including tidal flat, lagoon, open marine belts, is suggested for the depositional environment of the Taft and Abkuh formations, while the Darreh Zanjir Formation accumulated in a deep basin. The predominant facies demonstrate an overall transgression-regression cycle (the 2rd order cycle) during the depositional time of these formations in the southern Yazd Block.


2015 ◽  
Vol 7 (2) ◽  
pp. 51 ◽  
Author(s):  
Paike Htwe ◽  
Sugeng Sapto Surjono ◽  
Donatus Hendra Amijaya ◽  
Kyuro Sasaki

The early Middle Miocene Ngrayong Formation, an important reservoir of North East Java Basin, is well exposed in the central anticlinal part of Madura Island. The purpose of current study is to classify the depositional environments of the study area based on the characteristics and geometry of sedimentary facies. In the Madura island, the thicker clastics and deeper carbonates of Ngimbang Formation and Kujung Formation of Late Oligocene-Early Miocene deposited in the northeast-southwest asymmetrical half grabens. After the deposition of Kujung Formation, the basin morphology developed nearly eastwest trending shelf edge and the deposition of Tuban Formation began. The fine grained complex of Tuban Formation was followed by the Ngrayong Sandstones deposition. The depositional model of Ngrayong Formation is being producing of wide variety of depositional environments. Large scale cross-bedded sandstones and bioturbated massive sandstones with thin to medium bedded argillaceous limestone that outcrop in the northern part of the study area are deposited in costal environment. The heterolithic sandstone with planar and trough cross-lamination, fine grained sandstone with interlaminated structure and bioclastic carbonate exposed in the central part of the study area are deposited in upper shallow marine area. Dark grey siltstones and mudstones deposited in lower shallow marine area are well exposed in southern part of the study area. In conclusion, Ngrayong Formation in Madura area is developed in three depositional units which are coastal, upper shallow marine and lower shallow marine.


GeoArabia ◽  
2003 ◽  
Vol 8 (2) ◽  
pp. 275-294 ◽  
Author(s):  
Bernd Eilrich ◽  
Jürgen Grötsch

ABSTRACT The Jurassic and Lower Cretaceous carbonate succession exposed near Khatt provides exceptional conditions for the investigation of sedimentary facies and depositional geometries in a carbonate slope-to-platform-margin setting. A coarsening-upward sequence in Lower Cretaceous limestones indicates decreasing depth of deposition and platform progradation. A pronounced shedding of sediments containing reefal fragments occurs in a slope environment with a well exposed basin-to-platform transect. The carbonate succession consists of mudstone, wackestone, grainstone, coarse rudstone with conglomerate/breccia interbeds, and framestone at the top. The depositional architecture is characterized by the abundance of massive sheet- or channel-like limestone bodies within thinly bedded and generally uniform strata. Quantitative analysis of many carbonate channel deposits and their geometries measured in outcrop led to the distinction of two major types. Type I channel deposits are thin (0.3 to 5 m) but massive, and are commonly irregularly shaped in cross-section. They are as much as 200 m wide. Type I channel deposits are characterized by a wide size range of skeletal and non-skeletal carbonate components. Type II channel deposits, by contrast, are more regularly bedded and have much larger thickness-to-width ratios, in general close to 1:10. Furthermore, they are composed of packstone to grainstone calciturbidite sediments. As with some sheet deposits, they can be correlated through most of the 5.5-km-long Khatt outcrop. Stratigraphically, however, their occurrence is very much restricted, indicating significant alternation of depositional styles as a consequence of changing carbonate platform production and changing sedimentary environments. The data presented here can serve as input for 3-D geological modeling of equivalent depositional environments in the subsurface. They can also be applied to object-based deterministic and stochastic facies modeling.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yousif M. Makeen ◽  
Xuanlong Shan ◽  
Habeeb A. Ayinla ◽  
Ekundayo Joseph Adepehin ◽  
Ndip Edwin Ayuk ◽  
...  

AbstractThe Zarga and Ghazal formations constitute important reservoirs across the Muglad Basin, Sudan. Nevertheless, the sedimentology and diagenesis of these reservoir intervals have hitherto received insignificant research attention. Detailed understanding of sedimentary facies and diagenesis could enhance geological and geophysical data for better exploration and production and minimize risks. In this study, subsurface reservoir cores representing the Zarga formation (1114.70–1118.50 m and 1118.50–1125.30 m), and the Ghazal formation (91,403.30–1406.83 m) were subjected to sedimentological (lithofacies and grain size), petrographic/mineralogic (thin section, XRD, SEM), and petrophysical (porosity and permeability) analyses to describe their reservoir quality, provenance, and depositional environments. Eight (8) different lithofacies, texturally characterized as moderately to well-sorted, and medium to coarse-grained, sub-feldspathic to feldspathic arenite were distinguished in the cored intervals. Mono-crystalline quartz (19.3–26.2%) predominated over polycrystalline quartz (2.6–13.8%), feldspar (6.6–10.3%), and mica (1.4–7.6%) being the most prominent constituent of the reservoir rocks. Provenance plot indicated the sediments were from a transitional continental provenance setting. The overall vertical sequence, composition, and internal sedimentary structures of the lithofacies suggest a fluvial-to-deltaic depositional environment for the Ghazal formation, while the Zarga formation indicated a dominant deltaic setting. Kaolinite occurs mainly as authigenic mineral, while carbonates quantitatively fluctuate with an insignificant amount of quartz overgrowths in most of the analyzed cores. Integration of XRD, SEM, and thin section analysis highlights that kaolinite, chlorite, illite, and smectite are present as authigenic minerals. Pore-destroying diagenetic processes (e.g. precipitation, cementation, and compaction etc.) generally prevailed over pore-enhancing processes (e.g. dissolution). Point-counted datasets indicate a better reservoir quality for the Ghazal formation (ɸ = 27.7% to 30.7%; K = 9.65 mD to 1196.71 mD) than the Zarga formation (17.9% to 24.5%; K = 1051.09 mD to 1090.45 mD).


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