scholarly journals GEOLOGIA DA ÁREA NORDESTE DA FOLHA POÇO DA CRUZ, BACIA DE JATOBÁ, NORDESTE DO BRASIL

2020 ◽  
Vol 30 (1) ◽  
pp. 45-78
Author(s):  
Pamela Souza ◽  
Gelson Fambrini ◽  
Renan Queiroz ◽  
Leonardo Oliveira
Keyword(s):  
Lacustrine Sediments ◽  
Sedimentary Facies ◽  
Upper Jurassic ◽  
Rift System ◽  
Sedimentary Records ◽  
Preferred Direction ◽  
Tectonic Events ◽  
South Central ◽  
Depositional System ◽  
Initiation Sequence

The Jatobá Basin is located in the south-central portion of Pernambuco state and northern Bahia and Alagoas, it has an area of approximately 5000 km² in a NE-SW preferred direction and sedimentary record has approximately 3 km. It is a rift basin developed under extensional tectonic events related to the rupture of the Gondwana supercontinent and it marks the northern limit of the aborted Recôncavo-Tucano-Jatobá rift system. The stratigraphic succession in the Campos district, Ibimirim (PE), comprises the Syneclise sequence and Rift Initiation sequence as well as part of the Rift Climax sequence of the basin. Using columnar sections and identifying sedimentary facies, six stratigraphic units were recognized, in addition to the quaternary coverage. The two lower fluvial-marine units are related to the siluro-devonian sedimentary records of the Syneclise sequence,while fluvial-eolic and lacustrine sediments of the upper units mark the Rift Initiation and Rift Climax sequences. The Aliança Formation, discussed in a particular way in this paper, represents the first sedimentary records of the beginning of the Neojurassic rift (Dom João stage). Since it was deposited in a lacustrine system, this formation has highly fossiliferous decimetric carbonate levels arranged in thick pelitic packages, suggesting deposition during times of energy variations within a shallow lake. The detailing of the stratigraphy of these deposits, associated with petrographic and paleontological studies, brings a new understanding of the depositional system that occurred in this environment and the first processes that started the opening of the rift during the Upper Jurassic.

scholarly journals Seismic Characteristics and Development of the Upper Jurassic Carbonate Buildups from the Miechów Trough (Southern Poland)

Geosciences ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 239
Author(s):  
Łukasz Słonka ◽  
Piotr Krzywiec
Keyword(s):  
Seismic Data ◽  
Sedimentary Facies ◽  
Upper Jurassic ◽  
Seismic Facies ◽  
Depositional Model ◽  
Attribute Analysis ◽  
Deep Wells ◽  
Depositional System ◽  
Carbonate Buildups ◽  
Mass Flows

The presented study is devoted to the subsurface Upper Jurassic carbonate buildups and surrounding stratified inter-buildup deposits in the hitherto less recognized area, in comparison with other parts of the northern Tethyan shelf in Poland and Europe. The study area is located within the present-day Miechów Trough, almost entirely covered by thick Cretaceous and younger deposits. This paper shows results of the interpretation of 2D seismic data, calibrated by data from deep wells. Investigation of various elements of the Upper Jurassic carbonate depositional system in the Miechów Trough is supported by seismic facies and attribute analysis. The four distinctive seismic facies—(A) bedded, (B) mound-shaped, (C) contorted-chaotic, and (D) chaotic—were assigned to the main Upper Jurassic sedimentary facies, represented by (1) bedded facies, (2) massive facies (carbonate buildups) and (3) deposits of gravity mass-flows. The results of this study were used to construct a depositional model for the Upper Jurassic succession, that focuses on the initiation, growth and demise of the large carbonate buildups in this part of the basin. This paper also presents the more extensive distribution of the Upper Jurassic carbonate buildups than was previously proposed for the Miechów Trough.

scholarly journals 3D reconstruction of syn-tectonic strata in a salt-related orogen: learnings from the Llert syncline (South-central Pyrenees)

2020 ◽  
Vol 18 ◽  
pp. 1-19
Author(s):  
Adrià Ramos ◽  
Berta Lopez-Mir ◽  
Elisabeth P. Wilson ◽  
Pablo Granado ◽  
Josep Anton Muñoz
Keyword(s):  
3D Reconstruction ◽  
Field Research ◽  
Rift System ◽  
Passive Margins ◽  
Fold System ◽  
The North ◽  
Structural Framework ◽  
South Central ◽  
Insight Into ◽  
Central Pyrenees

The Llert syncline is located in the South-central Pyrenees, between the eastern termination of the EW-trending Cotiella Basin and the north-western limb of the NS-trending Turbón-Serrado fold system. The Cotiella Basin is an inverted upper Coniacian-lower Santonian salt-floored post-rift extensional basin developed along the northern Iberian rift system. The Turbón-Serrado fold system consists of upper Santonian – Maastrichtian contractional salt-cored anticlines developed along an inverted transfer zone of the Pyrenean rift system. Based on field research, this paper presents a 3D reconstruction of the Llert syncline in order to further constrain the transition between these oblique salt-related structures. Our results suggest that the evolution of the Llert syncline was mainly controlled by tectonic shortening related to the tectonic inversion of the Cotiella Basin synchronously to the growth of the Turbón-Serrado detachment anticline, and by the pre-compressional structural framework of the Pyrenean rift system. Our contribution provides new insight into the geometric and kinematic relationships of structures developed during the inversion of passive margins involving salt.

Using precise CA-TIMS ages of volcanic air-fall tuff beds in correlating the Walloon Coal Measures of the Surat Basin, Australia

2017 ◽  
Vol 57 (2) ◽  
pp. 810 ◽  
Author(s):  
Carmine Wainman ◽  
Peter McCabe
Keyword(s):  
High Precision ◽  
Sedimentary Facies ◽  
Time Frame ◽  
Upper Jurassic ◽  
Marine Strata ◽  
Stratigraphic Framework ◽  
Lithostratigraphic Units ◽  
Spectrometry Technique ◽  
Discontinuous Nature ◽  
Coal Measures

The Upper Jurassic Walloon Coal Measures of the Surat Basin is one of Australia’s largest and most productive gas provinces. Despite the drilling of over 8500 wells and numerous publications, the stratigraphic framework is poorly defined. The laterally discontinuous nature of the sedimentary facies, including coals and fluvial channel sandstones, makes correlation difficult. The abundance of volcanic air-fall tuff beds within strata across the basin provides a unique opportunity to independently verify existing stratigraphic frameworks. Using the high-precision chemical abrasion thermal ionisation mass spectrometry technique, zircon grains from 28 tuff beds have been successfully dated within an error margin of less than 100 kyr. These dates substantially revise biostratigraphic and lithostratigraphic frameworks. Lithostratigraphic units are diachronous across the basin. In addition, the sparsity of key spore–pollen taxa limits the application of biostratigraphy. The complex interplay of climate and subsidence on facies distributions can now be documented over a time frame of ~4 Ma. Syntectonism played an important role in variable palaeodrainage patterns across the basin, the frequency of fluvial avulsions and preferential sites of peat accumulation through time. The new stratigraphic framework should aid in future exploration for coal seam gas in the area. Dating tuff beds using high-precision dating techniques should also assist in correlation of non-marine strata elsewhere in the world.

An 18 ka to present pollen- and phytolith-based vegetation reconstruction from Hall's Cave, south-central Texas, USA

2019 ◽  
Vol 92 (2) ◽  
pp. 497-518 ◽  
Author(s):  
Carlos E. Cordova ◽  
William C. Johnson
Keyword(s):  
Vegetation Change ◽  
Last Deglaciation ◽  
Sedimentary Records ◽  
South Central ◽  
Drought Tolerant ◽  
Arboreal Pollen ◽  
Central Texas ◽  
Scattered Trees ◽  
Sizable Proportion ◽  
Drying Trend

AbstractPollen, spores, phytoliths, and microscopic charcoal from a sedimentary column in Hall's Cave, south-central Texas, provide information for local and regional vegetation change during the last deglaciation and the Holocene in the context of broader regional and global climatic changes. The combination of paleoenvironmental proxy data from the cave indicates that between about 18,000 and 16,500 cal yr BP the cave area was dominated by an open plant community consisting of herbaceous vegetation, dominated by C3 grasses, and scattered trees, primarily Quercus and Pinus species. After about 16,500 cal yr BP, the arboreal component fluctuated, attaining a peak between 14,000 and 13,000 cal yr BP with relatively equal proportions of C3 and C4 grasses, including a sizable proportion of Panicoideae grasses. The Younger Dryas is marked by a conspicuous decrease in arboreal pollen with an apparent increase of C4 grasses toward its termination. Early Holocene recovery of arboreal vegetation is followed by a drying trend marked by the increasing dominance of C4 drought-tolerant Chloridoideae grasses. Increasing human use of the cave in middle to late Holocene times creates noise in the climatic significance of pollen, phytolith, and other proxies, a factor to consider when interpreting paleoenvironmental proxies in other cave sedimentary records.

scholarly journals Upper Jurassic carbonate buildups in the Miechów Trough, Southern Poland – insights from seismic data interpretation

2019 ◽  
Author(s):  
Łukasz Słonka ◽  
Piotr Krzywiec
Keyword(s):  
Transition Zone ◽  
Seismic Data ◽  
Late Jurassic ◽  
Data Interpretation ◽  
Upper Jurassic ◽  
Carbonate Sediments ◽  
Northern Margin ◽  
Depositional System ◽  
Carbonate Buildups ◽  
Shelf Sedimentation

Abstract. The geometry and internal architecture of the Upper Jurassic carbonate depositional system in the epicontinental basin of western and central Europe, and within the northern margin of the Tethyan shelf are hitherto only partly recognised, especially in areas with thick Cretaceous and younger cover such as the Miechów Trough. In such areas, seismic data are indispensable for analysis of a carbonate depositional system, in particular for identification of the carbonate buildups and the enveloping strata. The study area is located in the central part of the Miechów Trough that in the Late Jurassic was situated within the transition zone between the Polish part of western and central European epicontinental basin and the Tethys Ocean. This paper presents the results of interpretation of 2D seismic data calibrated by deep wells that document the presence of large Upper Jurassic carbonate buildups. The lateral extent of particular structures is in the range of 400–1000 m, and their heights are in range of 150–250 m. Interpretation of seismic data revealed that the depositional architecture of the subsurface Upper Jurassic succession in the Miechów Trough is characterised by the presence of large carbonate buildups surrounded by basinal (bedded) limestone-marly deposits. These observations are compatible with depositional characteristics of well-recognised Upper Jurassic carbonate sediments that crop out in the adjacent Kraków-Częstochowa Upland. The presented study provides new information about carbonate open shelf sedimentation within the transition zone in the Late Jurassic, which proves the existence of much more extensive system of organic buildups which flourished in this part of the basin. Obtained results, due to high quality of available seismic data, provide also an excellent generic reference point for seismic studies of carbonate buildups from other basins and of different ages.

THE OTWAY BASIN

1989 ◽  
Vol 29 (1) ◽  
pp. 417 ◽  
Author(s):  
S. Laing ◽  
C.N. Dee ◽  
P.W. Best
Keyword(s):  
Lacustrine Sediments ◽  
South Australia ◽  
Commercial Production ◽  
Source Rocks ◽  
Mature Stage ◽  
Tectonic Events ◽  
Late Tertiary ◽  
Marine Carbonates ◽  
Initial Deposition ◽  
Commercial Oil

The Otway Basin covers an area of some 150 000 km2 both onshore and offshore southwestern Victoria and southeastern South Australia. Exploration within the basin is at a moderately mature stage by Australian standards (though immature by world standards), with a well density of one per 1500 km2, including offshore areas.Formation of the Otway Basin commenced in the late Jurassic with the initiation of rifting between Australia and Antarctica. As rifting continued, a number of depositional cycles occurred. Initial deposition comprised fluvio- lacustrine sediments, followed by marine transgressions and associated regressive deltaic cycles. As subsidence continued into the Late Tertiary, a series of marine carbonates and marls were deposited. The Otway Basin is structurally complex as a result of the superposition of a number of tectonic events which occurredboth during and after the development of the basin.The Otway Basin is a proven gas province, with commercial production at Caroline 1 (carbon dioxide) and North Paaratte Field (methane). Although no commercial oil production has yet been established in the basin, oil has been recovered at Port Campbell 4, Lindon 1 and Windermere 1. The presence of excellent reservoir units within the basin, mature source rocks and adequate seals, together with a number of untested play types and favourable economics, augurs well for the prospectivity of the Otway Basin.

scholarly journals Late Oligocene–Early Miocene Nukhul Sequence, Gulf of Suez and Red Sea

GeoArabia ◽  
2012 ◽  
Vol 17 (1) ◽  
pp. 17-44 ◽  
Author(s):  
Moujahed I. Al-Husseini
Keyword(s):  
Red Sea ◽  
Isotope Analysis ◽  
Sedimentary Facies ◽  
Early Miocene ◽  
Rift System ◽  
Gulf Of Suez ◽  
Late Oligocene ◽  
Depositional Sequence ◽  
Red Sea Rift ◽  
Northern Red Sea

ABSTRACT Egypt’s Late Oligocene–Early Miocene Nukhul Formation was deposited during the earliest geological evolution of the Gulf of Suez and Red Sea Rift System. In this paper the formation is cast as a depositional sequence based on published sections, and correlated across the Gulf of Suez and northern Red Sea. The resulting correlations indicate that deposition was initiated in local grabens by the oldest continental clastics of the lower member of the Nukhul Formation, the Shoab Ali Member. The member overlies the Suez Rift Unconformity, a term proposed for the entire Red Sea. Although this member can attain a thickness of ca. 1,000 ft (305 m) locally in grabens, it is generally absent over horsts. Sedimentary facies of the member are interpreted as indicating an initial alluvial-fluvial setting that evolved to an estuarine and coastal setting. The upper part of the Nukhul Formation records a regional shallow-marine transgression, which can be subdivided into three correlative Upper Nukhul members. These sediments are absent over the highest paleo-horsts, but reach up to 900 ft (275 m) in thickness in grabens. In the southern Gulf of Suez the Ghara Member represents the Upper Nukhul members. In places it consists of four cycles, each of which starts with an anhydrite bed and is overlain by deposits of mixed lithology (sandstone, marl, and limestone). The four cycles are interpreted as transgressive-regressive subsequences that can be correlated across ca. 60 km in the Gulf of Suez. The Ghara Member correlates to Saudi Arabia’s Yanbu Formation, which consists of massive salt in wells drilled on the Red Sea coastal plains. The Yanbu Salt is dated by strontium-isotope analysis at ca. 23.1–21.6 Ma (earliest Aquitanian). The Nukhul Formation is capped by the Sub-Rudeis Unconformity or correlative Rudeis Sequence Boundary, and overlain by the Rudeis Formation. The Nukhul Formation is here proposed as the Nukhul Sequence and defined in the Wadi Dib-1 Well, wherein it consists of Nukhul subsequences 1 to 10 (in descending order, ranging in thickness between 33–84 m). The lower six Nukhul subsequences 10 to 5 are characterized by shale-to-sandstone cycles of the Shoab Ali Member, and the upper four are represented by the cycles of the Ghara Member. The 10 subsequences are interpreted as tracking the 405,000 year eccentricity signal of the Earth’s orbit and to span ca. 4.0 million years between ca. 25.0 and 21.0 Ma.

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