Evidence for Mississippian Structural Activity Above a Precambrian Rift System, South-Central Kentucky: ABSTRACT

AAPG Bulletin ◽  
1996 ◽  
Vol 80 ◽  
Author(s):  
Garland R. Dever Jr.
Keyword(s):  
2020 ◽  
Vol 18 ◽  
pp. 1-19
Author(s):  
Adrià Ramos ◽  
Berta Lopez-Mir ◽  
Elisabeth P. Wilson ◽  
Pablo Granado ◽  
Josep Anton Muñoz

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.


2020 ◽  
Vol 30 (1) ◽  
pp. 45-78
Author(s):  
Pamela Souza ◽  
Gelson Fambrini ◽  
Renan Queiroz ◽  
Leonardo Oliveira

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.


Geology ◽  
2020 ◽  
Author(s):  
D.S. Stamps ◽  
C. Kreemer ◽  
R. Fernandes ◽  
T.A. Rajaonarison ◽  
G. Rambolamanana

East African Rift System plate geometries and surface motions are some of the least constrained in the context of global plate motion models. In this study, we used GPS data to constrain Somalian plate rotation and to suggest a new tectonic plate geometry for the region. In addition, we tested geologic data from the Southwest Indian Ridge and new GPS data on Madagascar to determine refined kinematics of the Lwandle microplate. A zone of broad deformation was discovered, extending from the eastern boundary of the Rovuma microplate, across the Comoros Islands, and including parts of central and northern Madagascar. Madagascar is fragmenting, with southern Madagascar rotating with the Lwandle microplate and a piece of eastern and south-central Madagascar moving with the Somalian plate. Divergence of the Nubian-Somalian plate system across the East African Rift System involves both diffuse deformation and strain accommodation along narrow rift segments that bound rigid blocks.


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