scholarly journals Lifecycle of an Intermontane Plio-Pleistocene Fluvial Valley of the Northern Apennines: From Marine-Driven Incision to Tectonic Segmentation and Infill

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 141
Author(s):  
Massimiliano Ghinassi ◽  
Mauro Aldinucci ◽  
Valeria Bianchi ◽  
Andrea Brogi ◽  
Enrico Capezzuoli ◽  
...  

Downcutting and infill of incised valley systems is mostly controlled by relative sea-level changes, and studies on valley-fill successions accumulated independently from relative sea-level or lake-level oscillations are limited. This study focuses on the Plio-Pleistocene evolution of a fluvial drainage system developed in Southern Tuscany (Italy) following a regional marine forced regression at the end of Piacentian. Subsequent in-valley aggradation was not influenced by any relative sea-level rise, and valley morphological and depositional history mainly resulted from interaction between sediment supply and tectonic activity, which caused segmentation of the major valley trunk into localized subsiding depocenters separated by upwarping blocks. Fluvial sedimentation occurred until late Calabrian time, when the major river abandoned that valley, where minor fluvio-lacustrine depocenters allowed accumulation of siliciclastic and carbonate deposits. The present study demonstrates that the infill of the valley was not controlled by the forcing that caused its incision. Accumulation of the fluvial succession is discussed here in relation with localized, tectonic-controlled base levels, which commonly prevent from establishing of a clear downdip stratigraphic correlations. Chronological reconstruction of the study depositional dynamics provides solid constrains to frame them in the tectono-sedimentary evolution of the Northern Apennines.

2016 ◽  
Vol 4 (1) ◽  
pp. T79-T101
Author(s):  
Joseph Bertrand Iboum Kissaaka ◽  
Joseph Marie Ntamak-Nida ◽  
François Mvondo ◽  
Paul Gustave Fowe Kwetche ◽  
Adrien Lamire Djomeni Nitcheu ◽  
...  

Using 2D seismic data and well logs from the Kribi-Campo subbasin in the south Cameroon margin, we have analyzed the postrift succession with the aim of deriving a chronostratigraphic chart and identifying stratigraphic traps. The Kribi-Campo subbasin related to the rifting between Africa and South America could be divided into a structurally complex eastern depocenter and a relatively less disturbed western depocenter in which a break-up unconformity approximately 107.5 Ma underlined the beginning of postrift history. We have used the modern concepts of sequence stratigraphy to identify and characterize seven second-order (SS1, SS2, SS3, SS4, SS5, SS6, and SS7) sequences and one third-order (SS8) sequences grouped into three megasequences (A, B, and C) from Albian to Recent. Sequence 1 (Albian-Cenomanian) was characterized by a retrogradation overlying a lowstand progradational pattern. The SS2 (Campanian-Maastrichtian) and SS3 (Maastrichtian) sequences were deposited during a highstand normal regression. From Paleocene to Eocene, the deposition of sequences SS4–SS5 was controlled by the development of submarine fan turbiditic system related to a forced regression of coastline. From the Middle Miocene to Recent age, the SS6, SS7, and SS8 sequences have been characterized by the development of sigmoidal-oblique clinoforms of a deltaic system well observed in the northern part of the study area. We have studied a new undocumented phase of forced regression of Mio-Pliocene in age within the postrift sequence SS7. The forced regression phases are associated with the Paleogene and Neogene uplift. Relative sea-level curves were constructed and compared with the existing published curves. The processes involved in the formation of these sequences were interpreted as a combination of tectonics, sediment supply, and sea-level changes. Potential reservoirs embedded within the sequences include channel fill, shingled turbidites, slope fan, and basin-floor fan complex.


2009 ◽  
Vol 147 (3) ◽  
pp. 321-338 ◽  
Author(s):  
ANDREAS SIEMES ◽  
TOM McCANN ◽  
ANNE FISCHER

AbstractThe Mesta half-graben is one in a series of extensional basins in SW Bulgaria that record the onset of extension within the Rhodope Zone in the Late Eocene. Tectonic activity on a continuous detachment along the eastern margin was a major control on subsidence, accommodation space creation, sediment supply and facies distribution in the basin. The sedimentary architecture was complicated by synsedimentary rotation, the presence of intrabasinal faults and the resulting compartmentalization, as well as synsedimentary volcanic activity. Facies and structural analysis of a key transverse section in the central part of the basin, together with supporting observations from other parts of the basin, indicate a pulsed tectono-sedimentary evolution of the basin with three distinct stages. The first stage (Late Eocene) is a phase of rapid extension with an initial alluvial setting. Basin margin fans and an axial fluvial through-drainage system were the major depositional systems in this stage. The second stage (Early Oligocene) marks the onset of volcanic activity within the Mesta Basin and is characterized by the formation of volcanic centres, an intense phase of explosive volcanism and rapid infilling of the previous basin topography with volcanic material deposited from pyroclastic density currents. The third stage (Late Oligocene) represents waning volcanic activity in a mixed alluvial–volcaniclastic environment. This stage is characterized by alternating alluvial and volcaniclastic depositional cycles, as well as partial reworking of volcanic material.


2007 ◽  
Vol 242 (1-3) ◽  
pp. 5-26 ◽  
Author(s):  
D.E. Smith ◽  
R.A. Cullingford ◽  
T.M. Mighall ◽  
J.T. Jordan ◽  
P.T. Fretwell

2011 ◽  
Vol 26 (4) ◽  
pp. 353-361 ◽  
Author(s):  
Ole Bennike ◽  
Bernd Wagner ◽  
Andreas Richter

2021 ◽  
Author(s):  
Frances E. Dunn ◽  
Philip S. J. Minderhoud

<p>As one of the largest deltas in the world, the Mekong delta is home to over 17 million people and supports internationally important agriculture. Recently deposited sediment compacts and causes subsidence in deltas, so they require regular sediment input to maintain elevation relative to sea level. These processes are complicated by human activities, which prevent sediment deposition indirectly through reducing fluvial sediment supply and directly through the construction of flood defence infrastructure on deltas, impeding floods which deliver sediment to the land. Additionally, anthropogenic activities increase the rate of subsidence through the extraction of groundwater and other land-use practices.</p><p>This research shows the potential for fluvial sediment delivery to compensate for sea-level rise and subsidence in the Mekong delta over the 21st century. We use detailed elevation data and subsidence scenarios in combination with regional sea-level rise and fluvial sediment flux projections to quantify the potential for maintaining elevation relative to sea level in the Mekong delta. We present four examples of localised sedimentation scenarios in specific areas, for which we quantified the potential effectiveness of fluvial sediment deposition for offsetting relative sea-level rise. The presented sediment-based adaptation strategies are complicated by existing land use, therefore a change in water and sediment management is required to effectively use natural resources and employ these adaptation methods. The presented approach could be an exemplar to assess sedimentation strategy feasibility in other delta systems worldwide that are under threat from sea-level rise.</p>


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