scholarly journals Stratigraphy and sedimentary evolution of a modern macro‐tidal incised valley – an analogue for reservoir facies and architecture

Sedimentology ◽  
2021 ◽  
Author(s):  
Claire McGhee ◽  
Dahiru Muhammed ◽  
Naboth Simon ◽  
Sanem Acikalin ◽  
James E. P. Utley ◽  
...  
Keyword(s):  
Incised Valley ◽  
Sedimentary Evolution ◽  
Reservoir Facies

Sedimentary conditioning of a rocky strait during the Holocene transgression: Ría de Ferrol (NW Spain)

2020 ◽  
Author(s):  
Soledad García-Gil ◽  
Víctor Cartelle ◽  
Castor Muñoz-Sobrino ◽  
Natalia Martínez-Carreño ◽  
Iria García-Moreiras
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Late Pleistocene ◽  
Nw Spain ◽  
The Holocene ◽  
Incised Valley ◽  
Sedimentary Evolution ◽  
Holocene Transgression ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>Understanding coastal responses to relative sea level rise is key to be able to plan for future changes and develop a suitable managing strategy. The sedimentary record of the Late-Pleistocene and Holocene transgression provides a natural laboratory to study the long-term changes induced in coastal landscapes by the rapid sea level rise. As sea level rises, coastal morphology continually adapts towards equilibrium changing the landscape and reshaping the distribution of sedimentary environments.<br>The Ría de Ferrol is a confined tide-dominated incised valley located in the mesotidal passive Atlantic margin of western Galicia (NW Spain).  A multidisciplinary approach was used to identify the elements of sedimentary architecture within its sedimentary record since the Last Glacial Maximum. The sedimentary evolution was reconstructed combining seismic and sedimentary facies analysis with radiocarbon, geochemical and pollen data.<br>The Ría de Ferrol is characterised by a particular morphology with a rock-incised narrow channel in the middle of the basin (the Ferrol Strait) connecting an inner shallower sector with an outer deeper sector. The inner sector is characterised by low energetic conditions and is where the main fluvial inputs occur. The outer sector is connected to the shelf.<br>The main factor influencing the sedimentary evolution of the Ría de Ferrol incised valley was Late Pleistocene and Holocene sea-level rise. However, this evolution was modulated by the antecedent morphology, particularly once the middle strait became flooded during the Holocene transgression. Three main phases of evolution are distinguished: a fluvial valley drained by a braided river system, a tide-dominated estuary and a shallow marine basin (ria).<br>During the lowstand of the Last Glacial Maximum (ca 20 kyr BP), the ria was a fluvial valley whose sediments are mainly preserved in the inner sector. Sediments cores recovered sediments from ponds and stagnant areas, dated to be older than 10790-11170 cal yr BP.<br>During the Holocene, the basin turned into a tide-dominated estuary whose facies distribution was conditioned by the strait. The strait acted as a rock-bounded tidal inlet enhancing tidal erosion and deposition at both ends, where an ebb-tidal delta and tidal sandbanks appear. At this time, extensive tidal flats occupied most of the inner sector, dissected by estuarine channels of varied dimensions. Radiocarbon data showed ages from 8610-8910 to 5760-5940 cal yr BP.<br>An erosive episode is identified after 6 cal kyr BP with the formation of a ravinement surface. Wave and tidal energy were split by the middle strait. A wave ravinement surface is identified in the outer sector, while a coetaneous tidal ravinement surface occurs in the inner sector.<br>Slow sea-level rise after ca 4 ka BP finally forced rivers to retreat to the present position, causing the dispersion of their energy and leading to the final evolution of the area into a fully marine system.</p>

A REAPPRAISAL OF THE CARBONIFEROUS STRATIGRAPHY AND THE PETROLEUM POTENTIAL OF THE SOUTHEASTERN BONAPARTE BASIN (PETREL SUB-BASIN), NORTHWESTERN AUSTRALIA

2005 ◽  
Vol 45 (1) ◽  
pp. 275 ◽  
Author(s):  
J.D. Gorter ◽  
P.J. Jones ◽  
R.S. Nicoll ◽  
C.J. Golding
Keyword(s):  
Large Scale ◽  
Seismic Profiles ◽  
Petroleum Potential ◽  
Incised Valley ◽  
Channel Incision ◽  
New Name ◽  
Valley Fills ◽  
Northwestern Australia ◽  
Marine Influence ◽  
Reservoir Facies

A revision of the latest Tournaisian to Namurian stratigraphy of the Petrel Sub-basin is proposed following the recognition of a series of megasequences based on seismic profiles, well logs and new palaeontological information. In late Tn3c, turbidites of the Waggon Creek facies were overlain by a seal, the Milligans Formation (redefined) during the Chadian (V1a, V1b). A basal Arundian (V2a) regression, possibly driven by tectonics, deposited the Yow Creek Formation (new name) with incised valley fills. A basal Asbian (V3a) regression, deposited coarser grained clastics and limestones, the Utting Calcarenite (V3a), forming a possible local reservoir facies overlain by a regional seal, Kingfisher Shale (new name). An intra-Asbian (V3b) regression followed, possibly glaciogenic and/or tectonically driven, with the deposition of the Tanmurra Formation, dominantly coarse clastics, during the Asbian, forming reservoir facies with some source potential. Following a basal Brigantian unconformity, the Sandbar Sandstone (new name) formed a restricted ?aeolian facies, a potential local reservoir. An intra-Brigantian unconformity was followed by deposition of the carbonate Sunbird Formation (new name), generally a tight shelf edge carbonate (V3c), near Lacrosse–1 and Sunbird–1. A major basal Pendleian sea-level fall, probably glaciogenic, with major channel incision and erosion, was followed by Arnsbergian clastics with G. maculosa, the Arco Formation (new name) with basinal shales in clinoforms. The latest Arco Formation (earliest Pennsylvanian) was followed by a Late Namurian regression, and deposition of the Aquitaine Formation (new name), consisting of fluvio-deltaic siliciclastics, with minor marine influence, large scale channelling, potentially good reservoirs, and a regional upper shaly seal. This sequence is unconformably overlain by the basal Kulshill Group, which marked the onset of major Gondwanan glaciation.

Sedimentary evolution of a bedrock-conditioned incised valley since the Last Glacial Maximum: the Ría de Arousa (NW Spain)

2020 ◽  
Author(s):  
Víctor Cartelle ◽  
Soledad García-Gil ◽  
Iria García-Moreiras ◽  
Castor Muñoz-Sobrino ◽  
Natalia Martínez-Carreño
Keyword(s):  
Sea Level ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Nw Spain ◽  
Incised Valley ◽  
Last Glacial ◽  
Sedimentary Evolution ◽  
River Mouths ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>Coastal sedimentary environments are dynamic systems in continuous change responding to different temporal and spatial scales. Their sedimentary record offers invaluable data to unveil the effect of different drivers, such as relative sea-level rise, on their evolution.</p><p>The Ría de Arousa is located on the Atlantic coast of Galicia (NW Spain) and represents the largest of the so-called “Galician Rias”, with a total area of 230 km2. It corresponds to a mesotidal tide-dominated incised valley characterized by a complex physiography with numerous smaller bays, islands and peninsulas.</p><p>The identification of elements of sedimentary architecture was used to study the sedimentary evolution of this incised valley since the Last Glacial Maximum (ca 20 kyr BP to present). This approach was based on the combined analysis of seismic and sedimentary facies, complemented with radiocarbon, geochemical and pollen data.</p><p>During the lowstand of the Last Glacial Maximum, a river basin occupied the deep axial valley whose physiography was controlled by the rocky basement morphology and the presence of preserved older sedimentary units. The postglacial transgression changed the base level of rivers, flooding the valley and leading to the formation of an estuary. Facies distribution during this phase (Late Pleistocene) was characterized by large tidal sandbanks and sandflats in the outer area and a bayhead delta at the river mouths. As the transgression proceeded, during the Early Holocene, the system evolved into a tide-dominated estuary. Tidal sandbanks and sandflats occupied large extensions in the axis of the valley, flanked by mudflats. The presence of a small group of islands in the middle area of the incised valley gave way to the existence of an ancient strait during most of the postglacial transgression (Late Pleistocene and Holocene), modulating the relative influence of hydrodynamic conditions and probably leading to tidal currents amplification due to the local morphological narrowing. These structural highs favored the formation of a rock-bounded tidal inlet in the middle of the valley, characterized by scarce deposition and erosional processes.</p><p>During the Middle and the Late Holocene, most of the incised valley became drowned, and wave influence increased. A wave ravinement surface is identified, which was developed around 8 cal kyr BP coeval with the initiation of large storm fans associated with rocky barriers.</p><p>Finally, a maximum flooding surface is recognized at ca 5 cal kyr BP while the slow rise of sea level forced river mouths to retreat to its present position and marine processes became dominant in the basin.</p>

scholarly journals Tectono-Sedimentary Evolution of the Cenozoic Basins in the Eastern External Betic Zone (SE Spain)

Geosciences ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 394
Author(s):  
Manuel Martín-Martín ◽  
Francesco Guerrera ◽  
Mario Tramontana
Keyword(s):  
Strike Slip ◽  
Alluvial Fan ◽  
Tectonic Activity ◽  
Time Interval ◽  
Se Spain ◽  
The Third ◽  
Sedimentary Evolution ◽  
Marine Sedimentation ◽  
Geodynamic Processes ◽  
Early Paleocene

Four main unconformities (1–4) were recognized in the sedimentary record of the Cenozoic basins of the eastern External Betic Zone (SE, Spain). They are located at different stratigraphic levels, as follows: (1) Cretaceous-Paleogene boundary, even if this unconformity was also recorded at the early Paleocene (Murcia sector) and early Eocene (Alicante sector), (2) Eocene-Oligocene boundary, quite synchronous, in the whole considered area, (3) early Burdigalian, quite synchronous (recognized in the Murcia sector) and (4) Middle Tortonian (recognized in Murcia and Alicante sectors). These unconformities correspond to stratigraphic gaps of different temporal extensions and with different controls (tectonic or eustatic), which allowed recognizing minor sedimentary cycles in the Paleocene–Miocene time span. The Cenozoic marine sedimentation started over the oldest unconformity (i.e., the principal one), above the Mesozoic marine deposits. Paleocene-Eocene sedimentation shows numerous tectofacies (such as: turbidites, slumps, olistostromes, mega-olistostromes and pillow-beds) interpreted as related to an early, blind and deep-seated tectonic activity, acting in the more internal subdomains of the External Betic Zone as a result of the geodynamic processes related to the evolution of the westernmost branch of the Tethys. The second unconformity resulted from an Oligocene to Aquitanian sedimentary evolution in the Murcia Sector from marine realms to continental environments. This last time interval is characterized as the previous one by a gentle tectonic activity. On the other hand, the Miocene sedimentation was totally controlled by the development of superficial thrusts and/or strike-slip faults zones, both related to the regional geodynamic evolutionary framework linked to the Mediterranean opening. These strike-slip faults zones created subsidence areas (pull-apart basin-type) and affected the sedimentation lying above the third unconformity. By contrast, the subsidence areas were bounded by structural highs affected by thrusts and folds. After the third unconformity, the Burdigalian-Serravallian sedimentation occurred mainly in shallow- to deep-water marine environments (Tap Fm). During the Late Miocene, after the fourth unconformity, the activation of the strike-slip faults zones caused a shallow marine environment sedimentation in the Murcia sector and a continental (lacustrine and fluvial) deposition in the Alicante sector represented the latter, resulting in alluvial fan deposits. Furthermore, the location of these fans changed over time according to the activation of faults responsible for the tectonic rising of Triassic salt deposits, which fed the fan themselves.

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