How to link modern and ancient barrier island systems: Dimensional comparisons and updated sedimentary facies models 

2021 ◽  
Author(s):  
Cari Johnson ◽  
Julia Mulhern ◽  
Andrew Green
Keyword(s):  
Time Scales ◽  
Barrier Island ◽  
Barrier Islands ◽  
Sedimentary Facies ◽  
Thickness Measurement ◽  
Tidal Inlet ◽  
Lateral Migration ◽  
Geologic Time ◽  
Facies Associations ◽  
Facies Models

<p>Existing depositional and facies models for ancient barrier island systems are primarily based on modern observations. This approach overlooks processes tied to geologic time scales, such as multi-directional motion, erosion, and reworking, and their resulting expressions in preserved strata. We have investigated these and other challenges of linking modern and ancient barrier islands through outcrop studies and through data compilation from the rock record compared to modern barrier island dimensions. Results emphasize key depositional and preservation processes, and the dimensional differences between deposits formed over geologic versus modern time scales. For example, when comparing deposits from individual barrier islands, thickness measurement comparisons between modern and ancient examples do not vary systematically, suggesting that local accommodation and reworking dictate barrier island thickness preservation. A complementary outcrop study focusing on paralic strata from the Upper Cretaceous Straight Cliffs Formation in southern Utah (USA) is used to update models for barrier island motion and preservation to include geologic time-scale processes. Barrier island deposits are described using four facies associations (FA): backbarrier fill (FA1), lower and upper shoreface (FA2), proximal upper shoreface (FA3), and tidal channel facies (FA4). Three main architectural elements (barrier island shorefaces, shoreface-dominated inlet fill, and channel-dominated inlet fill) occur independently or in combination to create stacked barrier island deposits. Barrier island shorefaces record progradation, while shoreface-dominated inlet fill records lateral migration, and channel-dominated inlet fill records aggradation within the tidal inlet. Barrier islands are bound by lagoons or estuaries and are distinguished from other shoreface deposits by their internal facies and outcrop geometry, association with backbarrier facies, and position within transgressive successions. Tidal processes, in particular, tidal inlet migration and reworking of the upper shoreface, also distinguish barrier island successions. In sum, these datasets demonstrate that improved depositional and facies models must consider multidirectional island motion, ravinement, erosion, inlet migration, and reworking when describing processes and predicting barrier island dimensions.</p>

scholarly journals When Is a Barrier Island Not an Island? When It Is Preserved in the Rock Record

2021 ◽  
Vol 8 ◽  
Author(s):  
Julia S. Mulhern ◽  
Cari L. Johnson ◽  
Andrew N. Green
Keyword(s):  
Barrier Island ◽  
Barrier Islands ◽  
Tidal Inlet ◽  
Lateral Migration ◽  
Geologic Time ◽  
Architectural Elements ◽  
Straight Cliffs Formation ◽  
Facies Associations ◽  
Straight Cliffs ◽  
Facies Models

Existing barrier island facies models are largely based on modern observations. This approach highlights the heterogeneous and dynamic nature of barrier island systems, but it overlooks processes tied to geologic time scales, such as multi-directional motion, erosion, and reworking, and their expressions as preserved strata. Accordingly, this study uses characteristic outcrop expressions from paralic strata of the Upper Cretaceous Straight Cliffs Formation in southern Utah to update models for barrier island motion and preservation to include geologic time-scale processes. Results indicate that the key distinguishing facies and architectural elements of preserved barrier island systems have very little to do with “island” morphology as observed in modern systems. Four facies associations are used to describe and characterize these barrier island architectural elements. Barrier islands occur in association with backbarrier fill (FA1) and internally contain lower and upper shoreface (FA2), proximal upper shoreface (FA3), and tidal channel facies (FA4). Three main architectural elements (barrier island shorefaces, shoreface-dominated inlet fill, and channel-dominated inlet fill) occur independently or in combination to create stacked barrier island deposits. Barrier island shorefaces record progradation, while shoreface-dominated inlet fill records lateral migration, and channel-dominated inlet fill records aggradation within the tidal inlet. Barrier islands are bound by lagoons or estuaries and are distinguished from other shoreface deposits by their internal facies and outcrop geometry, association with backbarrier facies, and position within transgressive successions. Tidal processes, in particular, tidal inlet migration and reworking of the upper shoreface, also distinguish barrier island successions. In sum, this study expands barrier island facies models and provides new recognition criteria to account for the complex geometries of time-transgressive, preserved barrier island deposits.

scholarly journals Depositional, diagenetic and stratigraphic aspects of Macaé Group carbonates (Albian): example from an oilfield from Campos Basin

2015 ◽  
Vol 45 (2) ◽  
pp. 243-258 ◽  
Author(s):  
Juliana Okubo ◽  
Ricardo Lykawka ◽  
Lucas Veríssimo Warren ◽  
Julia Favoreto ◽  
Dimas Dias-Brito
Keyword(s):  
Deep Water ◽  
Carbonate Rocks ◽  
Facies Analysis ◽  
Sedimentary Facies ◽  
Fair Weather ◽  
Thin Sections ◽  
Carbonate Sedimentation ◽  
Diagenetic Processes ◽  
Campos Basin ◽  
Facies Associations

<p>Carbonate rocks from the Macaé Group (Albian) represent an example of carbonate sedimentation related to the drift phase in Campos Basin. This study presents depositional features, integrating them with diagenetic and stratigraphic aspects of the Macaé Group carbonates including the upper part of the Quissamã Formation and the lower part of the Outeiro Formation. Macroscopic analyses in cores and microscopic ones in thin sections allowed the recognition of eleven sedimentary facies - nine of them corresponding to the Quissamã Formation and two of them representing the Outeiro Formation. These facies were grouped into five facies associations. Oolitic grainstones and oncolitic grainstones are interpreted to be deposited in shallow depth probably in shoals above the fair weather wave base. The interbanks between shoals were formed in less agitated waters and characterized by deposition of peloidal bioclastic packstones and wackestones representative of sedimentation in calm waters. Bioclastic packstones and oolitic packstones/wackestones represent allochthonous deposits related to the beginning of the regional drowning that occur in upper Quissamã Formation. Pithonellids wackestones and bioclastic wackestones with glauconite are related to deep water deposits, characteristics of the Outeiro Formation. Post-depositional features revealed the action of diagenetic processes as, micritization, cimentation, dissolution, compaction, dolomitization and recrystallization occurred during the eo- and mesodiagenesis phases. Vertical facies analysis suggests shallowing upward cycles stacked in a sequence progressively deeper towards the top (from the Quissamã Formation to the Outeiro Formation).</p>

A discussion concerning the floor of the northwest Indian Ocean - The recent sedimentary facies of the Persian Gulf region

1966 ◽  
Vol 259 (1099) ◽  
pp. 291-298 ◽  
Keyword(s):  
Indian Ocean ◽  
Coastal Plain ◽  
Persian Gulf ◽  
Barrier Islands ◽  
Sedimentary Facies ◽  
Dune Sand ◽  
Gulf Region ◽  
Marginal Sea ◽  
The Indian Ocean ◽  
The Persian Gulf

The Persian Gulf, which is a shallow marginal sea of the Indian Ocean, is an excellent model for the study of some ancient troughs. It is bordered on the west by the Arabian Precambrian shield and on the east by the Persian Tertiary fold mountains. Persia is an area of extensive continental deposition. It is bordered by a narrow submarine shelf. The deeper trough of the Persian Gulf lying along the Persian Coast seaward of the shelf is floored by marly sediments. East of this, the Arabian shelf is covered with skeletal calcarenites and calcilutites. To the northwest is the Mesopotamian alluvial plain and deltaic lobe. Arabia is bordered on the Persian Gulf littoral by a coastal complex of carbonate environments. Barrier islands, tidal deltas (the site of oolitic calcarenite formation) and reefs protect lagoons where calcilutites, pelletal-calcarenites and calcilutites and skeletal calcarenites and calcilutites are forming. There are Mangrove swamps, extensive algal flats and broad intertidal flats bordering the lagoons and landward sides of the islands. A wide coastal plain, the sabkha, borders the mainland. Here evaporation and reactions between the saline waters percolating from the lagoons, and calcium carbonate deposited during a seaward regression, leads to the production of evaporitic minerals including anhydrite, celestite, dolomite, gypsum and halite. Inland, wide dune sand areas pass into the outwash plains skirting the mountain rim of Arabia.

scholarly journals Modeling Barrier Island Habitats Using Landscape Position Information

2019 ◽  
Vol 11 (8) ◽  
pp. 976
Author(s):  
Nicholas M. Enwright ◽  
Lei Wang ◽  
Hongqing Wang ◽  
Michael J. Osland ◽  
Laura C. Feher ◽  
...  
Keyword(s):  
Machine Learning ◽  
Random Forest ◽  
Nearest Neighbor ◽  
Learning Algorithms ◽  
Barrier Island ◽  
Barrier Islands ◽  
Machine Learning Algorithms ◽  
Landscape Position ◽  
K Nearest Neighbor ◽  
Island Habitats

Barrier islands are dynamic environments because of their position along the marine–estuarine interface. Geomorphology influences habitat distribution on barrier islands by regulating exposure to harsh abiotic conditions. Researchers have identified linkages between habitat and landscape position, such as elevation and distance from shore, yet these linkages have not been fully leveraged to develop predictive models. Our aim was to evaluate the performance of commonly used machine learning algorithms, including K-nearest neighbor, support vector machine, and random forest, for predicting barrier island habitats using landscape position for Dauphin Island, Alabama, USA. Landscape position predictors were extracted from topobathymetric data. Models were developed for three tidal zones: subtidal, intertidal, and supratidal/upland. We used a contemporary habitat map to identify landscape position linkages for habitats, such as beach, dune, woody vegetation, and marsh. Deterministic accuracy, fuzzy accuracy, and hindcasting were used for validation. The random forest algorithm performed best for intertidal and supratidal/upland habitats, while the K-nearest neighbor algorithm performed best for subtidal habitats. A posteriori application of expert rules based on theoretical understanding of barrier island habitats enhanced model results. For the contemporary model, deterministic overall accuracy was nearly 70%, and fuzzy overall accuracy was over 80%. For the hindcast model, deterministic overall accuracy was nearly 80%, and fuzzy overall accuracy was over 90%. We found machine learning algorithms were well-suited for predicting barrier island habitats using landscape position. Our model framework could be coupled with hydrodynamic geomorphologic models for forecasting habitats with accelerated sea-level rise, simulated storms, and restoration actions.

Tectonic and geomorphic controls on the lacustrine deposits of the Neogene Vinchina basin, northwestern Argentina

2020 ◽  
Vol 90 (2) ◽  
pp. 250-267 ◽  
Author(s):  
Sergio A. Marenssi ◽  
Carlos O. Limarino ◽  
Laura J. Schencman ◽  
Patricia L. Ciccioli
Keyword(s):  
Water Depth ◽  
Drainage Basin ◽  
Low Frequency ◽  
Sedimentary Facies ◽  
Coarse Grained ◽  
Lacustrine Deposits ◽  
Facies Associations ◽  
Order Of Magnitude ◽  
Fluvial Sedimentation ◽  
The Individual

ABSTRACT Two episodes of lacustrine sedimentation, separated by an erosional surface and fluvial sedimentation, took place in the southern part of the broken foreland Vinchina basin (NW Argentina) between 11 and 5 Ma. The lacustrine deposits, 768 and 740 meters thick, are recorded in the upper part of the Vinchina Formation (“Vinchina lake”) and the lower part of the Toro Formation (“Toro Negro lake”) respectively. According to sedimentological features, four sedimentary facies associations (FAs) are recognized in the lacustrine deposits: 1) thinly laminated mudstones facies association (FA 1), 2) coarsening- and thickening-upward muddy to sandy cycles (FA 2), 3) medium- to coarse-grained sandstones (FA 3), and 4) mudstones, sandstones, and oolitic limestones (FA 4). Altogether, these facies correspond to ephemeral, shallow, lacustrine systems including saline mudflats. The total thickness of each lacustrine interval, the thickness of the individual cycles and their lithology, and the overall aggradational facies arrangement suggest that both lakes developed during underfilled stages of the basin. The coarsening-upward cycles can be regarded as lacustrine parasequences representing cyclic episodes of expansion and contraction of the lake, but unlike marine parasequences these cycles do not correlate to water depth. The development of lacustrine conditions and continuous base-level rise, together with the coeval southward-directed paleoflow indicators, suggest axial drainages and that the basin was externally closed (endorheic) at that time. The large thicknesses of each lacustrine interval also points to high accommodation in the southern part of the Vinchina basin during these times. Lake filling cycles are one order of magnitude thicker than lake depth, so we postulate that subsidence (tectonic) and rise of the spill point (geomorphology) increased accommodation but not water depth. Thus, unlike marine parasequences, the analyzed coarsening-upward cycles do not correlate to water depth, but rather they are controlled by more complex basinal accommodation processes. We hypothesize that the coeval uplift of the Umango and Espinal basement block to the south, coupled with the initial doming of the Sierra de Los Colorados to the east, may have generated the damming of the southward-directed drainage and a zone of maximum accommodation, then controlling the location of the two lakes and the preservation of their thick sedimentary records. Therefore, localized accommodation was enhanced by a combination of tectonic subsidence and topographic growth. The two lacustrine intervals and the intervening fluvial deposits record changing contributions from axial to transverse drainages and different cycles of closed and open conditions in the basin. A low-frequency, closed to open and back to closed (axial to transverse and return to axial drainage) basin evolution, is envisaged by the development of the two lakes (closed stages) and the erosional surface followed by the interval of fluvial sedimentation that separates them (open stage). In addition, several high-frequency lake fluctuations (expansion–contraction) are represented by the coarsening-upward cycles within each lacustrine interval. The thick lacustrine intervals and their intermediate incision surfaces record cyclic filling and re-excavation stages and localized episodes of increased subsidence in the Vinchina basin, which seem to be a common feature of tectonically active broken foreland basins.

Landscape Response to Lateral Advection in Convergent Orogens Over Geologic Time Scales

2019 ◽  
Vol 124 (8) ◽  
pp. 2056-2078 ◽  
Author(s):  
Paul R. Eizenhöfer ◽  
Nadine McQuarrie ◽  
Eitan Shelef ◽  
Todd A. Ehlers
Keyword(s):  
Time Scales ◽  
Geologic Time ◽  
Landscape Response ◽  
Lateral Advection
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