Accommodation Space Research Articles

Gravitational resedimentation as a fundamental process in filling fjords: Lessons from outcrops from a late Palaeozoic fjord in Namibia

AbstractThe stratigraphic architecture of fjords is complicated due to the delicate interplay between ice dynamics, sediment supply, relative sea‐level fluctuations and slope failures. Glaciogenic sediment is prone to failure and to be carried downslope to the fjord floor through the entire spectrum of mass movements and subaqueous density flows, as the unstable paraglacial submarine landscape moves towards stability. Palaeofjords formed by Gondwanan glaciers during the late Palaeozoic Ice Age contain a compelling record of gravitational resedimentation in fjord depositional systems. This paper showcases the geomorphology and depositional history of a glacial cycle in the Orutanda fjord in north‐western Namibia as an example of an overdeepened fjord basin fill dominated by products of subaqueous gravitational processes. During glaciation, the Orutanda glacier carved a 20 km long by 3.7 km wide glacial trough that embodies an overdeepened basin. Ice thickness during terminal glacial occupation of the fjord is estimated to had been up to 200 m based on the fjord geomorphology. The progressive retreat of the tidewater glacier, concomitant with marine flooding, increased accommodation space in the overdeepened basin during deglaciation. During this stage, proglacial sedimentation through iceberg rafting and settling of turbid plumes was outpaced by intense paraglacial downslope resedimentation of glacially‐transported debris. Successive failures from the fjord walls and downslope resedimentation resulted in coalescing debrite–turbidite lobes on the fjord floor. Slide deposits, composed entirely of deformed debrites and turbidites, indicate that these resedimented facies were prone to renewed mass wasting. As the Orutanda glacier melted, the fjord experienced the axial progradation of a fjord‐head delta registered only by turbidites and slide deposits derived from its collapse. The Orutanda fjord sheds light on the relevance of paraglacial mass wasting in overprinting glaciogenic deposits. This insight is key to understanding the role of glaciers versus non‐glacial processes in producing the glacial deep‐time record.

A Study of the Emotional Impact of Interior Lighting Color in Rural Bed and Breakfast Space Design

In architectural spaces, the ambiance created by lighting plays a significant role in influencing people’s emotions, often relying on the use of color and light. However, previous research has primarily focused on urban architectural spaces, with relatively less attention given to rural environments, especially the interior spaces of rural accommodation. The objective of this study is to investigate the impact of colored lighting within rural accommodation interiors on people’s emotions and visual perceptions. Additionally, the study aims to establish an emotional dimension model to map the experimental results onto eight basic emotions, utilizing the PAD model for quantitative analysis. To achieve this goal, the researchers recruited 90 participants and divided them into six groups, each experiencing different combinations of indoor lighting scenes with varying colors. Participants evaluated their emotions and visual perceptions. The study results indicate that the combination of cool and warm white light with colored light significantly influences the arousal level of participants but has a relatively lower impact on pleasure levels, dominance and relaxation levels. In comparing the emotions experienced after exposure to cool and warm white light followed by colored light, warm white light elicited more positive emotions. Furthermore, colored light following cool white light diminished the sense of warmth in light, while yellow–blue light enhanced visual comfort and blue–red light increased attraction. Overall, the effect of colored lighting in rural accommodation interior spaces on improving negative emotions was relatively weak. Conversely, the combination of warm white light with blue–yellow or green–yellow light had a more significant effect on enhancing visual perceptions and reducing participants’ anxiety. This research provides valuable insights and references for designing the lighting ambiance in rural accommodation interiors and lighting design, with the potential to enhance the spatial experience of rural accommodations.

Effects of geometric parameters on photoluminescence and photocatalytic performance in yolk-shell TiO2@void@TiO2:Eu3+ structure and mechanism study

The geometric parameters show great impacts on the properties of photoactivity materials. Herein, the geometric effects on photoluminescence and photodegradation of yolk shell structure were discussed through TiO2@void@TiO2:Eu3+ structure with simply adjusted cavity and shell thickness. The TiO2@void@TiO2:Eu3+ materials showed characteristic red-light emission of Eu3+. The emission intensity showed an increased and then decreased trend with the increase of titania source dosage. The tetracycline (TC) degradation could achieve the completed decomposition with 95.5 % total organic carbon removal efficiency within only 50 min. It was proved that the charge interaction between the core and shell is the main factor of thin shell and cavity samples. For samples with large cavity volume and thick shell, the light scattering and accommodation space of intermediates provided by cavity are the major factors. The TC degradation mechanism, possible degradation pathway, the major reactive oxidation radical and toxicity of products were also discussed in detail. This study not only provides an in-depth opinion on the geometric effects on yolk shell multi-functional photocatalysts and structure design of yolk shell structure but also offers a highly efficient way of water purification.

U–Pb ages and paleoenvironmental evolution of the guanchín formation (neogene fiambalá foreland basin), Central Andes, Argentina

The Guanchín Formation is a sedimentary unit that was deposited during the Andean orogeny and is preserved in the Fiambalá Basin in NW Argentina. It records an advanced stage of the broken-foreland evolution in a transitional zone between the morphotectonic domains of the Precordillera, the Sistema de Famatina, the Western Sierras Pampeanas, and the southern Puna. Furthermore, it preserves a record of Late Miocene explosive volcanism that is common in all the foreland basins in this Andean segment. The Guanchín Formation was studied at Cuesta Loro Huasi and Guanchíncito sections, where seven facies associations (FA) were recognized. These represent ephemeral sandy braided fluvial systems with thin mud floodplains (FA1), sheetflow-dominated sandy-tuffaceous alluvial plain (FA2), perennial sandy braided fluvial system (FA3), fine-grained alluvial plain built up by unconfined flows and less terminal splays (FA4), sheetflow-dominated sandy alluvial plain (FA5), and sandy-gravelly (FA6) and sandy-dominated (FA7) braided fluvial system, arranged in chronological order from oldest to youngest. To date the formation, zircon U/Pb ages from tephras were obtained from the Cuesta Loro Huasi section, which yielded depositional ages of 6.10 ± 0.07, 5.89 ± 0.09, 5.60 ± 0.06, and 5.20 ± 0.05 Ma, while a fifth sample from the Guanchíncito section yielded an age of 3.26 ± 0.05 Ma. Additionally, detrital zircon analyses were performed to infer sediment provenance and constrain the maximum depositional age of sedimentary units. These data combined with paleoenvironmental analysis and clast compositions in conglomerates suggest that the Western Sierras Pampeanas had been uplifted around ∼6 Ma. By this time the drainage was dissipated as a distributary fluvial system (DFS) under semiarid climatic conditions, which received sediments from northern, eastern, and to a lesser extent from western sources. Around ∼3 Ma the basin started to receive coarse-grained sediments of braided fluvial systems (FA6 and 7) indicating a closer proximity to the Pampean sources areas. The Guanchín Formation records an overall progradational trend manifested through two minor progradational cycles, each one controlled by changes in the equilibrium profile and accommodation space of the basin. This trend is likely associated with a basinward increase in the subsidence rate or enhanced water availability in the headwaters, potentially linked to tectonic uplift in the eastern and/or northern ranges, including the final uplift of the southern Puna. Since previous works placed the deposition of the overlying Rodado de la Puna Formation deposition began at 4 Ma, these news ages suggest the top of the Guanchin Formation is younger than previously thought.

Geochronology of reworked ash and its implications for accommodation space variations in distal foreland basins, McMurray Formation, Alberta, Canada

A bentonite bed consisting of reworked volcanic ash from the Barremian to Aptian lower McMurray Formation is dated using chemical abrasion thermal ionization mass spectrometry (CA-TIMS) on zircon. The bentonite bed is from a cored interval in the McKay Paleovalley in the northern Athabasca Oil Sands Region of Alberta, Canada. Deposition of the lower McMurray Formation took place in the distal portion of the Western Canada Sedimentary Basin early in the Cretaceous-to-Paleocene phase of widespread contractional deformation in the Canadian Cordillera. A 30 g sample of volcanic ash yielded >10,000 very small (<50 µm) zircon grains with the vast majority (~99.7%) being highly abraded and clearly detrital. Twenty-six sharply faceted grains were sufficiently large to be mounted for laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) analysis, which yielded seven Lower Cretaceous dates. These Lower Cretaceous grains were further analyzed using CA-TIMS. The five youngest CA-TIMS dates agree with a weighted mean of 121.51 ± 0.11 Ma which is conservatively interpreted as a maximum depositional age (MDA). The good agreement between the five zircon dates indicates the MDA is probably the depositional age. This study demonstrates that with careful analysis of zircon populations, high-confidence MDAs can be derived even from reworked ash beds that are dominated overwhelmingly by detrital zircon. The date from this study overlaps a previously published MDA of 121.39 ± 0.27 Ma for the top of the lower McMurray Formation in Firebag Tributary in the northeastern Athabasca Oil Sands Area. The overlapping dates establish a widespread chronostratigraphic surface within the northern Athabasca Oil Sands Area. Both ages are from ash beds preserved in coal seams, suggesting that the coal-bearing interval is a regional marker bed and that the ash beds may form an intraformational datum. Further, the occurrence of the ash beds in the McMurray Formation in close proximity to regional flooding surfaces suggests that tectonic activity in the emerging Canadian Cordillera influenced accommodation space variations in the distal portions of the adjacent foreland basin.

Sedimentology and geochemistry of Eocene source rocks in the east China sea: Controls on hydrocarbon generation and source rock preservation

As an important source rock for oil and gas generation, coal measure source rock has attracted much attention due to its high hydrocarbon generation potential. Therefore, we conducted a comprehensive evaluation of the source rocks based on organic geochemical and petrological data to clarify the sedimentary, geochemical, and hydrocarbon generation characteristics of the coal measure source rocks of the Pinghu Formation in the Xihu Depression. The source rocks were deposited in a shallow freshwater sedimentary environment with weak reduction-oxidation conditions. The organic matter is mainly derived from terrestrial higher plants, with less contribution from phytoplankton and bacteria. Compared to carbonaceous mudstone and mudstone, coal was deposited in an environment with stronger oxidation conditions, and stronger bacterial transformation. Within the study area, sag A receives relatively high contributions from phytoplankton and high liptinite content, whereas sag C receives the largest contribution from terrestrial higher plants. Sag A is dominated by source rocks with a relatively high oil generation potential and oil reservoirs, whereas other regions have limited oil generation capacity and are characterized by gas reservoirs and condensate gas reservoirs. The E2p2 member, with more terrestrial organic matter input, has a higher TOC content and hydrocarbon generation potential than the E2p1 and E2p3 members. Thick organic-rich mudstone is developed in the E2p2 member due to a high accommodation space, abundant terrestrial organic matter, corresponding to a high relative base-level. The vast intertidal setting is conducive to the development of peatlands, developing widely distributed carbonaceous mudstone and coal. The study interval is characterized by a coal measure source rock development model of ‘strong supply - rapid burial - facies-controlled’ in the Xihu Depression.

Investigating Airflow Patterns in the XYZ Passenger Ship’s Accommodation Room on the Potential for COVID-19 Exposure to Passengers

The pandemic condition due to the COVID-19 virus attack has affected all areas of life throughout the earth. Post-pandemic policies and new behaviors are one of the important efforts in getting life back to normal. The pandemic has triggered many technological innovations to be carried out as further mitigation and prevention efforts. In the shipping sector, the impact of shipping restrictions and the number of passengers is detrimental due to a decrease in productivity that affects the shipping and port business. Air exchange patterns and room design are important things to be conditioned to reduce the potential for virus exposure. This article presents an investigation of computational fluid dynamics in the accommodation space of the XYZ passenger ship and simulations of potential exposures in several scenarios of ventilation conditions. By simulating 12 models of ventilation conditions, two conditions of the ships being stationary and moving, and the influence of wind from outside. Layout redesign can be applied effectively in open ventilation conditions and has less exposed bench results compared to existing conditions with an effective percentage of 0.75% - 2.3%

Glacial Isostatic Adjustment modelling of the mid-Holocene sea-level highstand of Singapore and Southeast Asia

The mid-Holocene sea-level highstand refers to higher-than-present relative sea levels (RSLs) in far-field regions between 7000 and 4000 years ago because of equatorial ocean syphoning and continental levering. But the timing, magnitude, and spatial variability of the highstand are uncertain and the highstand parameterization in Glacial Isostatic Adjustment (GIA) modelling is understudied. Here, we use the RSL records of Southeast Asia to investigate the sensitivity of the mid-Holocene highstand properties to Earth and ice model parameters, including lithospheric thickness, mantle viscosity (both 1D and 3D), and deglaciation history of Antarctica and global ice sheets. We found that the Earth model variation only affects the magnitude of the mid-Holocene highstand unless extraordinary low upper mantle viscosity is used. The timing of the highstand moves towards present and there is an absence of the highstand if upper mantle viscosity is < 4.0 × 1019 Pa s or ≤ 1.0 × 1019 Pa s, respectively. Ice model variation changes both the timing and magnitude of the mid-Holocene highstand. Delaying the ice-equivalent sea level will shift the timing of the highstand later and result in a lower highstand magnitude. We produced a mid-Holocene highstand “treasure map” that considers topography change and accommodation space to guide future RSL data collection efforts in Southeast Asia. The highstand “treasure map” indicates that the northeast and central west coast of Malay-Thai Peninsula, east coast of Sumatra, north coast of Java, and southwest coast of Borneo are very likely (90% probability) to preserve mid-Holocene highstand evidence.

Depositional model of clastic and carbonate rocks in a continental rift basin: a case study of the Paleogene Shahejie Formation in the Cangdong Depression, Bohai Bay Basin

The study of a clastic and carbonate rock depositional model in a continental rift basin is helpful to better understand the sedimentary processes active in continental rift basins. However, the spatiotemporal evolution characteristics and controlling factors of clastic and carbonate rocks in continental rift basins are still unclear. Therefore, the sedimentary characteristics of the clastic and carbonate rocks in the Paleogene Eocene Shahejie Formation (Es) are analysed via seismic, well log, core, thin section, and geochemistry data. Then, the impacts of tectonic movement, sediment supply and hydrologic conditions on sedimentary characteristics are discussed, and a depositional model is finally established. Five 3rd-order sequences, named SQ1–SQ5 from bottom to top, are identified in the Es. Fan delta, braided delta, meandering river delta, and lake sedimentary systems are identified in the Es; clastic rock sedimentary systems are identified in SQ1–SQ4, while concurrent clastic and carbonate rock sedimentary systems are identified in SQ5. During the SQ1–SQ4 period, the palaeogeomorphology formed by differential faulting activity or fault interactions and the inherited palaeogeomorphology resulted in different distributions of the sedimentary systems. The changes in accommodation space and sediment supply caused by tectonic movement led the delta to prograde or disappear. During the SQ5 period, the clastic rock sedimentary systems underwent a transition into clastic rock and carbonate rock sedimentary systems as a result of rift weakening, broad crustal thermal subsidence, sediment supply reduction and high-salinity lake water. This study provides a typical case for the evolution characteristics of the clastic rock and carbonate rock systems in continental rift basins, identifies changes in the tectonic, sediment supply, and hydrologic characteristics during their mutual transformations, and provides an important reference for hydrocarbon reservoir prediction.

Connecting link between a sediment source and its deep-sea sink: Ilan Shelf offshore northeastern Taiwan

The northeast Taiwan margin provides an excellent example of the route of sediment flux from a small mountainous river, the Lanyang River, to a deep-sea basin, the Southern Okinawa Trough (SOT), via a very narrow（8–14 km in width）Ilan Shelf at different time scales. Based on seismic and sub-bottom chirp profiles and onshore borehole and offshore core data, we identify three echo types on the Ilan Shelf that delineate sheets of sediment, mass movement deposits, and echoes indicative of igneous activity. By recognizing lithofacies and seismic facies changes, the Last Glacial Maximum Unconformity and maximum flooding surface are correlated in onshore cores and offshore reflection seismic profiles. With the aids of sequence stratigraphic analysis, the postglacial sedimentation rates on the Ilan Shelf are estimated to range from 0.04 to 1.53 cm/yr. Considering its sediment budget in a source-to-sink system, the Ilan Shelf can be regarded primarily as a temporary trap for fluvial sediment discharged from the Lanyang River. Overall, it has trapped at least 50% of the discharged sediment during the Holocene, and the bulk of sediment was transported, primarily via mass movement to SOT. We deduce that earthquake-induced faulting, axial incision in the channel, and retrogressive failures appear to be triggers for mass wasting, which then combined with channel transport, can play leading roles in rapid downslope transportation to the trough. This inference is indicated by high deposition rates in the western end of SOT and widely distributed mass transport deposits observed in the shallow strata of SOT. We found that the deep strata of SOT are deformed by normal faults, indicating that the sediment accommodation space is structurally controlled by the active back-arc extension. This study documents that frequent typhoons and flooding events, together with strong tidal currents, are significant agents of sediment input over the short term. In contrast, earthquakes and volcanic events occasionally affect sediment dispersal from the Ilan Shelf to SOT.

Maintenance of Steam Bottle Water to Keep Operational Auxiliary Steam Bottles on The Mv. Ile De Re

Various types of marine vessels require fuel to drive the main engine and auxiliary engines. The fuel requires hot steam as a heater so that the fuel reaches the appropriate temperature, not only fuel but hot steam is also needed for the accommodation space on the ship. The steam boiler is a closed vessel that can produce hot steam with a pressure greater than one atmosphere, to be able to produce hot steam, a heated medium is needed, namely fresh water. The water used in the steam generation process greatly affects the condition of the boiler. Therefore, the quality of water in the boiler must always be considered and maintained so that it is always in good condition, so that the boiler will always be in prime condition. In reality, steam boilers often experience disturbances, such as on the MV. ILE DE RE there is a decrease in the quality of boiler water and the occurrence of scale in the boiler. In this case, the research used an observation research method on boiler water by testing boiler water and it was found that the quality of boiler water was not up to standard with low pH levels up to 6.8, high alkalinity and high chloride up to 200 ppm. there is also a scale formation on the boiler water pipe which can be seen from the dirty condition of the boiler water when taken.

Depositional architecture and sequence stratigraphic framework of the fluvio‐lacustrine Ash Shumaysi Formation, Jeddah‐Makkah Region, Saudi Arabia: Implications for climatic and tectonic changes in a local‐scale sub‐basin

AbstractThis study aims to interpret and document the depositional architecture styles and sequence stratigraphic framework of the Ash Shumaysi Formation in the Jeddah‐Makkah region, the west‐central part of Saudi Arabia, and presents an example of rarely discussed, local‐scale sub‐basins (half grabens). It also shows the relationships between synchronous sedimentary processes and pre, syn and post‐rift conditions. The described lithofacies and their facies associations indicate the presence of seven architectural depositional styles: proximal‐distal braided fluvial, meandering fluvial (point bar), crevasse splay, floodplain, estuarine and lacustrine. A proposed depositional model for the Ash Shumaysi Formation is drawn. The Ash Shumaysi Formation forms a second order depositional sequence, which is organised into two third order depositional sequences (sequences I and II) bounded by three sequence boundaries. Each third‐order sequence encloses the low accommodation systems tract and high accommodation systems tract. The low accommodation systems tract represents the coarse‐grained, braided‐distal fluvial facies developed during low accommodation space associated with high sediment supply (high discharge). The high accommodation systems tract encloses the fine‐grained deposits of point bar, estuarine and lacustrine facies that reflect the creation of significant accommodation space and low sediment supply (low discharge). Vertical and lateral variations of the inferred depositional architectural styles, sequences and systems tracts reflect that tectonic forces and climate are the main controlling factors during deposition of the Ash Shumaysi Formation, although base‐level changes in response to sea‐level changes cannot be ruled out.

Coastal response to Holocene Sea-level change: A case study from Singapore

The deceleration of early to mid-Holocene (10–7 cal. ka BP) relative sea-level rise (RSLR) played a key role in transforming coastal systems from estuaries to deltas. Palaeoenvironmental reconstruction of coastal evolution provide case studies that can help project the response of modern coastal systems to future RSLR. The response of deltas to future RSLR is particularly important to South, Southeast and East Asia which collectively contain 71% of the global coastal population living below 10 m in elevation and 75% of the global coastal floodplain population. However, few Holocene studies of equatorial delta systems exist.Here, we investigate the early to mid-Holocene coastal response to decelerating rates of RSLR through paleoenvironmental reconstruction of the Kallang River Basin, Singapore. We produce a multi-proxy (sedimentology, stable carbon isotope, XRF elemental ratios) record from sediment core MSBH01B to compare with the Holocene relative sea-level record for Singapore. We identify different phases of coastal response through the interplay between accommodation space (A) driven predominantly by RSLR and sedimentation rate (S).In the early Holocene rapid RSLR coupled with low sedimentation rates (A/S = 5.1 ± 0.3) led to mangrove disappearance in the Kallang River Basin coastal area within ∼300 years (9.5–9.2 cal. ka BP). Estuarine sediments were deposited from 9.2 to 8.8 cal. ka BP during continued high rates of RSLR coupled with highest sedimentation rates (A/S = 3.1 ± 0.8) as the coastline retreated. Prodelta sediments were deposited from 8.8 to 8.2 cal. ka BP during decreasing rate of RSLR and high sedimentation rates (A/S = 4.6 ± 5.2). Delta front sediments were deposited during this delta initiation phase from 8.2 to 7.6 cal. ka BP as during a period of low and consistent RSLR and sedimentation rates (A/S = 1.7 ± 0.2). Finally, a prograding delta started forming from 7.6 to 7.2 cal. ka BP during lowest rates of RSLR and sedimentation rates (A/S = 1.7 ± 0.2). Our record provides a case study of possible responses of modern delta systems under a spectrum of predicted sea-level rise scenarios and accompanying sedimentation rates. This study provides an estimated threshold A/S value of 1.7 for coastal retreat to inform policy and mitigation/adaptation measures for Singapore and a simple methodology to obtain local threshold values of other equatorial cities built on floodplain and/or delta systems.

Paleoenviromental evolution of the Cenozoic foreland basin to intermontane basins in the Eastern Cordillera, North-Western Argentina

The stratigraphic and sedimentological characteristics of the Cenozoic deposits are very important aspects to investigate the tecto-sedimentary evolution of the Andean foreland basin to intermontane hinterland basins in north-western Argentina. These deposits lie in an unconformity or paraconformity relationship over the Salta Group (Cretaceous-Paleocene) or older deposits. During the middle Eocene-Pleistocene, the changes in the sedimentary paleoenvironment and its evolution are the direct result of tectonic effects, a change in base level and accommodation space. This study provides the results of the integrated analysis of the middle-upper Eocene to Plio-Pleistocene basins in the Eastern Cordillera, in north-western Argentina. These basins that have been generated in the Central Andes region in north-western Argentina during the Cenozoic tectonic convergence, we divided in four sequences in the evolution from middle to upper Eocene to Plio-Pleistocene. They present fluvial deposits of different topographic slopes, with development of ephemeral fluvial systems associated with dune fields, meandering fluvial systems in arid climates, interlaced sandy-gravelly fluvial systems, sinuous sandy-gravelly fluvial systems of intermediate to high sinuosity, with the development of lagoons and swamps of tropical climate during ∼10 to ∼5 Ma, and the change to arid - semiarid claimed condition from ∼5 to ∼2.5 Ma. The sedimentary record of the Plio-Pleistocene hinterland basin in the Eastern Cordillera and the adjacent Andean Puna Plateau in the Central Andes of NW Argentina constitutes geological archive that provide spatio-temporal insights into geological evolution and associated surface uplift.These basins, probably connected at their onset during the middle Eocene, are characterized by different subsidence histories, differences in sedimentary paleoenvironment evolution, variations in topographic slopes, changes in provenance and paleocurrents, resulting in differences in tecto-sedimentary history.

Pre-salt carbonate cyclicity and depositional environment: NMR petrophysics and Markov cyclicity of lacustrine acoustic facies (Santos Basin, Brazil)

The Pre-salt strata are idealized as a lake-dominated breakup depositional sequence recorded between the South American and African continental margins to which there is no present-day analog. Most of the complexities of the Pre-salt reservoir rely on addressing carbonate cyclicities at different scales using limited cored intervals where well-log and seismic correlation is still unclear. In this case, the application of borehole image logs (BHI) and nuclear magnetic resonance (NMR) techniques allows not only the scale correlation and extensive data acquisition but also to establish a more robust relationship between acoustic facies and their petrophysical significance. For that, this work combines BHI and NMR data to propose a feasible scheme of depositional acoustic facies for the Barra Velha Formation in the Santos Basin. To verify the statistical significance of the acoustic facies’ vertical organization, this work applied the Markov chain analysis along a c. 500 m stratigraphic interval, deriving four carbonate cycles associated with shallowing and reworking lacustrine cyclicities. Abrupt changes in cyclicity patterns were adopted as stratigraphic markers to subdivide the succession into lowermost, intermediate, and uppermost intervals that record the depositional history of deep, shallow, and emergent lake environments, respectively. By comparing the thickness variation of the Markovian cycles (i.e., accommodation space) with the seismic onlap curve variation (i.e., lake level) throughout the Pre-salt interval, a larger-scale superimposed cycle was unraveled, suggesting that accommodation space of the studied Pre-salt paleolake was likely controlled by fluctuations in the lake level. Finally, this work aimed to explore the applicability of diagnostic criteria for the description and interpretation of depositional acoustic facies, their petrophysical significance, and cyclicity patterns in the Barra Velha Formation.

Regional source rock thermal stress modeling and map-based charge access modeling of the Port Isabel passive margin foldbelt, northwestern Gulf of Mexico

The Port Isabel passive margin foldbelt covers 17,000 km2 of the northwestern deepwater U.S. Gulf of Mexico. Seven oil exploration wells have been drilled in the area from 1996 to 2007, yielding a single uncommercial gas discovery. The 5–7 km thick Oligo-Miocene section prevents drilling from penetrating the underlying Paleogene and Mesozoic source rocks. Accommodation space for the Oligo-Miocene section is created by the collapse of a paleo-salt wall, leading to linked fault systems in the upper decollement to the east. We use 13 exploration wells to construct 1D and map-based 2D basin models to investigate the burial and thermal history of three inferred source rock horizons (Paleogene, Turonian, and Tithonian). We interpret a 2D seismic data grid tied to four wells to constrain stratigraphic depths and thicknesses of the younger and shallower Wilcox source rock horizons, and the Jurassic and Cretaceous source rock horizons. Our results indicate that vitrinite reflectance is a proxy for the thermal stress levels reached by the source rocks as supported by maps of hydrocarbon charge access. We conclude that all three source rock intervals have reached varying degrees of maturity, expelled hydrocarbons in late Paleogene to mid-Neogene, and likely continue expelling hydrocarbons to the present-day at a reduced rate. The deposition of the Oligocene and Middle Miocene sedimentary section has buried the underlying source intervals and likely brought them into the gas/condensate window in the present-day. Our mapping of the extensive seismic reflection grid reveals four-way structural closures, three-way stratigraphic traps, and salt truncation structures associated with amplitude anomalies which may support our predictions for maturity in the underlying source rocks. Our thermal stress maps predict that the modeled source rocks are mature and our charge access models for the available wells constrain migration patterns, although the timing of the early hydrocarbon charge and late trap formation remain significant risk factors.

Cobble Tracking Observations at Torrey Pines State Beach, CA, USA

AbstractCobbles provide a nature‐based method to help generate beach stability. However, few detailed cobble movement observations exist. This study deployed 344 radio‐frequency identification tagged cobbles in a California beach in November–December 2020. Coincident LiDAR surveys quantified beach morphology. Cobbles were mapped daily for 10 days and then ∼ monthly until January 2023. Cobble detection rates ranged 17%–92%, and generally declined with time (with slight increases during winter months). Cobble movement exhibited complex patterns, sometimes moving in opposing directions during the same time period. Large winter waves (up to ∼4 m) resulted in average displacements of 40 m per month between November 2020 and April 2021. From April 2021 to August 2022, most cobbles were located high on the beach and net alongshore movements were relatively low, despite several moderate size (∼2 m) wave events. The largest wave event in January 2023 (&gt;4 m) moved cobbles to the highest elevations of the study period. The initial release location and accommodation space in the back beach influenced cobble movement and final position. Cobbles high on the beach were relatively stable compared to lower elevation cobbles, and more than half of all cobble detections were within 50 m of the initial release location. However, three cobbles moved &gt;500 m. The probability distribution of displacement was approximately exponential. Statistically, alongshore cobble spreading followed a non‐Gaussian subdiffusive process. Despite myriad sources of noise, the results suggest that cobble shape and mass were related to maximum cobble displacement. Overall, displacements increased with incident wave energy and depended on elevation relative to total water level.

MIGRATION AND WELDING OF AN ESTUARINE BARRIER-SPIT DRIVEN BY DELTA EVOLUTION AND STORMS

As sea levels rise globally in response to anthropogenic climate change, coastal depositional systems that persist in dynamic equilibrium with accommodation space, sediment supply and hydrodynamic processes may begin to respond by redistributing sediment, causing erosion or migration of landforms that may have appeared as stable over previous decades to centuries. In contrast, systems that have adjusted to inherited or changing boundary conditions over historical times offer insights on the modes and timescales of potential future change in remobilised coastal systems. We investigate the coupled evolution of an estuarine sand barrier-spit and tidal delta over the past century, focusing on storm-driven erosion and overwash during recent decades that triggered recurrent barrier migration (rollover), ultimately welding it to the bedrock valley framework. Historical aerial photographs and recent high-resolution satellite and aerial imagery are analysed to map morphological change and calculate decadal trends in shoreline and barrier migration. Ocean wave and water level conditions between image dates capturing notable responses are analysed using wave and tide records from nearby measurement stations.

Permo-Triassic cyclicity on the western shoulder of Muzaffarabad-Hazara paleo-high, during the oceanisation of Neo-Tethys

The sedimentary record of Permo-Triassic (299 Ma to 201 Ma) is only found on the periphery of the Hazara-Kashmir Syntaxis (HKS), i.e., on the western (central Potwar Sub-basin and its west) and eastern (Zanskar-Spiti Basin) shoulders. During this period, HKS acted as an indentation named as Muzaffarabad-Hazara Paleo-high (MPH), where no sedimentation occurred. Previously, the existence of MHP remained questionable as it has yet to be defined with the help of an integrated sequence stratigraphic model built by using outcrop, petrography, drilled well, regional correlations, seismic and gravity data sets on its western shoulder.Permo-Triassic strata outcrop in the western Salt Range, where stratigraphic surfaces, stratal terminations, and their bounding sequences are designed. Permo-Triassic is a mega sequence comprising of two sequences (Permian and Triassic) bounded by SUs. Non-marine (fluvial) Warchha Sandstone split the Permian sequence into two sub-sequences (siliciclastic/clastic and carbonate sequences). The Triassic sequence has the same depositional architectural features have two sub-sequences. Flooding events (i.e., four MRS/MFSs) influenced every sub-sequence, which developed retrogradational and progradational cyclicity during this period. The defined cyclicity, stratigraphic surfaces, and stratal terminations are validated with the well-log motif cycles and seismic data.Composite unconformities developed towards the MHP; therefore, only flooding events are correlatable on both shoulders. During the Sakmarian (290 Ma) age, a flooding event with maximum accommodation space (15–20 m) deposited the middle shelf facies (Amb Formation), which is correlatable with carbonates of Panjal volcanics and transgressive Gechang Formation of Zanskar-Spiti Basin. The third flooding event of the Ceratite Bed of Lower Triassic is also correlatable. Flooding continued in Zanskar-Spiti Basin in Middle Triassic, but diastem was observed in the western Salt Range. Carbonates younger than Ladinian (242-237 Ma) age are only found in Zanskar-Spiti Basin, but during this phase, SU truncated the Triassic strata in the Salt Range.

Lagoonal Microfacies, Lithostratigraphy, Correlation and Shale Migration of the Basal Middle Eocene Seeb Formation (Rusayl Embayment, Sultanate of Oman)

The study improves the understanding of the basal part of the Eocene Seeb Formation of Oman, informally known as “Unit 1”, in terms of microfacies, lithostratigraphy and shale migration within the context of regional tectonics. We logged four sections bed-by-bed over a distance of 8.3 km, collected samples and analyzed thin-sections as well as XRD samples. For the first time, the microfacies and stratigraphic correlation of the lowermost part of the limestone-dominated Seeb Formation were studied in detail. In the analyzed area, Unit 1 is ~20 to 40 m thick, with the thickness increasing to the SE. In the upper part of Unit 1 is a laterally continuous shale horizon. The limestones of Unit 1 contain mostly packstones and grainstones. The dominant standard microfacies types are SMF 18-FOR and SMF 16. The former is dominated by benthic foraminifera, and the latter by peloids. Both SMFs indicate restricted lagoonal conditions. Foraminifera are common in Unit 1 and indicate a middle Eocene age. Considering the abundance of encountered foraminiferal bioclasts, it appears probable that the lagoon barrier was mainly composed of foraminiferal tests. Gutter casts, slumps and debrites indicate an active, partly unstable syndepositional slope, which was likely initially created by uplift of the Saih Hatat Dome and Jabal Nakhl Subdome. Differential regional uplift due to a more pronounced overall doming in the NW (Jabal Nakhl Subdome) than in the SE (Saih Hatat Dome) explains more accommodation space and greater thickness towards the SE. For the first time, we report visco-plastic shale migration/intrusion within the Seeb Formation, related to a shale horizon of Unit 1. This shale locally migrated as indicated by (1) local thickness variations, (2) detached limestone boulders floating in the shale, (3) limestone beds that have been cut-off by the shale and (4) dragged by the shale (5) an upward shale intrusion/injection which then spread parallelly to bedding similar to a salt tongue and (6) tilting overlying limestones. We suggest that shale migration is related to post-“mid”-Eocene E-W convergence between Arabia and India and to faulting or to the second, late Paleogene/early Neogene, faulting interval of the Frontal Range Fault. The shale horizon in the upper part of Unit 1 is a marker bed, which can be correlated across the study area.