Gunnar Sçlen, L. Spalluto, I. Grunnaleite, Atle Jørgen Hestad Sande, N. B. Jensen, Per Olav Eide Svendsen, Gaetano Osso, Nicola Paoli, M. Talbot
Generation of thick megabreccias along carbonate platforms apparently relies on the establishment of overpressured zones in the margin and upper slope deposits (particularly during relative sea-level lowstands), but the main triggering mechanism is thought to be seismic tremors. Here, we present a detailed sedimentological analysis of carbonate density-flow deposits south and north of the Mattinata Fault, a major strike-slip fault zone in the Gargano Promontory (Italy). The analysis shows that in the southern sector the deposits of Albian–Cenomanian age (Monte S. Angelo Formation) are made up predominantly of thick and amalgamated debrites (megabreccias), whereas some 25 km to the north they are composed predominantly of prograding high-density turbidites. Moreover, detailed analysis of Maastrichtian slope deposits (Monte Acuto Limestones) from the southern sector shows that they make up a N–S-prograding system of coalesced lobes composed of high-density turbidites and subordinate debrites. We infer that preconditional factors (e.g., platform progradation, tectonic oversteepening, and high pore pressures in the margin and upper-slope deposits) for triggering the density flows varied along strike of the platform, but the main controlling factors were the activity of the prominent strike-slip Mattinata Fault and the propagation of tremor energy to its near- and far-field regions: large earthquakes triggered thick (up to 40 m) and amalgamated Albian–Cenomanian debrites in proximity (south of) to the fault, whereas the subdued effect of the tremors triggered thinner debrites (5–10 m) and rock falls in the far-field region north of the fault. Moreover, predominantly high-density turbidite deposits were emplaced in the far-field region during lower-magnitude earthquakes. During the Maastrichtian the thick succession of high-density turbidites and scattered thick debrites south of and adjacent to the Mattinata Fault may record an overall quiescent period of the fault. The results are of relevance for understanding the spatiotemporal distribution of density-flow deposition along carbonate platforms in tectonically active regions—in particular with respect to the activity of large strike-slip faults.
沿碳酸盐岩台地厚巨型角砾岩的形成显然依赖于边缘和上斜坡沉积超压带的建立(特别是在相对海平面低洼时)，但主要的触发机制被认为是地震震动。本文对意大利加尔加诺海峡(Gargano Promontory)主要走滑断裂带Mattinata断裂南侧和北侧的碳酸盐岩密度流沉积进行了详细的沉积学分析。分析表明，在南部地区，Albian-Cenomanian时代的沉积物(Monte S. Angelo组)主要由厚的和合并的碎屑(大角砾岩)组成，而在北部约25公里处，它们主要由推进的高密度浊积岩组成。此外，对南段马斯特里赫特斜坡沉积(Monte Acuto石灰石)的详细分析表明，它们构成了一个由高密度浊积岩和次级碎屑组成的n - s向递进的聚并裂片体系。我们推断，触发密度流的前提因素(如台地进动、构造过陡化、边缘和上斜坡沉积的高孔隙压力)沿台地走向变化，但主要控制因素是突出的走滑Mattinata断裂的活动和震颤能量向其近场和远场区域的传播。大地震在断层附近(南部)触发了厚的(高达40米)和混合的阿尔巴尼亚-塞诺曼尼亚碎屑，而地震的减弱作用则在断层北部的远场地区触发了较薄的碎屑(5-10米)和岩石坠落。此外，在低震级地震期间，高密度浊积岩沉积主要位于远场区。在马斯特里赫特时期，Mattinata断裂南部和附近高密度浊积岩的厚层演替和分散的厚层碎屑可能记录了该断裂的整体静止期。研究结果对于理解构造活动区沿碳酸盐岩台地的密度流沉积的时空分布，特别是对大型走滑断层的活动具有重要意义。
{"title":"The impact of tectonic activity on carbonate density-flow deposition along two sectors of the Apulia Carbonate Platform","authors":"Gunnar Sçlen, L. Spalluto, I. Grunnaleite, Atle Jørgen Hestad Sande, N. B. Jensen, Per Olav Eide Svendsen, Gaetano Osso, Nicola Paoli, M. Talbot","doi":"10.2110/jsr.2021.031","DOIUrl":"https://doi.org/10.2110/jsr.2021.031","url":null,"abstract":"\u0000 Generation of thick megabreccias along carbonate platforms apparently relies on the establishment of overpressured zones in the margin and upper slope deposits (particularly during relative sea-level lowstands), but the main triggering mechanism is thought to be seismic tremors. Here, we present a detailed sedimentological analysis of carbonate density-flow deposits south and north of the Mattinata Fault, a major strike-slip fault zone in the Gargano Promontory (Italy). The analysis shows that in the southern sector the deposits of Albian–Cenomanian age (Monte S. Angelo Formation) are made up predominantly of thick and amalgamated debrites (megabreccias), whereas some 25 km to the north they are composed predominantly of prograding high-density turbidites. Moreover, detailed analysis of Maastrichtian slope deposits (Monte Acuto Limestones) from the southern sector shows that they make up a N–S-prograding system of coalesced lobes composed of high-density turbidites and subordinate debrites. We infer that preconditional factors (e.g., platform progradation, tectonic oversteepening, and high pore pressures in the margin and upper-slope deposits) for triggering the density flows varied along strike of the platform, but the main controlling factors were the activity of the prominent strike-slip Mattinata Fault and the propagation of tremor energy to its near- and far-field regions: large earthquakes triggered thick (up to 40 m) and amalgamated Albian–Cenomanian debrites in proximity (south of) to the fault, whereas the subdued effect of the tremors triggered thinner debrites (5–10 m) and rock falls in the far-field region north of the fault. Moreover, predominantly high-density turbidite deposits were emplaced in the far-field region during lower-magnitude earthquakes. During the Maastrichtian the thick succession of high-density turbidites and scattered thick debrites south of and adjacent to the Mattinata Fault may record an overall quiescent period of the fault. The results are of relevance for understanding the spatiotemporal distribution of density-flow deposition along carbonate platforms in tectonically active regions—in particular with respect to the activity of large strike-slip faults.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42626237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
What processes control grain size and bed thickness in submarine canyon deposits? Erosive, shelf-cutting canyons contrast with accretionary basin-floor submarine fan accretionary channels because the former tightly constrain turbidity flows in deep channels. This study addresses such a deep-water depositional system in the Indus Submarine Canyon using a series of cores collected along the canyon. Grain-size analysis was conducted for turbidite and hemipelagic sediment deposited in the Holocene Indus Submarine Canyon mostly by diffuse, fine-grained turbidity currents and hemipelagic hypopycnal plumes. We investigate the links between sedimentary grain size, bedding thickness, facies, and canyon morphology. Well-sorted silt in layers mostly < 2 cm thick dominates the canyon. Core sites in the canyon located downstream of knickpoints have coarser, less well sorted sediments because of current acceleration in these areas and then the slowing of flows downslope. Sediments fine with increasing height above the canyon thalweg, implying deposition from a turbulent plume head. The great depth of the canyon, caused by the exceptionally wide shelf and steep slope, prevents channel overspill which controls sedimentation and channel form in submarine fans. Thalweg sediment fines down-canyon into the mid canyon, where sediment bypassing is inferred. The thickest turbidites are found in the sinuous lower canyon where the gradient shallows from ∼ 0.7° to 0.3°. However, canyon gradient has little impact on mean grain size, but does correlate with bed thickness. The active canyon channel, located in a channel belt gradually becomes less steep, more meandering, and narrower farther downstream. Sinuosity is an influence on turbidite bedding thickness but does not control grain size, in contrast to the situation in submarine-fan channel–levee complexes. Compared to the well-known, more proximal Monterey Canyon of California the grain sizes are much finer, although both systems show evidence of > 200 m plume heads.
{"title":"Controls on grain-size variability in the Holocene fill of the Indus Submarine Canyon","authors":"Yuting Li, P. Clift","doi":"10.2110/jsr.2022.038","DOIUrl":"https://doi.org/10.2110/jsr.2022.038","url":null,"abstract":"\u0000 What processes control grain size and bed thickness in submarine canyon deposits? Erosive, shelf-cutting canyons contrast with accretionary basin-floor submarine fan accretionary channels because the former tightly constrain turbidity flows in deep channels. This study addresses such a deep-water depositional system in the Indus Submarine Canyon using a series of cores collected along the canyon. Grain-size analysis was conducted for turbidite and hemipelagic sediment deposited in the Holocene Indus Submarine Canyon mostly by diffuse, fine-grained turbidity currents and hemipelagic hypopycnal plumes. We investigate the links between sedimentary grain size, bedding thickness, facies, and canyon morphology. Well-sorted silt in layers mostly < 2 cm thick dominates the canyon. Core sites in the canyon located downstream of knickpoints have coarser, less well sorted sediments because of current acceleration in these areas and then the slowing of flows downslope. Sediments fine with increasing height above the canyon thalweg, implying deposition from a turbulent plume head. The great depth of the canyon, caused by the exceptionally wide shelf and steep slope, prevents channel overspill which controls sedimentation and channel form in submarine fans. Thalweg sediment fines down-canyon into the mid canyon, where sediment bypassing is inferred. The thickest turbidites are found in the sinuous lower canyon where the gradient shallows from ∼ 0.7° to 0.3°. However, canyon gradient has little impact on mean grain size, but does correlate with bed thickness. The active canyon channel, located in a channel belt gradually becomes less steep, more meandering, and narrower farther downstream. Sinuosity is an influence on turbidite bedding thickness but does not control grain size, in contrast to the situation in submarine-fan channel–levee complexes. Compared to the well-known, more proximal Monterey Canyon of California the grain sizes are much finer, although both systems show evidence of > 200 m plume heads.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43171815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The deposits of the tidal–fluvial transition zone are one of the most significant and complicated components of marginal marine systems. Sedimentological studies of these deposits are necessary due to their heterogeneous nature, which is controlled by competing tidal and fluvial parameters. Outcrop studies are required to understand the architecture, sedimentology, and evolution of tidal–fluvial deposits. The Cenomanian upper unit of the Bahariya Formation in the northern part of the Western Desert of Egypt is a tide-dominated fluvio-estuarine deposit sourced from crystalline basement and Early Cretaceous siliciclastic sedimentary rocks that lie to the southeast and south. Based on sedimentary facies analysis and paleocurrent data, the upper Bahariya Formation is composed of six main architectural elements: 1) river-dominated, tide-influenced point bar, 2) tide-dominated, river-influenced point bar, 3) floodplain, 4) crevasse splay, 5) crevasse channel, and 6) mud plug. These elements are stacked in a multistory tidal–fluvial channel complex and associated depositional elements. The reconstructed paleochannels trend from southeast to northwest, and migrated to the east and southeast. The relative contribution of fluvial processes decreased upwards through the stacked stories, with a corresponding increase in the contribution of tidal processes that were associated with transgression. An understanding of the architecture and sedimentology of the tidal–fluvial transition from outcrop successions allows the improved characterization of tidal–fluvial point-bar reservoirs and associated elements.
{"title":"Sedimentology and stratigraphic evolution of fluvial–tidal transition reservoirs: an outcrop analog for the hydrocarbon-bearing Bahariya Formation, Western Desert, Egypt","authors":"S. S. Selim","doi":"10.2110/jsr.2021.130","DOIUrl":"https://doi.org/10.2110/jsr.2021.130","url":null,"abstract":"\u0000 The deposits of the tidal–fluvial transition zone are one of the most significant and complicated components of marginal marine systems. Sedimentological studies of these deposits are necessary due to their heterogeneous nature, which is controlled by competing tidal and fluvial parameters. Outcrop studies are required to understand the architecture, sedimentology, and evolution of tidal–fluvial deposits. The Cenomanian upper unit of the Bahariya Formation in the northern part of the Western Desert of Egypt is a tide-dominated fluvio-estuarine deposit sourced from crystalline basement and Early Cretaceous siliciclastic sedimentary rocks that lie to the southeast and south. Based on sedimentary facies analysis and paleocurrent data, the upper Bahariya Formation is composed of six main architectural elements: 1) river-dominated, tide-influenced point bar, 2) tide-dominated, river-influenced point bar, 3) floodplain, 4) crevasse splay, 5) crevasse channel, and 6) mud plug. These elements are stacked in a multistory tidal–fluvial channel complex and associated depositional elements. The reconstructed paleochannels trend from southeast to northwest, and migrated to the east and southeast. The relative contribution of fluvial processes decreased upwards through the stacked stories, with a corresponding increase in the contribution of tidal processes that were associated with transgression. An understanding of the architecture and sedimentology of the tidal–fluvial transition from outcrop successions allows the improved characterization of tidal–fluvial point-bar reservoirs and associated elements.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45185148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Glacial marine sediment deposition varies both spatially and temporally, but nearly all studies evaluate down-core (∼ time) variations in sediment variables with little consideration for across core variability, or even the consistency of a data set over distance scales of 1 to 1000 m. Grain size and quantitative X-ray diffraction (qXRD) methods require only ≤ 1 g of sediment and thus analyses assume that the identification of coarse sand (i.e., ice-rafted debris) and sediment mineral composition are representative of the depth intervals. This assumption was tested for grain size and mineral weight % on core MD99-2317, off East Greenland. Samples were taken from two sections of the core that had contrasting coarse-sand content. A total of fourteen samples were taken consisting of seven (vertical) and two (horizontal) samples, with five replicates per sample for qXRD analyses and ∼ 10 to 20 replicates for grain size. They had an average dry weight of 10.5 ± 0.5 g and are compared with two previous sets of sediment samples that averaged 54.1 ± 18.9 g and 20.77 ± 5.8 g dry weight. The results indicated some significant differences between the pairs of samples for grain-size parameters (mean sortable silt, and median grain size) but little difference in the estimates of mineral weight percentages. Out of 84 paired mineral and grain-size comparisons only 17 were significantly different at p = < 0.05 in the post-hoc Scheffe test, all of which were linked to grain-size attributes.
{"title":"Grain size and mineral variability of glacial marine sediments","authors":"J. Andrews, Wendy J. Roth, A. Jennings","doi":"10.2110/jsr.2022.044","DOIUrl":"https://doi.org/10.2110/jsr.2022.044","url":null,"abstract":"\u0000 Glacial marine sediment deposition varies both spatially and temporally, but nearly all studies evaluate down-core (∼ time) variations in sediment variables with little consideration for across core variability, or even the consistency of a data set over distance scales of 1 to 1000 m. Grain size and quantitative X-ray diffraction (qXRD) methods require only ≤ 1 g of sediment and thus analyses assume that the identification of coarse sand (i.e., ice-rafted debris) and sediment mineral composition are representative of the depth intervals. This assumption was tested for grain size and mineral weight % on core MD99-2317, off East Greenland. Samples were taken from two sections of the core that had contrasting coarse-sand content. A total of fourteen samples were taken consisting of seven (vertical) and two (horizontal) samples, with five replicates per sample for qXRD analyses and ∼ 10 to 20 replicates for grain size. They had an average dry weight of 10.5 ± 0.5 g and are compared with two previous sets of sediment samples that averaged 54.1 ± 18.9 g and 20.77 ± 5.8 g dry weight. The results indicated some significant differences between the pairs of samples for grain-size parameters (mean sortable silt, and median grain size) but little difference in the estimates of mineral weight percentages. Out of 84 paired mineral and grain-size comparisons only 17 were significantly different at p = < 0.05 in the post-hoc Scheffe test, all of which were linked to grain-size attributes.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49301192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Alessandretti, L. Warren, F. G. Varejão, Raul Rassi, Maurício G.M. Dos Santos, Mariana N.M. Silva, Fernando R. Honorato, Michele J.T. Estrada, João V.O. Cunha
During the last stages of Gondwana fragmentation, large regions of the newly formed South American continent were covered by extensive deserts. Some parts of this continental landmass were synchronously affected by pronounced tectonism and magmatism, which were responsible for reshaping the regional topography. In this context, the southwestern part of the Sanfranciscana Basin in central Brazil is a key area for understanding this particular period in the geodynamic evolution of the South American continent. Aeolian deposits of the Posse Formation in the basin occur in direct association with volcanic rocks of the Upper Cretaceous Mata da Corda Group. Here, we report evidence of synsedimentary magmatism in direct association with soft-sediment-deformation structures, including flame structures, load casts and pseudonodules, water-escape structures, convolute lamination, faults, breccias, and clastic dikes, developed exclusively in aeolian sandstone and siltstone facies. The deformation features are interpreted as indicative of liquefaction, fluidization, and brittle behavior of the loose to partially lithified, wet sandy–silty sediments. The Late Cretaceous aeolian sedimentation is contemporaneous with the uplift of the Paranaíba High and associated magmatism in the Minas–Goiás Alkaline Province. In this context, these significant volcano-tectonic activities are considered to have triggered ductile to brittle deformation in the reported aeolian deposits.
在冈瓦纳大陆分裂的最后阶段，新形成的南美大陆的大片地区被广阔的沙漠覆盖。这块大陆的某些部分同时受到明显的构造和岩浆作用的影响，这是重塑区域地形的原因。在这种背景下，巴西中部的圣弗朗西斯卡纳盆地西南部是了解南美大陆地球动力学演化这一特殊时期的关键区域。盆地内波塞组风成沉积与上白垩统Mata da Corda群火山岩直接相关。在这里，我们报告了与软沉积变形构造直接相关的同沉积岩浆作用的证据，包括火焰构造、荷载铸模和假结核、水逸构造、卷曲层压、断层、角砾岩和碎屑岩脉，这些构造仅在风成砂岩和粉砂岩相中发育。变形特征被解释为松散到部分石化的湿砂粉质沉积物的液化、流态化和脆性行为的指示。晚白垩世风成沉积与Minas-Goiás碱性省Paranaíba隆起及伴生岩浆作用是同时期的。在这种背景下，这些重要的火山构造活动被认为在已报道的风成沉积中引发了韧性到脆性的变形。
{"title":"Uplifting mountains and shaking deserts: volcano-tectonic earthquakes revealed by soft-sediment-deformation structures in Upper Cretaceous aeolian deposits","authors":"L. Alessandretti, L. Warren, F. G. Varejão, Raul Rassi, Maurício G.M. Dos Santos, Mariana N.M. Silva, Fernando R. Honorato, Michele J.T. Estrada, João V.O. Cunha","doi":"10.2110/jsr.2021.143","DOIUrl":"https://doi.org/10.2110/jsr.2021.143","url":null,"abstract":"\u0000 During the last stages of Gondwana fragmentation, large regions of the newly formed South American continent were covered by extensive deserts. Some parts of this continental landmass were synchronously affected by pronounced tectonism and magmatism, which were responsible for reshaping the regional topography. In this context, the southwestern part of the Sanfranciscana Basin in central Brazil is a key area for understanding this particular period in the geodynamic evolution of the South American continent. Aeolian deposits of the Posse Formation in the basin occur in direct association with volcanic rocks of the Upper Cretaceous Mata da Corda Group. Here, we report evidence of synsedimentary magmatism in direct association with soft-sediment-deformation structures, including flame structures, load casts and pseudonodules, water-escape structures, convolute lamination, faults, breccias, and clastic dikes, developed exclusively in aeolian sandstone and siltstone facies. The deformation features are interpreted as indicative of liquefaction, fluidization, and brittle behavior of the loose to partially lithified, wet sandy–silty sediments. The Late Cretaceous aeolian sedimentation is contemporaneous with the uplift of the Paranaíba High and associated magmatism in the Minas–Goiás Alkaline Province. In this context, these significant volcano-tectonic activities are considered to have triggered ductile to brittle deformation in the reported aeolian deposits.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43074265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Yoon, W. Ryang, S. Chun, Alexander R. Simms, Jin Cheul Kim, T. Chang, D. Yoo, Seok-Hwi Hong
Decreasing rates of eustatic sea-level rise during the Holocene accompanied the deposition of transgressive coastal deposits worldwide. However, unraveling how transgressive deposition varies in response to different rates of relative sea-level (RSL) rise is limited by the scarcity of long (10+ m) well-dated cores spanning the entire middle to late Holocene record along macrotidal coasts. To investigate the sedimentary response of this macrotidal coast to decreasing rates of RSL rise, we acquired four cores up to 32 m in length and Chirp seismic profiles along the west coast of Korea. Core sediments were analyzed in terms of sedimentary texture, structure, and facies. Nineteen optically stimulated luminescence (OSL) and fourteen 14C accelerated mass spectrometry (AMS) ages constrain the timing of deposition of the sandy sediments. This relatively dense distribution of ages is used to determine how deposition rates changed through time. We also use a compilation of previously published RSL indices for the southwestern Korean coast in order to better constrain RSL changes through time. Results show that the evolution of the Gochang coastline switched from a tide-dominated environment to a wave-dominated environment during the latter stage of transgression as the rate of the sea-level rise decreased. Rugged antecedent topography likely led to the development of tidal currents and the formation of a tide-dominated tidal flat during rapid RSL rise from 10 to 6 ka. As the tidal channels filled with fine-grained sediments from 6 to 1 ka, tidal amplification likely waned leading to a greater role of wave energy in shaping the formation of the sandy open-coast tidal flat. Since 1 ka, wave-dominated environments formed sand-rich tidal beaches and flats. Decreasing changes in rates of the RSL rise resulted in changes in depositional environments from a tide-dominated intertidal flat to an open-coast tidal flat and finally a wave-dominated tidal beach. This study highlights the important role that rates of RSL rise play on not only sedimentation rates in a shelf setting but also playing a role in the switch from a tide-dominated to a wave-dominated setting.
{"title":"Coastal switching of dominant depositional processes driven by decreasing rates of Holocene sea-level rise along the macrotidal coast of Gochang, SW Korea","authors":"H. Yoon, W. Ryang, S. Chun, Alexander R. Simms, Jin Cheul Kim, T. Chang, D. Yoo, Seok-Hwi Hong","doi":"10.2110/jsr.2021.023","DOIUrl":"https://doi.org/10.2110/jsr.2021.023","url":null,"abstract":"\u0000 Decreasing rates of eustatic sea-level rise during the Holocene accompanied the deposition of transgressive coastal deposits worldwide. However, unraveling how transgressive deposition varies in response to different rates of relative sea-level (RSL) rise is limited by the scarcity of long (10+ m) well-dated cores spanning the entire middle to late Holocene record along macrotidal coasts. To investigate the sedimentary response of this macrotidal coast to decreasing rates of RSL rise, we acquired four cores up to 32 m in length and Chirp seismic profiles along the west coast of Korea. Core sediments were analyzed in terms of sedimentary texture, structure, and facies. Nineteen optically stimulated luminescence (OSL) and fourteen 14C accelerated mass spectrometry (AMS) ages constrain the timing of deposition of the sandy sediments. This relatively dense distribution of ages is used to determine how deposition rates changed through time. We also use a compilation of previously published RSL indices for the southwestern Korean coast in order to better constrain RSL changes through time. Results show that the evolution of the Gochang coastline switched from a tide-dominated environment to a wave-dominated environment during the latter stage of transgression as the rate of the sea-level rise decreased. Rugged antecedent topography likely led to the development of tidal currents and the formation of a tide-dominated tidal flat during rapid RSL rise from 10 to 6 ka. As the tidal channels filled with fine-grained sediments from 6 to 1 ka, tidal amplification likely waned leading to a greater role of wave energy in shaping the formation of the sandy open-coast tidal flat. Since 1 ka, wave-dominated environments formed sand-rich tidal beaches and flats. Decreasing changes in rates of the RSL rise resulted in changes in depositional environments from a tide-dominated intertidal flat to an open-coast tidal flat and finally a wave-dominated tidal beach. This study highlights the important role that rates of RSL rise play on not only sedimentation rates in a shelf setting but also playing a role in the switch from a tide-dominated to a wave-dominated setting.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41478580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Cardenas, J. Grotzinger, M. Lamb, K. Lewis, C. Fedo, A. Bryk, W. Dietrich, N. Stein, Madison Turner, G. Caravaca
The early environmental history of Mars is encoded in the planet's record of sedimentary rocks. Since 2012, the Curiosity rover has been ascending Mount Sharp, Gale crater's central mound, making detailed observations of sedimentary strata exposed there. The primary depositional setting represented by the rocks examined thus far has been a perennial lake, represented by the mudstones and sandstone lenses of the Murray formation. Here, we report on the sedimentology of outcrops examined in the Carolyn Shoemaker formation, which sits stratigraphically above the Murray formation. We interpret strata exposed in the Glasgow and Mercou members of the Carolyn Shoemaker formation to represent river bars in ancient alluvial and shoreline settings based on sedimentary structures, stratal geometries measured from photogrammetric data, and erosional morphology. The transition from a lacustrine to a fluvial depositional setting records the aggradation and progradation of coastal rivers into what was previously the extent of the Gale lake system. This may have occurred due to the shrinking of the lake over time due to climate-driven changes in the basin water balance, or local three-dimensionality in shoreline evolution, such as the formation of a new sedimentary lobe following a channel switch.
{"title":"Barform deposits of the Carolyn Shoemaker formation, Gale crater, Mars","authors":"B. Cardenas, J. Grotzinger, M. Lamb, K. Lewis, C. Fedo, A. Bryk, W. Dietrich, N. Stein, Madison Turner, G. Caravaca","doi":"10.2110/jsr.2022.032","DOIUrl":"https://doi.org/10.2110/jsr.2022.032","url":null,"abstract":"\u0000 The early environmental history of Mars is encoded in the planet's record of sedimentary rocks. Since 2012, the Curiosity rover has been ascending Mount Sharp, Gale crater's central mound, making detailed observations of sedimentary strata exposed there. The primary depositional setting represented by the rocks examined thus far has been a perennial lake, represented by the mudstones and sandstone lenses of the Murray formation. Here, we report on the sedimentology of outcrops examined in the Carolyn Shoemaker formation, which sits stratigraphically above the Murray formation. We interpret strata exposed in the Glasgow and Mercou members of the Carolyn Shoemaker formation to represent river bars in ancient alluvial and shoreline settings based on sedimentary structures, stratal geometries measured from photogrammetric data, and erosional morphology. The transition from a lacustrine to a fluvial depositional setting records the aggradation and progradation of coastal rivers into what was previously the extent of the Gale lake system. This may have occurred due to the shrinking of the lake over time due to climate-driven changes in the basin water balance, or local three-dimensionality in shoreline evolution, such as the formation of a new sedimentary lobe following a channel switch.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46202290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joris T. Eggenhuisen, Mike C. Tilston, Christopher J. Stevenson, Stephen M. Hubbard, Matthieu J.B. Cartigny, Maarten S. Heijnen, Jan de Leeuw, Florian Pohl, Yvonne T. Spychala
Turbidity currents transport vast amounts of sediment through submarine channels onto deep-marine basin-floor fans. There is a lack of quantitative tools for the reconstruction of the sediment budget of these systems. The aim of this paper is to construct a simple and user-friendly model that can estimate turbidity-current structure and sediment budget based on observable submarine-channel dimensions and general characteristics of the system of interest. The requirements for the model were defined in the spirit of the source-to-sink perspective of sediment volume modeling: a simple, quantitative model that reflects natural variability and can be applied to ancient systems with sparse data availability. The model uses the input conditions to parameterize analytical formulations for the velocity and concentration profiles of turbidity currents. Channel cross section and temporal punctuation of turbidity-current activity in the channel are used to estimate sediment flux and sediment budget. The inherent uncertainties of geological sediment-budget estimates motivate a stochastic approach, which results in histograms of sediment-budget estimations, rather than discrete values. The model is validated against small-scale experimental turbidity currents and the 1929 Grand Banks turbidity current. The model performs within acceptable margins of error for sediment-flux predictions at these smallest and largest scales of turbidity currents possible on Earth. Finally, the model is applied to reconstruct the sediment budget related to Cretaceous slope-channel deposits (Tres Pasos Formation, Chile). The results give insight into the likely highly stratified concentration profile and the flow velocity of the Cretaceous turbidity currents that formed the deposits. They also yield estimates of the typical volume of sediment transported through the channels while they were active. These volumes are demonstrated to vary greatly depending on the geologic interpretation of the relation between observable deposit geometries and the dimensions of the flows that formed them. Finally, the shape of the probability density functions of predicted sediment budgets is shown to depend on the geological (un)certainty ranges. Correct geological interpretations of deep marine deposits are therefore indispensable for quantifications of sediment budgets in deep marine systems.
{"title":"The Sediment Budget Estimator (SBE): A process model for the stochastic estimation of fluxes and budgets of sediment through submarine channel systems","authors":"Joris T. Eggenhuisen, Mike C. Tilston, Christopher J. Stevenson, Stephen M. Hubbard, Matthieu J.B. Cartigny, Maarten S. Heijnen, Jan de Leeuw, Florian Pohl, Yvonne T. Spychala","doi":"10.2110/jsr.2021.037","DOIUrl":"https://doi.org/10.2110/jsr.2021.037","url":null,"abstract":"Turbidity currents transport vast amounts of sediment through submarine channels onto deep-marine basin-floor fans. There is a lack of quantitative tools for the reconstruction of the sediment budget of these systems. The aim of this paper is to construct a simple and user-friendly model that can estimate turbidity-current structure and sediment budget based on observable submarine-channel dimensions and general characteristics of the system of interest. The requirements for the model were defined in the spirit of the source-to-sink perspective of sediment volume modeling: a simple, quantitative model that reflects natural variability and can be applied to ancient systems with sparse data availability. The model uses the input conditions to parameterize analytical formulations for the velocity and concentration profiles of turbidity currents. Channel cross section and temporal punctuation of turbidity-current activity in the channel are used to estimate sediment flux and sediment budget. The inherent uncertainties of geological sediment-budget estimates motivate a stochastic approach, which results in histograms of sediment-budget estimations, rather than discrete values. The model is validated against small-scale experimental turbidity currents and the 1929 Grand Banks turbidity current. The model performs within acceptable margins of error for sediment-flux predictions at these smallest and largest scales of turbidity currents possible on Earth. Finally, the model is applied to reconstruct the sediment budget related to Cretaceous slope-channel deposits (Tres Pasos Formation, Chile). The results give insight into the likely highly stratified concentration profile and the flow velocity of the Cretaceous turbidity currents that formed the deposits. They also yield estimates of the typical volume of sediment transported through the channels while they were active. These volumes are demonstrated to vary greatly depending on the geologic interpretation of the relation between observable deposit geometries and the dimensions of the flows that formed them. Finally, the shape of the probability density functions of predicted sediment budgets is shown to depend on the geological (un)certainty ranges. Correct geological interpretations of deep marine deposits are therefore indispensable for quantifications of sediment budgets in deep marine systems.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":"55 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138529364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Upper Triassic Shinarump Member forms the basal part of the Chinle Formation in the western interior United States and was deposited by a continental-scale fluvial system which ran approximately 2,500 km from the Ouachita Orogen in the east into the Auld Lang Syne marine basin in the west. Previous studies of the Shinarump Member have concluded that the deposits represent a braided-river system but have not produced estimates for paleo-sinuosity and paleo-discharge. Recent advances in sedimentology allow detailed morphometric assessment of the nature of the river system that deposited the Shinarump Member enabling us to produce quantitative estimates for these parameters. We therefore present architectural data from the Shinarump Member in northern Arizona and Utah, supported by lithofacies data and 39 sandstone petrographic analyses, and a dataset of 4,298 paleocurrent measurements from trough cross-strata. Lithofacies and architectural analysis supports previous interpretations of the Shinarump and equivalent strata as braided-river deposits. Petrographic analysis shows that the Shinarump is dominated by monocrystalline quartz and exhibits low spatial variation in composition, ranging from 85.4% to 99.8% total quartz. Paleocurrent measurements are used to calculate the channel sinuosity of the fluvial system as varying between 1.02 and 1.77, with a median value of 1.33 (compared to the Yangtze River, ranging from 1.05 to 1.50 and the Ganges–Brahmaputra, ranging from 1.05 to 1.13 in their lower 250 km). Paleohydrological estimates using data from the architectural surveys produce slope estimates from 2.01 × 10–4 to 6.51 × 10–4 and bankfull discharge estimates from 4.36 × 103 m3 s–1 to 2.38 × 104 m3 s–1 for individual channels, comparable to extant continental-scale fluvial systems. Estimates of lifetime sediment transport volume range from 7.75 × 104 km3 to 6.09 × 105 km3, which are in order-of-magnitude agreement with estimates for the volume of the depositional sink (1.35 × 105 km3 to 4.17 × 105 km3). These results demonstrate the potential for paleohydrologic estimates to provide new avenues for analysis of heavily studied units.
{"title":"Reconstructing paleosinuosity and sedimentary mass balance in the Upper Triassic Shinarump paleoriver in Utah and Arizona, U.S.A.","authors":"R. Hayes, P. DeCelles","doi":"10.2110/jsr.2021.122","DOIUrl":"https://doi.org/10.2110/jsr.2021.122","url":null,"abstract":"\u0000 The Upper Triassic Shinarump Member forms the basal part of the Chinle Formation in the western interior United States and was deposited by a continental-scale fluvial system which ran approximately 2,500 km from the Ouachita Orogen in the east into the Auld Lang Syne marine basin in the west. Previous studies of the Shinarump Member have concluded that the deposits represent a braided-river system but have not produced estimates for paleo-sinuosity and paleo-discharge. Recent advances in sedimentology allow detailed morphometric assessment of the nature of the river system that deposited the Shinarump Member enabling us to produce quantitative estimates for these parameters. We therefore present architectural data from the Shinarump Member in northern Arizona and Utah, supported by lithofacies data and 39 sandstone petrographic analyses, and a dataset of 4,298 paleocurrent measurements from trough cross-strata.\u0000 Lithofacies and architectural analysis supports previous interpretations of the Shinarump and equivalent strata as braided-river deposits. Petrographic analysis shows that the Shinarump is dominated by monocrystalline quartz and exhibits low spatial variation in composition, ranging from 85.4% to 99.8% total quartz. Paleocurrent measurements are used to calculate the channel sinuosity of the fluvial system as varying between 1.02 and 1.77, with a median value of 1.33 (compared to the Yangtze River, ranging from 1.05 to 1.50 and the Ganges–Brahmaputra, ranging from 1.05 to 1.13 in their lower 250 km). Paleohydrological estimates using data from the architectural surveys produce slope estimates from 2.01 × 10–4 to 6.51 × 10–4 and bankfull discharge estimates from 4.36 × 103 m3 s–1 to 2.38 × 104 m3 s–1 for individual channels, comparable to extant continental-scale fluvial systems. Estimates of lifetime sediment transport volume range from 7.75 × 104 km3 to 6.09 × 105 km3, which are in order-of-magnitude agreement with estimates for the volume of the depositional sink (1.35 × 105 km3 to 4.17 × 105 km3). These results demonstrate the potential for paleohydrologic estimates to provide new avenues for analysis of heavily studied units.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45795840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. McGlannan, A. Bonar, Lily S. Pfeifer, S. Steinig, P. Valdes, S. Adams, D. Duarte, Benmadi Milad, A. Cullen, G. Soreghan
Upper Devonian and Lower–Middle Mississippian strata of the North American midcontinent are ubiquitously fine-grained and silt-rich, comprising both so-called shale as well as argillaceous limestone (or calcareous siltstone) that accumulated in the Laurentian epeiric sea. Although long recognized as recording marine deposition, the origin and transport of the fine-grained siliciclastic material in these units remains enigmatic because they do not connect to any proximal deltaic feeder systems. Here, we present new data on grain size, whole-rock geochemistry, mineralogy, and U-Pb detrital-zircon geochronology from units across Oklahoma; we then integrate these data with models of surface wind circulation, refined paleogeographic reconstructions, and correlations from the greater midcontinent to test the hypothesis that wind transported the siliciclastic fraction to the marine system. The exclusively very fine silt to very fine sand grain size, clear detrital origin, widespread distribution over large regions of the epeiric sea, Appalachian sources, and paleogeographic setting in the subtropical arid belt far-removed from contemporaneous deltaic feeder systems are most consistent with eolian transport of dust lofted from subaerial delta plains of the greater Appalachian orogen and incorporated into subaqueous depositional systems. Delivery of dust that was minimally chemically weathered to Devono-Mississippian epeiric seas likely provided essential nutrients that stimulated organic productivity in these commonly organic-rich units.
{"title":"An eolian dust origin for clastic fines of Devono-Mississippian mudrocks of the greater North American midcontinent","authors":"A. McGlannan, A. Bonar, Lily S. Pfeifer, S. Steinig, P. Valdes, S. Adams, D. Duarte, Benmadi Milad, A. Cullen, G. Soreghan","doi":"10.2110/jsr.2022.013","DOIUrl":"https://doi.org/10.2110/jsr.2022.013","url":null,"abstract":"\u0000 Upper Devonian and Lower–Middle Mississippian strata of the North American midcontinent are ubiquitously fine-grained and silt-rich, comprising both so-called shale as well as argillaceous limestone (or calcareous siltstone) that accumulated in the Laurentian epeiric sea. Although long recognized as recording marine deposition, the origin and transport of the fine-grained siliciclastic material in these units remains enigmatic because they do not connect to any proximal deltaic feeder systems. Here, we present new data on grain size, whole-rock geochemistry, mineralogy, and U-Pb detrital-zircon geochronology from units across Oklahoma; we then integrate these data with models of surface wind circulation, refined paleogeographic reconstructions, and correlations from the greater midcontinent to test the hypothesis that wind transported the siliciclastic fraction to the marine system. The exclusively very fine silt to very fine sand grain size, clear detrital origin, widespread distribution over large regions of the epeiric sea, Appalachian sources, and paleogeographic setting in the subtropical arid belt far-removed from contemporaneous deltaic feeder systems are most consistent with eolian transport of dust lofted from subaerial delta plains of the greater Appalachian orogen and incorporated into subaqueous depositional systems. Delivery of dust that was minimally chemically weathered to Devono-Mississippian epeiric seas likely provided essential nutrients that stimulated organic productivity in these commonly organic-rich units.","PeriodicalId":17044,"journal":{"name":"Journal of Sedimentary Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47974830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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