The Sedimentary Record最新文献

{"title":"Discussion on “The Incompleteness Fallacy: The Stratigraphic Record Is Not an Imperfect Archive of Earth’s History” (Hessler, 2023)","authors":"A. Miall, Angela M. Hessler","doi":"10.2110/001c.94418","DOIUrl":"https://doi.org/10.2110/001c.94418","url":null,"abstract":"","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"43 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140253441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Downstream Morphological and Sedimentary Transformations in Modern Continental-Scale Rivers","authors":"Abdullah M. Wahbi, Michael D. Blum","doi":"10.2110/001c.90009","DOIUrl":"https://doi.org/10.2110/001c.90009","url":null,"abstract":"Morphological characteristics in river systems, including channel dimensions and river gradients, scale to drainage basin area, which provides the means for such elements to be predicted, measured and modeled. Moreover, recent studies interpret downstream changes in channel morphological and sedimentary characteristics to be the product of changing flow hydraulics as rivers transit from the normal flow to the backwater reach and approach the coastal ocean. This paper quantifies how large modern rivers undergo morphological and sedimentary transformations in response to normal flow to backwater transition. Morphologies adapting to such backwater hydraulic conditions is a potential for further investigation. With applications in modeling of modern river systems, this also provides the means for paleoenvironment reconstructions based on changing morphological characteristics since such quantitative framework is grounded by similar depositional processes. Building on previous studies, we construct river-long profiles, estimate backwater lengths, measure the ratio between channel-belt and channel widths (BChB/BCh), and measure the ratio between sand-rich to mud-dominated environments of deposition (S/M ratio) in five large modern river systems. We use results from >55,000 measurements of morphological and lithological characteristics from ~3,850 valley cross-sections over ~5,500 river kilometers to show that: (a) channel gradients decrease by ~30-50% as the channel goes through the normal flow to backwater transition, whereas (b) BChB/BCh decreases by >~60% and (c) S/M ratios decrease by ~35-90% within the upper backwater reach. These values further decrease in the lower backwater reach and approach unity (BChB/BCh = 1; S/M = 0) as the gradient reaches zero (sea level). Such systematic transformations in morphologic and sedimentary characteristics indicate they are both inherent and predictable, and can be used to interpret normal flow vs. backwater hydraulics in ancient fluvial deposits.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"46 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139279548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Telescopic Megafans on the High Plains, USA Were Signal Buffers in a Major Source-To-Sink System","authors":"Jesse Korus, R.M. Joeckel","doi":"10.2110/001c.89096","DOIUrl":"https://doi.org/10.2110/001c.89096","url":null,"abstract":"Sediment routing systems transport sediment and environmental signals inefficiently. The storage and recycling of sediment buffers the responses of sedimentary systems to tectonic, climatic, and geomorphic changes. Long-term ( <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><mml:mrow><mml:mo>&gt;</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mn>6</mml:mn></mml:msup></mml:mrow></mml:math> a.) storage may occur in megafans—large, low-relief, hemiconical fluvial deposystems—but the behavior of these systems over such timescales is unclear. We examine late Neogene megafan deposits on the High Plains, USA that are stored in the catchment of the continental-scale Rocky Mountain-Gulf of Mexico source-to-sink system. Using high-resolution elevation data, we map numerous fluvial ridges (inverted channel relics) that can be differentiated into five, chronologically distinct groups. The oldest four groups comprise radial arrays with multiple channel divergences (avulsion nodes). The inferred fan apices and longitudinal intersection points are offset successively downgradient, indicating that fanhead entrenchment and fan-lobe deposition were approximately contemporaneous and strongly suggesting a telescopic morphology. The youngest group of channels, also the lowest in elevation, is confined to terraces along the modern valley of the South Platte River. We interpret this group as direct evidence for the abandonment of the megafan and the incision of the present valley. Uplift was the chief driving mechanism for early telescoping, but channel widening and uniform downcutting in the younger groups suggest that change in stream power was the primary driver of later telescoping and incision. The storage of sediment in the megafan effectively decoupled sources from downstream sinks. Some of this sediment was recycled during entrenchment, but much of it remains in storage as the Ogallala Group and Broadwater Formation. Emplacement of telescopic megafans should be considered as a long-term ( <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><mml:mrow><mml:mo>≥</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mn>6</mml:mn></mml:msup></mml:mrow></mml:math> years) buffer in other modern and ancient sediment routing systems.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136376475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Submarine-Channel Element Architecture Demonstrates Facies Heterogeneity in Both Strike and Dip Views: Miocene Modelo Formation, Lake Piru, California, USA","authors":"J. Gilbert, Z. Jobe","doi":"10.2110/001c.84246","DOIUrl":"https://doi.org/10.2110/001c.84246","url":null,"abstract":"Submarine channels deliver vast quantities of sediment into ocean basins and the deposits left by these systems host important archives of paleoenvironmental change and are major targets for hydrocarbon production and carbon sequestration. However, similarities between channel subenvironments often make their identification difficult, particularly because some subenvironments are transitional or quite variable. While large channel complexes can often be resolved on seismic data, only outcrop data yields high-resolution detail of their internal heterogeneity. This study integrates 10 measured sections with drone-based photography to document lateral and vertical changes in depositional architecture in a well exposed outcrop of a submarine-channel element in the Miocene Modelo Formation at Lake Piru, California. The channel-element architecture is well constrained by erosional-surface mapping and lateral and vertical facies changes. The 3-dimensionality of the outcrop provides a unique example to demonstrate this heterogeneity in both strike (i.e., cross-sectional view) and dip orientations (i.e., longitudinal view). This channel element has a predictable vertical facies succession of thin sandstones and mudstones, mass transport deposits and amalgamated sandstones. The element is capped by a siliceous mudstones that provide a unique marker of hemipelagic deposition and the presence of an abandonment surface. The amalgamated sand packages are thickest in axial locations and thin over a distance of 500 m in the dip direction, but thin over 150 m in the strike direction toward two locations along the same margin. This thinning is used to constrain the dimensions and sinuosity of the channel element. We interpret a channel-element width of 550 m, a thickness of 29 m and an aspect ratio of 19:1, which is in agreement with previously published ranges of channel-element dimensions. With the documentation of lateral facies heterogeneity in orientations slightly oblique to both strike and dip, this study provides important data for understanding channelized sediment gravity flow dynamics in submarine channels and aids in evaluating reservoir-model volume and connectivity estimates.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128073499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Outsized Turbidity Currents as a Primary Mechanism for Neoproterozoic Organic Carbon Delivery to the Deep Sea","authors":"Celeste M. Cunningham, R. Arnott","doi":"10.2110/001c.77519","DOIUrl":"https://doi.org/10.2110/001c.77519","url":null,"abstract":"Levees in modern deep-marine systems have been shown to sequester significant amounts of organic carbon due largely to their expanse and high rates of sedimentation. However, relatively few studies have examined organic carbon sequestration in ancient deep-marine leveed slope channel systems. Physical and geochemical analyses of well-exposed levee deposits in the Neoproterozoic Windermere Supergroup in B.C., Canada have shown that intervals of organic-rich (up to 4% TOC) strata correlate with conditions of elevated sea level and primary productivity on the shelf. Organic matter (OM) occurs primarily as micro- to nano-scale carbon adsorbed onto the surface of clay grains and notably occurs mostly in anomalously thick, mud-rich sandstone beds that are interspersed within successions of thin-bedded, comparatively organic-poor turbidites. The concentration of organic carbon in thick beds suggests that even when primary productivity is high it only becomes mobilized in significant quantities into the deep sea by uncommon, outsized turbidity currents. Although markedly more common in organic-rich intervals, thick, organic-rich beds occur also in organic-poor levee deposits, suggesting that the occurrence and frequency of outsized flows may be linked to primary productivity on the shelf. High rates of OM production and fallout would result in rapid accumulation of OM on the seafloor that then binds and provides mechanical strength to the accumulating sediment. Later this overthickened, organic-rich sediment pile becomes gravitationally unstable and ultimately remobilized downslope. These failure events create large, surge-like flows that are considerably thicker than the depth of the slope channels through which they travel. Accordingly, continuous overspill over the channel margins results in the deposition of an anomalously thick, sand- and organic-rich bed. These episodic events not only deplete the outer continental shelf of OM, but apparently also reduces the gradient slope of the local seabed, which then results in the more typical smaller, channel-confined organic-poor turbidity currents. Additionally, the abrupt and single-bed occurrence of OM-rich strata suggests that the buildup of organic-rich strata and seafloor stabilization was rapid but only of limited duration. Significantly, this study suggests that outsized turbidity currents that originate on the outer continental shelf are the primary mechanism for organic matter delivery to the deep sea, at least in pre-vegetation times, and that flow size and frequency, in addition to primary productivity, exerts an important control on the distribution of organic carbon in deep-sea sediments.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130581326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of Remote-Sensing to Quantify the Distribution of Progradation/erosion Along a Forced-Regressive Modern Coastline: Driving Factors and Impact on the Stratigraphic Record","authors":"V. Zuchuat, M. Poyatos‐Moré, B. Nyberg, R. Nanson, S. Sagar, L. Lymburner, Robbi Bishop-Taylor","doi":"10.2110/001c.70239","DOIUrl":"https://doi.org/10.2110/001c.70239","url":null,"abstract":"The long-term development of ancient and modern coastal distributive fluvial systems (DFSs) during periods of relative sea-level highstand or fall usually drives net-progradation of shorelines. Such systems often develop in periods of relative sea-level highstand or fall and typically record annual to millennial-scale deviations in coastal trajectories. A new continental dataset (Digital Earth Australia Coastlines: DEA Coastlines) provides an opportunity to examine such variations in coastal behaviour over annual to decadal scales (1988-2019) at local to continental spatial scales. This dataset is herein applied to the 655 km coastline fronting Australia’s largest amalgamated coastal distributive fluvial systems, which is situated in the epicontinental seaway of the Gulf of Carpentaria in the north of the continent. Despite the overall forced regressive conditions (i.e. progradation during relative sea-level fall), only 54% of this coastlines length net-prograded, whereas 47% was eroded. Though temporal cyclicity in progradation and erosion is evident along segments of this coast, these patterns could not be correlated with either the Southern Oscillation Index (R2 = -0.20) or rainfall (R2 = 0.24). Instead, short-term coastline dynamics appear to be the result of complex interactions between fluvial, wave, longshore current, and tidal processes. The high-resolution DEA Coastlines dataset highlights the diachronous, heterochronous, composite, and amalgamated nature of net-progradational stratigraphic strata that can develop in shallow-marine environments where hinge-points between prograding and retrograding coastal segments are dynamic features that migrate with time. Our conclusions show that shorelines display granular temporal and spatial deviations in coastal trajectory, with contemporaneous progradation and erosion occurring over 1-100 km length scales. This is significantly more heterogeneity than previously envisaged, thereby suggesting the need for updating models of coastal systems.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134488529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphodynamic Preservation of Fluvial Channel Belts","authors":"B. Cardenas, M. Lamb, Z. Jobe, D. Mohrig, J. Swartz","doi":"10.2110/001c.66285","DOIUrl":"https://doi.org/10.2110/001c.66285","url":null,"abstract":"The fluvial sedimentary record is largely composed of deposits from relatively common flow events, rather than more catastrophic scour-and-fill events. At the scales of bedforms, such deposits are preserved within the stratigraphic record because they rapidly accumulate within, and are protected by, morphodynamic topographic depressions that occur naturally in the fluvial system as a result of feedbacks between flow, sediment transport, and topography. Examples include the preservation of ripples in front of dunes, dunes in front of bars, and bars within channels. Here, we used 3D seismic data that images preserved channel belts to test the hypothesis that alluvial-ridge basins, morphodynamic depressions formed between raised channel beds due to decreasing sedimentation rates away from channels in alluvial settings, are a source of topography driving channel-belt-scale preservation. Using the 3D seismic data, we measured the stratigraphic positions of channel belts, as well as their lengths, widths, sinuosities, and centerline orientations in the 3D seismic dataset. Results are consistent with well-preserved channel belts steered by alluvial-ridge-basin topography. Further, the thickness of the channel-belt interval exceeds the relief of any one alluvial-ridge basin, suggesting the volume records the filling of multiple alluvial-ridge basins and that the process is common. Characterizing the stratigraphic signature of alluvial-ridge basins is necessary for understanding contrasting fluvial architectures where external forcings prevented their formation.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133379459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Incompleteness Fallacy: The Stratigraphic Record Is Not an Imperfect Archive of Earth’s History","authors":"Angela M. Hessler","doi":"10.2110/001c.57494","DOIUrl":"https://doi.org/10.2110/001c.57494","url":null,"abstract":"","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131773277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microbial Activity and Neomorphism Influence the Composition and Microfabric of Ooids From Great Salt Lake, UT","authors":"Tyler A. Lincoln, S. Webb, T. Present, J. Magyar, E. Trower","doi":"10.2110/001c.56183","DOIUrl":"https://doi.org/10.2110/001c.56183","url":null,"abstract":"The sediment along the shorelines of Great Salt Lake (GSL), Utah is dominated by ooids, concentrically-coated carbonate sand grains. Two characteristics differentiate GSL ooids from typical modern marine ooids: well-developed radial aragonite microfabrics and the ubiquitous occurrence of a Mg-silicate phase. The radial microfabrics have formed the basis of conceptual models applied to understand the formation of radial fabrics in ancient ooids, but the formation of the Mg-silicates, and the relationship between Mg-silicates and radial aragonite crystals have received little attention. The occurrence of Mg-silicates in GSL ooids is surprising because GSL lake water pH is ~8.3, too low for Mg-silicate precipitation (requires pH>8.7). We use transmitted light microscopy, element mapping via wavelength-dispersive x-ray spectroscopy with electron microprobe, scanning electron microscopy, and synchrotron x-ray fluorescence (XRF) mapping and sulfur K-edge absorption spectroscopy to explore the spatial relationships between the mineral phases in GSL ooids. We observe large euhedral aragonite crystals penetrating Mg-silicate zones and cutting across laminar cortices, suggesting that the characteristic radial aragonitic fabrics in GSL ooids, traditionally interpreted as a primary structure, are enhanced, or in some cases entirely created via neomorphism. XRF maps reveal that Mg-silicate zones co-occur with elemental sulfur (S0), which we interpret as a metabolic intermediate of microbial sulfur cycling. This co-occurrence supports our hypothesis that microbial sulfur cycling plays a key role in the formation of GSL ooids by locally shifting pH beyond the threshold for Mg-silicate precipitation. This compositional fingerprint could serve as a biosignature in ancient lacustrine strata where Mg-silicates co-occur with carbonate minerals.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125137037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A “Local First” Approach to Glacigenic Sediment Provenance Demonstrated Using U-Pb Detrital Zircon Geochronology of the Permo-Carboniferous Wynyard Formation, Tasmanian Basin","authors":"Libby R. W. Ives, J. Isbell, K. Licht","doi":"10.2110/001c.38180","DOIUrl":"https://doi.org/10.2110/001c.38180","url":null,"abstract":"We propose that a “local first” approach should be applied to the interpretation of provenance indicators in glacigenic sediments of all depositional ages, especially where the glacier flow path is poorly constrained and the records of potential source lithologies are incomplete. Provenance proxies, specifically U-Pb detrital zircon geochronology, of glacigenic sediments are commonly used to infer the size and distribution of past ice centers, which are in turn used to inform ancient climate reconstructions. Interpretations of these proxies often assume that similar provenance signals between glacigenic units of the same depositional age are evidence that they were deposited by the same glacier, even when those units are, not infrequently, separated by thousands of kilometers. Though glaciers are capable of transporting sediment great distances, this assumption is problematic as it does not acknowledge observations from the geologic records of Pleistocene ice sheets that show provenance proxies in glacial sediments are most likely to reflect proximal (within 100 km) sediment sources located along a specific flow path. In a “local first” approach, provenance indicators are first compared to local source lithologies. If the indicator cannot be attributed to proximal sources, only then should progressively more distal sources be investigated. Applying a local first approach to sediment provenance in ancient glacial systems may result in significant revisions to paleo ice sheet reconstructions. The effectiveness of the local first approach is demonstrated here by comparing new U-Pb detrital zircon dates from the Permo-Carboniferous glacigenic Wynyard Fm with progressively distal source lithologies along the glacier’s inferred flow path. The Wynyard Fm and source lithologies were compared using an inverse Monte-Carlo unmixing model (DZMix). All measured Wynyard Fm detrital zircon dates can be attributed to zircon sources within 33 km of the sample location along the glacier’s flow path. This interpretation of a proximal detrital zircon provenance does not conflict with the popular interpretation made from sedimentological observations that the Wynyard Fm was deposited by a large, temperate outlet glacier or ice stream that flowed south-to-north across western Tasmania. Overall, a local first approach to glacial sediment provenance, though more challenging than direct comparisons between glacigenic sedimentary deposits, has the potential to elucidate the complex histories and flow paths of glacial sedimentary systems of all depositional ages.","PeriodicalId":137898,"journal":{"name":"The Sedimentary Record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129584486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}