Tracing fluid evolution in sedimentary basins with calcite geochemical, isotopic and U-Pb geochronological data: Implications for petroleum and mineral resource accumulation in the Nanpanjiang Basin, South China

Fluid migration in sedimentary basins enable mass and energy transport and play critical roles in geochemical and geodynamical evolution of sedimentary basins. Moreover, reconstructing sedimentary basin fluid evolution from the geological record aids in constraining the evolution of associated petroleum and mineralization systems. As a relict of fluid flow activity, calcite is often a record of fluid flow and therefore can be used to characterize the fluids responsible for its precipitation. Here we study the Nanpanjiang Basin in South China where petroleum reservoirs and Carlin-type gold deposits spatially coincide. Through in situ U-Pb dating and geochemical analysis (87Sr/86Sr, δ18OVienna standard mean ocean water, δ13CVienna Peedee belemnite, rare earth elements) of calcite, this work constrains the key times related to petroleum migration/accumulation and Carlin-type gold mineralization, defines the basin fluid evolution, and proposes a genetic model for petroleum accumulation and gold mineralization within the Nanpanjiang Basin. The U-Pb age (ca. 241.4 Ma) for the gray/black calcite related to bitumen indicates the petroleum migration/accumulation occurred during the Triassic. The U-Pb date (ca. 106−121 Ma) of the white calcite associated with the gold-bearing pyrite, realgar, and fluorite record the lower timing limit of the Carlin-type gold systems. The geochemical data suggest both calcite types are cogenetic but suffered complex evolution with the gray/black calcite precipitating under low temperatures related to the continuous basin burial and the white calcite affected by post formation alteration related to both hydrothermal and meteoric fluids. Combined with the regional tectonic history, the Early Triassic petroleum migration/accumulation and the Early Cretaceous secondary Carlin-type gold mineralization events are considered to be related to the collision between the Indo-China and South China blocks, and the subduction between the Paleo-Pacific and Eurasian plates, respectively.

A 4000-year debris flow record based on amphibious investigations of fan delta activity in Plansee (Austria, Eastern Alps)

The frequency of debris flows is hypothesized to have increased in recent decades with enhanced rainstorm activity. Geological evidence to test the relationship between climate and debris flow activity for prehistoric times is scarce due to incomplete sediment records, complex stratigraphy, and insufficient age control, especially in Alpine environments. In lacustrine archives, the link between onshore debris flow processes and the sedimentary record in lakes is poorly investigated. We present an amphibious characterization of alluvial fan deltas and a continuous 4000-year debris flow record from Plansee (Tyrol, Austria), combining light detection and ranging (lidar) data, swath bathymetry, and sediment core analyses. The geomorphic investigation of two fan deltas in different developmental stages revealed an evolutionary pattern of backfilling and new channel formation onshore, together with active subaqueous progradation on a juvenile fan delta, major onshore sediment deposition, and only few, but larger, subaqueous deposits on a mature fan delta. Geomorphic evidence for stacked and braided debris flow lobes, subaquatic landslide deposits, and different types of turbidites in sediment cores facilitated a process-based event identification, i.e. distinguishing between debris-flow-induced or earthquake-induced turbidites throughout the 4000-year sedimentary record. We directly correlate subaqueous lobe-shaped deposits with high backscatter signals to terrestrial debris flow activity of the last century. Moreover, turbidite thickness distribution along a transect of four cores allows us to pinpoint numerous events as being related to debris flow activity on a juvenile fan delta. In the sediment core, debris-flow-induced turbidites feature a more gradual fining upward grain size trend and higher TOC (total organic carbon) and δ13C values compared to earthquake-induced turbidites. The 4000-year event record contains 138 debris-flow-induced turbidites separated into four phases of similar debris flow activity (df phases). df phase 1 (∼2120 to ∼2040 before the common era – BCE) reflects the second-highest observed event frequencies and is interpreted as being a postseismic landscape response. After a long period of long recurrence intervals without any outstanding increases in debris flow activity during df phase 2 (∼2040 BCE to ∼1520 common era – CE), there are slightly increased event frequencies in df phase 3 (∼1520 to ∼1920 CE). df phase 4 (∼1920 to 2018 CE) exhibits a drastic increase in debris flow activity, followed by the overall highest debris flow frequency of the whole record, which is about 7 times higher than during df phase 3. We show that the frequency increase in the debris-flow-induced turbidite record matches a previously postulated increase in debris flow events derived from aerial photography at Plansee in the last century. The triggering of debris flows is more controlled by short, intense precipitation than any other mass movement process, and we demonstrate that lacustrine debris flow records provide a unique inventory of hazard-relevant rainstorm frequencies over decades, centuries, and millennia. The presented increase in debris flow frequency since the start of the 20th century coincides with a twofold enhanced rainstorm activity in the Northern European Alps and, therefore, provides a novel technique for the systematic understanding of non-stationary debris flow frequencies in a changing climate.

Periglacial preconditioning of debris flows in the Southern Alps, New Zealand

<p>The lower boundary of alpine permafrost extent is considered to be especially sensitive to climate change. Ice loss within permanently frozen debris and bedrock as a consequence of rising temperature is expected to increase the magnitude and frequency of potentially hazardous mass wasting processes such as debris flows. Previous research in this field has been generally limited by an insufficient understanding of the controls on debris flow formation. A particular area of uncertainty is the role of environmental preconditioning factors in the spatial and temporal distribution of debris flow initiation in high-alpine areas. This thesis aims to contribute by investigating the influence of permafrost and intensive frost weathering on debris flow activity in the New Zealand Southern Alps. By analysing a range of potential factors, this study explores whether debris flow systems subjected to periglacial influence are more active than systems outside of the periglacial domain. A comprehensive debris flow inventory was established for thirteen study areas in the Southern Alps. The inventory comprises 1534 debris flow systems and 404 regolith-supplying contribution areas. Analysis of historical aerial photographs, spanning six decades, identified 240 debris flow events. Frequency ratios and logistic regression models were used to explore the influence of preconditioning factors on the distribution of debris flows as well as their effect on sediment reaccumulation in supply-limited systems. The preconditioning factors considered included slope, aspect, altitude, lithology, Quaternary sediment presence, neo-tectonic uplift rates (as a proxy for bedrock fracturing), permafrost occurrence, and frost-weathering intensity. Topographic and geologic information was available in the form of published datasets or was derived from digital elevation models. The potential extent of contemporary permafrost in the Southern Alps was estimated based on the statistical evaluation of 280 rock glaciers in the Canterbury region. Statistical relationships between permafrost presence, mean annual air temperature, and potential incoming solar radiation were used to calculate the spatially distributed probability of permafrost occurrence. Spatially distributed frost-weathering intensities were estimated by calculating the number of annual freeze-thaw cycles as well as frost-cracking intensities, considering the competing frost-weathering hypotheses of volumetric ice expansion and segregation ice growth. Results suggest that the periglacial influence on debris flow activity is present at high altitudes where intense frost weathering enhances regolith production. Frost-induced debris production appears to be more efficient in sun-avert than sun-facing locations, supporting segregation ice growth as the dominant bedrock-weathering mechanism in alpine environments. No indication was found that permafrost within sediment reservoirs increases slope instability. Similarly, the presence of permanently frozen bedrock within the debris flow contribution areas does not appear to increase regolith production rates and hence debris flow activity. Catchment topography and the availability of unconsolidated Quaternary deposits appeared to be the cardinal non-periglacial controls on debris flow distribution. This thesis contributes towards a better understanding of the controls on debris flow formation by providing empirical evidence in support of the promoting effect of intense frost weathering on debris flow development. It further demonstrates the potential and limitations of debris flow inventories for identifying preconditioning debris flow controls. The informative value of regional-scale datasets was identified as a limitation in this research. Improvement in the spatial parameterisation of potential controls is needed in order to advance understanding of debris flow preconditioning factors.</p>

Periglacial preconditioning of debris flows in the Southern Alps, New Zealand

<p>The lower boundary of alpine permafrost extent is considered to be especially sensitive to climate change. Ice loss within permanently frozen debris and bedrock as a consequence of rising temperature is expected to increase the magnitude and frequency of potentially hazardous mass wasting processes such as debris flows. Previous research in this field has been generally limited by an insufficient understanding of the controls on debris flow formation. A particular area of uncertainty is the role of environmental preconditioning factors in the spatial and temporal distribution of debris flow initiation in high-alpine areas. This thesis aims to contribute by investigating the influence of permafrost and intensive frost weathering on debris flow activity in the New Zealand Southern Alps. By analysing a range of potential factors, this study explores whether debris flow systems subjected to periglacial influence are more active than systems outside of the periglacial domain. A comprehensive debris flow inventory was established for thirteen study areas in the Southern Alps. The inventory comprises 1534 debris flow systems and 404 regolith-supplying contribution areas. Analysis of historical aerial photographs, spanning six decades, identified 240 debris flow events. Frequency ratios and logistic regression models were used to explore the influence of preconditioning factors on the distribution of debris flows as well as their effect on sediment reaccumulation in supply-limited systems. The preconditioning factors considered included slope, aspect, altitude, lithology, Quaternary sediment presence, neo-tectonic uplift rates (as a proxy for bedrock fracturing), permafrost occurrence, and frost-weathering intensity. Topographic and geologic information was available in the form of published datasets or was derived from digital elevation models. The potential extent of contemporary permafrost in the Southern Alps was estimated based on the statistical evaluation of 280 rock glaciers in the Canterbury region. Statistical relationships between permafrost presence, mean annual air temperature, and potential incoming solar radiation were used to calculate the spatially distributed probability of permafrost occurrence. Spatially distributed frost-weathering intensities were estimated by calculating the number of annual freeze-thaw cycles as well as frost-cracking intensities, considering the competing frost-weathering hypotheses of volumetric ice expansion and segregation ice growth. Results suggest that the periglacial influence on debris flow activity is present at high altitudes where intense frost weathering enhances regolith production. Frost-induced debris production appears to be more efficient in sun-avert than sun-facing locations, supporting segregation ice growth as the dominant bedrock-weathering mechanism in alpine environments. No indication was found that permafrost within sediment reservoirs increases slope instability. Similarly, the presence of permanently frozen bedrock within the debris flow contribution areas does not appear to increase regolith production rates and hence debris flow activity. Catchment topography and the availability of unconsolidated Quaternary deposits appeared to be the cardinal non-periglacial controls on debris flow distribution. This thesis contributes towards a better understanding of the controls on debris flow formation by providing empirical evidence in support of the promoting effect of intense frost weathering on debris flow development. It further demonstrates the potential and limitations of debris flow inventories for identifying preconditioning debris flow controls. The informative value of regional-scale datasets was identified as a limitation in this research. Improvement in the spatial parameterisation of potential controls is needed in order to advance understanding of debris flow preconditioning factors.</p>

Redesign of Facility Layout at Pelangi Advertising Printing Using the SLP Method

This paper aim is to investigate the work system for printing service and redesign facility layout improvement. A case study was conducted in small company namely Pelangi Advertising Printing. The Systematic Layout Planning (SLP) was adopted in this paper. The input data and activities in the SLP process are as follows: material flow, activity relationship, string diagrams, area requirement, area available, space relationship diagrams, modification consideration and practical limitations. The results of this study indicated the application of SLP in case study company can increase in facility layout efficiency from 96.7% to 98.5%. The redesign facility layout result was more effective than the initial layout.

Modeling and Classification of Alluvial Fans with DEMs and Machine Learning Methods: A Case Study of Slovenian Torrential Fans

Alluvial (torrential) fans, especially those created from debris-flow activity, often endanger built environments and human life. It is well known that these kinds of territories where human activities are favored are characterized by increasing instability and related hydrological risk; therefore, treating the problem of its assessment and management is becoming strongly relevant. The aim of this study was to analyze and model the geomorphological aspects and the physical processes of alluvial fans in relation to the environmental characteristics of the territory for classification and prediction purposes. The main geomorphometric parameters capable of describing complex properties, such as relative fan position depending on the neighborhood, which can affect their formation or shape, or properties delineating specific parts of fans, were identified and evaluated through digital elevation model (DEM) data. Five machine learning (ML) methods, including a hybrid Euler graph ML method, were compared to analyze the geomorphometric parameters and physical characteristics of alluvial fans. The results obtained in 14 case studies of Slovenian torrential fans, validated with data of the empirical model proposed by Bertrand et al. (2013), confirm the validity of the developed method and the possibility to identify alluvial fans that can be considered as debris-flow prone.

Nonlinear electromagnetic interplay between fast ions and ion-temperature-gradient plasma turbulence

In strong electromagnetic regimes, gyrokinetic simulations have linked a substantial ion-scale turbulence stabilization to the presence of supra-thermal particles, capturing qualitatively well the experimental observations in different devices worldwide. An explanation for the underlying physical mechanism responsible for the fast-ion-induced turbulent transport reduction observed in the numerical simulations has been proposed only recently by Di Siena et al. (Nucl. Fusion, vol. 59, 2019, p. 124001; Nucl. Fusion, vol. 60, 2020, p. 089501). It involves a nonlinear cross-scale coupling (nonlinear interaction involving different modes at different wavenumbers) between ion-temperature-gradient and marginally stable Alfvén eigenmodes, which in turn increases zonal flow activity. In view of an optimization of this turbulence-stabilizing effect, the key parameters controlling the nonlinear cross-scale coupling are here identified. At the same time, these findings provide useful insights for reduced-turbulence models and integrative approaches, which might be trained on the results presented in this paper to grasp the underlying physics and the parameter scaling of the beneficial effects of fast particles on plasma turbulence.

A 4,000 year debris-flow record based on amphibious investigations of fan delta activity in Plansee (Austria, Eastern Alps)

The frequency of debris flows is hypothesized to increase in recent decades with enhanced rainstorm activity. Geological evidence to test this tendency for prehistoric times is scarce due to incomplete sediment records, complex stratigraphy, and insufficient age control especially in Alpine environments. In lacustrine archives, the link between onshore debris-flow processes and the depositional record in lake depocentres is poorly investigated. We present an amphibious characterization of alluvial fan deltas and a continuous 4,000 year debris-flow record from Plansee (Tyrol, Austria) combining Light detection and ranging (LiDAR) data, swath bathymetry, and sediment core analyses. The geomorphic investigation of two fan deltas in different developmental stages revealed a sediment delivery ratio of 7.9 % for the juvenile fan and no sediment transport into the lake on the mature fan within a 3-month summer period (May 2019–August 2019). Event deposits were dated and categorized according to their causal mechanism in a transect of four sediment cores. Debris flow-induced turbidites feature a more gradual fining-upward grain-size trend and higher TOC and δ13C values compared to earthquake-induced turbidites. Over the last 4,000 years, the record containing 138 debris flow-induced turbidites reveals four different debris-flow activity phases. Phase 1 (2050–1960 before the common era; BCE) depicts the second highest observed event frequencies. Phase 2 (1960 BCE–1550 common era; CE) shows large recurrence intervals. Phase 3 (1550–1905 CE) displays a gradual increase of event frequency. Phase 4 (1905–2018 CE) exhibits a debris-flow frequency increase between 1908 and 1928 CE, followed by the overall highest debris-flow frequency between 1928 and 1978 CE, and lower debris-flow frequencies since 1978 CE, which still exceed those of phase 1 to 3. Most remarkably, we find a ~7-fold increase of debris-flow frequency compared to the reference period 1700–1900 CE. The triggering of debris flows is more controlled by short intense rainstorms than for any other mass movement process and we demonstrate that lacustrine debris-flow records provide a unique inventory of hazard-relevant rainstorm frequencies over decades, centuries, and millennia. In a calibration period of 7 decades, we can show that the debris flow-induced turbidite record matches with the previously published debris-flow volume increase derived from aerial photography coincident to a pronounced rainstorm frequency increase. Here we show a millennium-scale debris-flow record that documents a ~7-fold increase in debris-flow frequencies in the 20th and 21st century coincident to 2-fold enhanced rainstorm activity in the Northern European Alps and provide a novel basis for systematic non-stationary estimation of future debris-flow frequencies in a changing climate.