Before the Frank Slide

2007 ◽  
Vol 44 (7) ◽  
pp. 765-780 ◽  
Author(s):  
David M Cruden ◽  
C Derek Martin
Keyword(s):  
Coal Mining ◽  
Alluvial Fan ◽  
Rock Joints ◽  
Clastic Rocks ◽  
River Erosion ◽  
East Limb ◽  
Slide Show ◽  
Steep Slopes ◽  
North And South ◽  
Fall Deposits

The Frank Slide occurred on the east limb of the Turtle Mountain Anticline, which was thrust up along the folded and splayed Turtle Mountain Fault. Easterly dipping, Paleozoic limestones and dolomites then rested on sheared, weaker, Mesozoic clastic rocks and coal strata. Cordilleran glaciers steepened the eastern flank of Turtle Mountain but left buttressing kame moraines. These were eroded by the Crowsnest River, which was pushed against Turtle Mountain between its North and South Peaks by the growth of the alluvial fan of Gold Creek. Blairmore Group mudstones and shales beneath the moraines were susceptible to toppling. Photographs of the east slope of Turtle Mountain before the Frank Slide show disturbed vegetation, uneven topography, steep slopes, and rock fall deposits, all consistent with active slope movements. The Frank Slide may have been triggered by the freezing of melting snow in rock joints and by coal mining. Our calculations show that, while individual stopes may have been unstable, the mine pillars and the coal mine itself were stable. Numerical simulations of the coal mining in the Frank Mine suggest mining reduced the strength of the east slope of Turtle Mountain by less than 10% before the Frank Slide.Key words: Rocky Mountains, Frank Slide, coal mining, river erosion, toppling.

scholarly journals U-Pb geochronology of rutile: deciphering the cooling history of the Oaxacan Complex granulites, southern Mexico

2020 ◽  
Vol 37 (2) ◽  
pp. 135-145
Author(s):  
Miguel Gerardo Adame-Martínez ◽  
Luigi Augusto Solari ◽  
Carlos Ortega-Obregón ◽  
Fanis Abdullin
Keyword(s):  
Sudden Change ◽  
Granulite Facies ◽  
High Grade ◽  
Southern Mexico ◽  
Cooling Rates ◽  
Clastic Rocks ◽  
The North ◽  
Precise Calculation ◽  
Fast Cooling ◽  
North And South

Rutile (TiO2) is a heavy mineral, commonly found as accessory in many lithologies, such as basic igneous rocks, high-grade metamorphic units, as well as a detritus in sedimentary clastic rocks. Its chemical composition is sensitive to the crystallization environment, allowing a characterization of either metabasic or metasedimentary protoliths in metamorphic rocks. Thanks to the capability to accept U in its crystalline network, at least in metasedimentary, high-grade protoliths, rutile can be dated by U-Pb geochronology. Furthermore, its closure temperature of ca. 600 °C for the U-Pb system makes rutile a suitable chronometer, complementary to zircon, to unravel provenance and exhumation paths in both sedimentary siliciclastic cover and basement units. Besides, the Zr-in thermometer allows for a very precise calculation of the rutile crystallization temperature. In the example case presented here, focused on granulite facies units of the Grenvillian Oaxacan Complex (OC), rutile crystallisation took place in the range 808–873 °C. Data for different localities indicate that cooling and exhumation after the Zapotecan granulite facies event (ca. 990 Ma) was heterogeneous among the different tectonic slices that constitute the OC. Cooling occurred in the central sector (Nochixtlán-Oaxaca) right after the granulite peak, with fast cooling rates of ca. 40 °C/Ma. To the north and south, the cooling to ca. 600 °C was much slower, with calculated cooling rates of ca. 3 °C/Ma for the northern OC outcrops in Coatepec (Puebla) to ca. 6 °C/Ma south of Ejutla (Oaxaca). This can be related to a combination of factors, such as an early collapse of some sectors of the orogen, a change of conditions in the subducing plate, or more in general, to a sudden change in the geodynamic conditions during the Zapotecan orogeny and Amazonia-Baltica amalgamation. This application example to some metasedimentary lithologies belonging to the OC demonstrates how the exhumation after the Zapotecan granulite facies event (ca. 990 Ma) was heterogeneous among the different tectonic slices that compose the OC, having occurred in the central sector (Nochixtlán-Oaxaca) right after the granulite peak, with fast cooling rates of ca. 40 ºC/M.y., whereas to the North and South the cooling to ca. 600 ºC was much slower, with calculated cooling rates of ca. 3 ºC/M.y. (north, OC outcrops in Coatepec, Puebla) to ca. 5.5 ºC/M.y. south of Ejutla (Oaxaca). This can be related to a combination of factors, such as an early collapse of some sectors of the orogen, change of conditions in the subjecting plate, or more in general, to a sudden change in the geodynamic conditions during the early stages of the Rodinia amalgamation. This example sharply illustrates the advantage of employing microanalytical techniques, able to resolve restricted crystal-domain chemical variations, to obtain accurate and precise temperature and age values. Furthermore, it is paramount to combine several mineral species with different closure temperatures, and collected in well-defined, recognized tectonic slices, to understand their behavior and construct meaningful cooling curves through geologic time, capable to better characterize and interpret their tectonic evolution.

Alluvial fan depositional records from north and south-facing catchments in semi-arid montane terrain

2017 ◽  
Vol 89 (1) ◽  
pp. 237-253 ◽  
Author(s):  
Michael J. Poulos ◽  
Jennifer L. Pierce
Keyword(s):  
Late Holocene ◽  
Source Area ◽  
Alluvial Fan ◽  
Potential Bias ◽  
Landform Evolution ◽  
Sediment Yields ◽  
Erosion Rates ◽  
South Central ◽  
Valley Incision ◽  
North And South

AbstractValley asymmetry reflects differences in landform evolution with aspect; however, few studies assess rates and timing of asymmetric erosion. In south-central Idaho, we combine alluvial fan volume reconstructions with radiocarbon deposit dating to compare the source-catchment normalized fan deposition rates of catchments incised into north (n=5) and south-facing (n=3) valleys, which differ during the late Holocene from 7.7 to 10.1 mm/ka, respectively, but are not significantly different. South-facing catchments produced 1.3× more fan sediment per unit source-area during the late Holocene, whereas over the last 10 Ma they have evolved to be 2.1× larger with 2.8× greater eroded volumes and 7.6° gentler slopes (24.5° versus 32.1°, average). Late Holocene differences in sediment yields with aspect cannot fully explain differences in landforms. Potential bias in sediment deposition and/or remobilization cannot fully explain the similarity of erosion rates during the late Holocene. Valley asymmetry appears to have developed primarily during different conditions. While valley asymmetry development may be quicker during glacial climates, development is likely accelerated early in a valley’s history, such as during initial valley incision, because asymmetric degradation serves as a negative feedback that reduces aspect-related differences in erosion and drives valleys towards steady state.

scholarly journals ASSESSMENT OF ALTERNATIVE BEACH PLACEMENT ON SURFING RESOURCES

2011 ◽  
Vol 1 (32) ◽  
pp. 34 ◽  
Author(s):  
Jon K Miller ◽  
Alicia M Mahon ◽  
Thomas O Herrington
Keyword(s):  
Project Area ◽  
The North ◽  
Standard Linear ◽  
Equilibration Process ◽  
Steep Slopes ◽  
North And South ◽  
Bar Formation

The beach fill was constructed using an innovative feeder beach design, rather than a standard linear fill template. The feeder beach design was adopted to address the concerns of local surfing groups by initially burying fewer structures, and by potentially creating additional surfing opportunities through enhanced bar formation during the equilibration process. Nine months of monitoring results show that roughly 84% of the placed material can be accounted for within the project area and on the downdrift beaches. The immediate impact of the fill on the local surfing conditions was negative within the project area as steep slopes, violent plunging breakers, and narrow surfzones limited the use of the feeder beach area; however traditional surf spots to the north and south were unaffected by the nourishment due to the concentrated nature of its placement. More recently, as the post-nourishment slopes have begun to equilibrate, surfing conditions have improved markedly within the project area, while the up drift and down drift beaches remain relatively unaffected.

scholarly journals Permafrost distribution in steep rock slopes in Norway: measurements, statistical modelling and implications for geomorphological processes

2019 ◽  
Vol 7 (4) ◽  
pp. 1019-1040 ◽  
Author(s):  
Florence Magnin ◽  
Bernd Etzelmüller ◽  
Sebastian Westermann ◽  
Ketil Isaksen ◽  
Paula Hilger ◽  
...  
Keyword(s):  
Rock Slope ◽  
Multiple Linear Regression Model ◽  
Permafrost Degradation ◽  
Rock Slopes ◽  
Northern Norway ◽  
Precise Knowledge ◽  
Discontinuous Permafrost ◽  
Southern Norway ◽  
Steep Slopes ◽  
North And South

Abstract. Permafrost in steep rock slopes has been increasingly studied since the early 2000s in conjunction with a growing number of rock slope failures, which likely resulted from permafrost degradation. In Norway, rock slope destabilization is a widespread phenomenon and a major source of risk for the population and infrastructure. However, a lack of precise knowledge of the permafrost distribution in steep slopes hinders the assessment of its role in these destabilizations. This study proposes the first nationwide permafrost probability map for the steep slopes of Norway (CryoWall map). It is based on a multiple linear regression model fitted with multi-annual rock surface temperature (RST) measurements, collected at 25 rock slope sites, spread across a latitudinal transect (59–69∘ N) over mainland Norway. The CryoWall map suggests that discontinuous permafrost widely occurs above 1300–1400 and 1600–1700 m a.s.l. in the north and south rock faces of southern Norway (59∘ N), respectively. This lower altitudinal limit decreases in northern Norway (70∘ N) by about 500±50 m, with a more pronounced decrease for south faces, as a result of the insolation patterns largely driven by midnight sun in summer and polar night in winter. Similarly, the mean annual RST differences between north and south faces of similar elevation range around 1.5 ∘C in northern Norway and 3.5 ∘C in southern Norway. The CryoWall map is evaluated against direct ice observations in steep slopes and discussed in the context of former permafrost studies in various types of terrain in Norway. We show that permafrost can occur at much lower elevations in steep rock slopes than in other terrains, especially in north faces. We demonstrate that the CryoWall map is a valuable basis for further investigations related to permafrost in steep slopes in terms of both practical concerns and fundamental science.

The middle Cretaceous (110−94 Ma) evolution of Tangza Basin in the western Tibetan Plateau and implications for initial topographic growth of northern Lhasa

2020 ◽  
Author(s):  
Xu Han ◽  
Jin-Gen Dai ◽  
Jie Lin ◽  
Shi-Ying Xu ◽  
Bo-Rong Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Early Cretaceous ◽  
Volcanic Rocks ◽  
Foreland Basin ◽  
High Elevation ◽  
Alluvial Fan ◽  
Magmatic Arc ◽  
Clastic Rocks ◽  
Western Tibetan Plateau ◽  
Spinel Composition

Reconstruction of Cretaceous geological evolution of Tibetan Plateau growth is critical for assessing the effect of India-Asia collision on the formation of its high elevation. However, Cretaceous topographic evolution and geodynamic mechanism in northern Lhasa remain ambiguous. Here we present results from sedimentology, zircon U-Pb ages, and detrital Cr-spinel composition of the Tangza Formation in the western part of northern Lhasa. Sedimentary lithofacies document that orbitolinid foraminifera−limestone beds were deposited in a shallow-marine setting, while clastic rocks accumulated in an alluvial fan during the middle Cretaceous. Zircon U-Pb ages of interbedded volcanic rocks place a robust constraint on the initiation of clastic rock deposition at ca. 106 Ma. Sandstones are enriched lithic fragments with abundant volcanic grains. U-Pb ages of detrital zircon display a prominent age population at 101−130 Ma with a 120 Ma peak. These data indicate that the clastic rocks were mainly derived from northern Lhasa, including an Early Cretaceous magmatic arc. Sedimentary and provenance characteristics are most consistent with deposition in a local foreland basin. The activation of south-vergent local thrusting may be responsible for loading of the Tangza foreland basin. This thrust faulting may be associated with crustal shortening induced by the continuous convergence of Lhasa and Qiangtang since collision initiated during the Early Cretaceous. The initial uplift of western and central parts of northern Lhasa and eastern Gangdese arc occurred at ca. 106 Ma, while the widespread uplift of northern and central Lhasa probably initiated at ca. 92 Ma. The mid−Late Cretaceous uplift in Lhasa was significantly earlier than the early Cenozoic India-Asia collision.

A spectrum of alluvial deposits in the Lower Carboniferous Bonaventure Formation of western Chaleur Bay area, Gaspé and New Brunswick, Canada

1983 ◽  
Vol 20 (7) ◽  
pp. 1098-1110 ◽  
Author(s):  
Brian A. Zaitlin ◽  
Brian R. Rust
Keyword(s):  
New Brunswick ◽  
Alluvial Fan ◽  
Alluvial Fans ◽  
Alluvial Deposits ◽  
Lower Carboniferous ◽  
Bay Area ◽  
Internal Structures ◽  
Sandstone Facies ◽  
Fault Scarps ◽  
Steep Slopes

The Lower Carboniferous Bonaventure Formation of western Chaleur Bay, Gaspé and New Brunswick, is a terrestrial redbed succession with abundant calcretes, deposited in a semi-arid paleoclimate. Facies can be grouped into three associations, conglomeratic, sandstone, and mud-dominated, within two 100–150 m upward-fining megasequences. The megasequences are attributed to alluvial fan progradation due to tectonic rejuvenation.Vertical facies relationships and internal structures indicate that varied alluvial environments are represented. Alluvial fans formed on steep slopes adjacent to fault scarps and are dominated by deposits of the conglomeratic association. Lateral and downslope coalescence of fans into a braid plain is represented by transition from the conglomeratic to the sandstone facies association. Distally, the braid plain is transitional into deposits of the mud-dominated association.Paleocurrents and clast compositions show that sediment in the Gaspé outcrops was derived from the northwest, and that in New Brunswick from the southwest. This indicates that Chaleur Bay is an exhumed Carboniferous paleovalley, with axial drainage to the east.

scholarly journals Overnight formation of a bouldery alluvial fan by a torrential rain in a granitic mountain (Mt. Seoraksan, Republic of Korea)

2021 ◽  
Vol 19 (2) ◽  
pp. 5-11
Author(s):  
Jisu Kim ◽  
Kyung Sik Woo ◽  
Kwang Choon Lee ◽  
Young Kwan Sohn ◽  
Howard Harper
Keyword(s):  
Source Area ◽  
Rainfall Event ◽  
Alluvial Fan ◽  
Seasonal Rainfall ◽  
Republic Of Korea ◽  
Threshold Condition ◽  
Flood Flows ◽  
Steep Slopes ◽  
Summer Rain

Mt. Seoraksan, Korea, is a rugged granitic mountain where extremely steep slopes and strongly seasonal rainfall have facilitated bedrock exposure and geomorphic changes mainly by rockfalls and streamflows. Although the environment was not suitable for alluvial fan formation, a bouldery alluvial fan, 170 m long and 330 m wide, formed overnight by a heavy summer rain in 2006. The fan consists of several meter-high boulder mounds and gently undulating cobble bars/sheets that are arranged in a fluvial longitudinal bar-like pattern. They are interpreted to have formed by highly competent and turbulent sheetfloods, which temporarily had the properties of hyperconcentrated flood flows. Formation of the whole alluvial fan by a single, casual hydro-meteorological event is inferred to have been possible because a threshold condition was reached in the source area. A rainfall event, which would have had no extreme effects before reaching the threshold, could probably trigger massive remobilization of bouldery sediments on the valley floors. The Seoraksan alluvial fan thus demonstrates the role of a geomorphic threshold in causing drastic changes in the hydrologic performance of the watershed. The morphology and sedimentology of the Seoraksan alluvial fan suggest that the fan is a modern example of a sheetflood-dominated alluvial fan, which has largely been ignored in spite of their potential diversity and abundance in glacial to periglacial, tropical, and temperate environments.

scholarly journals Prospects for the Coal-Line Transport Introduction in Russia

2019 ◽  
Vol 2019 (4) ◽  
pp. 441-447
Author(s):  
Egor Sherin
Keyword(s):  
Coal Mining ◽  
The Urals ◽  
Design Capacity ◽  
Final Destination ◽  
Freight Rates ◽  
The North ◽  
Coal Fuel ◽  
Line Extension ◽  
North And South ◽  
Mining Regions

The research featured an economic-geographical analysis of the main problems of Russian domestic coal transportation. The problems are related to the ultracontinental position of the main coal-mining regions, railroad workload, and overpriced freight rates. The paper focuses on the advantages of coal-line transport as an alternative to railroads. The author also describes positive aspects of water-coal fuel and summarizes related domestic studies. The article introduces a coal-line project that links Kuzbass and the Urals, its deployment factors, prospective consumers, and design capacity. The route runs from Novokuznetsk to Yekaterinburg with branches to the north and south. The route can be divided into stages, e.g. up to Novosibirsk and to Omsk. Each stage can become final destination, if needed. The prospects of coal-line extension in the western and eastern directions are considered.

scholarly journals Permafrost distribution in steep slopes in Norway: measurements, statistical modelling and geomorphological implication

2019 ◽  
Author(s):  
Florence Magnin ◽  
Bernd Etzelmüller ◽  
Sebastian Westermann ◽  
Ketil Isaksen ◽  
Paula Hilger ◽  
...  
Keyword(s):  
Rock Slope ◽  
Multiple Linear Regression Model ◽  
Statistical Modelling ◽  
Rock Surface ◽  
Permafrost Degradation ◽  
Northern Norway ◽  
Discontinuous Permafrost ◽  
Southern Norway ◽  
Steep Slopes ◽  
North And South

Abstract. Permafrost in steep slopes has been increasingly studied since the early 2000s in conjunction with a growing number of rock-slope failures, which likely resulted from permafrost degradation. In Norway, rock-slope destabilization is a widespread phenomenon and a major source of risk for the population and infrastructure. However, the lack of precise understanding of the permafrost distribution in steep slopes hinders the assessment of its role in these destabilizations. This study proposes the first nation-wide permafrost probability map for the steep slopes of Norway (CryoWall map). It is based on a multiple linear regression model fitted with multi-annual rock surface temperature (RST) measurements, collected at 25 rock-wall sites, spread across a latitudinal transect (59–69° N) over mainland Norway. The CryoWall map suggests that discontinuous permafrost widely occurs above 1300–1400 and 1600–1700 m a.s.l. in the north and south slopes of southern Norway (59° N), respectively. This lower altitudinal limit decreases in northern Norway (70° N) by about 500 ± 50 m, with more pronounced decrease for south faces, in reason of the insolation patterns largely driven by midnight sun in summer and polar night in winter. Similarly, the mean annual RST differences between north and south faces of similar elevation range around 1.5 °C in northern Norway and 3.5 °C in southern Norway. The CryoWall map is evaluated against direct ice observations in steep slopes and discussed in the context of former permafrost studies in various types of terrains in Norway. We show that permafrost can occur at much lower elevations in steep rock slopes than in other terrains, especially in north faces. We demonstrate that the CryoWall map is a valuable basis for further investigations related to permafrost in steep slopes in both practical concerns and fundamental science.

Paleogene sequence framework and depositional systems in the Sunda and Asri Basins, Indonesia

2018 ◽  
Vol 6 (2) ◽  
pp. T377-T391 ◽  
Author(s):  
Xiaomin Zhu ◽  
Shunli Li ◽  
Jiawang Ge ◽  
Dakang Zhong ◽  
Qin Zhang ◽  
...  
Keyword(s):  
Alluvial Fan ◽  
Structure Evolution ◽  
Sedimentary Evolution ◽  
Fan Delta ◽  
Basin Scale ◽  
Sequence Relationship ◽  
Seismic Records ◽  
Depositional Systems ◽  
Lacustrine Facies ◽  
Steep Slopes

Based on seismic reflection characteristics, lithologic associations, and basin structure evolution stages, the Banuwati Formation, Zelda and Gita Members in the Oligocene could be divided into six third-order sequences. The new sequence framework has been established in the Sunda and Asri Basins. Sequence relationship between wells and seismic data has been implemented in the basin scale through the use of synthetical seismic records of 14 wells. Depositional systems, such as delta, fan-delta, nearshore subaqueous fan, and fluvial, are identified in the Banuwati Formation, Zelda and Gita Members. Alluvial fan, subaqueous fan, and fan delta occurred on the steep slopes of the basins. Deltas were mainly developed on the gentle slopes of the basins. There were three separated small basins with fluvial and shore-shallow lake deposition in the Banuwati Formation (SQ1). During the Lower Zelda (SQ2) sedimentation, the former separated small basins enlarged in a certain extent where delta and subaqueous fan were developed. Major lacustrine facies under deepwater environments and deltaic facies developed in the Upper-Lower Zelda and Middle-Upper Zelda (SQ3, SQ4). The sedimentary situation was almost the same as the Middle Zelda, but the water depth became shallower during Upper Zelda sedimentation. Later, fluvial and swamp developed in the upper part of the Upper Zelda and Gita Member (SQ5, SQ6). In general, basin sedimentary evolution is consistent with tectonic evolution. Finally, the favorable sandstone distribution in the Banuwati and Mid-Upper Zelda Member for further exploration was predicted according to the depositional systems, slope break, and present hydrocarbon occurrence. Three fields or eight favorable plays should be paid attention to for further exploration in the Sunda and Asri Basins, Indonesia.

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