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Deep-seated rockslide-avalanches preceded by mass rock creep of sedimentary rocks in the Akaishi Mountains, central Japan
204A
GEOLOGY:ENVIRONMENTAL
955023 IoW on firm ground to make the most of landslide opportunities R. Bond, Surveyor, 182(5324), 1995, p 12. Findings of a study into the ground movement on the Isle of Wight are reported. The study, by consultants Rendel Geotechnics, reviewed the ground movement and slippage problem around Ventnor and St Lawrence, including the whole undercliff from Luccombe to Niton Village. Measures being adopted to reduce high groundwater levels and coastal erosion and minimize hazards of land movement are discussed. (P.M.Taylor) 955024 Relationship of the landslide distribution to geology in Hokkaido, Japan H. Yamagishi & Y. Ito, Engineering Geology, 38(3-4), 1994, pp 189-203.
EFFECTS
resistances. Thus flow thinning and deposit shape as well as flow kinematics may be modeled. Analysis indicates that a substantial decrease in flow resistance occurred as a function of displacement. Constant-property models that match runout tend to overestimate the peak velocities and to underestimate the emplacement times. A staged increase in mobility in both constant volume and variable volume models leads to results consistent with field data. Runout in a channel overflow area was also modeled. (from Authors) 955028 Tbe origin of diamonds in western Minas Gerais, Brazil G. M. Gonzaga, N. A. Teixeira & J. C. Gaspar, Mineralium Deposita, 29(5), 1994, pp 414-421.
The island of Holckaido, Japan, is subdivided into 19 regions on the basis of regional geology and landslide distribution. Four major geologic zones characterize these regions, as follows: 1) Volcanic Rock Zone, 2) ‘Green Tuff Zone, 3) Mudstone Zone, and 4) Serpentinite-‘Green Rock’ Zone. Each zone is marked by landslides of a distinctive type. In addition, the relationship between landslide distribution and geologic structure has been analysed. (Authors)
Important diamond mineralized alluvium/colluvium occurs in western Minas Gerais (WMG) in the Brasilia Orogenic Belt. Petrological data indicate that the rocks originally petrographically classified as kimberlites present mineralogical, chemical, and isotopical differences with Group I and II kimberlites and more closely resemble kamafugites. The Brasilia Grogenic Belt presents features of a Wilson Cycle implying that WMG does not fulfil the geotectonic and geothermometric requisites to host primary diamond sources. An analysis of field relations and sedimentology in WMG shows that the majority of the diamonds have been transported by glacial events from the Sao Francisco Craton further east. (from Authors)
955025 Geohistorlcal development of tbe Tocbiyama landslide in north-central Japan K. Chihara, S. Iwanaga, K. Ito, T. Ogawa, K. Hayatsu & K. Kosuge, Engineering Geology, 38(3-4), 1994, pp 205-219.
955029 Crystal features of supergene gold at Hannan South, Western Australia L. M. Lawrance & B. J. Griffin, Mineralium Deposita, 29(5), 1994, pp 391-398.
The Tochiyama landslide is one of several complex, deepseated and large-scale landslides occurring in the Hokuriku Province in central Japan. The landslide is about 2 km long and about 500-1100 m wide; it occupies an area of approximately 150 ha and has a maximum depth of 60 m. The slide developed on a dip-slope structure, and is divisible into three layers in ascending order: older landslide debris and avalanche deposits, younger debris-avalanche deposits, and talus. The landslide complex is still active. (from Author)
Deep weathering of basalt-hosted sulphidic gold mineralisation has resulted in remobilisation of the gold and the formation of a supergene deposit. A general downward movement of an iron redox front associated with the weathering has controlled the distribution of the gold and its morphology. Small octahedra, up to 50 pm, are the most abundant form of gold crystals but large, up to 3 mm, octahedral plates are common. Crystal morphology variations suggest that the gold is initially precipitated as euhedral octahedra and plates. Subsequent dissolution and recrystallisation led to the development of the more common irregular dendritic or wire gold forms observed in other supergene deposits. (from Authors)
955026 Deep-seated rockslide-avalanches preceded by mass rock creep of sedimentary rocks in the Akaishi Mountains, central Japan M. Chigira & K. Kiho, Engineering Geology, 38(3-4), 1994, pp 221-230. Seven large rockslide-avalanches of sedimentary rocks are known in Japan. Almost all of these major landslides were preceded by gravitational deformation of rocks (mass rock creep, MRC), as inferred from geologic and geomorphic investigations of five m&slide-avalanches in the Akaishi Mountains. The MRC that preceded the rockslide-avalanches in the Akaishi Mountains was characterized by a slow but steady downslope bowing of steeply dipping foliations, which accompanied intensive deformation and fragmentation of the rock mass by shearing along foliations. (from Authors) 955027 Lessons from Ontake-san: a comparative analysis of debris avalanche dynamics B. Voight & J. Sousa, Engineering Geology, 38(3-4), .1994, pp 261-297. Dynamic aspects of the long runout Gntake-san debris avalanche are evaluated by a comparison of several models. An unsteady numerical model assumes two-dimensional flow of an incompressible biviscous or Newtonian fluid, represented as a continuum with a free surface. Internal deformation of the flowing mass is considered, as well as boundary
955030 Hydrology and denudation rates of halite karst A. Frumkin, Journal of Hydrology, 162(1-2), 1994, pp 171189. Salt karst terrains exist mainly in arid climates where rock salt outcrops may escape complete destruction by dissolution. Such is the case with Mount Sedom, on the SW shore of the Dead Sea. Many small catchments developed over the relatively insoluble cap rock which overlies the highly soluble rock salt. The catchments were surveyed and classified. Some 57% of the surface area is drained by an underground karst system. Water samples from various points in the system were analysed, and water development was inferred. Based on the available evidence, regional karst denudation is tentatively estimated to be about 0.5-0.75 mm year-‘, occurring mainly within the rock salt. (from Author) 955031 Fabric changes during reclamation of a scalded, red duplex soil by waterpondiag A. J. Ringrose-Voase & S. G. McClure, in: Soil micromorphology, ed A.J. Ringrose-Voase & G.S. Humphreys, (Elsevier Science; Developments in Soil Science, 22), 1994, pp 777-786.
GEOLOGY:ENVIRONMENTAL
955023 IoW on firm ground to make the most of landslide opportunities R. Bond, Surveyor, 182(5324), 1995, p 12. Findings of a study into the ground movement on the Isle of Wight are reported. The study, by consultants Rendel Geotechnics, reviewed the ground movement and slippage problem around Ventnor and St Lawrence, including the whole undercliff from Luccombe to Niton Village. Measures being adopted to reduce high groundwater levels and coastal erosion and minimize hazards of land movement are discussed. (P.M.Taylor) 955024 Relationship of the landslide distribution to geology in Hokkaido, Japan H. Yamagishi & Y. Ito, Engineering Geology, 38(3-4), 1994, pp 189-203.
EFFECTS
resistances. Thus flow thinning and deposit shape as well as flow kinematics may be modeled. Analysis indicates that a substantial decrease in flow resistance occurred as a function of displacement. Constant-property models that match runout tend to overestimate the peak velocities and to underestimate the emplacement times. A staged increase in mobility in both constant volume and variable volume models leads to results consistent with field data. Runout in a channel overflow area was also modeled. (from Authors) 955028 Tbe origin of diamonds in western Minas Gerais, Brazil G. M. Gonzaga, N. A. Teixeira & J. C. Gaspar, Mineralium Deposita, 29(5), 1994, pp 414-421.
The island of Holckaido, Japan, is subdivided into 19 regions on the basis of regional geology and landslide distribution. Four major geologic zones characterize these regions, as follows: 1) Volcanic Rock Zone, 2) ‘Green Tuff Zone, 3) Mudstone Zone, and 4) Serpentinite-‘Green Rock’ Zone. Each zone is marked by landslides of a distinctive type. In addition, the relationship between landslide distribution and geologic structure has been analysed. (Authors)
Important diamond mineralized alluvium/colluvium occurs in western Minas Gerais (WMG) in the Brasilia Orogenic Belt. Petrological data indicate that the rocks originally petrographically classified as kimberlites present mineralogical, chemical, and isotopical differences with Group I and II kimberlites and more closely resemble kamafugites. The Brasilia Grogenic Belt presents features of a Wilson Cycle implying that WMG does not fulfil the geotectonic and geothermometric requisites to host primary diamond sources. An analysis of field relations and sedimentology in WMG shows that the majority of the diamonds have been transported by glacial events from the Sao Francisco Craton further east. (from Authors)
955025 Geohistorlcal development of tbe Tocbiyama landslide in north-central Japan K. Chihara, S. Iwanaga, K. Ito, T. Ogawa, K. Hayatsu & K. Kosuge, Engineering Geology, 38(3-4), 1994, pp 205-219.
955029 Crystal features of supergene gold at Hannan South, Western Australia L. M. Lawrance & B. J. Griffin, Mineralium Deposita, 29(5), 1994, pp 391-398.
The Tochiyama landslide is one of several complex, deepseated and large-scale landslides occurring in the Hokuriku Province in central Japan. The landslide is about 2 km long and about 500-1100 m wide; it occupies an area of approximately 150 ha and has a maximum depth of 60 m. The slide developed on a dip-slope structure, and is divisible into three layers in ascending order: older landslide debris and avalanche deposits, younger debris-avalanche deposits, and talus. The landslide complex is still active. (from Author)
Deep weathering of basalt-hosted sulphidic gold mineralisation has resulted in remobilisation of the gold and the formation of a supergene deposit. A general downward movement of an iron redox front associated with the weathering has controlled the distribution of the gold and its morphology. Small octahedra, up to 50 pm, are the most abundant form of gold crystals but large, up to 3 mm, octahedral plates are common. Crystal morphology variations suggest that the gold is initially precipitated as euhedral octahedra and plates. Subsequent dissolution and recrystallisation led to the development of the more common irregular dendritic or wire gold forms observed in other supergene deposits. (from Authors)
955026 Deep-seated rockslide-avalanches preceded by mass rock creep of sedimentary rocks in the Akaishi Mountains, central Japan M. Chigira & K. Kiho, Engineering Geology, 38(3-4), 1994, pp 221-230. Seven large rockslide-avalanches of sedimentary rocks are known in Japan. Almost all of these major landslides were preceded by gravitational deformation of rocks (mass rock creep, MRC), as inferred from geologic and geomorphic investigations of five m&slide-avalanches in the Akaishi Mountains. The MRC that preceded the rockslide-avalanches in the Akaishi Mountains was characterized by a slow but steady downslope bowing of steeply dipping foliations, which accompanied intensive deformation and fragmentation of the rock mass by shearing along foliations. (from Authors) 955027 Lessons from Ontake-san: a comparative analysis of debris avalanche dynamics B. Voight & J. Sousa, Engineering Geology, 38(3-4), .1994, pp 261-297. Dynamic aspects of the long runout Gntake-san debris avalanche are evaluated by a comparison of several models. An unsteady numerical model assumes two-dimensional flow of an incompressible biviscous or Newtonian fluid, represented as a continuum with a free surface. Internal deformation of the flowing mass is considered, as well as boundary
955030 Hydrology and denudation rates of halite karst A. Frumkin, Journal of Hydrology, 162(1-2), 1994, pp 171189. Salt karst terrains exist mainly in arid climates where rock salt outcrops may escape complete destruction by dissolution. Such is the case with Mount Sedom, on the SW shore of the Dead Sea. Many small catchments developed over the relatively insoluble cap rock which overlies the highly soluble rock salt. The catchments were surveyed and classified. Some 57% of the surface area is drained by an underground karst system. Water samples from various points in the system were analysed, and water development was inferred. Based on the available evidence, regional karst denudation is tentatively estimated to be about 0.5-0.75 mm year-‘, occurring mainly within the rock salt. (from Author) 955031 Fabric changes during reclamation of a scalded, red duplex soil by waterpondiag A. J. Ringrose-Voase & S. G. McClure, in: Soil micromorphology, ed A.J. Ringrose-Voase & G.S. Humphreys, (Elsevier Science; Developments in Soil Science, 22), 1994, pp 777-786.