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Earthquakes are considered to be important triggers of deep-seated gravitational slope deformation (DGSD) in seismically active regions, and if that is the case, DGSD features could be candidates for off-fault paleoseismology investigations. On the basis of pit excavations and sediment cores at an off-fault DGSD site and a trench excavation across the active Neodani fault at a nearby site, we examined the records of DGSD and surface-rupturing paleoearthquakes of the Neodani fault. The four most recent DGSD events were dated at after 240 cal BP, 1710–340 cal BP, 4730–3970 cal BP, and 5570–5340 cal BP. The four most recent surface-rupturing earthquakes were dated at 1891 CE (the Nobi earthquake), 2010–1220 cal BP, 7180–2110 cal BP, and before 9540 cal BP. We conclude that the ages of the four DGSD events are consistent with surface-rupturing earthquakes on the adjacent Neodani fault. We infer that static crustal strain from repeated seismogenic faulting plays an important role in the occurrence of DGSD events, at least in the immediate vicinity of active faults, although coseismic severe shaking would have at least some effect on them. Our case study suggests that off-fault DGSDs can be used to reconstruct or refine the paleoseismic history of a nearby active fault. We propose that an ideal DGSD for that purpose would be located in an area of concentrated strain near a termination, bend, or stepover of the target fault.

We present a new approach for recognizing the origin of accreted basaltic rocks based on ocean plate stratigraphy (OPS), and on the petrology and geochemistry of basalts from mid-oceanic ridges (MORB) and oceanic islands (OIB) using examples from four accretionary complexes (AC) in SW Japan: Akiyoshi, Mino–Tamba, Chichibu and Shimanto. The key to the problem is the model of OPS, which includes an association of igneous and sedimentary rocks that form on an oceanic plate during its travel from a mid-oceanic ridge to a subduction zone. We propose the reconstruction of the tectonic settings of basalts according to their relationships with associated OPS sediments, their petrogenesis and their geochemical features. Five types of OPS are recognized in the accretionary complexes of SW Japan: (1) sandstone/shale; (2) sandstone/shale and chert; (3) sandstone/shale, chert and MORB; (4) sandstone/shale, chert, MORB and gabbro (± peridotite); (5) seamount OPS including OIB, cap carbonates, slope clastics and basal shale/chert. The alkaline, tholeiitic or calc-alkaline composition of basaltic melts, which are typical of oceanic islands, mid-oceanic ridges and island-arcs, respectively, can be identified by the sequence in crystallization of their major phenocrysts, i.e. olivine (ol), clinopyroxene (cpx) and plagioclase (pl), and by their compositions. Alkaline and calc-alkaline mafic lavas are characterized by an ol → cpx → pl succession, whereas tholeiitic melts by their ol → pl ± cpx succession. Titanium-rich minerals, e.g., Ti–augite, kaersutite, Ti–biotite, are typical of alkaline lavas. The application of geochemistry-based tectonic discrimination diagrams is also a powerful tool, if not supported by geological and petrological data, may result in confusion due to magma contamination, post-magmatic alteration, and secular change of mantle thermal conditions. We propose that a direct comparison of normalized multi-element patterns and key binary plots from older volcanic rocks with their modern analogues provides a more viable and reliable method of basalt discrimination. Our OPS–petrology–geochemistry method allows us to confirm the above conclusions that the lavas of the Akiyoshi, Mino–Tamba and Southern Chichibu AC formed in oceanic islands, because they are associated with seamount OPS sediments, crystallized from ol to cpx and pl, contain Ti–augite and kaersutite and are enriched in TiO2, LREE and Nb. In this paper we present geochemical data from the Inuyama basalts of the Mino–Tamba AC and from the Toba complex in the huge Mikabu greenstone belt of the Chichibu AC. The Inuyama basalts are in contact with Jurassic pelagic cherts, but their geochemical features are confusing; they contain phenocrysts of ol, Ti–augite and kaersutite and therefore probably formed in seamounts. The Toba volcanic rocks are a part of the huge ophiolite belt; they have flat to slightly LREE-enriched REE patterns, are characterized by an ol → cpx succession of phenocrysts and they plot in the OIB field in binary plots suggesting they formed in an oceanic plateau.

In managed forests, partial harvest within riparian areas is one way to provide harvest opportunities and maintain some of the functions of riparian vegetation. We examined the response of coniferous seedlings to a 50 %-partial harvest in a second-growth, coniferous riparian forest in the Pacific Northwest. Partial canopy opening facilitated the establishment of Tsuga heterophylla and Thuja plicata, but Pseudotsuga menziesii did not show the same tendency. Results suggested that differences in seedling establishment were related to differences in light. Increased light availability also stimulated growth of Rubus spectabilis, especially in moist sites, and the dense cover precluded establishment of coniferous seedlings. Once R. spectabilis was established, continued stem recruitment maintained a dense stable cover, and even intense disturbance did not affect the stability of the populations. R. spectabilis would be a major competitor to constrain conifer seedlings to regenerate in riparian zones. Although Gaultheria shallon extended their cover, competition from dense G. shallon was not as severe as from R. spectabilis.

The relationship between large deep-seated landslides and geologic structures characteristic of accretionary complexes were examined in the Chichibu belt on the eastern part of the Kii Peninsula, central Japan. In the Chichibu belt, bedrock consists of Jurassic accretionary complexes composed of basalt, limestone, chert, Permian–Triassic boundary siliceous shale (PTBS), mudstone, sandstone, and melanges with sheared shale matrices. The landslides treated in this paper include prehistoric examples involving volumes greater than one million cubic meters (located in the Karako, Sono, Kasagi, and Aso areas), and the modern Kasugadani landslide that was triggered by the Typhoon Meari on 29–30 September 2004. The age of the landslide in the Sono area was estimated at 20,440 ± 70 BP and 20,820 ± 70 BP based on AMS-14C ages of wood fragments embedded in the dammed lake sediments, while ages of the other prehistoric slides are not known. All of the landslides occurred on dip slopes. The bedding, foliation, and fault planes of the rocks in the area generally trend E–W and dip to the north, although those in the Kasugadani area dip to the south as a result of local folding. The landslides selectively slid along the planes of (1) PTBS horizons that were less strong than those of underlying chert, (2) lithologic boundaries with physical contrasts, or (3) boundary faults between melange units. These geologic structures, including the north-dipping bedding/cleavage/fault planes, were formed during Jurassic subduction–accretion and later uplift processes. The movement directions estimated for the 269 landslides and unstable slopes in this region are also N–NNE, and their slip planes are subparallel to the general bedding/cleavage planes in this area. Thus, future slides are also likely to occur on north-facing slopes.

Petrographic analyses of plutons across the Karakoram fault in the Shyok-Nubra confluence of northern Ladakh area revealed that the rocks consist of diorite, granodiorite, granite and leucogranite. Pyroxene and biotite chemistries by EPMA indicate that most of the diorite, granodiorite and granite are calc-alkaline and formed in an arc-related tectonic setting. These calc-alkaline plutons yield K–Ar biotite ages from 49.3 ± 1.1 to 51.2 ± 1.1 for Ladakh batholith in Khardung La and from 60.8 ± 1.3 to 65.8 ± 1.4 Ma for granites and diorites in Hundar area. The K–Ar ages of the Hundar igneous complex are within the age range of 46–70 Ma of the Ladakh batholith near Leh town and the neighbor sites, indicating the Hundar igneous complex as a part of the Ladakh arc. Their ages are also coincident with the Khardung volcanics (67.4 and 60.5 Ma). The calc-alkaline granites from Panamik of Karakoram block yield K–Ar biotite ages of 95.7 ± 2.1 and 96.7 ± 2.1 Ma, suggesting that the granites are member of the plutons (90–120 Ma) occurring in northern Pakistan, Tangtse in Ladakh and western Tibet that emplaced during subduction of the Neo-Tethyan oceanic plate under the Karakoram block. The leucogranite and granodiorite in the Panamik region yield K–Ar biotite and muscovite ages ranging from 9.18 ± 0.21 to 9.45 ± 0.21 Ma. The leucogranites are the S-type related to post-collision tectonic setting and are considered to have emplaced in relating to activation of the Karakoram fault.

Plume-related oceanic magmatism form oceanic islands, seamounts and plateaus (hereafter “seamounts” or “paleoseamounts”), which are important features in geological history. The accretion of oceanic seamounts to active continental margins significantly contributed to the formation of the continental crust. This paper reviews occurrences of Late Neoproterozoic–Mesozoic seamounts of the Paleo-Asian and Paleo-Pacific oceans, which are hosted by accretionary complexes (ACs) of Russian Altai, East Kazakhstan, Mongolia, Russian Far East and Japan. The paleoseamounts commonly consist of Ti–LREE–Nb-enriched plume-related basalts (OIB-type or intraplate basalts) capped with massive limestone and associated with other units of oceanic plate stratigraphy (OPS): oceanic floor basalts (MORB), pelagic chert, epiclastic slope facies, etc. The paper presents available geochemical data on the plume-related basalts including the first geochemical data on the Middle Paleozoic OIB-type basalts of the Paleo-Asian Ocean hosted by the Ulaanbaatar AC of Mongolia. An emphasis is made for the structural setting of OPS units, specific geochemical features of intraplate basalts, problems of their identification, and distinguishing from magmatic units of a different origin such as MORB, island-arc and back-arc basalts. Finally, we propose a continuous, though periodical, evolution of the Pacific superplume-related magmatism, which can be more reliably proved by studying Middle Paleozoic OPS units hosted by ACs of Mongolia and Tien Shan, and discuss prospects of future studies.

The Khabarovsk Complex, a Jurassic accretionary complex distributed in and around the Khabarovsk city area, Far East Russia, comprises melange and schist facies. From the review of previous studies including Russian papers, the lithology and age of the constituent rocks of the melange facies can be summarized as follows: Upper Paleozoic basic volcanic rocks, mainly pillow lava, and altered gabbro, Upper Carboniferous to Upper Permian fusulinoidean-bearing limestone associated with tuff, Lower and Middle Jurassic siliceous mudstone, Upper Jurassic tuffaceous mudstone, uppermost Jurassic carbonate concretions embedded in mudstone, and age-unknown sandstone. Newly found sequences of limestone-chert and of basalt-chert in the melange facies crop out along the Amur River in the Khabarovsk city area. A chert sample of the limestone-chert sequence contains Albaillella aff. asymmetrica and Pseudoalbaillella aff. lomentaria, and a chert sample of the basalt-chert sequence includes Follicucullus monacanthu...

Small-scale geomorphic features of sagging have been known to occur in mountainous areas in Japan by the analyses of high resolution map images made from the LiDAR data. Development histories of the sagging landforms were analyzed by the GIS analyses, field mapping, machine and hand auger boring, AMS 14C dating, and tephra geochronology in the Mt. Kanmuriyama, Tsuenomine and Nogo-Hakusan areas. Sediments accumulated in the ridge-top depression in the Mt. Kanmuriyama area yield wood fragments with the ages of 1,234–1060, 6,191–5,996 and 7,931–7,731 cal BP, and also include the K-Ah tephra of ca 7.3 ka. These ages indicate that the depression started to form at the beginning of warm and humid climate after the last glacial period. On the other hand, the double ridges in the Mt. Tsuenomine area formed much earlier before the deposition of the Kikai-Tozurahara tephra about 95 ka. The GIS analyses of sagging in the Mt. Nogo-Hakusan area indicate that most of them are distributed on the flat or gentle surface just above the knick line (erosion front); it means that the knick lines retreat through the repetitive formation and destruction of the sagging landforms.

The paper presents the results of a detailed geochemical study (major and trace elements, Sr, Nd and Pb isotopes) of early Carboniferous to Miocene volcanic rocks of the Akiyoshi, Mino–Tamba, Chichibu and Shimanto accretionary complexes of Japan in combination with an analysis of their geological relations with sedimentary units and their petrogenesis (melting modeling). Most of the samples are oceanic island basalts (OIBs) associated with Carboniferous–Cretaceous sediments of Ocean Plate Stratigraphy (OPS): carbonate “cap” limestones, hemipelagic siliceous mudstone and pelagic radiolarian chert. The basalts are enriched in TiO2, LREE (La/Smn = 1.9), and Nb (Zr/Nbav. = 10), have differentiated HREE (Gd/Ybn = 2.0), medium to low eNd (7.8–2.2) and are characterized by clear Nb positive anomalies in multi-element plots (Nb/Thpm = 1.3, Nb/Lapm = 1.1). The Carboniferous–Cretaceous OIBs originated at relatively low degrees of melting (

Relationships between the NDVI and vegetation, especially for the nine dominant vegetation types of Tibetan Plateau, were examined and discussed using GIS and remotely sensed data. The results showed that the yearly averaged NDVI of the study region was 0.064. In 88.5% of the area, NDVI were lower than 0.1 and the monthly mean values never exceeded 0.1 throughout the whole year in half of the Plateau. The NDVI values steadily decreased from the southeast where evergreen and semi-evergreen rain forest was well developed to northwest where cold desert was dominant. It is clearly shown that the main vegetation types have their own NDVI character values, despite of the fact that the vegetation is sparse for the most part of the region.

Magnitudes and extent of forest decline due to industrial pollution in Monchegorsk on the Kola Peninsula, Russia, were assessed by Landsat data and ground observation. A total of 1, 098 km2 was identified to be affected. The area was classified into three damage classes. i. e., light, medium, and heavy, and their areal extents were estimated to be 865 km2, 147 km2 and 86 km2, respectively. Economical loss due to the decline was evaluated. Potential annual total loss of wood increment amounted to be 81, 000 m3 for the entire area and its commercial value was estimated to be 8.1 million US dollars. Wild berry production of 3, 300 ton/year was also lost, which would worth 16.5 million US dollars approximately. Loss of ecological functions of the forest ecosystems was immeasurable. Such economical and ecological losses would last “forever” from our perception of time. This was totally contradictory to the notion of sustainable resource use with which the whole world was so much concerned.

Fossil forests, where petrified stumps were preserved in growth position, have been found within Early Tertiary sediments near Strathcona Fiord, Ellesmere Island, Canadian Arctic Archipelago. These fossil forests are obvious evidence for Early Tertiary climate much warmer than that of today. We analyzed the growth rings of petrified woods from two fossil forest sites (one in middle Paleocene, and the other in late Early Eocene) to extract information on climate change. The woods consist most abundantly of Metasequoia and cf. Glyptostrobus, suggesting that these forests grew in similar environments of warm to cool temperate climates. Mean ring width, mean sensitivity and power spectrum were calculated for ring-width sequences. Although significant difference in the mean ring width between the two forests was found, a comparison with living trees suggests that the difference can be attributed to the specific difference between the forests, so that a significant climate change may not necessarily be invoked. We found little significant difference in the mean sensitivity and power spectrum between the forests, neither did we find any strong indication of periodicities. Consideration of all features suggests that there was no significant difference in climate of middle Paleocene and late Early Eocene time in the High Arctic. However, the mean ring-widths of these forests were significantly smaller than that reported for mid-Cretaceous High Arctic fossil forest.

On the basis of the predictions of the global climatic warming induced by anthropogenic activities, as provided by climatologists, current state of knowledge regarding possible ecological consequences of the warming on the boreal biome was discussed. A 600 to 700 km northward advance of the biome along with the warming was predicted. Such a shift could take place for half a century or so, which would be an unprecedentedly fast rate of progression. This might cause a serious disorder in species composition of the biome, particularly in the boundary regions. As to the carbon sink or source issues, considerable uncertainties and knowledge gaps existed. Elevated temperature and CO2 levels would stimulate photosynthesis to result in an increase of CO2 uptake, while the temperature increase would promote decomposition of organic matter especially that stored in the soils to release CO2 to the atmosphere. Behaviors of northern peat bogs, whereca. 700 Gt of organic matter was thought to be accumulated, would seriously affect the balance. However, overall ecosystematic carbon balance was yet to be fully studied. It was realized that multifunctional approaches needed to be developed so as to integrate pieces of various information into a holistic picture. Need for international collaboration research efforts was also addressed.

Rocks of the Mino terrane, central Japan, are composed mainly of Permian basalts capped by shallow-marine limestone, Lower Permian to Early Jurassic deep-sea radiolarian chert, and post-Early Jurassic terrigenous rocks. Melanges incorporating blocks of these Permian to Jurassic rocks within a Middle to Upper Jurassic shale matrix are also major components of the terrane. The Mino terrane rocks are interpreted as Jurassic accretionary complexes on the basis of their lithology, age, and structure. The chert units contain two lines of evidence for submarine landslide episodes that occurred intermittently in mid-ocean regions during the Permian and Triassic. First, the upper Lower to middle Middle Permian chert unit incorporates resedimented carbonates, which were transported in submarine debris and turbidity flows from a shallow-marine buildup on the top of a seamount, down onto its lower flank, where the cherts were accumulating. Second, although most of the Mino terrane pelagic chert facies lack coarse land-derived clastic grains, the Middle to Upper Triassic chert contains thin beds and laminae of clastic debris. These grains are sand- to granule-sized and polymictic, consisting of chert, siliceous shale, basic or intermediate volcanic rocks, altered volcanic glass, polycrystalline quartz, and a glauconite-like mineral. These clastic sediments are interpreted as representing the distal facies of submarine landslide deposits, most likely derived from nearby oceanic islands. Comparable clastic sediment layers are also found in Middle Triassic deep-sea chert in a Jurassic accretionary complex in Far East Russia.