Vegetation, hydrology, and development of a coastal mire in Hokkaido, Japan, affected by flooding and tephra deposition

2001 ◽  
Vol 79 (3) ◽  
pp. 341-361 ◽  
Author(s):  
Stefan Hotes ◽  
Peter Poschlod ◽  
Hiroshige Sakai ◽  
Takashi Inoue
Keyword(s):  
Sea Water ◽  
Ionic Composition ◽  
Plant Macrofossils ◽  
Vegetation Pattern ◽  
Water Levels ◽  
Myrica Gale ◽  
Mineral Deposition ◽  
Volcanic Ejecta ◽  
Induced Changes ◽  
Flooding Events

Mires in coastal lowlands in Hokkaido, northern Japan, have repeatedly been affected by flooding events and tephra (aerially transported volcanic ejecta) deposition during their development. Vegetation, hydrology, and stratigraphy of Kiritappu Mire in eastern Hokkaido were investigated along two transects and are discussed in relation to disturbance by mineral deposition. The vegetation pattern showed little relation to past geologic events. Five plant communities, two of which (A and C) could be further divided into subgroups, were distinguished (A, Alnus japonica - Spiraea salicifolia community; B, Sasa chartacea community; C, Myrica gale var. tomentosa - Sphagnum fuscum community; D, Carex lyngbyei community; E, Carex subspathacea - Aster tripolium community). Water levels, pH, electric conductivity, and ionic composition of groundwater and surface water were measured in communities A-C. Mean water levels were similar in communities A and C; in community B, it was lower. The pH was higher in community A than in communities B and C. Ion concentrations were influenced by sea water at some sites. Plant macrofossils and ash contents of 31 cores were analysed. Sedge roots were the dominant peat component, often mixed with remains of Phragmites australis, Sphagnum spp., and Polytrichum juniperinum var. strictum. Ash contents were high, and up to nine different mineral layers consisting of tephra, sand, silt, and clay were detected. In some cases, mineral deposition induced changes in the macrofossil composition of the peat. However, in a greater number of cases, no changes in the macrofossil composition were found at the mineral layers, and most shifts were not related to mineral deposition.Key words: mire, vegetation, hydrology, disturbance, flooding, tephra.

scholarly journals Advanced Industrial Utilization of Volcanic Ejecta, Shirasu.

1999 ◽  
Vol 46 (4) ◽  
pp. 230-237
Author(s):  
Kazuhiko JINNAI ◽  
Kunio KIMURA
Keyword(s):  
Industrial Utilization ◽  
Volcanic Ejecta

scholarly journals VII.—On a new Metamorphic Area in Shropshire

1884 ◽  
Vol 1 (8) ◽  
pp. 362-366 ◽  
Author(s):  
C. Callaway
Keyword(s):  
Volcanic Rocks ◽  
The South ◽  
North East ◽  
South West ◽  
Volcanic Ejecta ◽  
Volcanic Series

The occurrence of two Archæan groups in Shropshire is now well known to geologists. The chain of hills which strikes to the south-west from Lilleshall, north-east of Wellington, to the region south of Church-Stretton, is mainly composed of bedded volcanic rocks; but gneissic and granitoid types have been recognized at the Ercal and at Primrose Hill, the elevations forming the opposite extremities of the Wrekin, and a small exposure was detected near Hope Bowdler, east of Church-Stretton. A second axis of the old rocks, ranging parallel to the Wrekin chain, consists of volcanic ejecta and highly indurated grits, which are probably to be referred to the younger of the two Archæan groups hitherto recognized in the county. The relations between the volcanic and the gneissic systems is clearly defined by the Charlton Hill (see map) conglomerate (a band in the volcanic series), which contains numerous well-rounded pebbles of rock precisely similar to the granitoid gneiss of Primrose Hill. This fact implies a considerable break between the two groups.

scholarly journals Report on the eruptions of the soufrière in St. Vincent in 1902, and on a visit to Montagne Pelée in Martinique. Part II.—The changes in the districts and the subsequent history of the volcanoes

1908 ◽  
Vol 80 (538) ◽  
pp. 281-284
Keyword(s):  
West Indies ◽  
Field Observations ◽  
The West ◽  
Volcanic Ejecta ◽  
History Of

This Report, and the accompanying Report by Dr. Flett on The Petrology of the Ejected Materials, form the sequel to the Report by Drs. Tempest Anderson and J. S. Flett on “The Eruptions of the Soufrière in St. Vincent in 1902, and on a Visit to Montagne Pelée in Martinique, Part I.” At the time when that Report was published it was contemplated that an account should be given later on of the subsequent changes in the deposits of volcanic ejecta, and also on the petrology of the specimens collected in 1902. In the spring of 1907 I visited the West Indies, but Dr. Flett was unfortunately detained in England by his official duties. I am therefore responsible for the field observations on the topography and geology, and on the return of vegetation, while Dr. Flett’s Report deals with the petrology of the ejected materials.

Tektites - volcanic ejecta from the moon?

The Moon ◽  
1975 ◽  
Vol 12 (3) ◽  
pp. 331-360 ◽  
Author(s):  
Winifred S. Cameron ◽  
Barbara E. Lowrey
Keyword(s):  
The Moon ◽  
Volcanic Ejecta

scholarly journals Secondary disturbance following a deposit of volcanic tephra: A 30 year record from old-growth forest understory

2021 ◽  
Author(s):  
Donald B Zobel ◽  
Joseph A. Antos ◽  
Dylan Grey Fischer
Keyword(s):  
Vegetation Change ◽  
Forest Disturbance ◽  
Canopy Cover ◽  
Soil Disturbance ◽  
Tree Canopy ◽  
Forest Understory ◽  
Old Growth ◽  
Old Growth Forest ◽  
Volcanic Ejecta ◽  
Woody Litter

Forest disturbance is usually described by effects on trees, and small disturbances to forest understory are seldom studied. Nevertheless, effective analyses of succession need to consider both stand-replacing and subsequent “secondary” disturbances in both canopy and understory. We estimated characteristics of 13 types of secondary disturbance in old-growth forest understory, and of canopy cover, after the 1980 tephra (aerially transported volcanic ejecta) deposition from Mount St. Helens, Washington. We sampled 100 1-m2 plots at each of four sites for vegetation change and types of disturbance at ten times from 1980-2010; we sampled tree canopy above each plot in 1980 and 2016. The number of canopy gaps increased 23 % and mean gap dimension 68 % during 36 years, mostly from loss of Abies amabilis. Secondary disturbance in understory affected 1.4 % of stand area per year. The areas affected by soil disturbance and effects of woody litter were similar. Erosion, greater in deep than in shallow tephra, peaked in 1981, whereas most litter-caused disturbances increased after 2000. Less frequent litter-based disturbances covered greater area. Our results differ from conclusions about non-volcanic understory disturbances. Secondary disturbances are variable, need more study, and are likely to affect many other systems.

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