Hydrological management of a cutover peatland     

A. L. Heathwaite 《水文研究》1994,8(3):245-262

Mechanisms for preserving the hydrological balance of Thorne Moors National Nature Reserve (NNR) while allowing peat extraction to continue in the surrounding peatland are examined. Three strategies exist for modifying seepage losses from the NNR: (I) re-direction of pump drainage waters from the peat extraction areas; (II) provision of a hydrological buffer zone around the NNR; and (III) mechanical compaction of the boundaries of the buffer zone. Strategy II (increased width of the buffer zone) should be used together with strategy III (compaction) for the maximum reduction of seepage losses from the NNR. If strategy I (water level manipulation) is also adopted, it may be possible to reduce the width of the hydrological buffer zone around the NNR.  相似文献   

The evolution of a tropical rainforest/grassland mosaic in southeastern Brazil since 28,000 C yr BP based on carbon isotopes and pollen records     

Luiz Carlos Ruiz Pessenda  Paulo Eduardo De Oliveira  Milene Mofatto  Vanda Brito de Medeiros  Ricardo Jos Francischetti Garcia  Ramon Aravena  Jos Albertino Bendassoli  Accio Zuniga Leite  Antonio Roberto Saad  Mario Lincoln Etchebehere 《Quaternary Research》2009,71(3):437-452

The lack of paleoecological records from the montane Atlantic Rainforest of coastal Brazil, a hotspot of biological diversity, has been a major obstacle to our understanding of the vegetational changes since the last glacial cycle. We present carbon isotope and pollen records to assess the impact of the glaciation on the native vegetation of the Serra do Mar rainforest in São Paulo, Brazil. From ca. 28,000 to  22,000 ¹⁴C yr BP, a subtropical forest with conifer trees is indicative of cool and humid conditions. In agreement carbon isotopic data on soil organic matter suggest the presence of C₃ plants and perhaps C₄ plants from  28,000 to  19,000 ¹⁴C yr BP. The significant increase in the sedimentation rate and algal spores from  19,450 to  19,000 ¹⁴C yr BP indicates increasing humidity, associated to an erosion process between  19,000 and  15,600 ¹⁴C yr BP. From  15,600 ¹⁴C yr BP to present there is a substantial increase in arboreal elements and herbs, indicating more humid and warmer climate. From  19,000 to  1000 ¹⁴C yr BP, δ¹³C values indicated the predominance of C₃ plants. These results are in agreement with studies in speleothems of caves, which suggest humid conditions during the last glacial maximum.  相似文献   

Analysis of the peat slide at Pollatomish, County Mayo, Ireland     

Michael Long  Paul Jennings 《Landslides》2006,3(1):51-61

A major landslide event occurred at Pollatomish, County Mayo, Ireland in September 2003, during a period of intense rainfall. It comprised about 30 significant individual longitudinal planar type slides of peat and weathered rock. Relatively simple limit state stability analyses, using the method of slices and an infinite slope analysis, were used to model the slide and it was found that the features observed on site could easily be reproduced. These included confirmation that thin layers of peat could be stable on steep slopes but the margin of safety reduces rapidly under elevated pore pressure conditions. As was observed in the field, the analyses suggested the most vulnerable zone was the upper layer of weathered rock but that slides could occur in the peat if its thickness was appreciable. Careful site characterization is vital in such studies. Here efforts have been made to understand the effect of fibers on the peat strength and some sensitivity analyes have been performed to assess the critical engineering parameters of the peat.  相似文献   

A short-term establishment of forest fen habitat during Pliocene lignite formation in the Ptolemais Basin, NW Macedonia, Greece     

S. Kalaitzidis  A. Bouzinos  S. Papazisimou  K. Christanis   《International Journal of Coal Geology》2004,57(3-4):243-263

The intermontane basin of Ptolemais is part of a major tectonic trench, located in NW Greece and includes around 65% of Greek coal reserves. The Upper Xylite Layer (UXL) is a distinct lignite layer, being 3–6 m thick and outcropping in the upper part of the Pliocene Lignite-bearing Sequence at the Notio Field and Tomeas Eksi Mines of Ptolemais. Compared with the xylite-rich lithotypes, the matrix lithotypes within UXL contain more ash. Micropetrographic studies suggest that the Upper Xylite Layer is rich in huminite (>90%). Textinite dominates in the xylite-rich lithotypes, while attrinite dominates in the matrix lithotypes. The liptinite content is <10%, while inertinite rarely occurs. Palaeobotanical determination revealed that the xylite-rich coal originated from Coniferous vegetation, specifically from Glyptostrobus europaeus. The occurrence of G. europaeus as a coal-forming element is significant because, though this kind of vegetation was common in many Greek coals of Miocene age, this is the first time it has been recorded from the Pliocene. This study suggests that the Upper Xylite Layer is autochthonous. According to coal-facies diagrammes, peat accumulated under pure telmatic conditions in a relatively wet forest fen. Both herbaceous and arboreal vegetation contributed to peat formation.  相似文献   

Accumulation of heavy metals in Oostriku peat bog,Estonia: -site description,conceptual modelling and geochemical modelling of the source of the metals     

Syrovetnik  K.  Puura  E.  Neretnieks  I. 《Environmental Geology》2004,45(5):731-740

Oxidation of sulphides leads to the dissolution of metals, which are transported with water and accumulate at geochemical barriers. Such barriers can form in peat bogs. This paper gives an introduction into the long-term processes in Oostriku peat bog where high accumulations of heavy metals are observed. Peat and water samples are analysed for Fe, As and heavy metals (Cd, Cu, Mn, Ni, Pb and Zn) using different methods. A concept is based on the observations. Metals are leached by sulphide oxidation in the carbonate rocks upstream of the peat. The water feeds the peat from below. The metals are sorbed and precipitated in the peat. The sulphide oxidation is simulated to examine the origin and metal speciation in the water. The simulated solution is compared with the groundwater entering the peat. The results showed a fair agreement for the major constituents. There were considerable differences for species with low concentrations.  相似文献   

Complexes dunaires et tourbeux holocènes du littoral du Nord de la France     

Murielle Meurisse  Brigitte Van Vliet-Lanoë  Brigitte Talon  Philippe Recourt 《Comptes Rendus Geoscience》2005,337(7):675-684

This survey of the coastal dunes of northern France is based on stratigraphy, ¹⁴C dating, sedimentology and morphology applied for palaeoclimatic and palaeodynamic purpose. The dunes rest on a Flandrian prism sealed by Atlantic peats grown backward from a subboreal dune ridge. Two historical building phases are recorded: the late Roman dunes and the 13th century dunes. These events are separated by pedogenesis. Contribution of reworked fluvial sands also records the recent climatic degradation, with an increased storminess (Little Ice Age) associated with more efficient erosion (soil erosion and floods). The dunes of Picardy also record the Global Warming: their morphologies attest a shift from parabolic into longitudinal, by coupling storminess and sea-level rise. To cite this article: M. Meurisse et al., C. R. Geoscience 337 (2005).  相似文献   

我们需要保护自然资源吗？     

Bambang Hero Saharjo  Basuki Wasis 《地球科学进展》2006,21(2):178-182

正常而言，在印度尼西亚的苏门答腊和加里曼丹岛，即使在非厄尔尼诺年，每年6月或7月的旱季会出现烟雾问题。研究发现，近年来烟雾问题并不仅仅出现在旱季，雨季也有发生。进一步的观测和野外调研表明，这些烟雾来源于用火烧的方式进行油棕榈及其它林木种植前的土地整理，然而这种方式早已被完全禁止。结果，这两个省的绝大多数的水灾灾区位于这些植被被焚毁的地区。  相似文献   

Geochemical and stratigraphic evidence of environmental change at Lynch's Crater, Queensland, Australia     

Joanne Muller  Raphael A.J. Wüst  Dominik Weiss  Yi Hu 《Global and Planetary Change》2006,53(4):269

This is one of the first applications of geochemical proxies to define changes in vegetation, hydrology and atmospheric dust influence on a peat deposit in the southern hemisphere. A 6.6 m deep peat record from Lynch's Crater in NE-Queensland, Australia, provides a sensitive  5000 to 30,000 cal years BP archive of environmental change. The deposit consists of 1.5 m of ombrotrophic peat underlain by a minerotrophic peat. Within the minerotrophic section, sponge spicules and diatom fragments offer evidence of prolonged flooding of the peat environment resulting in several layers containing (up to 50%) high inorganic material. The Ca and Mg data display episodes of enhanced dust influx and nutrient recycling and support previous palynological studies that show a Pleistocene to Holocene switch from sclerophyll woodlands to rainforest vegetation.  相似文献   

哈泥贫营养泥炭沼泽毛壁泥炭藓种群密度制约初探   总被引：1，自引：0，他引：1  

孙强  卜兆君  王升忠  孟祥军 《湿地科学》2005,3(2):116-120

在哈泥贫营养沼泽,研究了毛壁泥炭藓(Sphagnumimbricatum)种群的密度制约规律,结果表明,种群出生率、死亡率和增长率均表现为负密度制约;随初始密度的增加,种群出生率和增长率下降,死亡率增加;分株高度和生物量及其分配无严格的密度制约规律。毛壁泥炭藓种群密度制约规律的特殊性与复杂性与其特殊的生物学特性有关。保水合作与光资源竞争的权衡是决定种群数量特征对密度变化响应的主要原因。  相似文献   

Sediment yield and delivery in the blanket peat moorlands of the southern Pennines     

J. C. Labadz  T. P. Burt  A. W. R. Potter 《地球表面变化过程与地形》1991,16(3):255-271

In contrast to much previous research on blanket peat moorland, which has concentrated upon studies of the form and causes of gully erosion, this paper attempts to investigate sediment transport and to estimate both short-term and long-term sediment yields in such terrain. The research was conducted on Wessenden Head Moor to the west of Huddersfield, Yorkshire, where automatic stream sampling continued over a period of two years. Use of corrected rating curves (Ferguson, 1988) provided a mean estimate of sediment yield over this period of 55 t km^?2 yr^?1. In addition an estimate of longer-term sediment yield was derived from four reservoir sediment surveys in the Wessenden Valley. Total yield was 203.69 t km^?2 yr^?1, including an organic fraction of 38.82 t km ^?2 yr^?1. Stream sampling at three sites on Shiny Brook, including headwaters and the outflow to the reservoir, suggested that there is great temporal and spatial variability in mineral and organic inputs to the reservoirs. Although not excessive in gravimetric terms, the low density of peat means that there is a serious erosion problem. Estimates of erosion rates for the peat gully network at Shiny Brook appear to confirm earlier evidence concerning the relatively recent occurrence of this erosion, within the last two centuries.  相似文献