The Kwakshua Watersheds Observatory,central coast of British Columbia,Canada

The Kwakshua Watersheds Observatory (KWO) is an integrative watersheds observatory on the coastal margin of a rain-dominated bog-forest landscape in British Columbia (BC), Canada. Established in 2013, the goal of the KWO is to understand and model the flux of terrestrial materials from land to sea – the origins, pathways, processes and ecosystem consequences – in the context of long-term environmental change. The KWO consists of seven gauged watersheds and a network of observation sites spanning from land to sea and along drainage gradients within catchments. Time-series datasets include year-round measurements of weather, soil hydrology, streamflow, aquatic biogeochemistry, microbial ecology and nearshore oceanographic conditions. Sensor measurements are recorded every 5 min and water samples are collected approximately monthly. Additional observations are made during high-flow conditions. We used remote sensing to map watershed terrain, drainage networks, soils and terrestrial ecosystems. The watersheds range in size from 3.2 to 12.8 km², with varying catchment characteristics that influence hydrological and biogeochemical responses. Despite local variation, the overall study area is a global hotspot for yields of dissolved organic carbon, dissolved organic nitrogen and dissolved iron at the coastal margin. This observatory helps fill an important gap in the global network of observatories, in terms of spatial location (central coast of BC), climate (temperate oceanic), hydrology (very high runoff, pluvial regime), geology (igneous intrusive, glacially scoured), vegetation (bog rainforest) and soils (large stores of organic carbon).     

Erosion by catastrophic floods on Mars and Earth

The large Martian channels, especially Kasei, Ares, Tiu, Simud, and Mangala Valles, show morphologic features strikingly similar to those of the Channeled Scabland of eastern Washington, produced by the catastrophic breakout floods of Pleistocene Lake Missoula. Features in the overall pattern include the great size, regional anastomosis, and low sinuosity of the channels. Erosional features are streamlined hills, longitudinal grooves, inner channel cataracts, scour upstream of flow obstacles, and perhaps marginal cataracts and butte and basin topography. Depositional features are bar complexes in expanding reaches and perhaps pendant bars and alcove bars. Scabland erosion takes place in exceedingly deep, swift floodwater acting on closely jointed bedrock as a hydrodynamic consequence of secondary flow phenomena, including various forms of macroturbulent votices and flow separations. If the analogy to the Channeled Scabland is correct, floods involving water discharges of millions of cubic meters per second and peak flow velocities of tens of meters per second, but perhaps lasting no more than a few days, have occurred on Mars.     

Goat Paddock,Western Australia: an impact crater near the simple – complex transition

Goat Paddock in northern Western Australia is a ～5 km-diameter impact crater of Eocene age excavated in gently dipping Proterozoic sandstones. Roughly radial gorges formed by post-impact erosion provide cross-sectional views of the wall and rim zone. The predominant structural theme is one of synclinal rim folding with broad zones in which bedrock strata were deformed by impact to steep, vertical and overturned attitudes. Impact breccia is found craterward of deformed bedrock, on top of it, and downdropped into fault troughs roughly concentric to the crater. The bedrock?–?breccia contact is sharp in some places and gradational in others. In at least one section, the entire mass of upturned bedrock and breccia was displaced radially over essentially undisturbed bedrock, as indicated by slickensides on the horizontal contact. Talus deposits are similar to breccia, but show rough size sorting and clast orientation that dips steeply craterward, indicating that the talus formed as slides down the oversteepened crater wall immediately after crater formation. Shatter cones in some clasts indicate that allogenic material is incorporated in these deposits. Suevite, characterised by ropy flow textures, and by microclasts of quartz with planar deformation features, planar fractures, and of vesiculated silica glass, was found overlying deformed bedrock at a point where the surface of the bedrock forms a nearly horizontal bench midway up the crater wall. The crater was at least partially filled by later sediments, represented by bedded conglomerate close to the crater wall grading inward to sand, silt and mudstone recovered by drillholes on the crater floor. Some of the talus and conglomerate occupy re-entrants in the crater walls, suggesting an original scalloped outline to the crater. Two drillholes, one central and one halfway to the wall, both reached brecciated sandstone after penetrating 210 m of lake sediments. Goat Paddock has a flat floor with no indication of a central uplift and a depth/diameter ratio of ～0.073. This crater form, coupled with the modification of the crater walls by slumping and the scalloped outline of the crater rim suggests that Goat Paddock bridges the two traditional classes of impact crater: simple and complex.     

The implications of permafrost thaw and land cover change on snow water equivalent accumulation,melt and runoff in discontinuous permafrost peatlands

In the discontinuous permafrost zone of the Northwest Territories (NWT), Canada, snow covers the ground surface for half the year. Snowmelt constitutes a primary source of moisture supply for the short growing season and strongly influences stream hydrographs. Permafrost thaw has changed the landscape by increasing the proportional coverage of permafrost-free wetlands at the expense of permafrost-cored peat plateau forests. The biophysical characteristics of each feature affect snow water equivalent (SWE) accumulation and melt rates. In headwater streams in the southern Dehcho region of the NWT, snowmelt runoff has significantly increased over the past 50 years, despite no significant change in annual SWE. At the Fort Simpson A climate station, we found that SWE measurements made by Environment and Climate Change Canada using a Nipher precipitation gauge were more accurate than the Adjusted and Homogenized Canadian Climate Dataset which was derived from snow depth measurements. Here, we: (a) provide 13 years of snow survey data to demonstrate differences in end-of-season SWE between wetlands and plateau forests; (b) provide ablation stake and radiation measurements to document differences in snow melt patterns among wetlands, plateau forests, and upland forests; and (c) evaluate the potential impact of permafrost-thaw induced wetland expansion on SWE accumulation, melt, and runoff. We found that plateaus retain significantly (p < 0.01) more SWE than wetlands. However, the differences are too small (123 mm and 111 mm, respectively) to cause any substantial change in basin SWE. During the snowmelt period in 2015, wetlands were the first feature to become snow-free in mid-April, followed by plateau forests (7 days after wetlands) and upland forests (18 days after wetlands). A transition to a higher percentage cover of wetlands may lead to more rapid snowmelt and provide a more hydrologically-connected landscape, a plausible mechanism driving the observed increase in spring freshet runoff.     

Upgrades to the Boundary-Layer Scheme in the Met Office Numerical Weather Prediction Model

Recent upgrades to the boundary-layer scheme in the UK Met Office operational global Numerical Weather Prediction model are documented. These comprise a reduction in turbulent mixing in stable conditions over the sea, and the inclusion of non-local momentum mixing in convective conditions. The dependence of low-level winds on changing stability is shown to have been significantly improved. Crucially, it is also found that these improvements in local performance have been achieved without degrading the model skill in terms of synoptic evolution—something that has proved difficult to achieve in the past in many operational models. In fact some aspects of the large-scale flow (e.g. zonal mean winds) have been slightly improved.     

Petrogenesis of massif-type anorthosite complex, Gruber, Central Dronning Maud Land, East Antarctica： Implications for magma source and evolution

The origin of anorthosite and associated igneous gabbronorite and ferrodiorite was investigated through detailed study of a typical massif-type anorthosite complex from Gruber, Central Dronning Maud Land, East Antarctica. Field observations showed that the Gruber Complex is made up of gabbronorite-anorthosite pluton which was intruded by ferrodiorite dykes. Systematic samples collected from the Gruber Complex revealed significant geochemical variations within the region. Four rock types have been identified, based on modal proportions of mineral phases and their geochemistry data. Clinopyroxene-gabbronorite and plagioclase-gabbronorite are the two types of gabbronorite with the dominance of clinopyroxene and plagioclase, respectively. Anorthosite is represented by rocks having predominance of plagioclase with minor clinopyroxene. Ferrodiorite is characterized by modal abundance of orthopyroxene and Fe-Ti oxide. Major and trace element systematics showed that all the four rock types are co-magmatic and are related through fractional crystallization. Based on this study, it is reported that clinopyroxene was the first phase to crystallize followed by plagioclase and then Fe-Ti oxides. Furthermore, trace element composition of the parental melt was calculated using LA-ICPMS analysis of the most primitive, pure clinopyroxene found in the clinopyroxene gabbronorite. Our analyses suggested that the parental melt was similar to that of continental arc basalt and showed signatures of subduction-related metasomatism. Based on mineral chemical and geochemical data, it is interpreted that the parent melt went through changing sequence of crystallization which led to the formation of massive anorthosite.     

电测量在中国地震预报中的应用

唐山等大地震地电阻率中期下降系压缩应变积累所致 ,为基线缩短、井水位下降所支持。地电阻率、自然电位对起潮力的异常响应及自然电位快急始、慢衰减特殊图象与废油井喷油同步等短临前兆 ,与中期前兆相反显示出向震中迁移的规律 ,表明能量积累从震中向外围传播 ,而能量释放从外围向震中传播。海城地震时喷砂冒水可引起自然电位垂直分量跃变及地光。IIMT法和过剩海洋电流H极化结果表明 ,唐山地震与地壳高阻层及其中存在深大断裂有     

Identification and geochemical significance of some aromatic components of coal

The aromatic fraction of a Homestead, Kentucky, coal extract was analyzed by combined gas chromatography-mass spectrometry using glass capillary columns. The aromatic fraction was further analyzed by gas chromatography using sulfur specific flame photometric detection. Seventy-eight compounds were identified, some of which have been traced to their possible biological origins. Sulfur-containing aromatic compounds are thought to originate from reaction of elemental sulfur or pyrite with hydrocarbons.