Mineral matter and trace elements in coals of the Gunnedah Basin, New South Wales, Australia

The concentrations of major and trace inorganic elements in a succession of Permian coals from the Gunnedah Basin, New South Wales, have been determined by X-ray fluorescence techniques applied to both whole-coal and high-temperature ash samples. The results have been evaluated in the light of quantitative data on the minerals in the same coals, determined from X-ray diffraction study of whole-coal samples using a Rietveld-based interpretation program ( ™), to determine relationships of the trace elements in the coals to the mineral species present. Comparison of the chemical composition of the coal ash interpreted from the quantitative mineralogical study to the actual ash composition determined by XRF analysis shows a high degree of consistency, confirming the validity of the XRD interpretations for the Gunnedah Basin materials. Quartz, illite and other minerals of detrital origin dominate the coals in the upper part of the sequence, whereas authigenic kaolinite is abundant in coals from the lower part of the Permian succession. These minerals are all reduced in abundance, however, and pyrite is a dominant constituent, in coals formed under marine influence at several stratigraphic levels. Calcite and dolomite occur as cleat and fracture infillings, mostly in seams near the top and bottom of the sequence. The potassium-bearing minerals in the detrital fraction are associated with significant concentrations of rubidium, and the authigenic kaolinite with relatively high proportions of titanium. Zirconium is also abundant, with associated P and Hf, in the Gunnedah Basin coal seams. Relationships exhibited by Ti, Zr, Nd and Y are consistent with derivation of the original sediment admixed with the seams from an acid volcanic source. Pyrite in the coals is associated with high concentrations of arsenic and minor proportions of thallium; no other element commonly associated with sulphides in coals, however, appears to occur in significant proportions with the pyrite in the sample suite. Small concentrations of Cl present in the coal are inversely related to the pyrite content, and appear to represent ion-exchange components associated with the organic matter. Strontium and barium are strongly associated with the cleat-filling carbonate minerals. Ge and Ga appear to be related to each other and to the coal's organic matter. Cr and V are also related to each other, as are Ce, La, Nd and Pr, but none of these show any relationship to the organic matter or a particular mineral component.     

Granulite xenoliths from western Saudi Arabia: the lower crust of the late Precambrian Arbian-Nubian Shield

Mafic and intermediate granulite xenoliths, collected from Cenozoic alkali basalts, provide samples of the lower crust in western Saudi Arabia. The xenoliths are metaigneous two-pyroxene and garnet granulites. Mineral and whole rock compositions are inconsistent with origin from Red Sea rift-related basalts, and are compatible with origin from island arc calc-alkaline and low-potassium tholeiitic basalts. Most of the samples are either cumulates from mafic magmas or are restites remaining after partial melting of intermediate rocks and extraction of a felsic liquid. Initial⁸⁷Sr/⁸⁶Sr ratios are less than 0.7032, except for two samples at 0.7049. The Sm-Nd data yield T_DM model ages of 0.64 to 1.02 Ga, similar to typical Arabian-Nubian Shield upper continental crust. The isotopic data indicate that the granulites formed from mantle-derived magmas with little or no contamination by older continent crust. Calculated temperatures and pressures of last reequilibration of the xenoliths show that they are derived from the lower crust. Calculated depths of origin and calculated seismic velocities for the xenoliths are in excellent agreement with the crustal structure model of Gettings et al. (1986) based on geophysical data from western Saudi Arabia. Estimation of mean lower crustal composition, using the granulite xenoliths and the Gettings et al. (1986) crustal model, suggests a remarkably homogeneous mafic lower crust, and an andesite or basaltic andesite bulk composition for Pan-African juvenile continental crust.     

华南、巽他和掸邦地块之间边界断裂的上新世—第四纪大规模构造反转

印度- 亚洲碰撞后，大陆板块沿着大型的左行走滑断裂挤出。规模最大的哀牢山- 红河剪切带(ASRR)将印支地块(巽他地块)与华南地块分隔开来。长约1000 km的红河活动断裂(RRF)沿哀牢山的北侧延伸，目前呈现出右行走滑兼正断的活动性质。本文在讨论了红河断裂系及其周缘的第三纪和现今变形特征(滑移性质反转、渐新世/第四纪位错、全新世滑动速率、GPS测量、地震机制等)基础之上，重点论述了其在上新世—第四纪从云南东南部到越南西北部、北部湾西部、再到更南的沙巴地区的断裂分布和运动学特征。新的数据证实，跨过三联点和越南西北部的奠边府断层之后，华南地块与巽他地块之间的现今大部分右行走滑主要沿着Da River断裂向Day Nui Con Voi(或称大象山)东南方向延伸。Da River断裂与RRF大致平行，是2020年M w 5. 0莫州地震的发震断层。进一步研究表明，Da River断裂很可能沿着渐新世—中新世莺歌海/宋红盆地西缘和越南东南海岸(归仁剪切带)向南延伸得更远，至少延伸到“Ile des Cendres”火山群，并可能继续延伸到沙巴- 文莱逆冲带的西端，靠近婆罗洲北部的近海活动边缘。最后，我们讨论了在菲律宾群岛、台湾岛和巽他群岛之间南海大部分地区大规模构造反转的运动学效应。     

Statistical analysis of CDM capacity-building needs

Abstract

This article presents statistical analysis of a selection of data collected under a World Bank survey on Kyoto Protocol capacity-building needs in 16 potential clean development mechanism (CDM) host countries. It focuses on three interrelated issues: perceived barriers to the implementation of the CDM, expert judgment regarding the human, institutional and systemic capacity that must be built to overcome these barriers, and views on the most urgent steps that need to be taken to facilitate CDM implementation. The analysis reveals that in many countries there is a wide diversity of opinion across the group of respondents, which could be caused by a number of factors, including the inherent complexity of the Kyoto flexible mechanisms, limited understanding of their basic functioning and potential in the local context, and the differing needs and interests of stakeholder groups. Despite this, many statistically significant preferences can be identified at the national level. Among nations, two broad groups of countries emerge, which can be traced back to their overall level of capacity development. The statistical analysis presented in this article lends credibility to qualitative conclusions drawn from previous interpretations of the survey data and has implications for the design of capacity-building efforts. However, in evaluating capacity-building needs and the readiness of countries to engage in CDM deals, potential investors and providers of capacity-building services will need to consider not only the results of this type of opinionbased needs assessment, but also the practical experience gained through CDM transactions.     

Large-Eddy Simulation of Inhomogeneous Canopy Flows Using High Resolution Terrestrial Laser Scanning Data

The effect of sub-tree forest heterogeneity in the flow past a clearing is investigated by means of large-eddy simulation (LES). For this purpose, a detailed representation of the canopy has been acquired by terrestrial laser scanning for a patch of approximately 190 m length in the field site “Tharandter Wald”, near the city of Dresden, Germany. The scanning data are used to produce a high resolution plant area distribution (PAD) that is averaged over approximately one tree height (30 m) along the transverse direction, in order to simplify the LES study. Despite the smoothing involved with this procedure, the resulting two-dimensional PAD maintains a rich vertical and horizontal structure. For the LES study, the PAD is embedded in a larger domain covered with an idealized, horizontally homogeneous canopy. Simulations are performed for neutral conditions and compared to a LES with homogeneous PAD and recent field measurements. The results reveal a considerable influence of small-scale plant distribution on the mean velocity field as well as on turbulence data. Particularly near the edges of the clearing, where canopy structure is highly variable, usage of a realistic PAD appears to be crucial for capturing the local flow structure. Inside the forest, local variations in plant density induce a complex pattern of upward and downward motions, which remain visible in the mean flow and make it difficult to identify the “adjustment zone” behind the windward edge of the clearing.     

Holocene floristic diversity and richness in northeast Norway revealed by sedimentary ancient DNA (sedaDNA) and pollen

We present a Holocene record of floristic diversity and environmental change for the central Varanger Peninsula, Finnmark, based on ancient DNA extracted from the sediments of a small lake (sedaDNA). The record covers the period c. 10 700 to 3300 cal. a BP and is complemented by pollen data. Measures of species richness, sample evenness and beta diversity were calculated based on sedaDNA sampling intervals and 1000‐year time windows. We identified 101 vascular plant and 17 bryophyte taxa, a high proportion (86%) of which are still growing within the region today. The high species richness (>60 taxa) observed in the Early Holocene, including representatives from all important plant functional groups, shows that modern shrub‐tundra communities, and much of their species complement, were in place as early as c. 10 700 cal. a BP. We infer that postglacial colonization of the area occurred prior to the full Holocene, during the Pleistocene‐Holocene transition, Younger Dryas stadial or earlier. Abundant DNA of the extra‐limital aquatic plant Callitriche hermaphroditica suggests it expanded its range northward between c. 10 200 and 9600 cal. a BP, when summers were warmer than present. High values of Pinus DNA occur throughout the record, but we cannot say with certainty if they represent prior local presence; however, pollen influx values >500 grains cm^?2 a^?1 between c. 8000 and 7300 cal. a BP strongly suggest the presence of pine woodland during this period. As the site lies beyond the modern tree limit of pine, it is likely that this expansion also reflects a response to warmer Early Holocene summers.     

The Multiscale TROPIcal CatchmentS critical zone observatory M-TROPICS dataset II: Land use,hydrology and sediment production monitoring in Houay Pano,northern Lao PDR

Mountain regions of the humid tropics are characterized by steep slopes and heavy rains. These regions are thus prone to both high surface runoff and soil erosion. In Southeast Asia, uplands are also subject to rapid land-use change, predominantly as a result of increased population pressure and market forces. Since 1998, the Houay Pano site, located in northern Lao PDR (19.85°N 102.17°E) within the Mekong basin, aims at assessing the long-term impact of the conversion of traditional slash-and-burn cultivation systems to commercial perennial monocultures such as teak tree plantations, on the catchment hydrological response and sediment yield. The instrumented site monitors hydro-meteorological and soil loss parameters at both microplot (1 m²) and small catchment (0.6 km²) scales. The monitored catchment is part of the network of critical zone observatories named Multiscale TROPIcal CatchmentS (M-TROPICS). The data shared by M-TROPICS in Houay Pano are (1) rainfall, (2) air temperature, air relative humidity, wind speed, and global radiation, (3) catchment land use, (4) stream water level, suspended particulate matter, bed particulate matter and stones, (5) soil surface features, and (6) soil surface runoff and soil detachment. The dataset has already been used to interpret suspended particulate matter and bed particulate matter sources and dynamics, to assess the impact of land-use change on catchment hydrology, soil erosion, and sediment yields, to understand bacteria fate and weed seed transport across the catchment, and to build catchment-scale models focused on hydrology and water quality issues. The dataset may be further used to, for example, assess the role of headwater catchments in large tropical river basin hydrology, support the interpretation of new variables measured in the catchment (e.g., contaminants other than faecal bacteria), and assess the relative impacts of both climate and land-use change on the catchment.     

Prediction of river temperature surges is dependent on precipitation method

Urban river systems are particularly sensitive to precipitation‐driven water temperature surges and fluctuations. These result from rapid heat transfer from low‐specific heat capacity surfaces to precipitation, which can cause thermally polluted surface run‐off to enter urban streams. This can lead to additional ecological stress on these already precarious ecosystems. Although precipitation is a first‐order driver of hydrological response, water temperature studies rarely characterize rain event dynamics and typically rely on single gauge data that yield only partial estimates of catchment precipitation. This paper examines three precipitation measuring methods (a statutory automatic weather station, citizen science gauges, and radar estimates) and investigates relationships between estimated rainfall inputs and subhourly surges and diurnal fluctuations in urban river water temperature. Water temperatures were monitored at 12 sites in summer 2016 in the River Rea, in Birmingham, UK. Generalized additive models were used to model the relationship between subhourly water temperature surges and precipitation intensity and subsequently the relationship between daily precipitation totals and standardized mean water temperature. The different precipitation measurement sources give highly variable precipitation estimates that relate differently to water temperature fluctuations. The radar catchment‐averaged method produced the best model fit (generalized cross‐validation score [GCV] = 0.30) and was the only model to show a significant relationship between water temperature surges and precipitation intensity (P < 0.001, R² = 0.69). With respect to daily metrics, catchment‐averaged precipitation estimates from citizen science data yielded the best model fit (GCV score = 0.20). All precipitation measurement and calculation methods successfully modelled the relationship between standardized mean water temperature and daily precipitation (P < 0.001). This research highlights the potential for the use of alternative precipitation datasets to enhance understanding of event‐based variability in water quality studies. We conclude by recommending the use of spatially distributed precipitation data operating at high spatial (<1 km²) and temporal (<15 min) resolutions to improve the analysis of event‐based water temperature and water quality studies.     

Glacial history of the Greenland Ice Sheet and a local ice cap in Qaanaaq,northwest Greenland

In this study, we present new information on the glacial history of the Greenland Ice Sheet (GrIS) and a local ice cap in Qaanaaq, northwest Greenland. We use geomorphological mapping, ¹⁰Be exposure dating of boulders, analysis of lake cores, and ¹⁴C dating of reworked marine molluscs and subfossil plants to constrain the glacial history. Our ¹⁴C ages of reworked marine molluscs reveal that the ice extent in the area was at or behind its present‐day position from 42.2 ± 0.4 to 30.6 ± 0.3k cal a BP after which the GrIS expanded to its maximum position during the Last Glacial Maximum. We find evidence of early ice retreat in the deep fjord (Inglefield Bredning) at 11.9 ± 0.6 ka whereas the Taserssuit Valley was deglaciated ~4 ka later at 7.8 ± 0.1k cal a BP. A proglacial lake record suggests that the local ice cap survived the Holocene Thermal Maximum but moss kill‐dates reveal that it was smaller than present for a period of time before 3.3 ± 0.1k until 0.9 ± 0.1k cal a BP, following which the ice in the area expanded towards its Little Ice Age extent. Copyright © 2019 John Wiley & Sons, Ltd.