Abstract
The 3D modelling of basic bodies of the Koperberg Suite (1060 to 1030 Ma) and their wall rocks from Narrap Mine illustrates the distribution, geometries and, by implication, processes that ...determined the ascent and emplacement of the mantle-derived mafic magmas into the partially-molten, mid-crustal granite-gneiss sequence of the Okiep Copper District in Namaqualand. The lens-like, discontinuous geometry of basic bodies suggests the transfer of the mafic magmas as self-contained, buoyancy-driven hydrofractures. The presence of both shallowly-dipping, foliation-parallel sills and subvertical lenses in zones of steep foliation development, so-called steep structures, indicates an emplacement of the mafic magmas under low deviatoric stresses and irrespective of the regional stress field. Instead, the emplacement of the mafic magmas parallel to pre-existing anisotropies (tectonic fabrics or lithological contacts) highlights those differences in tensile strength and fracture toughness parallel to or across anisotropies determined the propagation of the magmas. This also accounts for the common occurrence of basic bodies in steep structures in which the vertical gneissosity promoted the buoyancy-driven ascent of the mafic magmas.
On a regional scale, the mechanical stratification of the subhorizontal, sheet-like granite gneisses and interlayered metasediments exerted important controls on the ascent of Koperberg Suite magmas. The preferential emplacement of basic bodies in schist and gneiss units suggests that the lower rigidity of the ductile wall rocks facilitated magma emplacement through a combination of viscous wall-rock deformation and fracture blunting that led to the arrest of the magma-filled hydrofractures. Multiple intrusive relationships of successively emplaced magma batches suggest that later magmas reutilised earlier established magma pathways, particularly in steep structures. High-rigidity lithologies, such as the massive Springbok Quartzite, in contrast, only allowed for smaller fracture apertures and limited dilation, resulting in the pinching of basic bodies and rather stringer-like geometries. It is conceivable that the higher fracture toughness of the quartzite may also have prevented propagation of the mafic magmas through the Springbok Quartzite and, instead, led to the ponding of basic bodies below the metasediments.
The geometry and structural and lithological controls of basic bodies at Narrap Mine are similar to Koperberg Suite intrusions documented from many of the other mine workings in the Okiep Copper District. This suggests similar underlying emplacement controls of the cupriferous rocks, which can be extrapolated on a regional scale and that may guide exploration.
The nighttime economy has always been regarded as an important part of the economy. Monitoring and evaluating the nighttime economic level is of great significance for promoting consumption and ...economic growth and optimizing industrial structure. However, it is difficult to evaluate the nighttime economy in China due to the data being unavailable. Hence, the objective of this study is to identify and evaluate the nighttime economy in China from different perspectives. First, a comprehensive nighttime economic index (CNEI) was constructed by integrating the nighttime light intensity and the points of interest data to represent the nighttime economic level. The CNEI was then verified using the business report data and socioeconomic statistical data. The results show that the CNEI is highly correlated with the verified data. We also found that Shanghai, Chengdu, Guangzhou, and Shenzhen have the highest CNEI values, and the CNEI values of southern cities are generally higher than those of northern cities. This is mainly because the differences in the lifestyles, climatic factors, and cultural customs in the north and south determine the nighttime economic activities. Counties with very high CNEI values are mostly located in the capital cities of each province. The spatial agglomeration at the county level performed more strongly than that at the prefecture level. The study will not only help better understand the nighttime economic level on different scales but also contribute to city-level policymaking on urban planning and economic development.
ABSTRACTArtificial night-time lights (ANTL) pose environmental, economic, and social problems. To effectively manage this issue, it is important to understand the sources that contribute to it. ...Previous research has presented conflicting views on the relative importance of streetlamps and spill-over light from buildings as contributors to ANTL. In this study, we used satellite images, ground surveys of streetlamps and buildings in the city of Hobart, Tasmania, Australia, to determine the major contributing sources of ANTL. Imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite was used to map ANTL. We developed a predictive random forest regression (RFR) model and found that streetlamps were the major contributor, followed by the building footprint area. We also found that an increase in both the number of streetlamps and buildings leads to an increase in ANTL observable in VIIRS satellite data. The RFR model performed well with an R2 of 0.94 and a median normalised root mean square error of 6.25%.
The magnesian suite (Mg‐suite) of rocks record some of the earliest intrusive magmatism on the Moon. Studies of these Mg‐suite rocks find they are plutonic or hypabyssal, formed typically kilometers ...under the lunar surface. Several models exist to explain the formation and evolution of the Mg‐suite but distinguishing between hypotheses can be difficult given the limited sample availability. The global extent of Mg‐suite magmatism remains in debate and is key to constraining models of early secondary crust building. In this study, we present magnesian clasts within Apollo impact melt rock 68815. These clasts contain olivine, plagioclase, with minor amounts of Mg‐Al‐spinel and pyroxene similar to spinel troctolites of the Mg‐suite, but they lack plutonic textures. We provide evidence that some of the clasts may be of extrusive volcanic origin akin to terrestrial komatiites while others might represent crystalline impact melts. There exists a large breadth of evidence for Mg‐suite intrusives, whereas here, we present possible evidence of Mg‐rich volcanic counterparts. If valid, this would broaden the known diversity of lunar volcanism during the initial stages of secondary crust building. We anticipate this finding to provide a greater constraint onto models of Mg‐suite ascent and emplacement, which only currently consider intrusive magmatism, as well as renewed motivation to examine impact melt breccias for rare and understudied lithologies. Future trace element studies or radiometric dating could be used to further interrogate the connections of these clasts to the Mg‐suite.
Plain Language Summary
Magnesium‐rich rocks found on the Moon are collectively termed the Mg‐suite and generally crystallized kilometers beneath the lunar surface. There are several competing models that explain how these rocks formed and evolved. Distinguishing between these models involves characterizing a wide variety of Mg‐rich lunar material. In this work, we present unique Mg‐rich rock fragments that contain the same minerals of similar composition as the Mg‐suite rocks but have textures that indicate they did not crystallize at depth under the surface. There are two general ways these rock fragments could have formed. First, the same Mg‐rich magmas that formed the Mg‐suite could have erupted onto the Moon’s surface, creating a volcanic deposit. Second, an impact event could have struck the lunar surface and melted pre‐existing Mg‐suite rocks, which then cooled quickly on the lunar surface. We present evidence that some of these rock fragments could possibly be volcanic in origin, while others almost certainly formed via an impact. If some of the rock fragments are indeed volcanic, it would call for a reevaluation of Mg‐suite emplacement models because these models currently only consider rocks crystallized beneath the lunar surface. More work is needed to definitively identify these rock fragments as volcanic.
Key Points
Fine‐grained lunar Mg‐rich clasts have been identified in Apollo impact melt breccia 68815
Some of these clasts may be volcanic in origin, while others are likely crystalline impact melt
The finding of potential volcanic Mg‐suite clasts adds to the complexity and diversity of early lunar secondary crust building
Population and economic growth within the Durban Metropolitan region in eastern South Africa have increased the demand for water supply. Though the region's water supply comes mainly from surface ...water sources, the ever-increasing demand means that all available water supply sources including groundwater will be looked at, particularly in the peri-urban areas. However, the state of the groundwater resource in the region is poorly understood. This study aims to contribute towards improved understanding of the state of groundwater resources in the Metropolitan District through an integrated hydrogeological, hydrochemical and environmental isotope investigations. Results of the hydrogeological and hydrogeochemical characterization identified at least five hydrostratigraphic units of varying hydraulic and hydrochemical characteristics: the weathered and fractured basement aquifers of the Mapumulo Group, Oribi Gorge, Mzimlilo and Mkhomazi Suites characterized by average borehole yield and transmissivity (T) of 1.2 l/s, and 3.9 m2/day, respectively, and hydrochemical facies of Ca-Mg-HCO3; the fractured Natal Group sandstone characterised by average borehole yield and hydraulic conductivity (K) of 5.6 l/s and 2.8 m/day, respectively and with Na-Mg-HCO3-Cl dominant water type;the fractured aquifers of the Dwyka Group diamictite and tillite characterized by average borehole yield of 0.4 l/s, transmissivity of 1.3 m2/day and Na-Cl-HCO3 dominant water type;the Vryheid Formation of the Ecca Group characterized by average borehole yield of 2.5 l/s, T of 4.9 m2/day, K values 0.17 m/day, and Na-Cl-HCO3 water type. The Pietermaritzburg Formation of the Ecca Group is characterized by a shale lithology with very low borehole yields and average transmissivity of 0.28 m2/d with Na-Ca-Cl dominant water type. It is considered as an aquiclude than an aquifer;the intergranular aquifer of the Maputaland Group which comprises the Bluff, Berea type sands and harbour beds (recent alluvium and estuarine deposits). These units collectively have average borehole yield of 14.8 l/s, transmissivity of up to 406 m2/day and a mainly Na-Cl-HCO3 hydrochemical signature. The region receives mean annual precipitation (MAP) of 935 mm/yr of which an estimated 6.6% recharges the various aquifers. Environmental isotope data (2H, 18O and 3H) indicated that groundwater is recharged from modern precipitation. High concentrations of tritium, as high as 92 T.U., measured around landfill sites, indicates groundwater contamination from leachate leakage posing a risk to human and environmental health.
The aim of this article is to reconstruct the events that accompanied the writing of Tempête en juin, the first part of Suite française, to which Irène Némirovsky devoted herself in the months before ...her deportation in July 1942. We consider this novel to be the last piece of evidence of a literary season that saw the author gradually rid herself of her favourite themes in favour of a new subject, war. The aim is therefore to analyse the way in which Irène Némirovsky confronts the motifs that traditionally go hand in hand with the representation of war, and how this evolves from 1938, the year of publication of Naissance d'une révolution, right up to her last working days.
In Canada and the United States, pressurized corridor ventilation systems are common in older high-rise multi-unit residential buildings (MURBs). There is growing evidence that these systems exhibit ...poor performance, necessitating the evaluation of alternatives. This study used a CONTAM air flow model to compare six ventilation systems to the pressurized corridor, including various decentralized and direct-to-suite ducted configurations. The model was generated using field data from a representative 24-storey post-World War II MURB in Toronto, Canada, along with field data from the literature. Simulations were run for each system under cold (−16.1 °C, 3 °F) and warm (29.0 °C, 84.2 °F) outdoor conditions and the results were analyzed for the 2nd and 23rd levels. The novel contributions from this work are insights into air flow within the target building typology and the design recommendations that these insights permit. Key findings include: 1) Reliance on door undercuts to facilitate air flow from corridors to suites results in increased in/exfiltration across the exterior wall by up to 230% under cold conditions; 2) Automated air flow control at ducted supply terminals does not significantly improve the performance of any tested system; and 3) Inter-suite air flow is significant in all of the tested systems, with 20%–31% of the air in the 23rd level suite being attributed to either direct (5%–13%) or indirect (15%–18%) inter-suite air flow during the cold condition. We recommend reducing indirect inter-suite flow, where possible, and avoiding door undercuts and automated ducted supply terminal flow control.
•An air flow model was generated in CONTAM of a 24-storey post-war high-rise MURB.•Field and literature data were used to generate and validate the model.•Pressurized corridors and six alternative ventilation strategies were analyzed.•Ventilation, total, and inter-suite air flow rates were compared.•Design recommendations were generated based upon model results.
•Studies how effectively test suites with high code coverage find 45 different faults.•Certain faults were found much less frequently than others.•Six faults were identified as outliers by a ...statistical test.•A suggestion is made for improving test suite effectiveness based on the results.
Code coverage criteria are commonly used to determine the adequacy of a test suite. However, studies investigating code coverage and fault-finding capabilities have mixed results. Some studies have shown that creating test suites to satisfy coverage criteria has a positive effect on finding faults, while other studies do not. In order to improve the fault-finding capabilities of test suites, it is essential to understand what is causing these mixed results. In this study, we investigated one possible source of variation in the results observed: fault type. Specifically, we studied 45 different types of faults and evaluated how effectively human-created test suites with high coverage percentages were able to detect each type of fault. Our results showed, with statistical significance, there were specific types of faults found less frequently than others. However, improvements in the formulation and selection of test oracles could overcome these weaknesses. Based on our results and the types of faults that were missed, we suggest focusing on the strength of test oracles along with code coverage to improve the effectiveness of test suites.
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