BIFoR FACE: Water–soil–vegetation–atmosphere data from a temperate deciduous forest catchment,including under elevated CO2

The ecosystem services provided by forests modulate runoff generation processes, nutrient cycling and water and energy exchange between soils, vegetation and atmosphere. Increasing atmospheric CO₂ affects many linked aspects of forest and catchment function in ways we do not adequately understand. Global levels of atmospheric CO₂ will be around 40% higher in 2050 than current levels, yet estimates of how water and solute fluxes in forested catchments will respond to increased CO₂ are highly uncertain. The Free Air CO₂ Enrichment (FACE) facility of the University of Birmingham's Institute of Forest Research (BIFoR) is the only FACE in mature deciduous forest. The site specializes in fundamental studies of the response of whole ecosystem patches of mature, deciduous, temperate woodland to elevated CO₂ (eCO₂). Here, we describe a dataset of hydrological parameters – seven weather parameters at each of three heights and four locations, shallow soil moisture and temperature, stream hydrology and CO₂ enrichment – retrieved at high frequency from the BIFoR FACE catchment.     

The δ13C–δ18O variations in marble in the Hida Belt,Japan

Marble has a great potential to understand a history of various geological events occurring during tectonic processes. In order to decode metamorphic–metasomatic records on C–O isotope compositions of marble at mid-crustal conditions, we conducted a C–O–Sr isotope study on upper amphibolite-facies marbles and a carbonate–silicate rock from the Hida Belt, which was once a part of the crustal basement of the East Asian continental margin. Carbon and oxygen isotope analyses of calcite from marbles (Kamioka area) and a carbonate–silicate rock (Wadagawa area) show a large variation of δ¹³C [VPDB] and δ¹⁸O [VSMOW] values (from −4.4 to +4.2 ‰ and +1.6 to +20.8 ‰, respectively). The low δ¹³C values of calcites from the carbonate–silicate rock (from −4.4 to −2.9 ‰) can be explained by decarbonation (CO₂ releasing) reactions; carbon–oxygen isotope modeling suggests that a decrease of δ¹³C strongly depends on the amount of silicate reacting with carbonates. The occurrence of metamorphic clinopyroxene in marbles indicates that all samples have been affected by decarbonation reactions. All δ¹⁸O values of calcites are remarkably lower than the marine-carbonate values. The large δ¹⁸O variation can be explained by the isotope exchange via interactions between marble, external fluids, and/or silicates. Remarkably low δ¹⁸O values of marbles that are lower than mantle value (~+5 ‰) suggest the interaction with meteoric water at a later stage. Sr isotope ratios (⁸⁷Sr/⁸⁶Sr = 0.707255–0.708220) might be close to their protolith values. One zircon associated with wollastonite in a marble thin-section yields a U–Pb age of 222 ± 3 Ma, which represents the timing of the recrystallization of marble, triggered by H₂O-rich fluid infiltration at a relatively high-temperature condition. Our isotope study implies that the upper amphibolite-facies condition, like the Hida Belt, might be appropriate to cause decarbonation reactions which can modify original isotope compositions of marble if carbonates react with silicates.     

Tectonic cycles of the New England Orogen,eastern Australia: A Review

The New England Orogen (NEO), the youngest of the orogens of the Tasmanides of eastern Australia, is defined by two main cycles of compression–extension. The compression component involves thrust tectonics and advance of the arc towards the continental plate, while extension is characterised by rifting, basin formation, thermal relaxation and retreat of the arc towards the oceanic plate. A compilation of 623 records of U–Pb zircon geochronology rock ages from Geoscience Australia, the geological surveys of Queensland and New South Wales and other published research throughout the orogen, has helped to clarify its complex tectonic history. This contribution focuses on the entire NEO and is aimed at those who are unfamiliar with the details of the orogen and who could benefit from a summary of current knowledge. It aims to fill a gap in recent literature between broad-scale overviews of the orogen incorporated as part of wider research on the Tasmanides and detailed studies usually specific to either the northern or southern parts of the orogen. Within the two main cycles of compression–extension, six accepted and distinct tectonic phases are defined and reviewed. Maps of geological processes active during each phase reveal the centres of activity during each tectonic phase, and the range in U–Pb zircon ages highlights the degree of diachronicity along the length of the NEO. In addition, remnants of the early Permian offshore arc formed during extensive slab rollback, are identified by the available geochronology. Estimates of the beginning of the Hunter-Bowen phase of compression, generally thought to commence around 265?Ma are complicated by the presence of extensional-type magmatism in eastern Queensland that occurred between 270 and 260?Ma.     

UDEC软件对矿山采空区崩塌过程进行应力分布的研究

为了研究矿山采空区坡体的应力(裂隙)分布情况,并对崩塌过程分析进行检验,本文采用离散元数值软件(UDEC)对纳雍县张家湾镇普洒煤矿采煤过程中覆岩裂隙发生、发展及其变化过程进行模拟。结果表明:随着煤层开采的推进,覆岩裂隙向上发展且密度逐渐增多;由于采空区范围过大时,部分被重新压实,裂隙发育至地表形成开切眼;最后在外力作用下整条裂缝垂直贯通,形成危岩体的发展规律,可为类似的矿山地质灾害防治提供基础依据。     

广东河台整装勘查区百旁金矿成矿规律

百旁金矿是广东地质五队近年来新发现的一处中型蚀变糜棱岩型金矿。百旁金矿地处粤西—桂东成矿带东段NE向罗定—广宁断裂带北东端部位,矿体受糜棱岩带内面理、裂隙带控制;金矿化具明显的以硅化、硫化物为中心的对称性分布特征,金矿体具有平行斜列、侧伏的分布规律,表现为向NE向侧伏;区内金矿化富集主要与热液活动有关,燕山期的重熔花岗岩侵入的同时伴随有富含硫化物的含金热液充填在糜棱岩、断裂带内而成矿。     

坡面流层流区动力学特性

为完善坡面水流的基础理论研究,基于定床水槽试验,以甘油溶液为试验流体,采用超声波测量技术,进行了4种粗糙度、5种坡度和13种单宽流量条件下的组合试验,研究了坡面流层流区的动力学特性及滚波特征。研究结果表明:在雷诺数为8~160的范围内,流态指数在理论值0.33附近波动,且随粗糙度的增大呈现先增大后减小的变化趋势,在粗糙度为0.10 mm附近达到峰值;阻力系数受坡度和粗糙度影响显著,可较好地由坡度、粗糙度和雷诺数的关系式表示;随着雷诺数的增大,滚波波速和波峰均呈幂函数形式递增,滚波周期大小无明显变化;坡度的增大会使层流失稳临界单宽流量减小,粗糙度的增大会使临界弗劳德数的均值减小。     

Late Jurassic to Early Cretaceous volcanism of Hong Kong: Insights from the Ping Chau Formation

The vast expanse of Mesozoic igneous rocks in Hong Kong contain important geological records of late Mesozoic magmatic events and tectonic processes from the coastal region of Southeast China. Of these,the Ping Chau Formation in the northwestern New Territories is the youngest known stratum. We perform a detailed study of the volcanic rocks of the Ping Chau Formation utilizing zircon U-Pb dating,with major and trace elements geochemistry. LA-ICP-MS zircon U-Pb data reveal Early Cretaceous age from two volcanic rock samples, with zircon crystallization from magmas at 140.3 ± 0.8 Ma and 139.3 ± 0.9 Ma,respectively. These rocks have high contents of total alkalis(Na_2O + K_2O = 5.58-9.45 wt.%), high-field-strength elements and light rare earth elements, conspicuous negative Eu anomalies, and depletions in Nb, Ta, Ti, Sr, Ba and P. Using this data, in combination with previous studies on the late Mesozoic volcanic belt in Southeast China, we propose that the volcanic rocks of the Ping Chau Formation probably originated from deep melting of the crust in a back-arc extensional setting induced by the subduction of the paleo-Pacific Plate. This formation represents the final stages of Early Cretaceous volcanic activity in Hong Kong, as associated with large-scale lithospheric extension, thinning and magmatism. Our results provide new information that can be used in evaluating the significance of Early Cretaceous volcanism and tectonics in Southeast China.     

Winkler model for dynamic response of composite caisson–piles foundations: Seismic response

A simplified method with a dynamic Winkler model to study the seismic response of composite caisson–piles foundations (CCPF¹) is developed. Firstly, with the dynamic Winkler model, the kinematic response of the CCPF subjected to vertically propagating seismic S-wave is analyzed by coupling the responses of caisson part and pile part. Secondly, a simplified model for the foundation–structure system is created with the structure simplified as a lumped mass connected to the foundation with an elastic column, and through the Fast Fourier Transformation (FFT) this model is enabled to solve transient seismic problems. Thirdly, the proposed method for the seismic response of CCPF-structure systems is verified by comparison against 3D dynamic finite element simulation, in which the Domain Reduction Method (DRM²) is utilized. Lastly, the mechanism and significance of adding piles in improving the earthquake resistance of the foundation and structure is analyzed through an example with different soil conditions. Discovered in this study is that adding piles under the caisson is an efficient way to increase seismic resistant capability of the soil–foundation–structure system, and the main mechanism of that is the elimination of the pseudo-resonance.     

The politics of greening unceded lands in the settler city

ABSTRACT

Urban greening is a buzz term in urban policy and research settings in Australia and elsewhere. In a context of settler colonial urbanism, like Australia, a first fact becomes clear: urban greening is always being practiced on unceded Indigenous lands. Recognising this requires some honest reckoning with how this latest urban policy response perpetuates dispossessory settler-colonial structures. In this paper, we listen to the place-based ontologies of the peoples and lands from where we write to inform understanding the city as an always already Indigenous place – a sovereign Aboriginal City. In so doing, the paper tries to practice a way of creating more truthful and response-able urban knowledge practices. We analyse three distinct areas of scholarly research that are present in the contemporary literature: urban greening and green infrastructure; urban political ecology; and more-than-human cities. When placed in relationship of learning with the sovereign Aboriginal City, our analysis finds that these scholarly domains of urban greening work to re-organise colonial power relations. The paper considers what work the practice and scholarship of ‘urban greening’ might need to do in order to become response-able and learn to learn with Indigenous sovereignties and ontologies.     

地理相似性：地理学的第三定律?

定律对知识的理解和传播具有极大的推动作用。本文通过对比地理学中的定律和物理学中的定律的异同之处,认为地理学的定律虽然在形式上和提出的方式上与经典的力学定律有所区别,但仍符合人们对“定律”的定义。在共识地理学定律存在的前提下,本文阐述了地理学的第一定律和第二定律中所体现出的地理学定律的特征——描述性和归纳性。基于这些对地理学定律所具有的特征的认识,本文首先介绍了Zhu等从空间推测的角度将所提出的地理学第三定律,即“地理环境越相似,地理特征越相近”,或称地理相似性定律。本文从普遍性、独立性和应用性3个方面探讨了地理相似性是否可以作为地理学的一个定律,认为地理相似性与地理学第一和第二定律相比,有着同样的普遍性,且与第一和第二定律所涉及的规律有着本质上的区别,在应用上可能解决第一和第二定律所面临的挑战,因此应可作为地理学第三定律。