A historical review and assessment of urban heat island research in Singapore

This historical review of 20 studies since the 1960s examines the influence of urban development on the thermal environment in Singapore, a fast growing tropical island city‐state. Past observations are critically assessed with regard to experimental controls and station metadata. Given the availability of historical climate and developmental data spanning almost 50 years, changes in urban heat island (UHI) intensity and spatial coverage can be traced temporally. Rapid urban expansion in Singapore is clearly reflected in spatially and temporally changing air and surface temperature patterns. The nocturnal canopy‐layer UHI intensity – measured as the difference between the commercial urban core and undeveloped areas close to primary or secondary rainforests for example – doubled in magnitude between 1965 and 2004. At the same time, the spatial extent of the nocturnal UHI has also expanded with the development of new housing and industrial districts. The influence of the growing city is also reflected in surface temperature. Two satellite images dated 13 years apart demonstrate the encroachment of areas with high surface temperatures into previously cooler areas during daytime corresponding with new public housing estates and low‐rise residential areas or facilities being built. The results from our study contribute to the growing body of tropical heat island research. They provide baseline data for future research and urban development in the Singapore context and, more generally, offer important cues for urban planners to make tropical cities more sustainable.     

First report of trace fossils from Palaeogene succession (Namunagarh grit) of Andaman and Nicobar islands

The Namunagarh grit of Eocene age in South Andaman island is a submarine fan deposit where sedimentation occurred in deep marine environment mainly by turbidity currents. The mudstone and fine-grained sandstone of the turbidite sequence yielded three ichnogenera viz Thalassinoides, Teichichnus and Lorenzinia. Typically shallow marine Thalassinoides burrows co-occur with deep water burrows represented by Teichichnus and Lorenzinia, indicating a dominant control of substrate, availability of food and rate of sedimentation against bathymetry on distribution of trace fossils. Trace fossils are particularly abundant in the mudstones pointing to a strong lithofacies control. A well-oxygenated muddy bottom with a low rate of sedimentation is envisaged. An order in the succession of traces could be deciphered. Simply constructed burrows of Thalassinoides appeared initially followed by complex structures of Teichichnus and ornate Lorenzinia.     

基于遥感技术的城市热岛效应研究——以成都地区为例

在分析利用遥感技术研究城市热岛效应的理论与技术方法基础上,利用成都地区2000年Landsat 7 ETM＋遥感数据,通过图像数字处理和地物热红外波段辐射值反演,得到成都地区地面热场分布图,取得较好的模拟结果。研究表明：成都地区热岛效应明显,热场分布带有规律性,成都市区及周围城镇及人口较集中区地面亮温明显高于周边地区,形成多个高值热场中心（热岛）,与这些地区城市化、工业化等快速发展、地面结构等因素有关。此外,研究结果表明,水域和绿色植被能够明显的缓解城市热岛效应。     

西秦岭同仁隆务峡蛇绿岩矿物成分特征及构造环境

同仁隆务峡蛇绿岩大地构造位置位于西秦岭造山带与中祁连带结合部,其组成为:地幔橄榄岩(纯橄岩、蛇纹石化纯橄岩)、超镁铁质堆晶单元(单辉橄榄岩、橄榄辉石岩)、镁铁质堆晶单元(含橄榄石辉长岩、辉长岩等)及少量辉绿岩,各单元均以断层接触,弱蚀变.镜下研究发现其岩浆结晶序列为橄榄石-单斜辉石-(斜方辉石)-斜长石,与典型的SSZ型(Supra-Subduction Zone type)蛇绿岩结晶序列吻合.对各单元矿物电子探针研究发现:橄榄石成分多为贵橄榄石,单斜辉石则多为普通辉石和透辉石,在利用其成分进行构造环境判别中,本区蛇绿岩形成于与挤压背景密切相关的环境.该蛇绿岩表现出轻稀土元素略富集、重稀土元素平坦的稀土元素配分形式,与MORB有较大差异.微量元素特征为相对富集大离子亲石元素Ba、Rb、K,而强烈亏损Nb、P,这恰与俯冲带组分特点吻合;同时高场强元素构造判别图解佐证了前述构造环境的判定.研究区的蛇绿岩应形成于成熟度较高的岛弧环境中.     

Identifying late Carboniferous sanukitoids in Hala’alate Mountain,Northwest China: new constraint on the closing time of remnant ocean basin in West Junggar

ABSTRACT

Volcanic rocks in the Hala’alate and Aladeyikesai formations, which are composed of basaltic andesite and pyroxene andesite, are widespread in Hala’alate Mountain, West Junggar, Northwest China. These rocks (plagioclase + clinopyroxene/olivine) formed in the late Carboniferous and show a remarkable geochemical affinity with typical sanukitoids with oversaturated SiO₂ (52.9–56.9 wt.%) and high MgO (3.47–6.88 wt.%, Mg^# >48) contents. They also exhibit a narrow range of Sr-Nd-Pb isotopes within (⁸⁷Sr/⁸⁶Sr)_i = 0.7037–0.7041, εNd(t) = 4.4–6.2, ²⁰⁶Pb/²⁰⁴Pb = 18.22–18.41, ²⁰⁷Pb/²⁰⁴Pb = 15.48–15.52, ²⁰⁸Pb/²⁰⁴Pb = 37.99–38.30. Hala’alate Formation volcanic rocks are similar to the sanukitoids of Karamay, with high Sr (633.5–970.1 ppm), Ba (268.7–796.3 ppm), and Sr/Y (61.34–84.28), formed by partial melting of the mantle metasomatized by slab-derived adakitic melts. In contrast, Aladeyikesai Formation volcanic rocks show some affinity with sanukitoids of the Hatu area and the Setouchi Volcanic Belt, with low Sr (442.2–508.7 ppm), Ba (199.2–485.1 ppm), and Sr/Y (25.03–30.28), generated by the partial melting of subducting sediments. Identification of late Carboniferous sanukitoids in Hala’alate Mountain provides important constraints on the closing time of the remnant ocean basin in West Junggar, and implies that multi-stage subduction–accretionary orogeny plays a crucial role in the evolution and growth of the continental crust in the Central Asian Orogenic Belt.     

内蒙古翁牛特旗晚志留世二长花岗岩年代学及地球化学特征

内蒙古翁牛特旗小营子地区铅锌矿周围分布有大面积花岗岩,野外地质调查及室内鉴定为二长花岗岩。通过LA-ICPMS锆石U-Pb同位素测试,确定其形成时代为419.3±9.2Ma,属于晚志留世。二长花岗岩中SiO_2含量为74.41%~75.05%,K_2O含量为3.05%~4.42%,K_2O/Na_2O值介于0.70~1.11之间,Al_2O_3含量为13.22%~14.02%,铝饱和指数(A/CNK)为0.99~1.1,Fe、Mg、Ti氧化物含量较低,这些特征显示二长花岗岩为富硅、略富铝、中高钾钙碱性I型花岗岩。轻、重稀土元素比值(LREE/HREE)在10.61~16.61之间,(La/Yb)_N值在12.52~27.44之间,轻、重稀土元素分馏明显,δEu值为0.48~0.81,显示中等负Eu异常。富集大离子亲石元素Rb、Ba、U、K,相对亏损高场强元素Nb、Zr、Hf,具有低的Sr、Yb含量。地球化学特征显示,二长花岗岩形成于活动大陆边缘火山弧。结合区域地质资料推断,小营子二长花岗岩是在古亚洲洋向华北板块俯冲背景下白乃庙岛弧消亡过程中形成的。     

大兴安岭托河林场毕利亚山碱长花岗岩黑云母地球化学特征及地质意义

根据大兴安岭毕利亚山碱长花岗岩黑云母的电子探针(EPMA)测试结果,对黑云母的化学成分特征、成因类型及结晶时的温度和氧逸度进行了研究,并探讨岩浆源区的性质及成岩背景。毕利亚山碱长花岗岩黑云母具有高Si(SiO_2:39.876%~42.419%)、富Mg(MgO:18.138%~20.02%)、贫Fe(FeO~t:10.549%~11.468%)特征,属镁质黑云母;黑云母的结晶温度为590℃~650℃,且具有较高的氧逸度。其∑Al的值为1.01~1.044,Fe/(Mg+Fe)的值为0.228~0.262。Mg/(Mg+Fe~(2+)+Mn)的值为0.673~0.834,FeO~t/(FeO~t+MgO)的值为0.345~0.387,指示了其岩浆源区为富镁的岩石圈地幔,并且在岩浆演化过程中发生混染作用。     

大兴安岭环二库新元古代变质辉长岩的厘定及其地质意义

环二库地区位于大兴安岭大扬气林场,岩石组合为斜长角闪岩、变质辉长岩、橄榄岩和大理岩,主要以NE向呈似层状、透镜状或碎片状产出。LA-ICP-MS锆石U-Pb测年结果表明,其中变质辉长岩形成于新元古代末期(696.8±2.9 Ma);岩石地球化学分析显示,环儿库变质辉长岩具有类似N-MORB的地球化学特征,且与部分岛弧拉斑玄武岩(IAT)具有成分上的亲缘性,表明变质辉长岩的形成与俯冲作用有关。结合区域上吉峰、嘎仙蛇绿岩可知,环二库岩石组合具有类似于蛇绿混杂岩的特征,其中变质辉长岩可能代表了新元古代末期的洋壳残片,表明大兴安岭北段地区新元古代时期存在古洋盆。     

阴山大青山山系特异重力场与深部构造

根据阴山山系及邻近地区的布格重力异常分布特征,提出阴山山系和呼包盆地地区的布格重力异常分布与地形高程呈“同步型”的特异变化特征．通过重力数据资料的处理分析给出阴山山系和呼包盆地地区的地壳底界面都没有明显的下凹与上凸的特征,是阴山山系和呼包盆地布格重力异常呈现特异变化的可能原因。     

非均匀下垫面边界层的观测和数值模拟研究(I):冷岛效应和逆湿现象的完整物理图像

利用HEIFE、DHEX和GAME/Tibet 3个观测试验和部分常规气象站观测资料,分析了下垫面非均匀条件下产生的冷岛效应和逆湿现象的完整物理图像以及它们对地表能量和五水转化的影响.分析结果表明,下垫面非均匀特征对五水转化有着明显的影响;冷岛效应和逆湿现象是下垫面非均匀性的必然结果,它们在自然界普遍存在;现有陆面过程模式很难刻画冷岛效应和逆湿现象,通常现有陆面过程模式很难将冷岛效应中的热量平流转化成蒸发潜热,同时陆面过程模式也混淆了逆湿现象和发生在下垫面上的大气水的冷却凝结.这些评述将有助于今后非均匀陆面过程的进一步研究.