区域地表水资源可利用量问题研究

区域地表水资源可利用量问题是一个比较复杂的问题,常规计算仅考虑境内地表水可利用水量,得出的结果往往不合理。本文结合福建省情况,提出区域地表水资源可利用量的定义,指出区域地表水资源可利用量应分析计算4个部分可利用水量．即境内地表水可利用水量、过境河流可利用水量,调入境内水资源量、境内调出水资源量,并提出了计算方法,结合福建各市水资源开发利用程度分析,得出比较合理的结论。     

岭南东江流域晚更新世哺乳动物化石的新发现

近年在南岭以南的广东东江流域河源地区东源县上莞镇的碧寿洞中发现较丰富的古哺乳动物牙齿化石。经鉴定为6个目5属5种,称之为碧寿动物群。根据碧寿动物群指示的古生态、化石层位、热释光测试结果和生物地层对比初步认为,该动物群与西江流域的罗沙岩动物群一样,都属于晚更新世时期的大熊猫—剑齿象动物群,生活在MIS5a时的间冰期,但罗沙岩动物群的时代略早,为(79.0±15)kaBP,而碧寿动物群则存在于末次冰期/末次间冰期之交的MIS5a之末叶。此动物群为广东东江流域历年首现,代表了当时的热带北缘森林草原的自然环境。     

新安江流域上游地区水资源经济价值估算

流域水资源价值的核算,不仅是上下游之间水权交易和流域生态补偿标准制定的基础,还可为当地水价的合理制定提供科学依据,促进水资源的可持续利用和高效管理。本文对新安江流域上游地区水资源的经济价值作出了估算,以期为流域生态补偿标准的建立提供理论支持,为开展水资源保护与水价改革提供数据参考。     

Ordovician intrusive rocks from the eastern Central Asian Orogenic Belt in Northeast China: chronology and implications for bidirectional subduction of the early Palaeozoic Palaeo-Asian Ocean

ABSTRACT

The eastern segment of the Central Asian Orogenic Belt is traditionally called the Xing’an Mongolia Orogenic Belt (XMOB). Ordovician intrusive rocks exposed in the XMOB, from north to south, are the Abaga-East Ujimqin Qi-Duobaoshan belt, the Sonid Zuoqi-West Ujimqin Qi belt, and the Damaoqi-Baimaimiao-Tulinkai belt, respectively. Zircon U–Pb dating and geochemical data are presented for the intrusive rocks in East Ujimqin Qi and West Ujimqin Qi, Inner Mongolia. The intrusive rocks from East Ujimqin Qi consist of gabbro, diorite, and granodiorite. LA-MC-ICP-MS zircon U–Pb ages range 446 to 461 Ma. Geochemical data suggest that the gabbros and diorites from East Ujimqin are a tholeiitic series, both of arc-related and N-MORB (mid-ocean ridge basalt) signature, indicating a back-arc basin setting. The granodiorites have a shoshonitic series and arc-related signature. Rare earth element (REE) patterns and trace element characteristics suggest gabbros, diorites, and granodiorites are petrogenetically correlated. These intrusive rocks from East Ujimqin Qi have high light REE, Th, and U concentrations, suggesting the effect of middle–upper continental crustal contamination. Major oxides display positive or negative correlations, with increasing MgO or SiO_2, indicating that fractional crystallization occurred during magma evolution. Geochemical data of diorite from West Ujimqin Qi indicate a tholeiitic series, arc-related signature. Zircon U–Pb dating yielded an age of 441.8 ± 1.5 Ma. Integrated with the regionally exposed Mid–Late Ordovician plutons and metasedimentary strata, we concluded that the northward subduction of the Palaeo-Asian Ocean (PAO) that occurred beneath the southern margin of the South Mongolian Micro-continent along the Sonid Zuoqi-Xilinhot gave rise to early Palaeozoic igneous rocks from the Abaga–East Ujimqin Qi–Duobaoshan and the Sonid Zuoqi–West Ujimqin Qi belts. Southward subduction beneath the North China Craton generated the Damaoqi–Baimaimiao–Tulinkai belt. The results support the bidirectional subduction model of the PAO in the early Palaeozoic.     

小兴安岭西北部花岗质糜棱岩锆石LA-ICP-MSU-Pb年龄、岩石地球化学特征及地质意义

通过对位于小兴安岭西北部黑河-呼玛地区与元古宙变质岩系伴生出露的三处强变形的花岗质岩石的锆石U-Pb LA-ICP-MS测年和岩石学、岩石地球化学研究,确认样品岩性分别为花岗闪长质糜棱岩(样品1-3-4和1-5-1)、角砾状花岗闪长岩(样品1121和1211)和花岗质糜棱岩(样品1218),锆石U-Pb年龄为299.6±1.0Ma、300.8±1.1Ma和294.3±1.0 Ma,形成于晚石炭世末至早二叠世初,而非前人确定的元古宙或早石炭世,并初步认为岩石韧性变形作用发生时间介于184~170 Ma之间。三种花岗岩分别属于富硅、高铝、贫钾的过铝质钙碱性系列(I-3-4和1-5-1)、贫硅偏铝、高钙铁镁的偏铝质高钾钙碱性系列(1121和1211)和富硅钾、低钙镁铝的弱过铝质钾玄质系列(1218),稀土元素特征相似,富集轻稀土,相对亏损重稀土,具有明显或弱的Eu负异常,微量元素富集Rb、La、Th、U等大离子亲石元素,相对亏损Sr和高场强元素Nb、Ta、Zr、Hf,具有高分异Ⅰ型花岗岩和A型花岗岩的特征,在构造环境判别图R_1-E_2图上分别落在同碰撞造山、晚造山和造山后环境,在Nb-Y图落入火山弧-同碰撞环境和板内环境。结合区域资料,认为上述花岗岩是兴安地块与松嫩地块晚古生代碰撞造山的产物,记录了两块体间碰撞造山到造山后伸展作用。     

A Periglacial Palaeoenvionment in the Upper Carboniferous–Lower Permian Tobra Formation of the Salt Range, Pakistan

The Upper Carboniferous—Lower Permian(Upper Pennsylvanian-Asselian) Tobra Formation is exposed in the Salt and Trans Indus ranges of Pakistan.The formation exhibits an alluvial plain(alluvial fan-piedmont alluvial plain) facies association in the Salt Range and Khisor Range.In addition,a stream flow facies association is restricted to the eastern Salt Range.The alluvial plain facies association is comprised of clast-supported massive conglomerate(Gmc),diamictite(Dm)facies,and massive sandstone(Sm) Hthofacies whereas the stream flow-dominated alluvial plain facies association includes fine-grained sandstone and siltstone(Fss),fining upwards pebbly sandstone(Sf),and massive mudstone(Fm) Hthofacies.The lack of glacial signatures(particularly glacial grooves and striatums) in the deposits in the Tobra Formation,which are,in contrast,present in their timeequivalent and palaeogeographically nearby strata of the Arabian peninsula,e.g.the AI Khlata Formation of Oman and Unayzah B member of the Saudi Arabia,suggests a pro-to periglacial,i.e.glaciofluvial depositional setting for the Tobra Formation.The sedimentology of the Tobra Formation attests that the Salt Range,Pakistan,occupied a palaeogeographic position just beyond the maximum glacial extent during Upper Pennsylvanian-Asselian time.     

泰安市城区岩溶地下水水化学特征及成因分析

岩溶地下水是泰安市城区重要供水水源,近年来随着气候环境变化和人为活动的影响,岩溶地下水水化学特征日趋复杂,但其水化学特征及成因尚不明晰。为识别研究区地下水水化学特征、成因机制,本文采用数理统计方法、离子比值、水化学图解等方法,研究了该区岩溶地下水的水文地球化学特征。结果表明：研究区内岩溶地下水水化学类型主要为HCO3Ca型、HCO3·SO4Ca 型、HCO3·SO4·ClCa型。地下水水化学成分主要受水岩相互作用控制,以溶滤作用为主,地下水中的Ca2+、Na+、HCO-3、SO2-4主要来源于方解石、白云石的碳酸盐岩及石膏、盐岩等蒸发岩的溶解,且存在逆向的阳离子交替吸附作用,导致Ca2+含量增加,Na+含量减少,人为活动影响导致地下水中Cl-、NO-3浓度增加。研究成果为研究区内岩溶地下水的合理开发与保护提供了依据。     

Prograde P–T path of medium-pressure granulite facies calc-silicate rocks, Higo metamorphic terrane, central Kyushu, Japan

This paper reports an occurrence of medium-pressure granulite facies calc-silicate rocks intercalated with pelitic gneisses in the Higo metamorphic terrane, central Kyushu, Japan, which is classified as a low- P /high- T (andalusite-sillimanite type) metamorphic belt. Three equilibrium stages are recognized in the calc-silicate rock based on reaction textures: M1 stage characterized by an assemblage of porphyroblastic garnet + coarse-grained clinopyroxene + plagioclase included in the clinopyroxene; M2 stage by two kinds of breakdown products of garnet, one is plagioclase + coronitic clinopyroxene within garnet and the other is plagioclase + vermicular clinopyroxene surrounding garnet; and M3 stage by amphibole replacing clinopyroxene. The key assemblage in the calc-silicate rock common to M1 and M2 stages is Grt + Cpx + Pl ± Qtz, which constrains the pressure and temperature ( P – T ) conditions for these stages by Fe–Mg exchange reaction and the two univariant net-transfer reactions: 2Grs + Alm + 3Qtz = 3Hd + 3An or 2Grs + Prp + 3Qtz = 3Di + 3An. The P – T conditions for M1 and M2 stages were estimated to be about 8.4 ± 1.9 kbar and 680 ± 122 °C, and 6.7 ± 1.9 to 8.9 ± 2.2 kbar and 700 ± 130 to 820 ± 160 °C, respectively. Estimates are consistent with an isobaric heating P – T path. The high peak temperature conditions at normal crustal depths and the prograde isobaric heating path probably require heat advection due to melt migration during the high- T metamorphism.     

Forest biodiversity assessment in Peruvian Andean Montane cloud forest

Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as regards biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the "Bosque de Neblina de Cuyas", in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity.     

鲁西地区“泰山红宝石”的发现及其地质特征

在山东新泰市新太古代泰山岩群变质岩系中,首次发现宝石级红刚玉,又称红宝石,商业名称暂定为"泰山红宝石"。红宝石产于鲁西地区新太古代二长花岗岩的壳源岩石包体之中,包体岩性以黑云更长变粒岩、黑云片岩、角闪石岩、斜长角闪岩、浅绿色含铬二云片岩为主,是新太古代古老地壳的深融残留;红刚玉与浅绿色含铬二云片岩关系密切,推测是新太古代变质岩中原岩残留斑晶矿物。