Relating hydrograph components to rainfall and streamflow: a case study from northern Taiwan

Abstract

This study investigates the characteristics of hydrograph components from a watershed in Taiwan. Hydrograph components were modelled by using a model of three serial reservoirs with one parallel reservoir. Mean rainfall was calculated by using the block kriging method. The model parameters for 38 events were calibrated by using the shuffled complex evolution optimization algorithm. The model verification was made using 18 events. Based on the study results, the following findings were obtained: (1) for single-peak events, times to peak of hydrograph components are an increasing power function of the peak time of rainfall; (2) peak discharges of hydrograph components are linearly proportional to that of total runoff, and the ratios of quick and slow runoff are approximately 83% and 17% of total runoff, respectively; and (3) the total volume of quick runoff component is 52% of total runoff and that of slow runoff is 27%.

Editor D. Koutsoyiannis

Citation Li, Y.-J., Cheng, S.-J. Pao, T.-L. and Bi, Y.-J., 2012. Relating hydrograph components to rainfall and streamflow: a case study from northern Taiwan. Hydrological Sciences Journal, 57 (5), 861–877.     

地质历史时期海洋Li同位素演变

Li是一种碱金属元素,由于它不受氧化还原和生物效应的影响,因此在追踪地球元素循环方面非常有利。并且Li在海洋中的留存时间远大于海水混合时间,因此海洋中的Li具有相对均一的组成,从而能够代表对应地质历史时期整体海洋情况。近年来海洋Li同位素被应用在示踪大陆风化模式领域,并取得了很多成果。笔者等在系统总结全球海洋Li循环作用和表生地质作用的Li同位素分馏机制的基础上,通过收集并整理、估算了不同时期海洋Li同位素组成,对地质历史时期海洋Li同位素组成变化与改变大陆风化模式相关的地质事件进行分析,再结合同时期碳酸盐岩C、Sr同位素数据进行对比分析,探讨Li、C、Sr同位素演化与地质事件之间的关系。最后,讨论了目前海洋Li同位素组成方面研究的不足,为后续利用海洋Li同位素记录示踪大陆风化模式的应用提供了参考。     

西南三江金厂河矽卡岩型多金属矿床铁同位素分馏机制及其对成矿物质来源的制约SCIEI北大核心CSCD

金厂河矿床是西南三江成矿省保山地块最具代表性的远端矽卡岩型多金属矿床之一,查明其成矿金属来源对理解该类矿床成因以及区域成矿规律具有重要意义。本文通过分析不同成矿阶段代表性含铁矿物的铁同位素组成,探讨其在成矿过程中的分馏机制,从而示踪成矿金属的源区特征。金厂河矽卡岩型矿床中成矿前阶段未蚀变的石榴子石和氧化物成矿阶段的磁铁矿均相对富集铁的重同位素,其δ;Fe值分别为0.05‰~0.16‰和0.07‰~0.18‰,而硫化物成矿阶段的黄铁矿和黄铜矿则相对富集铁的轻同位素,其δ;Fe值分别为-0.12‰~0.17‰和-0.54‰~-0.38‰,整体显示出从高氧逸度的成矿前阶段向低氧逸度的硫化物成矿阶段演化过程中矿物δ;Fe值逐渐降低的趋势,指示Fe;富集铁的重同位素,Fe;富集铁的轻同位素。同时,金厂河矿床各阶段矿物的δ;Fe值均显著低于碳酸盐围岩,而接近全球花岗岩的δ;Fe值,表明成矿的铁不是由围岩贡献,而是来自于隐伏的中酸性岩体。     

腾冲地块晚白垩世-古近纪富锡花岗岩成因:岩浆源区及分异演化条件SCIEI北大核心CSCD

腾冲地块锡成矿作用主要与晚白垩世-古近纪岩浆活动相关,但仅矿区花岗岩体具有较高的锡含量(平均25×10^(-6)),区域上同时代的非成矿花岗岩体并未发生锡的富集。本文通过搜集分析现有研究数据,总结了富锡成矿岩体和区域非成矿岩体在岩浆源区、演化条件和结晶分异程度的异同:区域非成矿岩体锆石ε_(Hf)(t)值(-15.1~+3.39)表明,自东北向西南幔源物质加入有升高的趋势,但区域玄武岩中低含量的Sn(1.61×10^(-6))表明幔源物质混入不利于岩浆中锡的富集。晚白垩世部分非成矿岩体与成矿岩体具有相同ε_(Hf)(t)(-9.7)值,表明其皆源于古老地壳物质的部分熔融,但岩体均表现为准铝质-弱过铝质特征,且锆石Hf同位素(t_(DM2)=1724Ma)和全岩Nd同位素(t_(DM2)=1836Ma)二阶段模式年龄基本一致,因此其源区可能并非富锡的高黎贡山群变质沉积岩,而可能是其中未经风化的变质花岗岩。根据腾冲地块地层厚度(28km)和莫霍面深度(47~35km)推断岩浆源区至少位于地下30km(8.4kbar),由于仅靠地温梯度(25℃/km)无法达到初始熔融温度(>1066℃),源区部分熔融过程很可能受地幔热的影响。根据Fe_(2)O_(3)/FeO比值,非成矿岩体(0.59)与成矿岩体(0.48)均具有较低的氧逸度,属钛铁矿系列,但成矿岩体的结晶分异程度明显高于非成矿岩体,且成矿岩体富含挥发分,高含量的挥发分降低了岩浆固结温度(650~550℃),延长了结晶分异时间,促进了锡在晚期岩浆中的富集。因此腾冲地块富锡花岗岩主要是普通岩浆在低氧逸度环境下发生高度结晶分异的结果。     

Petrological and chronological characteristics of medium-high grade metamorphic rocks in Gonjo area,southeastern margin of Qamdo block,eastern Tibet.SCIEI北大核心CSCD

青藏高原东缘的昌都地块是连接青藏高原腹地和藏东南三江-印支地区的关键区域,发育有较完整的晚古生界,以三叠系、侏罗系-白垩系广泛分布为特色;但其前寒武纪基底岩系出露较少,主要以宁多岩群(Pt_(1-2)Nd.)和草曲群(Pt_(3)C)为代表。本文针对昌都地块东南缘贡觉地区出露的一套被前人称为“宁多岩群”的中深变质岩系,开展了系统的野外地质调查、显微薄片分析、锆石U-Pb年代学等研究工作,认为该套中深变质岩系属于一套变质杂岩,其岩石组合既包括了原岩沉积时代不早于奥陶纪的片麻岩、变粒岩和大理岩等副变质岩,又包含了原岩时代分别为中二叠世的斜长角闪岩和中三叠世花岗质片麻岩等正变质岩。其原岩时代特征与昌都地块北缘的宁多岩群有较大差别,不应当归属为昌都地块的前寒武纪结晶基底。结合片麻岩的变质新生云母类矿物Ar-Ar测年数据和变质后期侵入的闪长玢岩脉锆石U-Pb年龄,认为贡觉地区出露的中深变质岩的变质时代为ca.260~244Ma(P_(2)-T_(2))。该期发生在昌都地块东南缘的角闪岩相变质作用,是金沙江古特提斯洋向西俯冲-碰撞的构造响应。     

加拿大纽芬兰岛Indian Head Range地块格林威尔期二长花岗岩年龄、Nd-Hf同位素特征——块体属性与演化新证据

加拿大阿巴拉契亚造山带纽芬兰岛Humber带基底地块属性及地壳生长演化是近年来关注的科学问题,尤其是岛内西南部的Indian Head Range地块,其年龄组成与同位素特征研究对区域基底构造属性划分与对比至关重要。本文对Indian Head Range地块内的二长花岗岩岩体进行了锆石U-Pb定年,得到其²⁰⁶Pb/²³⁸U加权平均年龄值为1 149±4 Ma,代表该岩体的侵位年龄。这一定年结果表明该岩体具有中元古代晚期的年龄,为该地块格林威尔期岩浆事件的存在提供了新的年龄证据。Nd-Hf同位素分析结果显示,该二长花岗岩岩体εNd值为-2.3,εHf值介于+1.93～+3.65之间,两阶段Hf模式年龄介于1.84～1.73 Ga之间。结合前人研究,我们认为Humber带内各地块发育约1.5 Ga、1.15 Ga和1.0 Ga的3期花岗质岩浆事件,它们具有相似的Hf模式年龄值,暗示它们均来源于古元古代新生地壳物质的再造。带内格林威尔基底地块均为原地基底,且与劳伦大陆远端东部边缘具有一致的岩浆-构造演化史。以上研究对Humber带内格林威尔基底...     

滇中南中元古代撮科蛇绿混杂岩地质特征及构造背景

撮科蛇绿混杂岩出露于元江县撮科大寨及周边地区,受到后期构造作用影响发生一定的变质和变形。蛇岩性较为复杂,岩块与基质之间为断层接触。基质以硅质岩、熔结凝灰岩和花岗质砾岩为主,岩块的类型主要有辉石岩、辉长岩、辉绿岩、闪长岩、玄武岩、斜长花岗岩等。其中,撮科蛇绿混杂岩中熔结凝灰岩的SHRIMP锆石U-Pb龄为(1 170±7) Ma(MSWD=0.54,n=12),花岗质砾岩基质具有单一的年龄,为(1 151±5) Ma(MSWD=1.3,n=17);辉长岩岩块的SHRIMP锆石U-Pb年龄为(1 168±8) Ma(MSWD=0.72,n=17),斜长花岗岩岩块的SHRIMP锆石U-Pb年龄为(1 163±9) Ma(MSWD=1.83,n=15),花岗斑岩岩块的SHRIMP锆石U-Pb年龄为(1 186±6) Ma(MSWD=0.92,n=17)。这些年龄指示该蛇绿混杂岩形成于中元古代晚期。撮科蛇绿混杂岩中辉长岩REE标准化曲线整体表现较为平坦的右倾趋势,具有与E-MORB相似的稀土元素特征。在MORB标准化图解中Nb、Ta没有出现明显的负异常,极低的Zr/Nb(8.65)、La/Nb(1.05)、Ba/Nb(10.72)、Th/Nb(0.10)、Th/La(0.09)、Ba/La(10.56)、Zr/Hf(43.4)平均值,且微量元素判别投点主要落入板内玄武岩范围,指示撮科蛇绿混杂岩应属于MORB型蛇绿岩,可能形成于板块伸展的构造环境。熔结凝灰岩锆石的ε_Hf(t)值为-8.7 ~-4.7,平均值为-6.6,所有ε_Hf(t)均为负,Hf同位素模式年龄(t_DMC)为2 534~2 296 Ma,平均为2 408 Ma,指示熔结凝灰岩来自古元古代结晶基底的重熔。撮科蛇绿混杂岩的厘定,对重新认识原大红山群老厂河组的属性,研究扬子陆块西南缘中—新元古代岩浆和构造事件,划分扬子陆块基底大地构造单元具有重要意义。     

鄂尔多斯盆地东缘临兴区块页岩气成藏因素分析及富集区预测

结合中联公司前期勘探成果,基于钻井、岩心、测井资料及实验数据,对鄂尔多斯盆地东缘临兴区块本溪组、太原组和山西组泥页岩沉积特征、有机地球化学特征、储层特征以及含气性特征进行了研究,重点讨论了页岩气的富集区。研究成果表明:本溪组和太原组发育潮坪相沉积环境,山西组发育三角洲相沉积环境;整体属于中等-优质烃源岩,太原组烃源岩最好;本溪组和山西组有机质类型主要以腐殖型为主,太原组有机质类型主要以混合型-腐殖型为主;有机质成熟度整体处于成熟-高成熟阶段,具有良好的生烃潜力;储集层微裂隙较发育,属于低孔低渗类型;山西组和太原组的脆性矿物含量在50%以上,有利于后期压裂;研究区泥页岩具有较高的含气量和较强的吸附能力;山西组页岩气富集区主要集中在北部和西南部,太原组页岩气富集区主要集中在北部,且资源潜力最优,本溪组页岩气富集区主要集中在西北部和东北部边缘一小块区域,且资源潜力有限。     

Types, Petrophysical Properties and Pore Evolution of Late Ediacaran Microbial Carbonates, Tarim Basin, NW China

The Upper Ediacaran microbial carbonates of the Tarim Basin are potential reservoir geobodies for future hydrocarbon exploration with rising interest in exploration for deeply-buried reserves. However, little knowledge has been acquired on the types of microbial carbonates that are present, the properties of the reservoir and the pore evolution, hampering predictions of high-quality reservoirs in these carbonates. Integrated with petrography and in-situ U-Pb dating geochronology analyses, this study aims to clarify the types of microbial carbonates present and to reconstruct the pore evolution processes of the potential reservoir rocks. The Upper Ediacaran microbial carbonates of the Tarim Basin can be divided into four types, based on their features in terms of different scales (macro- to micro-): microbial laminite, stromatolite, spongiomicrobialite and microbial-peloidal wackestone/mudstone. Petrophysical properties show that all these microbial carbonates have low porosity and very low permeability with poor connectivity. These carbonates were subject to long-term and complex diagenetic processes, mainly consisting of dissolution, compaction, pervasive dolomitization, cementation and fracturing. The most important reservoir spaces are contributed by vugs and dissolution-enlarged pores, which are likely to have been associated with the widespread uplift of the Aksu area in the terminal Ediacaran. In contrast, the cementation of the fine-to-medium crystalline dolomite greatly reduced the pre-existing pores. Pore types are closely related to different microbial fabrics, which played an important role in the pore evolution of the microbial carbonates.     

Autochthonous Dolomitization and Dissolution in the Microbial Carbonate Rocks of the Fengjiawan Formation in the Ordos Basin

Many euhedral dolomite crystals and related pores are found in the microbial siliceous stromatolite dolomite and siliceous oolitic dolomite in the Fengjiawan Formation of the Mesoproterozoic Jixian System in the southern Ordos Basin. With the application of the microscope, scanning electron microscope, cathodoluminescence and in-situ trace element imaging, it can be seen that different from the phase I dolomite that was damaged by silicification, the intact euhedral phase II dolomite occurred through dolomitization after silicification, concentrated mainly in the organic-rich dark laminae of the stromatolite and the dark spheres and cores of the ooids. A considerable number of phase II dolomite crystals were dissolved, giving rise to mold pores and vugs which constituted the matrix pores and also the major pore space of the Fengjiawan Formation. The formation and dissolution of the dolomite were controlled by the microenvironment favorable, respectively, for carbonate precipitation and dissolution under the influence of microbial biological activities and related biochemical reactions. The driving force and material supply of dolomitization and dissolution were confined to the fabrics enriched with microorganisms, which are highly autochthonous. This mechanism may be a key factor for the development of Precambrian dolomite and related reservoirs, in the context of the domination of microbial rocks.