黄土高原河流演化研究中的几个地学问题——与朱照宇、丁仲礼先生商榷

以河流阶地与堆积黄土、河流起源与冰期、河流演化与新构造运动等3个问题与《专著》商榷.其中风成黄土不应属河流冲积阶地组分,黄土层厚度尺寸不应计入河流阶地面高度中;河流起源应考虑冰期要素,离石黄土中第二砂质黄土层应属鄱阳冰期层位.冰期前为河流起源Ⅰ期,冰期后为河流起源Ⅱ期;河流演化是在新构造运动支配下发生,黄河、洛河、汾河等演化均属各自流域内多个盆地间贯通的首次演化;河流尚有跨两大已成河流域间的二次演化;给出了洛河演化模式阶地位相图.     

Recent glacial retreat and its effect on water resources in eastern Xinjiang

The eastern Xinjiang Basin is desperately short of water. Most rivers in the basin originate in the high eastern Tianshan, which has abundant precipitation and numerous alpine glaciers. Fieldwork conducted on three reference glaciers around Mt. Bogda in 1981 and 2009 suggests that they all strongly melt in summer, a process that has tended to accelerate in recent decades. Based on topographic maps from 1962 and 1972 and 2005/2006 satellite imagery, we investigated 203 glaciers near Mt. Bogda and 75 glaciers near Mt. Harlik. The results show that the surface area of the Mt. Bogda glaciers decreased by 21.6% (0.49% a?1) from 1962 to 2006. This was accompanied by a 181 m decrease in length and a 28% drop in ice volume. In the Mt. Harlik region, areal extent was reduced by 10.5% (0.32% a?1), length by 166 m, and volume by 14% between 1972 and 2005. South-facing glaciers lost more of their area than those that are north facing, yielding an areal loss of 25.3% and 16.9% for southern and northern slopes of Mt. Bogda, respectively, and 12.3% and 6.6% for the comparable slopes of Mt. Harlik. Glaciers smaller than 0.5 km2 in area experienced the strongest retreat, whereas glaciers larger than 2 km2 in area experienced gentle recession but may be the main contributors in the future to river runoff. Glacial ablation in eastern Xinjiang tends to be strong, and the water resources in this region are deteriorating. Also, a heavy reduction in the capacity of the local karez system, as well as a significant change in river runoff, can be related to glacial retreat. Combined, this will adversely affect the downstream city of Urumqi and the Turfan Basin.     

冰碛物年代及其环境变化

冰碛物年代一直是冰川学研究的一个重要内容，也是环境变化深入研究的对象，冰川沉积物对于气候地层的建立起着不可忽视的作用。但是由于冰碛物自身与海洋、黄土等记录环境变化的内容相比存在局限性，所以造成对冰期划分，对比的不利。另外，自身年代缺乏也限制着全球冰期的划分与对比，笔者认为，目前的冰碛物研究对于气候地层起到了补充、验证的作用，在较大的时间尺度上是可行的，但是要提取高分辨率的环境变化信息，应该探索新的替代载体；同时要大力加强冰碛物绝对年代的研究。     

Diatoms from the southwestern continental slope, South China Sea, and their paleoenvironmental significance since the last glacial times

A quantitative study was undertaken on diatoms from cores (SA08-34) obtained from the southwestern continental slope of the South China Sea (SCS). A total of 165 diatom species belonging to 45 genera were identified. We constructed a stratigraphic subdivision and correlation according to the characteristics of diatom assemblages together with ¹⁴C dating and carbonate analysis. We also discuss the sedimentary environment in the sea area since the last glacial times. The research shows that the diatom assemblages coincide with interglacial and glacial times, and changes in diatom abundance reflect the instability of the climate in the southern part of the SCS, such that short-term, temperature descending events correlate with the interglacial interval. The abundance of diatoms is relevant to interglacial and glacial times, since high abundance values were associated with an interglacial interval, and low abundance values with the last glacial maximum. We assume that strong upwelling developed in the interglacial interval, the development of which was influenced by variations of monsoons in the East Asian region.     

羧酸衍生物氨解实验的改进

针对传统羧酸衍生物氨解实验内容单一,涉及知识面较小,产物被浪费等问题,文章从实验微型化入手,将验证性实验延伸应用于物质制备和提纯等方面。并解决了常温过滤过程中的堵塞、污染问题,减少了副产物的产生。     

山西宁武冰洞成因分析

从冰洞所处位置分析该地区在地质时期曾经是岩溶发育区,并且经历了温暖潮湿的气候作用,逐渐形成石灰岩溶洞;而且该地区曾经是山岳冰川发育区,在第四纪冰期及间冰期时,大量的积雪、冰川融水甚至破碎冰块堆积于洞中,经过复杂的物理变化,融化和重新凝结,再加上大气降水的不断渗入,在溶洞内形成各种形态冰物质的广泛分布现象———冰洞形成;以后的年代,由于当地比较特殊的地形、气候等自然地理环境因素,冰洞得以有效保存。宁武冰洞的形成是由岩溶作用和冰川作用以及环境因素共同作用的结果。     

全球气候变化及冰期与间冰期交替的原因及其计算

许多科学家都怀疑温室气体的排放是全球变暖的主要因素，他们认为自然驱动才是全球气候变化的主要因素，但他们并未找出具有说服力的自然驱动力。于是作者研究了各种可能引起气候变化的自然驱动力，发现火山活动能改变地球的轨道，因而是引起气候明显变化的关键因素。其中主要推导了火山喷发改变地球转速的公式以及地球变速引起地球变轨的公式。根据这些公式，通过计算机的高精度计算可以发现一定规模的火山喷发确实能使地球变轨，从而使全球变冷或变暖，甚至进入冰期或间冰期。因此，解决了气候变暖以及冰期与间冰期交替的成因问题，并找出了相应的对策。     

天山乌鲁木齐河源区冰川擦痕级配特征及其空间分布探讨

通过对天山乌鲁木齐河源区一号冰川和七号冰川羊背石上冰川擦痕实测数据的统计分析，探讨了基岩磨光面上冰川擦痕的级配特征．得出冰川擦痕级配服从指数分布，擦痕级配指数分布的参数可以作为描述擦痕密度的指标．在此基础上进一步探讨了擦痕级配参数的空间分布特征及其对冰川动力状况的指示意义．     

Genetic consequences of postglacial colonization by the endemic Yarkand hare （Lepus yarkandensis） of the arid Tarim Basin

Orogenesis of the Qinghai-Tibetan Plateau,which occurred in a stepwise manner,contributed to the extreme aridity of the Tarim Basin,resulting in vulnerable and unstable ecosystems.Quaternary climatic oscillations may have affected the ecosystems and,consequently,the distributions and genetic structuring of the Tarim Basin’s biota.We used nucleotide sequence data from 2 mitochondrial (mt) DNA genes (Cyt b and the D-loop) to test hypotheses associated with the matrilineal and demographical histories of the Tarim Basin’s endemic Yarkand hare (Lepus yarkandensis).Range-wide sampling involving 20 populations and 224 individuals detected 126 haplotypes that clustered into 5 major lineages in both the phylogenetic tree and median-joining network.Populations from the northern and eastern Tarim Basin shared a similar history,as did those from the western and southern regions.Demographical analysis and genetic diversity estimations suggested that the western and southern regions might have served as glacial refugia for the Yarkand hare during Quaternary climatic oscillations.The distribution of the Yarkand hare,especially in the northern and eastern parts,probably represented 3 postglacial colonization events,dated to 0.21,0.090 and 0.054 MYA,which corresponded to known interglacial periods.Given the relatively complete geographic isolation between the eastern and southern populations,the Yarkand hare likely dispersed during postglacial periods from the southwest to the north,and then onward to the east.The absence of water likely forced the species into refugia,and this differed from other Pleistocene biogeographical drivers.The demographical and historical patterns have important implications for conservation.     

静乐水文站冰期日平均流量试验分析

介绍了静乐水文站进行的冰期日平均流量试验,分析了试验结果,提出了合理推算流量的建议。