生物演化同宗殊途 物竞天择乃其一也——也为达尔文辩护

自从基因学说—骤变主义、寒武纪生命大爆发、地史上发生多次大灭绝—大复苏等学说兴起后,达尔文的渐变论和物竞天择学说更受非议,甚至出现了全盘否定达尔文进化论的书文,譬如著名学者许靖华先生。达尔文的学说确有这样那样的片面性,但批评应取历史主义态度,对前人不必如此苛求,因而为之做了某些辩护;同时认为生物进化同宗殊途,进化的动力和机制,无论是必然/偶然、内因/外因,遗传/变异,渐变/质变,均变/骤变(突变)或灾变,大灭绝/大复苏,物竞天择/天促物进,生存竞争/协同演化或共存共荣,适者生存/幸运者生存,自然选择/用进废退,宏演化/微演化,在生物和大的生态系统演化中,它们不都是有此无彼的,而是相辅相成的,都含或多或少的部分真理,任何单一的演化模式都解释不了如此精彩纷呈、奇妙无比的生物世界。     

Geochemical Features of the Two Early Paleozoic Ophiolitic Zones and Volcanic Rocks in the Central —Southern Tianshan Region ,Xinjiang

This paper deals with the geochemical features of the two Early Paleozoic ophiolite zones in the central-southem Tianshan region and the central Tianshan igneous rock belt between them.Study results suggest that the central Tianshan belt was an Ordovician volcanic arc with an affinity of continental crust, and the Kumux-Hongluhe ophiolitic zone that is located on the southern margin of central Tianshan has a crustal affinity to back-arc marginal sea.The Aqqikkudug-Weiya ophiolitic zone is an accretionary boundary between the Tuha continental block and the central Tianshan volcanic arc during Late Silurian to Devoniann;Ordovician ophi-olitic blocks,Silurian flysch sequence and HP metamorphic rock relics are distributed along the Aqqikkudug-Weiya zone.Geochemically,ophiolitic rocks in the Aqqikkudug-Weiya zone have an affinity to oceanic crust,reflecting a tectonic setting of paleo-trench or subduction zone .The Early Carboniferous red molasses were deposited unconformably on the pre-Carboniferous meta-mrophosed and ductile sheared volcanic and flysch rocks,providing an upper limit age of the central and southern Tianshan belts.     

A Paleoproterozoic orogeny recorded in a long-lived cratonic remnant (Wuyishan terrane), eastern Cathaysia Block, China

The Precambrian basement of northern Wuyishan (southern Zhejiang Province, eastern Cathaysia Block, South China), consists mainly of Paleoproterozoic granites and metamorphic rocks of the Badu Complex, which are the oldest rocks found in the Cathaysia Block. LA-ICPMS zircon U–Pb ages for a gneiss and five gneissic granites from the Tianhou, Danzhu, Xiaji and Lizhuang plutons indicate that magmatism and metamorphism took place between 1888 and 1855 Ma. The Xiaji (1888 ± 7 Ma) and Lizhuang (1875 ± 9 Ma) granites have high SiO₂, K₂O and Rb contents, high A/CNK (1.09–1.40) and Rb/Sr, and low contents of Sr, REE and mafic components (Mg, Fe, Ti, Mn and other transition metals). They have the geochemical signature of S-type granites, and a sedimentary protolith is confirmed by the presence of abundant inherited zircons with a range of ages and Hf-isotope compositions. The Tianhou and Danzhu granites are metaluminous to weakly peraluminous (A/CNK = 0.80–1.07), and have low SiO₂ contents, high Ga/Al and FeO/(FeO + MgO) ratios, and Zn and HFSE concentrations typical of A-type granites. They also record high crystallization temperatures (885–920 °C), consistent with A-type granites. High Y/Nb ratios (>1.4) indicate that they belong to the A₂ subgroup, suggesting that they probably formed in a post-orogenic tectonic setting. Their ages range from 1867 to 1855 Ma, slightly later than the syn-collisional Lizhuang and Xiaji S-type granites. These granitic rocks and the metamorphic rocks of the Badu Complex define a late Paleoproterozoic orogenic cycle in the area. All the 1.86–1.90 Ga zircons, whether derived from S- or A-type granites, show similar Hf-isotopic compositions, with Hf model ages clustering at 2.8 Ga. These model ages, and inherited zircons (ca. 2.5–2.7 Ga) found in some rocks, indicate that the late Paleoproterozoic magmatism and tectonism of the eastern Cathaysia Block represent an overprint on an Archaean basement. This Paleoproterozoic orogeny in the Wuyishan terrane coincides with the assembly of the supercontinent Columbia, suggesting that the Wuyishan terrane was the part of this supercontinent.Zircon ages also record an early Mesozoic (Triassic) tectonothermal overprint that was very intensive in the northern Wuyishan area, leading to high-grade metamorphism of Paleoproterozoic basement, Pb loss from Paleoproterozoic zircons and overgrowth of new zircon. The central and southern parts of Wuyishan and the Chencai area (northern Zhejiang Province) also experienced strong reworking in Neoproterozoic and early Paleozoic times. The Wuyishan terrane (especially in the north) represents a long-lived remnant of the old craton, which has survived for at least one billion years. The compositions of the basement rocks, the Paleoproterozoic orogeny and the Triassic tectonothermal imprint in the Wuyishan terrane are similar to those recognized in the Yeongnam massif of South Korea, suggesting that the two terranes may have been connected from Paleoproterozoic to Triassic time.     

新疆吐哈盆地侏罗纪湖相动物遗迹化石的发现及古环境意义

对首次在吐哈盆地台北凹陷侏罗系发现的分布于不同剖面、不同层位中的动物遗迹化石进行了系统研究。主要分析了研究区内动物遗迹化石的特征 ,将之划分为六大类型 :( 1 )垂直居住迹 ;( 2 )垂直觅食迹 ;( 3 )“U”形管 ;( 4)潜穴系统 ;( 5)逃逸迹 ;( 6)停息迹。较详细地分析了各类型的形态特征和保存特点 ,简要分析了造迹生物的行为习性及环境意义。在此基础上 ,建立了本区动物遗迹化石的环境模式。同时指出 ,遗迹化石在陆相含油气盆地确实大量存在 ,并在储层研究中具广泛的实践意义。     

地理信息系统与水文模型集成研究述评

从地理信息系统与水文模型的集成方式,水文模型计算域的空间离散等方面讨论了GIS与水文模型的集成问题,再从四个方面分析了GIS与水文模型集成存在的问题。由于分布式水文模型对空间数据的需求,又从GIS、RS与水文模型的集成现状与发展讨论了集成研究的目标。     

地球化学场的连续多重分形模式

研究了粤北4292km^2内1448个基岩样品的35项元素、安徽省江南江北各约22000km^2和18100km^2内5489个和4524个水系沉积物样品的14项元素、塔里木盆地5个含油气区的7419个土壤样品的酸解烃（C1－C5）、蚀变碳酸盐、紫外、荧光等油气地球化学指标值的面积校正累计频率（ACAF）特征。研究表明，地球化学指标值的ACAF均显示连续多重分形特征，而且具两种特定模式：简单连续多重分析（SCM）模式和具高浓集的连续多重分形（HACM）模式；主要成矿元素和主要油气化探指标均不同程度地显示为HACM模式，而其他指标多表现为SCM模式。不同的分形模式可望用于区域含矿含油性和区域环境评价，而开始出现高含量叠加的“临界”含量值可能作为区域成矿成油强度的一种度量。     

川西北微细浸染型金矿床区域成矿动力学模式

川西北微细浸染型金矿床的空间展布受构造岩浆带的严格控制,金成矿作用与构造、岩浆、流体作用密切相关.本文根据其成矿成因特点,建立了该区的构造-成矿时空演化模式和成矿构造系统动力学模式.     

豫陕中-晚元古代沉积盆地(一)

河南西部和陕西东部的秦岭以北地区,以及山西南部中条山地区,广泛分布的中、上元古界未变质地层,近年来受到越来越多的重视。由于剖面完整,厚度巨大,沉积建造又别具一格,因而多将本区视为华北断块上一个独立的地层和沉积分区。本文着重讨论该盆地类型及其与东秦岭拉张运动的关系<^[1,2]。     

多氯联苯的环境特性及分析测试进展

由于多氯联苯(PCBs)在环境样品中残留浓度低,基质复杂干扰多,必须对环境样品进行预处理,并且结合先进的分析测试方法进行分析。文章综述了PCBs的性质及其主要来源;近年来分析PCBs的前处理方法,主要包括加速溶剂萃取、超临界流体萃取、微波萃取、固相微萃取、基质分散固相萃取等提取方法和固相萃取小柱、凝胶渗透色谱等净化方法;目前气相色谱和气相色谱-质谱联用技术发展以及一些新技术在分析PCBs方面的应用,包括全二维气相色谱法、快速气相色谱法、气相色谱-离子肼串联质谱法、高分辨气相色谱-高分辨质谱法等。总结了国内外PCBs的研究现状。     

大别山碧溪岭未经历超高压变质的片麻状花岗岩

关于大别山超高压变质带中与榴辉岩密切伴生的花岗片麻岩是否也经历了超高压变质作用一直是个争议的问题。笔者最近在碧溪岭片麻状花岗岩中首次发现了可靠的岩相学和矿物学证据 ,证明该岩石只遭受到绿片岩相变质作用的改造 ,而未曾记录超高压变质矿物组合。根据片麻状花岗岩与围岩接触部位强烈糜棱岩化的发育 ,认为超高压岩石在抬升到地壳范围时与以花岗质岩石为主构成的扬子陆壳发生了大规模的构造并置。