山西临汾盆地中对应于S_2古土壤发育前后时期的一次湖退—

临汾盆地的第四纪调查发现,在湖相沉积层之上广泛覆盖着部分L3黄土层或S2古土壤层,表明在S2古土壤发育前后时期盆地内发生了一次显著湖退;在海拔稍低的一些区域,出现晚期灰绿色湖相层覆盖在L2黄土层之上的现象,表明在L2黄土堆积时期盆地内发生了一次小幅湖侵;广大的盆地区域都存在S1古土壤广泛覆盖晚期湖相地层现象,表明这次小幅湖侵结束于S1古土壤开始发育之时.盆地的湖退—湖侵变化证明,盆地深部"上地幔强烈上隆→减弱或渐趋稳定→再次强烈上隆……"这样的构造循环是存在的.同时,盆地的湖退时序差异也初步证明了"青藏高原的阶段性隆升对其广大外围地区的地貌发育有着重大影响和控制作用".     

甘肃临夏盆地8～6 MaBP的构造变化

甘肃临夏盆地毛沟剖面上半部高精密度古地磁测年结果表明该剖面磁极性年龄为4.34～13.07 MaBP,其中东乡组、柳树组与何王家组的年龄分别为13.07～7.8 Ma,7.8～6.4 Ma和6.40～4.34 MaBP.该测年结果与文献[1]测得的结果基本一致.临夏盆地6.40～6.16 MaBP湖泊沉积环境突变,8 MaBP左右毛沟剖面地层磁偏角发生明显偏转,盆地中王家山剖面银川沟背斜大约在6 MaBP左右发生倾斜与变形,这表明临夏盆地8～6 MaBP经历了一次强烈的构造运动.     

祁连山冷龙岭南麓的冰川序列、黄土记录和阶地系列的初步研究

已经发现的冰川沉积和黄土记录证明冷龙岭至少经历了３次冰期的冰川作用，其中倒数第３次冰期与沉积黄土Ｌ４（或Ｌ５）的时期相当，其时冰川规模最大，随后各个冰期冰川规模逐渐变小．即使在倒数第三次冰期，冰川末端也只到达冷龙岭南侧门源盆地的边缘，未能覆盖整个盆地形成冰盖；门源盆地南侧发育的５级大通河阶地与分布于盆地中的５级冰水（扇）阶地以及盆地北侧的５套冰碛可以进行对比，它们记录了自倒数第三次冰期以来门源盆地的冰川作用，河流发育与地貌演化。     

采用沉积地貌学方法分析"丁村组"的年代

自1954年发现“丁村组”化石至今，“丁村组”的年代长期存在很大争论。作者通过对S5以来临汾盆地地貌和沉积环境演化过程的研究，揭示出“丁村组”的堆积是在S1早期的一次区域构造抬升引起盆地湖退后才开始发生的，时间距今大约13万年。结合上覆“丁村组”的黄土古土壤分析，发现其堆积结束于距今约5.3万年。“丁村组”的堆积与气下S1古土壤的发育和L1黄土下半段的堆积几乎的同期的。     

陇中西部黄土区黄河及其支流阶地发育的若干问题

隴中西部黄土区黄河及其各支流以发育3极阶地为最典型,中高阶地普遍为黄土所埋藏。基于黄土地层的划分,三組阶地的年龄依次定为Q_2,Q_3,Q_4。根据对阶地纵横剖面与冲积层結构及其厚度的分析,可以确定本区阶地是在构造运动与气候变迁共同作用下形成的。前者表現为三次普遍性的上升,后者可以划分为三次湿潤期和其间的二次干燥期,二者韵律相符,共同制約着河流的蝕积过程。最后通过阶地分析討論了本区河谷起源与发育史。     

临汾盆地13万年以来古气候变化研究

本文运用气候代替指标粒度对临汾盆地滨河东剖面S1以来的古气候进行了重建,在末次间冰期-冰期气候旋回中,临汾盆地的古气候经历了暖湿—冷干—暖湿的变化过程.结果发现临汾盆地滨河东剖面黄土-古土壤序列沉积物既有与大区气候变化的一致性,也有本地变化的特点.     

鄂尔多斯东南部上古生界混积层沉积特征

为了认识鄂尔多斯盆地东南部本溪组、太原组混合沉积特征,利用区域地质、钻/测井和岩芯资料,对碳酸盐-碎屑岩混合沉积层进行了研究。结果表明,本溪组-太原组既是带障壁海岸的海陆过渡相沉积,又是混合沉积;本溪组混积层岩性组合主要为碎屑岩、煤层夹灰岩,而太原组为灰岩夹泥岩及煤层组成;本溪组发育混积相类型为混积潮坪、混积瀉湖、混积障壁砂坝,太原组发育混积台地;结合区域沉积资料总结出了两种沉积相组合模式——本溪组发育混积障壁海岸相、太原组发育混积陆棚相;构造、海平面变化和气候是影响混积发育和组合模式的主要因素,其中,陆表海多期次海侵是混积主要原因。混合沉积决定了本溪组具有丰富的烃源岩、优质储集体和多套生储盖组合,是油气富集的有利层位。     

陕西富县地区晚三叠世延长期岩相古地理特征

通过岩心观察、岩石薄片鉴定、古生物和测井曲线等资料的综合分析,对鄂尔多斯盆地富县地区延长组进行了详细的沉积相研究,认为研究区发育了湖泊三角洲、湖泊和浊积扇三种沉积相类型。在此基础上,编制的岩相古地理图显示,各时期的古地理面貌主要受湖盆演化阶段和湖平面升降变化的控制:长8长7期,为湖盆扩张强烈坳陷阶段,湖平面总体上升,以发育三角洲前缘、浅湖半深湖和浊积扇为特征;长6长4+5期,为湖盆稳定坳陷阶段,湖平面缓慢下降,湖泊退缩至南部边缘地带,以发育三角洲前缘沉积为主;长3长2期,为湖盆缓慢沉降萎缩阶段,湖平面快速下降,岸线大幅度向南迁移,三角洲平原进入研究区,沉积范围与三角洲前缘相当。古地理研究揭示的砂体展布规律对陕北斜坡油气富集带东南缘富县地区的油气勘探部署具有重要的指导意义。     

体积分配原理在河流-三角洲相储层分析中的应用——以大庆长垣萨葡油层为例

通过大庆长垣油田萨葡油层大量钻井资料的沉积相分析、基准面旋回划分、等时地层对比为基础的砂体解剖,对该油层中相当于中、短期旋回规模级别的河流-三角洲相储集砂体在不同可容空间变化过程中的发育程度及其与体积分配关系的地层过程分析,表明在中期旋回基准面升、降过程的范围内,短期旋回的河流-三角洲相储集砂体的体积分配与A/S值具有特定的匹配关系,出现四种情况:(1)对应A/S<<1→A/S＜1的基准面由下降折向上升的转变期,为强迫进积→主动进积的体积分配由缩小折向加大的转换期,因此为有利储层发育的时期,尤其是基准面上升初期的主动进积期,为最有利储层发育的时期.(2)对应A/S＜1→A/S=1→A/S＞1的基准面持续上升过程,为主动进积→加积→退积的过程,体积分配由大缩小.(3)对应A/S＞1的湖泛期,为可容纳空间最大而沉积物供给量最少与向盆地方向迁移距离和体积分配最小的稳定加积期,因此为不利储层发育的时期.(4)对应A/S＞1→A/S=1→A/S＜1的基准面下降过程,体积分配出现由加积→强迫进积的由大而小过程,虽然沉积物向盆地方向迁移距离最大,但被分配的体积却最小.基准面旋回的体积分配过程分析,表明高分辨率层序地层学可有效地指导油气藏开发工程中对储层宏观分布的预测.     

南盘江坳陷泥盆系层序地层格架及古地理环境

南盘江坳陷泥盆系划分为18个三级层序,下、中、上泥盆统分别包括7、5、6个三级层序,平均每个层序延续时限为2.87Ma。按界面性质可将三级层序划分为10个Ⅰ型层序,8个Ⅱ型层序。上述18个三级层序构成二个超层序（二级层序）。盆地腹部泥盆系层序发育齐全,而靠近继承性古陆边缘或沉积高地的浅水区则通常缺失下部1～4层序或顶部17～18层序,并具有自南部钦防海槽向中部右江地区和北部扬子古陆南缘,底部缺失层序增多的趋势。SS1低水位时期形成六盘水—南丹、曲靖—开远两个次级陆源碎屑浅海盆地,滇东曲靖—宜良一带为河—湖环境,而钦防海槽则为次深海海槽环境。海进时期,南盘江坳陷初步形成台—盆相间格局。高水位时期,盆地古地理环境分异较大,边缘形成三角洲环境、滨浅海环境及碳酸盐岩潮坪—泻湖环境;内部发育混积台地、盆地环境。台—盆相间的古地理格局进一步明显。SS2沉积时期,滇东北及黔中南地区形成碳酸盐岩台地;广西地区呈现出台—盆相间格局,常见生物礁及礁前塌积;钦防海槽则演化成统一的陆内裂谷盆地。在SS2沉积未期,滇东北、黔中南地区演化为广泛分布的局限台地。     

亚洲中部中更新世以来气候环境变化--来自天山北坡黄土沉积的证据

亚洲中部干旱区的形成演化对于理解干旱区大气粉尘的全球气候环境效应等具有极重要的科学价值。天山北坡沙湾县东湾镇厚71m的风成黄土为探讨该区环境演化提供了极好素材。对该剖面气候代用指标分析表明，中更新世以来气候环境经历了3个时期，在0．60和0．25Ma左右发生了重要气候事件，现在干旱气候格局是0．25Ma左右形成延续至今。     

末次间冰期陇西黄土记录与气候不稳定性问题的初步研究

陕西黄土高原黄土记录的分辩率较高，Ｓ１古土壤厚达８．５ｍ，主要由两个古土壤组和其间黄土层组成。临夏塬堡剖面上可分为５个古土壤层，主要黄土层记录了末次间冰期内的较干冷高粉尘堆积时期。     

S2以来下蜀黄土沉积序列磁化率记录与深海氧同位素记录的对比

对镇江下蜀黄土剖面进行了系统的磁化率测试,并同深海氧同位素记录进行了对比。结果表明,S2以来下蜀黄土磁化率记录与深海氧同位素记录存在良好的对应关系。首次在下蜀黄土记录中发现了相当于深海氧同位素5a,5b,5c,5d和5e亚阶段的波动特征;下蜀黄土S2磁化率记录则可与深海氧同位素7阶段进行细节上的详细对比。对比揭示,最近20多万年以来,下蜀黄土堆积区对全球古气候变化有着积极的响应;同时,下蜀黄土记录的古气候变化在某些阶段又具有明显的区域特征,可能反映的是全球气候变化效应与东亚古季风气候影响的叠加作用。镇江下蜀黄土剖面能获得精度较高的全球变化信息与其特定的地理位置、纬度位置和地貌条件有关。     

Uplift processes for the Qinghai-Tibet Plateau: A comparative study of Yecheng section and Siwalik group

Comparative studies of the Yecheng section at the northern piedmont of the Kunlun Mountain, and the Surai Khola section at the southern piedmont of the Himalayan Mountain, indicates that the Qinghai-Tibet Plateau is dominated by continuous uplift over the past 10 Ma. And the effective time scale for dividing the uplift stages would be 1 Ma. The uplift processes of the entire plateau can be divided mainly into three stages, i.e., a slow uplift stage (10.0-6.0 MaBP), a transitional uplift stage (6.0-2.5 MaBP) and a rapid uplift stage (since 2.5 MaBP). The plateau might have risen to 2000 m above sea level by 4.6 MaBP in response to uplift and to more than 3000 m by 2.5 MaBP.     

Loess-soil sequences in southern Anhui Province： Magnetostratigraphy and paleoclimatic significance

Two parallel loess-soil sequences from Xuancheng and Fanchang in southern Anhui Provinces are dated using geomagnetic and luminescence methods.The Brunhes/Matuyama(B/M) reversal boundary is recognized within the lower part of the so-calles Vermiculated Red Soil (VRS) in the Xuancheng section while the entire Fanchang sequence is of Brunhes age.This indicated that the most recent VRS in southern China,a stratigraphic marker and an indication of extremely warm-humid conditions,was formed during the middle Pleistocene,chronologically correlative with the S4 and S5 soil units in northern China.Microscopic and sedimentologic in vestigations reveal that eolian deposition started in this region at about 0.85 MaBp,roughly synchronous with the well-known Mid-Pleistocene climate change of global significance.The strengthening of both summer and winter monsoon circulations and the consequent river hydrological changes at that time would have provided favorable conditions for sustained eolian deposition in the middle-lower reaches of the Yangtze River since 0.85 MaBP.     

1.2～0.6MaBP青藏高原的隆升与东亚地表各圈层的相互作用

结合近年来黄土、河流阶地、冰冻圈、沙漠、植被等地表各个圈层在1.2～0.6 MaBP青藏高原构造隆升期间环境变化的最新研究成果,综合论述了在此期间青藏高原的隆升对地表其他各个圈层的影响.研究表明:1.2～0.6 MaBP期间,青藏高原的隆升对东亚地表环境产生了重大影响,中国内陆主要沙漠(主要是西部沙区的沙漠)在这一时期形成并极端扩张;黄土在祁连山、昆仑山、天山等高山山前和西秦岭等地开始大范围地堆积;以昆仑山和念青唐古拉山为代表的西部高山开始了冰冻圈的发育,各地植被变化都不同程度地反映了环境的逐步干旱化.结合这些研究,提出了1.2～0.6 MaBP期间东亚地表圈层间相互作用的简单模式,并探讨了青藏高原隆升与地表圈层变化之间的内在耦合.     

Radiolarian record to paleoecological environment change events over the past 1.2 MaBP in the southern South China Sea

This note studies the Radiolarian fossil groups since 1.2 MaBP in ODP leg 184 site 1143, the southern South China Sea (SCS). The result shows that radiolarian abundance experienced a significant variation: before 0.9 MaBP it remained at the extremely low level, but increased with low extent between 0.9–0.65 Ma, which corresponded to the Mid-Pleistocene Transition stage, and it increased rapidly after 0.65 MaBP. During the whole process, the average abundance became higher and higher in each stage, and showed regularly periodic fluctuations. The obvious increase after 0.65 MaBP is inferred to result from the enhanced upwelling in this region, which was induced by the intensified monsoon circulation after the “Mid-Pleistocene Transition”. An outstanding result of the spectral analyses is that a long oscillation of ∼ 0.2 Ma cycle was found in the records of radiolarian abundance and complex diversity, which corresponds well to the result of other paleoceanographic indexes. This probably indicated a special cycle characteristic of paleoecological environment evolution in this area. In addition, all of the radiolarian indexes show an obvious boundary in about 0.47 MaBP, indicating the abrupt variation of the community structure and radiolarian abundance level before and after 0.47 MaBP. So we suppose that there existed a distinct change event of oceanic ecology environment during that period.     

Molecular phylogeny of the specialized schizothoracine fishes （Teleostei： Cyprinidae）,with their implications for the uplift of the Qinghai-Tibetan Plateau

Molecular phylogeny of three genera containing nine species and subspecies of the specialized schizothoracine fishes are investigated based on the complete nucleotide sequence of mitochondrial cytochrome b gene. Meantime relationships between the main cladogenetic events of the specialized schizothoracine fishes and the stepwise uplift of the Qinghai-Tibetan Plateau are also conducted using the molecular clock, which is calibrated by geological isolated events between the upper reaches of the Yellow River and the Qinghai Lake. Results indicated that the specialized schizothoracine fishes are not a monophyly. Five species and subspecies of Ptychobarbus form a monophyly. But three species of Gymnodiptychus do not form a monophyly. Gd.integrigymnatus is a sister taxon of the highly specialized schizothoracine fishes while Gdo pachycheilus has a close relation with Gd. dybowskii, and both of them are as a sister group of Diptychus maculatus. The specialized schizothoracines fishes might have originated during the Miocene(about 10 MaBP), and then the divergence of three genera happened during late Miocene (about 8 MaBP). Their main specialization occurred during the late Pliocene and Pleistocene (3.54-0.42 MaBP). The main cladogenetic events of the specialized schizothoracine fishes are mostly correlated with the geological tectonic events and intensive climate shift happened at 8, 3.6, 2.5 and 1.7 MaBP of the late Cenozoic.Molecular clock data do not support the hypothesis that the Qinghai-Tibetan Plateau uplifted to near present or even higher elevations during the Oligocene or Miocene, and neither in agreement with the view that the plateau uplifting reached only to an altitude of 2000 m during the late Pliocene(about 2.6 MaBP).