南海沉积记录中Uk37指数与颗石藻生长季节对应性的探讨

根据表层沉积物长链不饱和烯酮的不饱和度(Uk37指数)以及现代海洋0～30 m层平均温度(Sea Surface Temperature,SST),探讨在低温和高温海区利用Uk37指数重建上层古温度的合理性.同时,结合文献报道的南海上层水体中颗石藻(E.huxleyi,G.oceanica和G.ericsonii)细胞丰度的季节特征,探讨了沉积记录中Uk37指数与季节的对应性.结果表明:(1)在极端低温和高温海区(-0.6℃和28℃)Uk37指数仍是重建上层水体古温度的良好替代指标;(2)由于南海长链烯酮源生物——颗石藻的主要生长季节为冬季,因此,尽管南海表层沉积物中的Uk37指数与4个季节的SST均显著相关,但沉积记录中的Uk37指数反演的SST可能仅代表冬季上层水体的温度.     

黄河中游新近系红粘土粒度特征及其古环境——以陕西府谷老高川为例

黄河中游新近系红粘土粒度分布表现出明显的三峰分布，说明它是由多种成因组份构成，而且每种成因组份对整体的贡献率也不同。其粒度组成主要是以粉土粒级(5～50μm)为主，而250μm以上的颗粒少见。除小于1μm和小于2μm粒级含量变化相对稳定外，其余粒级均表现出旋回起伏的特征。大于63μm和大于30μm及中值曲线变幅较大，说明当时冬季风比较盛行，而且变化强度比较大；而小于2μm粒级曲线变化相对稳定，说明当时夏季风很弱，而且没有太大变化。粒度曲线与野外岩性所得结论相一致，说明当时气候总体上是以干冷为背景，但也有干冷与暖湿的交替。野外岩性上表现为粘土层与钙结核层相互交替，粒度曲线上表现为峰谷旋回起伏的变化，同时也有古生物证据与岩石学证据相佐证。     

藏北中侏罗世遗迹化石Tisoa Serres的发现及其环境意义

遗迹化石TisoaSeres国内尚无报导,70多块遗迹化石Tisoa标本见于藏北羌塘地区中侏罗统色哇组。本文对所采集的Tisoa标本作了详细的研究,Tisoa通常由紧靠的圆柱状平行潜穴管组成,单一潜穴管直径2～7mm间,两栖管间距1～4mm,外部由锥形或圆柱形钙质结核所包围,钙质结核直径10～25mm。保存完好的标本表明Tisoa为两个潜穴管底部相连的“Ｕ”形管,大多数只含两个平行潜穴管的标本实际上只是保存的一个“Ｕ”形管的上部。在大多数Tisoa管壁通常发育不规则的黄铁矿层或一微晶方解石薄层;栖管中常充填微晶和亮晶方解石以及黄铁矿、云母及泥质和石英。一般认为Tisoa是一种节肢动物潜穴。沉积环境分析,产Tisoa的沉积环境为正常浅海环境。     

香港西博寮海峡WB7孔的第四纪沉积及硅藻研究

香港西搏寮海峡ＷＢ７孔第四纪沉积物中共有硅藻５４属，１８６个分类单位，该硅藻生物群以沿岸潮间带和近岸浅海种为主，伴有热性，暖热性浮游硅藻。依据硅藻在剖面中的分布特征，丰度及百分比含量变化，自下而上可划分出６个硅藻组合带。并明显反映该沉积时期的古气候与古环境特征，其中第５，６，带相当于全新世，其余４个带均属更新世。     

北美东部威斯康星中、晚期古环境与气候变化的甲虫化石证据

北美Laurentide冰盖于末次冰期的大部分时间在北美东北部一直存在，冰盖的活动对北美东部冰期时的环境和气候有很大的影响。甲虫分析表明，北美东部中纬度地区在威斯康星中、晚期的气候以寒冷为主，中间分别在42000aB.P.,34000aB.P.和28000aB.P.出现3次明显的气候变暖。此区威斯康星中期气候冷暖波动的幅度和出现的时间可以与同期的格陵兰冰芯记录及北大西洋Heinrich事件对比。     

Epibionts, their hard-rock substrates, and phosphogenesis during the Cenomanian–Turonian boundary interval (Bohemian Cretaceous Basin, Czech Republic)

Hard inorganic substrates (rock clasts and rocky bottom) belonging to the Ka k Member of the Korycany Formation (upper Cenomanian–?lower Turonian) and to the Bílá Hora Formation (lower Turonian) have offered a good opportunity for the study of encrusting faunas of the Cenomanian–Turonian boundary interval. Distributional features of cemented epibionts and the recorded period of phosphogenesis enabled the differentiation of two-phases in the Ka k Member conglomerate formation. During the first phase, the rock substrates were occupied by a so-called A-association of encrusters (29 species, with dominance of oysters and bryozoans). This fauna partly changed during the subsequent phosphogenic period and not only survived the following period of reworking and the second phase of conglomerate formation, but also persisted until the onset of calmer sedimentation in the early Turonian. This changed community is named theAtreta-Bdelloidinacommunity (23 species). The opportunistic agglutinated foraminifersBdelloidina cribrosaand/orAcruliammina longalocally dominated the respective communities during several physico-chemically stressed episodes. On sloping substrates, the bivalvesAtretaandSpondylusattached themselves in a preferred orientation (so-called slope orientation). This feature indicates the original position in which some mobile substrates were colonized. Other questions, such as the taphonomy of encrusters and the character of their substrates are also briefly discussed.     

The upper pleistocene loess of southern Tunisia: A statement

On the Matmata Plateau, the sedimentological characteristics of the peri-desert loess and the interbedded palaeosols (particle-size distribution; chemical and mineralogical composition of major components; trace elements; clay mineral assemblage; heavy mineral assemblage; SEM-examined surficial textures of the quartz and palygorskite grains) show notable homogeneity: they also indicate its allochthonous origins (the main sedimentary source being the Great Eastern Erg), its transport as an aeolian suspension sediment prior to deposition, and moderate pedogenesis acting during deposition. The emplacement of the loess was synchronous with a ‘pluvial’ steppe palaeoenvironment moister than at present, as shown by ¹⁸O and ¹³C data. The palaeosols point to a weak pedogenesis and colluvial and alluvial reworking that were contemporary with the aeolian deposition. ¹⁴C radiometric dating suggests a main period of pluvial dust-fall/loess deposition in the Upper Pleistocene (until 10 000 yr BP) and a shorter one in the Middle Holocene.     

西藏札达盆地晚上新世古植被型分析

札达盆地晚上新世生长着以高山荒漠小灌木、草原、亚高山常绿针叶林和中低山常绿针叶林为主的植被。气候显示了从干旱寒冷至温暖湿润的垂向分异，总体偏于干、寒，属亚热带高山或亚高山类型。当时区内海拔已较高，南低北高的地势特征也已形成。古植被重建及现青藏高原的植被调查资料表明，当时盆地最低处的海拔可能不会超过2 500 m，其周围及北部可能存在海拔4 000 m的高地或更高的山峰。中、晚上新世迄今，该地区隆升的高度的可能不会超过1千米，幅度较喜马拉雅山中部地区小。     

内蒙白彦花水塘中现生叶肢介的生态考察及其对古环境重建的意义

在内蒙古自治区白彦花车站附近分布的20余个坑塘和1个较大的湖泊中,生活着大量的叶肢介。对该地区叶肢介的生活习性（游动、觅食、交配等）和生存环境（坑塘的大小、水温、水体的pH值和气温）进行的调查显示：叶肢介一般活动在浅水水域,如坑塘和湖泊边缘的浅水地带;他们的游动非常缓慢,大约1cm/s;当他们交配时就停留在某处,雄性用附肢拨动含有其精子的水流,使其流向雌性的壳内（即雌性壳体与软体之间）,以使卵子受精。这些事实表明,叶肢介只能适应于静水或弱流水环境。叶肢介的现代环境与古环境的对比研究显示两者是非常相似的,因此,现生叶肢介生态和环境的研究对恢复他们的古生态与古环境具有重要的意义。