热释光断代技术测定断层活动时代可能性的研究

本文根据多年来研究断层活动所积累的热释光年龄资料和断层运动过程中各种温、压条件变化的模拟实验结果,阐述了断层运动所产生的摩擦升温有可能使断层面上乃至断层带内某些矿物原有的热释光“退火”,初步探讨了用热释光测年技术测定断层活动年代的可能性     

西安地区部分古遗址考古地磁研究

通过对陕西耀州窑遗址内4个古窑,临潼兵马俑一号坑,西铜一级公路经过黄堡工地开挖的两个五代窑,以及耀州窑博物馆仓库工地内开挖的一个金代窑和一个春秋窑遗址的古地磁研究,初步得出了西安地区古地磁场变化的规律,为鉴定从春秋到金代西安地区的古遗址、古文物提供了考古地磁学上的一个粗略的标准。     

Spatiotemporal Dynamics of a Páramo Ecosystem in the Northern Ecuadorian Andes 1988-2007

Páramo is a term used to describe tropical alpine vegetation between the continuous timberline and the snow line in the Northern Andes. Páramo environments provide important species habitat and ecosystem services. Changes in spatial extent of the páramo ecosystem at Pambamarca in the Central Cordillera of the northern Ecuadorian Andes were analysed using multi-temporal Landsat TM/ETM+ satellite data. The region suffered a loss of 1826.6 ha or 20% of the total area at a rate of 100 ha/annum during 1988-2007 period. It is found that permanent páramo cover decreased from 8350 ha in 1988 to 5864 ha in 2007 at a fairly constant rate(R2=0.94). This loss is attributed to expansion of commercial agriculture and floriculture in the valleys coupled with increased population pressure. Land at higher elevations has been cleared for small scale agriculture. Loss of the páramo ecosystem will exert a number of negative impacts on ecosystem services and livelihoods of the local population at Pambamarca.     

Grain-size related nitrogen distribution in southern Yellow Sea surface sediments

Forty-eight surface sediments of the southern Yellow Sea are separated into three grain-size fractions. Four forms of extractable nitrogen (nitrogen in ion-exchangeable form (Nie), nitrogen in weak-acid extractable form (Nwa), nitrogen in strong-alkali extractable form (Nsa) and nitrogen in strong-oxidant form (N50))are obtained by the sequential extraction. The results show that the contents and the distributions of the extractable nitrogen in the southern Yellow Sea surface sediments are closely related to sediment grain size. The distributions ofNie, Nso and total nitrogen (TN) present positive correlations with fine particles content, while Nwa and Nsa does not have such correlation. The net contents of all the forms of nitrogen increase with sediment grain size finer.     

分形方法在苏北盆地金湖凹陷石油资源评价中的应用

成熟勘探区剩余资源量的多少倍受关注。根据金湖凹陷的油藏规模分布特征,应用分形方法估计该区的石油地质资源。石油地质资源总量为12284×10⁴t,分布在507个油藏中;其中未发现的具有经济价值的石油地质资源量为2740×10⁴t,分布在126个油藏中。这反映了该区的油气勘探程度较高,但仍有一定的勘探潜力,大量中-小油藏是今后勘探的主攻目标。分形方法作为油气资源评价的一种新途径,计算过程简便,结果可靠,应用前景广阔。     

Silicon limitation on primary production and its destiny in Jiaozhou Bay, China——Ⅳ：Study on cross-bay transect from estuary to ocean

The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m³/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05–0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55 (mgC/m²·d)/(m³/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m²·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs. 1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth. This study was funded by NSFC (No. 40036010), and the Director's Fund of the Beihai Sea Monitoring Center, the State Oceanic Administration.     

Subunit composition and chromophore content of R-phycocyanin and allophycocyanin from Porphyra haitanensis

ＳｕｂｕｎｉｔｃｏｍｐｏｓｉｔｉｏｎａｎｄｃｈｒｏｍｏｐｈｏｒｅｃｏｎｔｅｎｔｏｆＲ－ｐｈｙｃｏｃｙａｎｉｎａｎｄａｌｌｏｐｈｙｃｏｃｙａｎｉｎｆｒｏｍＰｏｒｐｈｙｒａｈａｉｔａｎｅｎｓｉｓ￥ＧａｏＨｏｎｇｆｅｎｇ；ＣａｏＷｅｎｄａａｎｄＪｉＭｉｎｇ...     

北祁连山东部早石炭世早期腕足动物群落的古地理意义

北祁连山东部早石炭世早期经历了一次完整的海水进退旋回。此期该区腕足动物的演化明显受控于相对海平面变化。生存环境的稳定性似乎是群落演替过程能否持久进行的基础。在影响生物群落演替的诸多因素中,底质性质及其稳定性最为重要,其次是食物供应、海水盐度和水动力强度等。各群落在时间上相互取代的主要控制因素是海水深度,与海平面的变化直接相关。而造成这一时期腕足动物群落横向变化的主要因素除了海水深度外,陆源碎屑供应量、海水循环性以及含盐度都具有十分重要的影响。本区早石炭世早期腕足动物群落的生态位介于BA1和BA2之间,缺乏BA3－BA5较深水群落（BA－Benthic Assemblage,底栖组合）,说明此期该区早石炭世早期海水深度一般不超过10米。受沉积古地理环境的制约,本区早石炭世早期BA2生态域的主要分布范围局限于东部的景泰一带,向西水体明显变浅。     

Discovery of scandium enrichment and its geological significance in the Dawanshan Neoproterozoic metamorphic basalts from the Mouding area in Central Yunnan Province,ChinaSCIEI北大核心CSCD

钪(Sc)是世界各国竞相争夺的关键金属矿产资源之一。滇中牟定大弯山变质玄武岩厚度>36.5m,出露面积0.5km^(2),形成时代为新元古代南华纪(781.3±1.9Ma)。本文对该变质玄武岩开展了全岩地球化学分析、全自动矿物分析(TESCAN TIMA)观测、NPPM薄片区域面扫和单矿物原位LA-ICPMS分析等研究,结果显示变质玄武岩全岩Sc含量为47.0×10^(-6)~97.9×10^(-6),平均含量为69.1×10^(-6),钪氧化物(Sc_(2)O_(3))平均含量为106×10^(-6),变质玄武岩空间Sc矿化特征稳定,具有形成钪矿资源的潜力。同时,变质玄武岩共伴生有钛和铁矿化,全岩TiO_(2)含量为2.57×10^(-2)~6.13×10^(-2),平均为4.25×10^(-2);TFe含量为13.3×10^(-2)~23.7×10^(-2),平均为17.7×10^(-2)。Sc可能存在类质同象和离子相两种赋存形式,类质同象形式Sc主要赋存于钛铁矿和金红石矿物中,钛铁矿中Sc含量为70.0×10^(-6)~168×10^(-6),平均值为108×10^(-6);金红石中Sc含量高达297×10^(-6);而磁铁矿、黑云母等矿物中Sc含量较低,均低于全岩Sc含量,对全岩Sc矿化贡献较小。牟定大弯山Sc矿化与以往报道侵入岩及其风化壳中Sc矿化在富集特征、赋存岩性和载体矿物等方面不同,是变质火山岩中新发现的Sc矿化信息,显示了较好的找矿潜力,对Sc资源勘查和研究具有重要指示意义。