冀西北水晶屯金矿F8断裂带深部定位预测     

魏俊浩 《现代地质》1995,9(1):69-74

摘要：以冀西北水晶屯金矿为例,通过对该矿床Ｆ８断裂带成矿地质条件和找矿标志的分析研究,建立起了Ｆ８断裂带的地球化学原生晕模型和灰色系统ＧＭ（１．１）模型,并利用这些模型对其深部合矿性进行了预测．经工程验证,该预测效果是可信的．  相似文献   

Distribution characteristics of size-fractionated chlorophyll a and primary productivity in Beibu Gulf   总被引：2，自引：1，他引：1  

Liu Zilin  Cai Yuming  Ning Xiuren 《海洋学报(英文版)》1998,17(1):71-83

The distribution of the abundance of phytoplankton, chlorophyll a (Chl.a) concentration and primary productivity in the Beibu Gulf were observed from May 23 to June 4, 1994.The results show that there were marked featares of spatial zonation in the survey area due to the differences between the geographic environment and the hydrological conditions.Chlorophyll a and primary productivity were higher in the inshore than in the middle area and higher in the north than in the south of the Beibu Gulf.The average concentration of Chl.a, primary productivity and the abundance of phytoplankton were 0.94±0.45 μg/dm³, 351±172 mg/(m²·d) (C) and 0.97×10⁴-10.050×10⁴ ind./m³ in the area, respectively.There were 176 species belonging to 4 phyla and 56 genera based on microscope identification.The results of the size-fractionation show that the contribution of nanoplankton and picoplankton was 77% to total Chl.a and 91% to total primary productivity, which proved their importance to phytoplankton communities in the Beibu Gulf.  相似文献   

Estimation of standing stock of chlorophylla and primary production from remote-sensed ocean color in the Oyashio region, the Western subarctic Pacific, during the spring bloom in 1997     

Hiromi Kasai  Hiroaki Saito  Atsushi Tsuda 《Journal of Oceanography》1998,54(5):527-537

In order to examine the applicability of remotely-sensed ocean color for the estimation of phytoplankton biomass and primary production in the Oyashio region, the western subarctic Pacific, vertical distributions of chlorophylla concentration and primary production were observed in April and May 1997. Spring bloom was observed in both April and May, and the surface concentration of chlorophylla exceeded 40 mg m⁻³. The relationship between the standing stocks of chlorophylla within the layer from the sea surface to one optical depth (0–1/k layer) and the surface chlorophylla concentration is expressed as a Michaelis-Menten equation. The mean ratio of the standing stock of chlorophylla in the euphotic layer to that in the 0–1/k layer was 4.41, this ratio did not significantly differ from 4.61 which was obtained at homogeneous distribution of chlorophylla within the euphotic layer. These facts suggest that the distribution of chlorophylla could be assumed to be homogeneous in the euphotic layer during the spring bloom. Results of primary production measurements by simulatedin situ method were compared with those by an algorithm with two variables; chlorphylla and non-spectral PAR. Daily primary production in the euphotic layer estimated by the algorithm varied in a range of 38–274% of that estimated by incubation, although the primary productions by the algorithm agreed with those by the incubation at a half of stations. Primary production within the euphotic layer calculated using simply the surface data was the same as that estimated using vertical distribution of chlorophylla. These results show that the primary production in the euphotic layer may be estimated from the remote sensed measurements during the spring bloom in the Oyashio region.  相似文献   

Primary Product Distributions from the Reaction of OH with m-, p-Xylene, 1,2,4- and 1,3,5-Trimethylbenzene     

D. F. Smith  T. E. Kleindienst  C. D. McIver 《Journal of Atmospheric Chemistry》1999,34(3):339-364

A study was conducted to examine the OH-initiated degradation products of the four title compounds in the presence of sub-part-per-million levels of NO_x. The oxidation was conducted in a dynamic reactor to minimize the conversion of the aromatic compounds. The experiments were designed to represent reaction pathways that occur in the atmosphere at ambient NO₂ concentrations. A wide range of ring-retaining and ring-cleavage products having widely varying yields were measured during the study. For m-xylene, the major primary products observed (with molar yields) were methyl glyoxal (0.40), 4-oxo-2-pentenal (0.12), glyoxal (0.079), and m-tolualdehyde (0.049). For p-xylene, the major primary products were p-tolualdehyde (0.103), 2,5-dimethylphenol (0.13), cis-3-hexene-2,5-dione (0.176), trans-3-hexene-2,5-dione (0.045), 2-methyl-butenedial (0.071), glyoxal (0.394), and methylglyoxal (0.217). Several other reaction products were measured at yields less than 3%. The primary products for OH + 1,2,4-trimethylbenzene were found as follows: methylglyoxal (0.44), glyoxal (0.066), cis-3-hexene-2,5-dione (0.13), trans-3-hexene-2,5-dione (0.031), biacetyl (0.114), 3-methyl-3-hexene-2,5-dione (0.079), and 2-methyl-butenedial (0.045). Six other (ring retaining) products were measured at yields less than 3%. The primary products for OH + 1,3,5-trimethylbenzene were methylglyoxal (0.90), 3-methyl-5-methylidene-5(2H)-furanone (0.1), 3,5-dimethyl-3(2H)-2-furanone (0.1), 3,5-dimethyl-5(2H)-2-furanone biacetyl (0.08), and 2-methyl-4-oxo-2- pentenal (0.05). Three other products were detected at molar yields less than 5%. In some cases, the yields for the ring fragmentation products could only be based on calibrations from surrogate compounds. Yields for several of the unsaturated dicarbonyl compounds have not been reported previously while yields for methylglyoxal, glyoxal, and biacetyl are largely consistent with previous reports. Some of the primary furanone products are the identical to those reported as secondary products in aromatic systems.  相似文献   

景观地球化学研究在土壤地球化学测量中的作用   总被引：3，自引：0，他引：3  

王志华 《地质与勘探》1999,35(6):55-57

通过对内蒙古大水清金矿区地球化学景观的研究,分析了该地区金矿床的次生晕形成特点,特别是在次生晕中,主要成矿元素Au、Ag等偏低,形成了该区所特有的景观地球化学特点  相似文献   

恢复沉积构造原始产状要素的微机程序     

佟洁 《甘肃地质》1999,8(1):86-91

由于构造变动,改变了沉积岩层的原始水平状态,其中的沉积构造（砾石群或斜层理）的产状也随之发生了变化。因此,恢复其原始产状,是古水流分析的一项重要环节。以往是用吴氏（吴尔福,１９０２）网投影法完成的。现在提供设计的一微机程序,以快速、准确、批量及高效等优点弥补了旧法的诸多不足,为拟创新法的尝试。  相似文献   

1998/1999年南极夏季普里兹湾及北部海区叶绿素a和初级生产力的分布特征   总被引：11，自引：1，他引：11       下载免费PDF全文

刘子琳  蔡昱明  陈中元  刘诚刚  朱根海  王小谷 《极地研究》2002,14(1):12-21

1998 /1 999年南极夏季 ,作者随“雪龙船”在南极普里兹湾及其北部海区 (63° - 69°1 2′S ,70°30′- 75°30′E) 3条断面 2 4个测站进行浮游生物现存量和初级生产力的现场观测 ,研究叶绿素a浓度和初级生产力的分布特征。测区表层叶绿素a浓度为 0 .1 6 - 3 .99μg/dm3,普里兹湾内和湾西部四女士浅滩海域浓度在 3 .5μg/dm3以上 ;平面分布趋势从湾内向西北方向递减 ,深海区浓度在 0 .5μg/dm3以下。从垂向看叶绿素a浓度的最大值大多出现于 2 5m或 50m层 ,50m以下更深层的浓度随深度的增加而降低 ,2 0 0m层叶绿素a浓度分布范围为 0 .0 1 - 0 .95μg/dm3。粒径分级叶绿素a浓度以微小型浮游生物的贡献占优势 (56 % ) ,微型浮游生物的贡献占2 4 % ,微微型浮游生物的贡献占 2 0 %。测区潜在初级生产力为 0 .1 1～ 1 1 .67mgC/(m3·h) ,平均值为 2 .0 0± 2 .80mgC/(m3·h)。高生产力区位于普里兹湾 ,平均现场生产力达到 0 .86gC/(m2 ·d) ;依次为陆架区、陆坡区 ,深海区生产力较低 ,平均现场生产力为 0 .1 7gC/(m2 ·d)。光合作用同化数较低 (1 .53± 1 .1 1mgC/(mgChla·h) )。粒径分级初级生产力以微小型浮游生物的贡献占优势 (58% ) ,微型浮游生物的贡献占 2 6 % ,微微型浮游生物的贡献占 1 6 %。浮游植  相似文献   

武汉东湖主要湖区的藻类与营养型评价   总被引：11，自引：3，他引：8  

况琪军  夏宜琤 《湖泊科学》1995,7(4):351-356

对东湖９个湖区藻类的群落结构、生长潜力、初级生产力和营养状况进行了比较研究。结果表明,９个湖区藻类的种类组成无明显差异,绿藻为主,蓝藻和硅藻次之;藻类的生长潜力和初级生产力各湖区差异较大,均以茶港湾重污染区最高和牛巢湖最低。根据各项指标综合分析,９个湖区水质优劣的顺序是：牛巢湖、汤林湖、后湖、郭郑湖、菱角湖、筲箕湖、庙湖、喻家湖和茶港湾重污染区。对东湖的大水面郭郑湖４０年来藻类的有关参数进行比较发  相似文献   

微型生态系统中鲢、鳙下行影响的实验研究——1.浮游生物群落和初级生产力   总被引：7，自引：0，他引：7  

阮景荣  戎克文  王少梅 《湖泊科学》1995,7(3):226-234

在营养物供给量较大的实验条件下,鲢、鳙放养明显地改变了微型生态系统的群落结构、代谢和理化环境,以致实验后期鳙单养和鲢、鳙混养系统出现不同程度的富营养化。微型生态系统中浮游植物密度的增长不完全由营养级联效应所致,但初级生产力的组间差异可大致依据营养级联假说来解释。实验结果认为,以提高鱼产量为目标的鲢、鳙高密度放养,对加速营养物来源丰富的天然水域的富营养化起着重要的作用。  相似文献   

全球变暖对淡水湖泊浮游植物影响研究进展   总被引：9，自引：6，他引：3  

邓建明  秦伯强 《湖泊科学》2015,27(1):1-10

全球变暖对湖泊生态系统的影响已经成为近年来湖沼学领域的研究热点.本文首先列举了目前研究全球变暖对淡水湖泊浮游植物影响的常用方法:监测数据分析、时空转换、遥感信息提取、控制实验、模型预测和古湖沼学技术等.研究结果表明气候变暖导致的气温升高、湖泊热力分层提前破坏以及无冰期提前等因素可导致春季物候提前;在全球变暖大背景下浮游植物群落结构正朝着蓝藻占优的方向发展,但是不同地区以及不同物种对全球变暖的响应不一致.在营养盐充足的湖泊中,由于全球变暖延长了浮游植物生长季节等,从而能提高浮游植物初级生产力;但在贫营养湖泊中,浮游植物初级生产力与变暖趋势甚至可能呈负相关.由于生态系统往往是多因子的共同作用,这也使得全球变暖对浮游植物群落的影响效应复杂化,区分各因子的净影响份额是目前研究的一个难点;全球变暖引起的风场改变会促进浅水湖泊中营养盐从底泥的释放,同时也会增加水体中悬浮物的浓度而影响水下光场,因此开展气候变化对再悬浮及浮游植物群落结构的影响可能是将来研究的一个切入点.  相似文献