蒙特卡洛模拟法在辽宁层控碳酸盐岩型铅锌银矿产预测中的应用

蒙特卡洛模拟法是一种概率抽样的方法,它是利用模型区内已知矿床资源量的分布曲线,通过抽样实验模拟出该区在某种概率意义下具有的资源潜力的方法。通过对辽宁省11个矿带、16个矿田层控碳酸盐岩型未知铅锌、银矿床(点)的资源潜力模拟,获得了省内层控碳酸盐岩型铅、锌、银的资源潜力。在模拟过程中所使用的评价方法及所应用的前提条件是成功的,其所获得的层控碳酸盐岩型铅锌、银矿产资源潜力是可信的。本文只讨论第Ⅳ矿带及第16矿田的资源潜力。     

空间信息统计学应用系统在广西大厂长坡区的应用研究

结合广西华锡集团的重点科技攻关项目“广西大厂矿田地质矿产数据库的建立与开发”选题,以空间信息统计学这一边缘交叉学科的理论为指导,以先进的VisualBaisc为开发工具,开发出了以Windows98或Windows NT为操作平台的“空间信息统计学应用系统——SISAS系统”。并重点介绍了该系统在大厂长坡区的运用,认为该系统的应用为研究矿体自然状态的三维空间特征提供了新的研究手段,并为描述具有空间结构的自然现象提供了一些新的思路。     

论矿床的分形性质

地壳中元素和矿化分布的不均匀性是一个普遍规律。从超大型矿床→大型矿床→小型矿床→矿点、矿化点（或高异常点）的分布，是近似于从有限稀硫分布逼近无穷多且无限稀硫分布。因此可以把矿床的分布看成是随机康托集（Cantordust）在空间上的分布。浙江中生代热液萤石、银、铅锌矿床的分形丛集分布存在于两个尺度范围内，分形丛集的分维数为0．196～0．40（1～20km）和1．161～1．219（20～750km）。矿床的频度—大小分布也是分形的，其储量分形分布的分维数为：萤石（中国）D=2．13；萤石（浙江）D=2．34；银（浙江）D=1．63；铅锌（浙江）D=2．27；钨（中国）D=2．16；铜（世界）D=2．55。我们认为，矿床储量的分形分布，对于各种标度的成矿作用可能是一个普遍性的特征。根据矿床的频度—大小分形关系，有可能对一地区大于某一指定储量的潜在矿床数作出预测。     

Movement patterns of the sea urchin Paracentrotus lividus in a marine reserve and an unprotected area in the NW Mediterranean

Sea urchins can alter the composition and dynamics of algal communities by grazing. Changes in their displacement capability can influence their grazing and thus their effect on algal communities. The daily and monthly movement of Paracentrotus lividus inside and outside a marine reserve in the NW Mediterranean Sea was studied in order to determine the role of predation in sea urchin movements and its potential grazing impacts. During the 3‐month study, the total distance travelled by sea urchins ranged from 71.8 to 673.6 cm (mean = 379.2 cm, SD = 221.3). Home ranges (distances from the initial position) were between 50 and 302 cm (mean = 150.7 cm, SD = 99.4). Movements were not directional but random, with a mean of 150 cm around the initial position. The activity of Paracentrotus lividus was significantly higher at night than during daylight. Total displacement at the end of the experiment was significantly higher in the unprotected area than in the reserve, as was the home range. The linear distance travelled in a 24‐h period ranged between 6 and 220 cm with a mean home range of 51 cm. These results agree with those of other authors, and allow us to rule out major migratory processes of sea urchin populations in this area. Nevertheless, these results underline the role of predatory fishes in reducing herbivory pressure by trophic cascades, reinforcing the evidence that sea urchin escape behaviour may be an important factor in structuring algal communities.     

气藏天然气聚集速率计算方法的改进——以我国41个大中型气田为例

为了更准确地研究气藏天然气聚集的能力和速度,在前人气藏天然气聚集速率计算方法研究的基础上,考虑了气藏形成后的扩散散失量,改进了气藏天然气聚集速率的计算方法。选取我国41个大中型气田为例,利用改进前后气藏天然气聚集速率计算方法对其天然气聚集速率进行了计算,得到两种计算结果差异较大,后者为前者的1.01~3.05倍,平均为1.29倍。表明改进后方法计算得到的气藏天然气聚集速率更接近真值,更能准确地反映地下实际情况。     

湖南柿竹园多金属矿床地质储量改算及其效果评价

湖南柿竹园钨钼铋矿床是世界上罕见的特大型多金属矿床,根据矿山生产现状,提出了一种新的地质储量计算方法,不仅有利于指导采矿生产,对进一步探讨成矿规律及进行找矿预测都具有一定的实际和理论意义。     

多中心空间结构对城市地价影响研究

城市地价的飞速上涨和成本提高,对企业选址、个人购房带来越来越重要的影响,城市多中心发展能否有效抑制地价亟待实证检验.基于2008年和2013年全国285个地级及以上城市的微观土地出让数据,分析城市空间结构对地价的影响.研究发现:①多中心空间结构能有效抑制城市过高地价,但会显著提升城市低段地价和城市整体平均地价;②城市多...     

Direct impacts of commercial and recreational fishing on spiny lobster,Panulirus interruptus,populations at Santa Catalina Island,California, United States

The California spiny or red rock lobster, Panulirus interruptus, is an ecologically and economically important species that has been exploited since the 1800s. No previous study in California has assessed the impacts of the recreational or commercial lobster harvest. Before the 2003–04 commercial and recreational lobster seasons, we conducted a fishery‐independent trap survey at Santa Catalina Island to document the impact of the lobster fisheries on the size structure, abundance, and sex ratios of mature P. interruptus (>65 mm carapace length (CL)). We concurrently sampled a predominantly commercially fished area, a recreationally fished area, and a 23‐year‐old invertebrate no‐take (INT) reserve. Relative to the INT reserve, legal‐size lobsters in the recreational area were similar in CL, but 31% less abundant. Legal‐size lobsters in the commercial area were 8% smaller and 70% less abundant than those in the INT reserve. The sex ratio of legal‐size lobsters, although near 50:50 in the recreational and INT reserve areas, was male‐dominated (67:33) in the commercial area. Differences in CPUE and mean CL of sub‐legal lobsters in the recreational and commercial areas suggest that factors in addition to harvesting pressure may affect these populations. Total biomass of mature lobsters in the recreational and commercial areas was 92% and 45%, respectively, of biomass in the INT reserve. Fecundity in the recreational and commercial areas was 83% and 42%, respectively, of fecundity in the INT reserve. This study provides preliminary data for future ecological studies and fisheries management evaluations.     

河南老和尚帽预查区资源量及靶区预测

老和尚帽预查区位于桐柏地区围山城金银成矿带以南,老湾金矿带以北,圈有大量1∶ 1万土壤地球化学衬值异常.在大调查桐柏地区银多金属调查评价项目中,以桐柏地区已探明银资源储量的8个矿床、矿点形成的银(衬值)异常为模型单元,采用矿床模型法,建立预测模型;然后对老和尚帽预查区40个预测单元(衬值综合异常)进行资源定量预测与靶区定位预测,确定了8个找矿靶区.经对确定的靶区进行初步查证,发现了矿体和矿化体,取得了一定找矿效果.     

国外商业地理学研究的近期进展及趋向

运用文献分析法,对近10年来国外商业地理学研究的主要进展做简要评介,并展望其发展趋向。分析表明：商品交换、流通和消费的新商业地理学,零售业国际化,购物中心的吸引、扩张与竞争,市场接近性、市场规模与产业区位,商业空间重构与消费者选择行为,市场潜力与区域经济发展,商圈与集聚经济等已成为近期研究主题;创意商业、低碳商业、伦理商业与贸易、商品流及市场网络系统、定量分析和模拟是商业地理学发展的新趋向。