不发达地区区域开发的几个理论问题   总被引：10，自引：0，他引：10  

汪一鸣 《地理学报》1993,48(6):497-504

本文在论述区域发展一般原理的基础上,分析了不发达地区的特殊性、不发达地区经济起飞必须具备的前提条件,肯定了国家干预对不发达地区开发的作用,提出了不发达地区区域开发的目标选择及综合开发战略。  相似文献   

辽南晚前寒武纪地层中的宏体化石之地层意义的探讨   总被引：2，自引：0，他引：2       下载免费PDF全文

陈孟莪 《地质科学》1991,(2):120-128

辽南地区晚前寒武纪地层中多层位宏体化石的发现,使序列更完善。根据化石生物机体的复杂程度,可列入前冰期的辽南系,它介于震旦系和青白口系之间。其南关岭组的宏体化石组合类似淮南地区的九里桥组,提高了两区的晚前寒武纪地层的对比度。复州湾沙山村赵家坎子剖面再次证明大连市南、北部晚前寒武纪地史发育的一致性及原区调队等单位对地层叠接的正确性。  相似文献   

新丰江水库区1989年11月26日4.5级地震的主要特征     

黄河生  魏柏林等 《华南地震》1991,11(2):68-73

本文总结分析了发生在新丰江水库老震区，距1962年6.1级主震27年的1次4.5级地震的活动和特点，认为此次4.5级地震及其伴生的小震群仍系新丰江水库诱发地震序列的中晚期强余震。  相似文献   

1991年大同—阳高5.8级地震的序列     

啜永清 《山西地震》1991,(3):13-17

对1991年3月大同—阳高5.8级地震的震源特点、序列特征及震前序列活动进行了分析研究,得出这次5.8级地震是1989年大同—阳高地震的晚期强余震、地震子序列为主余震型序列的结论。从1989年以来大同老震区的弱震活动分析表明,其弱震的几个起伏是大同及其周围应力场加强的信号,可作为今后地震监测预报的窗口。  相似文献   

新疆昆仑山乌斯腾塔格—喀拉米兰晚三叠世植物化石的首次发现   总被引：1，自引：0，他引：1  

李洁  甄保生  孙革 《新疆地质》1991,(1)

新疆昆仑山乌斯腾塔格—喀拉米兰地区晚三叠世植物群Drepanozamites nilssoni-Otozamites indosinensis-Thinnfeldia nordenskioldi-Glossophyllum sheisense等的首次发现,揭示了该地区中国南方型晚三叠世植物群的面貌.对研究新疆南部地区晚三叠世地层、中国地层区划及晚三叠世植物群地理分区、以及板块构造等均具有重要意义.  相似文献   

新疆富蕴县恰库尔特—带碱性花岗岩的基本特征及形成的大地构造背景   总被引：2，自引：0，他引：2  

岳永君 《新疆地质》1991,(3)

恰库尔特一带的碱性花岗岩按侵入顺序和岩性可分为:晶洞(霓石)钾长花岗岩、(霓石)碱长花岗斑岩、霓石花岗岩.这些岩石大都含碱性暗色矿物.发育指示浅成特点的晶洞构造及文象结构,从矿物组合看岩石具贫水特征;岩石化学方面以高硅、高碱或过碱,贫铝、镁、钙为主要特征;岩石通常具有高的∑REE,其中以过碱性的霓石花岗岩为最高;轻稀土较重稀土富集,并具有强的负Eu异常;微量元素地球化学图谱表明,岩石相当于洋脊花岗岩,具有高钾、铷、钍的含量,而钡、钽、铌的富集程度相对较低.以上特征和区域构造分析表明,恰库尔特一带的碱性花岗岩为阿尔泰造山带造山作用结束以后于中晚三叠世的非造山环境下形成的A型花岗岩.  相似文献   

小区域地震预测的新方法     

赵军 《华北地震科学》1994,12(2):66-71

本文应用动态系统时间连续模型建立的新方法（ＤＭ（ｎ，ｈ）模型），通过对唐山老震区ＭＬ＞４．７级地震的建模，讨论ＤＭ（ｎ，ｈ）模型对唐山老震区晚期强余震预测的可行性。并比较了ＤＭ（ｎ，ｈ）模型与ＧＭ（ｎ，ｈ）模型，发现ＤＭ（ｎ，ｈ）模型优于ＧＭ（ｎ，ｈ）模型，同时，给出了唐山老震区晚期强余震的预报结果。  相似文献   

四川省芦山—宝兴地区花岗石石材产出地质特征及其品质     

周振冬  张占鳌 《矿物岩石》1994,14(1):90-96

本文扼要阐明四川省芦山－宝兴地区花岗石石材产出地质特征的基础上，重点讨论花岗石石材的品种、规模和质量。  相似文献   

吉林省北部A型花岗岩的初步认识   总被引：2，自引：0，他引：2  

石新增  李树田 《吉林地质》1995,14(2):64-70

分布在吉林省北部的香水、治安一带的正长花岗岩、碱长花岗岩，研究后认为属Ａ型花岗岩。其行征钾长石为微斜长石一条纹长石，斜长石大部分为奥长石Ａｎ＝１３－１７。并有碱性碱物无辉石。  相似文献   

Geomorphic evolution of the Southern Alps,New Zealand     

J. Mark Tippett  Peter J. J. Kamp 《地球表面变化过程与地形》1995,20(2):177-192

The Southern Alps are the topographic expression of late Cenozoic (<8 Ma ago) uplift of the crust of the leading edge of the Pacific plate in South Island, New Zealand. New fission track data on the basement exposed in the Southern Alps quantify the age, amount, and rate of rock uplift, and in combination with geomorphic parameters permit the construction of a new model of the geomorphic evolution of the Southern Alps. The model emphasizes the development over time and space of rock uplift, mean surface elevation, exhumation of crustal section, and relief. The earliest indications of mean surface uplift are between 4 and 5 Ma ago at the Alpine Fault. Mean surface uplift, which lagged the start of rock uplift, propagated southeastward from the Alpine Fault at a rate of 30 km/Ma. By about 4 Ma ago, exhumation had exposed greywacke basement adjacent to and east of the entire 300 km long central section of the Alpine Fault. At 3 Ma ago, greenschist was exposed in the southern parts of the Southern Alps near Lake Wanaka, and since then has become exhumed along a narrow strip east of the Alpine Fault. The model infers that amphibolite grade schist has been exhumed adjacent to the Alpine Fault only in the last 0·3 Ma. The age of the start of rock uplift and the amount and rate of rock uplift, all of which vary spatially, are considered to be the dominant influences on the development of the landscape in the Southern Alps. The Southern Alps have been studied in terms of domains of different rock uplift rate. At present the rate of rock uplift varies from up to 8–10 mm/a adjacent to the Alpine Fault to 0·8–1·0 mm/a along the southeastern margin of the Southern Alps. This spectrum can be divided into two domains, one northwest of the Main Divide where the present rock uplift rates are very high (up to 8–10 mm/a) and exceed the long-term value of 0·8–1·0 mm/a, and another to the southeast of the Main Divide where the long-term rate is 0·8–1·0 mm/a. A domain of no uplift lies immediately to the east of the Southern Alps, and is separated from them by a 1·0–1·5 km step in the basement topography. We argue that this spatial sequence of uplift rate domains represents a temporal one. The existing models of the geomorphic development of the Southern Alps—the dynamic cuesta model of J. Adams and the numerical model of P. Koons—are compared with the new data and evolutionary model. Particular constraints unrealized by these two earlier models include the following: the earlier timing of the start of rock uplift of the Southern Alps (8 Ma ago); the spatial variation in the timing of the start of rock uplift (8 Ma ago to 3 Ma ago); the lower long-term rock uplift rate (0·8–1·0 mm/a) of the Southern Alps for most of the late Cenozoic; the lag between the start of rock uplift and the start of mean surface uplift; and the patterns of the amounts of late Cenozoic rock uplift and erosion across the Southern Alps.  相似文献