Igneous Rocks,Fluidolites, and Rodingites of Paleocene Explosive Structures of the Taukha Terrane (Sikhote-Alin)

Geology of Ore Deposits - The Taukha terrane of the Sikhote-Alin hosts outcrops of rocks with unusual structural and textural features, the compositions of which vary from ultrabasic to...     

On the Devonian of Northern Yunnan

The first Chinese geologist who investigated the Devonian rocks of northernYunnan was Y. T. Chao who, in 1929, went from Suifu to northernChaotung where he met his tragic death at the hands of bandits. Ten yearslater, W. Y. Lin made a swift reconnaissance in the same region but he did     

Considerations on the seismotectonics of the Northern Apennines

The Northern Apennines have been subdivided into homogeneous zones, on the basis of recent structural evolution and crustal structure, in which the earthquake distribution can find a coherent framework. These zones, whose physiography is in strict connection with their structure, are: the Internal Peri-Tyrrhenian Belt; the External or Main Belt; the Buried Belt; and the Pede-Alpine Homocline. Earthquake activity has a tendency to cluster along well-defined bands, particularly in the easternmost border of the Peri-Tyrrhenian Belt, as well as along the zone between the External Belt and the Buried Belt, i.e. along the Padanian margin of the Northern Apennines.A minimum of seismic activity seems to be correlated with some zones of the External Belt, as well as with the Late Tertiary and Quaternary magmatic province of Tyrrhenian Southern Tuscany.The fault-plane solutions are coherent with the structural picture.A tentative seismotectonic model of the Northern Apennines is discussed.     

北秦岭造山带中的拆沉作用

秦岭造山是一个非常有特色的碰撞造山带,来自地球物理、地球化学以及地质学的证据说明秦岭造山带中发生过拆沉作用,笔者主要讨论了北秦岭造山发生拆沉作用地地球物理、地球化学以及地质学证据,重点运用北秦岭地壳的地球化学特征进行对经,并用拆沉作用解释商丹地区的一些特殊地质现象。     

Pyrological Situation in the Steppes of Northern Eurasia

Doklady Earth Sciences - The emergence and spreading of grass fires in the steppe regions of Northern Eurasia occurs against the background of spatial heterogeneity of landscapes and differences in...     

Cenozoic stratigraphy of the Sahara,Northern Africa

This paper presents an overview of the Cenozoic stratigraphic record in the Sahara, and shows that the strata display some remarkably similar characteristics across much of the region. In fact, some lithologies of certain ages are exceptionally widespread and persistent, and many of the changes from one lithology to another appear to have been relatively synchronous across the Sahara. The general stratigraphic succession is that of a transition from early Cenozoic carbonate strata to late Cenozoic siliciclastic strata. This transition in lithology coincides with a long-term eustatic fall in sea level since the middle Cretaceous and with a global climate transition from a Late Cretaceous–Early Eocene “warm mode” to a Late Eocene–Quaternary “cool mode”. Much of the shorter-term stratigraphic variability in the Sahara (and even the regional unconformities) also can be correlated with specific changes in sea level, climate, and tectonic activity during the Cenozoic. Specifically, Paleocene and Eocene carbonate strata and phosphate are suggestive of a warm and humid climate, whereas latest Eocene evaporitic strata (and an end-Eocene regional unconformity) are correlated with a eustatic fall in sea level, the build-up of ice in Antarctica, and the appearance of relatively arid climates in the Sahara. The absence of Oligocene strata throughout much of the Sahara is attributed to the effects of generally low eustatic sea level during the Oligocene and tectonic uplift in certain areas during the Late Eocene and Oligocene. Miocene sandstone and conglomerate are attributed to the effects of continued tectonic uplift around the Sahara, generally low eustatic sea level, and enough rainfall to support the development of extensive fluvial systems. Middle–Upper Miocene carbonate strata accumulated in northern Libya in response to a eustatic rise in sea level, whereas Upper Miocene mudstone accumulated along the south side of the Atlas Mountains because uplift of the mountains blocked fluvial access to the Mediterranean Sea. Uppermost Miocene evaporites (and an end-Miocene regional unconformity) in the northern Sahara are correlated with the Messinian desiccation of the Mediterranean Sea. Abundant and widespread Pliocene paleosols are attributed to the onset of relatively arid climate conditions and (or) greater variability of climate conditions, and the appearance of persistent and widespread eolian sediments in the Sahara is coincident with the major glaciation in the northern hemisphere during the Pliocene.     

Malaria reinfestation on the Northern Border of Argentina

Until 1950 malaria was a major public health hazard in Argentina affecting a large number of people in the northern territory. In that year a Malaria Eradication Programme began and this initiated a dramatic fall in incidence especially in the north east in subsequent years.In 1970 there was an increase in the incidence in the north west of the country. Than, in 1989 malaria was diagnosed along the northeastern border. The earlier outbreak was associated with the growth of border traffic and increasing immigration. Ecological changes consequent upon the building of large dams in the Paraná basin have been blamed for the outbreak in 1989.The reinfestation of malaria of northern Argentina is analysed, from the point of view of the trends in incidence during the period 1937–89 and especially the increase after 1970. Control measures are also proposed.     

Lithostratigraphy of the Windermere Supergroup,Northern England

A formal lithostratigraphy is erected for the Late Ordovician and Silurian rocks of northern England. The scheme presented herein emphasizes natural depositional sequences within the supergroup and defines new type sections or cites existing definitions where appropriate. It is intended to be sufficiently flexible and comprehensive to apply to all the inliers, and to bear some rational relationship to lithostratigraphical usage in other British Lower Palaeozoic inliers.     

Fire-dependent forests in the Northern Rocky Mountains

One objective of wilderness and parkland fire-ecology research is to describe the relationships between fire and unmanaged ecosystems, so that strategies can be determined that will provide a more nearly natural incidence of fire. More than 50 yr of efforts directed toward exclusion of wildland fires in the Northern Rocky Mountains (western Montana and northern Idaho) have resulted in a definite and observable impact on the forest ecosystems in this region. Fire-ecology investigations in Glacier National Park and the Selway-Bitterroot Wilderness have helped to reveal the nature of this impact and to provide a better understanding of the natural role of fire within these coniferous ecosystems. Such areas provide a unique opportunity to study and test approaches designed to perpetuate unmodified ecosystems. However, we still don't understand all of the long-term consequences of fire control in those forest communities that have evolved fire-dependent characteristics.     

北美地区页岩储层特征分析

页岩本身既是生油层又是储层。本文对美国几个著名页岩气产区的页岩进行了对比分析,对页岩岩性特征（岩性、矿物组成、化石种类含量、碳含量）、储集空间特征、物性特征方面做了简要介绍。并简要介绍了国外此类研究所采用的先进技术,简要分析了当前中国国内勘探页岩气的现状,希望能在今后中国勘探页岩气的道路上给予一定的参考。     

Surface temperature trend for the Northern Hemisphere-updated

The surface temperature curve for the Northern Hemisphere was extended to include the years 1969 through 1973 following the same procedure used by H. C. Willett, J. M. Mitchell, Jr., and C. H. Reitan. The analysis showed a slight warming of 0.02°C between the periods 1965–1969 and 1970–1973, and a significant decrease in the number of negative temperature changes at individual stations (indicating a decrease in the total area experiencing temperature decrease).     

Northern Ireland lignite

Conclusion There is no doubt that Northern Ireland's lignite deposits are of high quality and constitute a natural resource of considerable potential value in this small, peripheral part of the European Community. Whether or not one or more will be used commercially and, if so, when depends on an interacting complex of economic, social and political factors. In purely economic terms, use will be effectively determined by lignite's economic competitiveness as a fuel dor electricity generation and on the relationship between capital and fuel costs. The economics of other possibly viable products such as lignite briquettes will be heavily dependent on the use of by-products of electricity generation, most notably surplus heat.The availability of lignite offers an alternative fuel option to those charged with formulating the Province's energy policy. If, as now seems likely, it is no longer a serious competitor for the power station planned for the mid-1990's, it most certainly is a competitor for the early part of the next century. This is particularly so in view of its low sulphur content which is about half that of Scottish coal on an energy equivalent basis. Lignite also offers security of supply at predictable prices, an important advantage, and thus carries a premium over coal, oil and natural gas which are imported at prices determined wholly exogenously.As the Province has by far the highest rate of regional unemployment in the United Kingdom, one argument advanced for the use of indigenous lignite is that its use in electricity generation would create much needed additional employment — an estimated 400 jobs being associated with the mining operations needed to support a 450 MW power station. But the Coagh example shows that other considerations must be taken seriously. It is extremely unlikely that the lignite in this area will ever be worked unless local attitudes change dramatically or there is some national fuel crisis which would over-ride local opposition. It is difficult enough developing lignite without having to contend with such strong resistance at the local level.This study has shown that certainly in the Northern Irish context it is highly important for the policy makers not only to consider the economic factors involved in choice of an energy fuel but to work closely with local communities and the various environmental bodies, to take their perceptions, right or wrong, into consideration.     

Desertification Direction of the Northern Margin of Hobq Desert

<正>The Hobq Desert,located in the northern Ordos Plateau is a typical in-situ desertification desert,which is quite different in characteristics and genesis from the Tengger Desert to the west and Muus Desert to the south.The northern margin of Hobq Desert is strictly constrained to     

鲁北地区地热资源区划研究

本文分析了新近系馆陶组热储、古近系东营组热储和下古生界寒武-奥陶系基岩热储三个热储层组,认为这些层组属具有勘探和开发意义的热储目的层组,特别是新近系馆陶组热储组具有良好的热储地质条件.并根据地质构造条件、热储类型、地温梯度特征进行了鲁北地热资源区划分.在地热资源区划区基础上,按优先开发、次优先开发、一般开发、远景开发四级原则进行地热资源亚区划分,将鲁北地热资源划分为6个区划区16个区划亚区.     

On the age of the Kiruna Greenstones,Northern Sweden

Three types of zircons from an albite diabase sill within the Kiruna Greenstone Group have been investigated to determine their age and order of crystallization. The youngest, pink and transparent zircons probably crystallized in late fissures and in association with a thermal event. The intermediate, white zircon populations could not be readily dated because of significant lead loss. The lead 207/206 ages of both the pink and white zircons agree roughly with that of the Sm-Nd isochron (about 1.93 Ga) on secondary minerals from a Kiruna greenstone (Skiöld and Cliff). The oldest, brown zircons indicate an age of about 2.2 Ga, and probably reflect the initial crystallization of the rock. The formation of the early Proterozoic greenstones in the Kiruna area thus commenced about 2.2 Ga ago or earlier. These results are consistent with the proposed chronostratigraphy of the Jatulian formations in Finland (e.g., Simonen; Meriläinen). A time interval of at least 0.3 Ga is assumed for the volcano-sedimentary period which pre-dates the Svecokarelian orogeny of the Kiruna area.