Palaeozoic flysch series in the Coastal Cordillera of Northern Chile     

Dr. Christoph Breitkreuz  Heinrich Bahlburg Dipl.-Geol. 《International Journal of Earth Sciences》1985,74(3):565-572

A discontinuous outcrop of Palaeozoic rhythmic clastites appears in the North Chilean Coastal Cordillera. The Formación El Toco (21°15–22°15S) whose scarce flora points to a presumably Upper Devonian age forms the northernmost part of the outcrop. It is discordantly overlain by Lower Jurassic volcanics (Fm. La Negra), its base, however, is not exposed. Hercynian heteromorphous deformation led to predominantly NW trending folds strongly inclined mostly to the SW. Chevron-like folds of 0.1 to 30 m occur locally and seem to display properties transitional between synsedimentary-gravitational and early tectonic deformation.The series which is at least 2300 m thick consists of proximal, in parts pebbly turbidites with non-turbiditic finegrained intercalations. Incomplete BOUMA-sequences frequently begin with A-beds of grey to green immature, badly sorted coarse sandstones of up to 6 m thickness containing isolated quartz- and pelite-clasts.Measurements of flute casts and f oresets show palaeocurrents which came from NW and NNE. Along with petrographic observations they indicate southward directed transport of detritus from low metamorphic sedimentary and magmatic source areas into an Upper Devonian nonvolcanic basin.

---

Zusammenfassung Die Formación El Toco ist der nördlichste Aufschluß einer Kette von Vorkommen paläozoischer rhythmischer Klastite in der nordchilenischen Küstenkordillere. Diese Formation (21°15–22°15S), deren spärliche Flora vorbehaltlich dem Oberdevon zuzuordnen ist, wird diskordant von unterjurassischen Vulkaniten (Fm. La Negra) überlagert —das Liegende ist nicht aufgeschlossen. Variszische heteromorphe Deformation führte zu vorherrschend NW-streichender Faltung, die meist starke SW-Vergenz zeigt. Lokal tritt eine scharfe Verfaltung im 0,1 bis 30 m-Bereich hinzu, die sowohl synsedimentär-gravitative als auch frühtektonische Deformationsmerkmale zeigt.Die mindestens 2300 m mächtige Serie ist ein proximaler Flysch mit z. T. kiesführenden Turbiditen, in die nichtturbiditische feinkörnige Partien eingeschaltet sind. Die unvollständigen BOUMA-Sequenzen beginnen häufig mit einer aus grauen bis grünen unreifen und schlechtsortierten Grobsandsteinen bestehenden A-Division von bis zu 6 m Mächtigkeit, die isolierte Quarz- und Pelitklasten enthalten kann.Flute cast- und Foreset-Messungen weisen auf Paläoströmungsrichtungen aus NW und NNO hin. Zusammen mit petrographischen Analysen läßt sich daraus ein südwärts gerichteter Transport von schwachmetamorphsedimentärem und magmatischem Detritus in ein oberdevonisches nicht-vulkanisches Becken ableiten.

---

Résumén Ritmitas clásticas de edad paleozoica forman afloramientos discontinuos en la Cordillera de la Costa del Norte de Chile. La Formación El Toco (21°15–22°15S), que contiene una flora escasa de probable edad Devónico Superior, constituye la parte más septentrional de estos afloramientos. La base no se conoce, mientras que el techo infrayace discordantemente a volcanitas jurásicas inferiores (Fm. La Negra). Deformaciones hercínicas heteromórficas llevan a la formación de pliegues orientados predominantemente al NW inclinados fuertemente al SW. Localmente aparecen pliegues en forma de chevron de un tamano de 0.1 a 30 m que muestran caracteristicas de deformación transicional entre sinsedimentana-gravitativa y tectónica temprana.La serie que tiene una potencia de por lo menos 2300 m consiste en turbiditas proximales parcialmente con gravas e intercalaciones finas no-turbidíticas. Secuencias incompletas de BOUMA empiezan frecuentemente con capas de la division A (espesor maximo 6 m) los cuales se componen con frecuencia de areniscas gruesas gris-verdes, composicionalmente inmaduras y mal seleccionadas, con clastos aislados de cuarzo y pelita.Medidas de flute casts y foresets muestran paleocorrientes provenientes de NW y NNE. Junto con observaciones petrográficas, las paleocorrientes indican un transporte de material detrítico, originado de áreas con rocas sedimentarias, metamórficas de bajo grado e ígneas, dirigido al sur hacia una cuenca no volcánica de edad Devónico Superior.

---

- , - . (21°15 - 22°15 ) , ; - ( -). . , . . NW , SW. 0,1 30 , , - , - . 2300 , . , . , NW a NNE. , , .

  相似文献   

Aminostratigraphy of European marine interglacial deposits     

Gifford H. Miller  Jan Mangerud 《Quaternary Science Reviews》1985,4(4):215-278

Molluscan fossils collected from shallow water marine sediment across NW Europe and nearby Arctic regions have been analysed for the extent of isoleucine epimerization ( ratio) in indigenous protein residues. The ratios confirm that essentially all ‘classical’ Eemian sites from NW Europe are of the same age, and are correlative with the type locality near Amersfoort in the Netherlands; shells from interglacial marine sediment beneath the type Weichselian till in Poland also correlate with the type Eemian site. ratios in Holsteinian marine shells (0.29) are substantially higher than in their Eemian counterparts (0.17); ‘Late Cromerian’ shells yield even higher ratios (0.46). ratios in late glacial shells (0.06) and Middle Weichselian shells (0.09) permit differentiation from modern (0.01) and last interglacial material. Based on the position of the Matuyama-Brunhes boundary and the differences in ratios, the Eemian must correlate with isotope substage 5e, whereas the Holsteinian is most likely substage 7c, possibly stage 9 but certainly younger than stage 11. Intra-Saalian warm periods may be terrestrial equivalents of the younger substages of stage 7. Extensive pre-Eemian marine sediments along the SW coast of Denmark previously correlated with the Holsteinian are shown to be of ‘Late Cromerian’ age. The underlying till there is the first widespread evidence of a pre-Elsterian till in NW Europe. ratios in molluscs from last interglacial sites along the Arctic coast of the USSR, the Arctic Islands and eastern Greenland are substantially lower than in their European counterparts due to their low thermal histories. The combined mid- and high-latitude data are used to develop a predictive model for the expected ratio in any of several moderate epimerization-rate taxa for last interglacial sites with mean temperatures between −20 and +15°C.Not all sites could be unambiguously assigned to an established interglacial. The Fjøsanger (Norway) and Margareteberg (Sweden) sites previously thought to be Eemian, yield ratios higher than in secure nearby Eemian material. It is yet unresolved whether these are aberrant sites or if they predate the last interglacial. In situ shoreline deposits encountered in borings in SW Belgium and in exposures on the Belgium coastal plain contain molluscs that yield ratios intermediate between secure Eemian and Late Weichselian ratios, raising the possibility that a late stage 5 high-sea-level event attained near-modern levels in the southern North Sea basin. Resolution of these uncertainties is the focus of future work.  相似文献   

Magnetic susceptibility anisotropy of deformed rocks     

Aleš Kapička  Reviewer F. Janák 《Studia Geophysica et Geodaetica》1984,28(1):90-100

¶rt;au uu aum nuuumu u aumnuu ¶rt; aa aam n¶rt; am amuu u namuu ¶rt;au. amu uu aumnuu nuuumu, a amu ¶rt;au, m ¶rt;mu au ma nma aaumu m¶rt; ¶rt;a, m a amu uu aum m mnu n¶rt;u ¶rt; mm uaum amua n¶rt; ¶rt;au. u aumnuu nu a namu ¶rt;auu(<1%) a uuu m nuuumu _i uaum amua. u aumnuu ¶rt;mu uu uum aauuau ¶rt;ua am m uu, m, m ¶rt; u au namu ¶rt;auu.  相似文献   

Atmospheric effects from post-nuclear fires     

Paul J. Crutzen  Ian E. Galbally  Christoph Brühl 《Climatic change》1984,6(4):323-364

During a large nuclear war, the atmosphere would be loaded with huge quantities of pollutants, which are produced by fires in urban and industrial centers, cultivated lands, forests and grasslands. Especially detrimental are the effects of light absorbing airborne particles. An analysis of the amounts of the various types of fuels which could burn in a nuclear war indicates that more than 10¹⁴ g of black smoke could be produced by fires started by the nuclear explosions. Due to this, the penetration of sunlight to the earth's surface would be reduced greatly over extended areas of the northern hemisphere, maybe even globally. This could temporarily cause extreme darkness in large areas in midlatitudes and reduce crop growth and biospheric productivity.This situation would last for several weeks and cause very anomalous meteorological conditions. Much solar radiation would be absorbed in the atmosphere instead of at the earth's surface. The land areas and lower atmosphere would, therefore, cool and the overlying atmosphere warm, creating strong vertical thermal stability in a highly polluted atmosphere. For extended periods and in large parts of the world, weather conditions would be abnormal. The resulting cold, probably freezing, temperatures at the ground would interfere severely with crop production during the growing season and cause extreme conditions for large sections of the biosphere. The combination of lack of sunlight, frost and other adverse meteorological conditions would add enormously to the already huge problems of the survivors.  相似文献   

Some possibilities of predicting radio wave absorption in the lower ionosphere     

Josef Boška  Jan Laštovička  Reviewer L. Křivský 《Studia Geophysica et Geodaetica》1986,30(1):87-92

Summary An attempt is made to show possible ways of predicting radio wave absorption in the midlatitude lower ionosphere using relations between absorption and the intensity of solar ionizing radiation and/or common solar activity indices, and between absorption and f₀F2.

---

aa mu nuau nu a¶rt;u ¶rt;um u u a mu ¶rt; nu u umum uuu uu (uu uu u¶rt;au amumu) u ¶rt; nu u f₀F2.

  相似文献   

Effects of the imf sector structure in the midlatitude troposphere and stratosphere     

Jan Laštovička  Reviewer F. Pechala 《Studia Geophysica et Geodaetica》1986,30(4):394-403

Summary The data on geopotential heights and temperatures at 7 pressure levels between 1000-10 hPa above Berlin(52.5 °N, 13.4 °E) are analysed for the winters of 1963–1973. No demonstrable effect of the interplanetary magnetic field sector boundary crossing (IMF SBC) is found in the lower and middle stratosphere, but there is a demonstrable effect in the middle troposphere at the 500 hPa level. This effect is less important than the IMF SBC effect in the tropospheric vorticity area index and seems to be of a different type.

---

auum ¶rt;a nnmua m u mnam a 7 nm ¶rt;au ¶rt; 1000-10 a a¶rt; u(52,5 °.., 13,4 °.¶rt;.) ¶rt; u 1963–1973. ua ¶rt;aam m nu mau nam aum n( ) ¶rt;a amu u u ¶rt; mam, ma m a¶rt; ¶rt; mn a 500 a. mm m a, m u¶rt; na¶rt;u aumu am, u am m ¶rt; muna.

  相似文献   

The relation between the heat flow field and the distribution ofP n -wave velocities for the European continent     

Jaroslav Kubík  Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1986,30(1):60-78

Summary The dependence of P_n-wave velocities on the heat flow, temperature at the crustmantle boundary and the thickness of the Earth's crust in Europe was investigated in relation to the problem of lateral inhomogeneities in the upper mantle. A map was constructed of the distribution of P_n-wave velocities on the territory of Europe. The relations these investigations yielded, were compared with the results of laboratory experiments and all the results are discussed from the physical point of view. The conclusion drawn is that that temperature and pressure effect provide a sufficient explanation of the observed regional changes of P_n-wave velocities for the European continent.

---

auum ¶rt;auu mu n¶rt; ¶rt; nmu uua (P_n) u mn nm, mnam a nmu amuu u m a mumuu n a u¶rt;aa u numa ¶rt;¶rt;m amuu. mumuu n a maa a uu m P_n- a nmu uua. u¶rt;u umam ¶rt;a mama aam u¶rt;au uuu m n¶rt; amuu u u ¶rt;au u mnam mmmm mama n¶rt;aa am. ¶rt;a ¶rt;, m ua uu m P_n- a n mum ¶rt;mam um uuu mnam u ¶rt;au a nmu uua.

  相似文献   

КРИТИКА     

Jan Kostelecký 《Studia Geophysica et Geodaetica》1986,30(1):112-112

  相似文献   

Total ozone response to major geomagnetic storms and changes in meteorological situations     

Pavel Mlch  Jan Laštovička 《Studia Geophysica et Geodaetica》1995,39(2):189-207

Summary The total ozone response to strong major geomagnetic storms (A_p≥60) in winter along the 50° N latitudinal circle is studied. The results add to the recent results of Laštovička et al. (1992) obtained for European middle latitudes (∼50°N) and to the results of Mlch (1994). A significant response of total ozone is only observed in winter under high solar activity/E-phase of QBO conditions (E-max) and seems to be caused by geomagnetic storm-induced changes of atmospheric dynamics. There are two sectors along latitude 50°N, which are sensitive to forcing by geomagnetic storms both in total ozone and the troposphere — north-eastern Atlantic-European and eastern Siberia-Aleutian sectors. The total ozone response under E-max conditions manifests itself mainly as a large decrease in the longitudinal variation of ozone after the storm, which means an increase of ozone in Europe. The observed effects in total ozone consist in redistribution, not production or loss of ozone.  相似文献   

Influence of the IMF sector boundaries on cosmic rays and tropospheric vorticity     

Jan Laštovička  Reviewer L. Křivský 《Studia Geophysica et Geodaetica》1987,31(2):213-218

Summary The effect of the IMF sector boundary crossing (IMF SBC) in the vorticity area index (VAI) — the well-known dip in the VAI after IMF SBC — is found to be independent of the IMF SBC effect in the cosmic ray flux. This finding refutes a recent suggestion by Lundstedt [1] that the IMF SBC effect in VAI is caused by a decrease in cosmic ray flux, but supports the concept of the IMF SBC effects in the ionosphere and atmosphere developed by Latovika [2–4]. Cosmic rays seem to affect the troposphere in another way.

---

¶rt;mu nu mau nam aum n ( ) a u¶rt; na¶rt;u aumu () — um uu n — a¶rt; auu m ma nm uu . mm mam nam ¶rt;a n¶rt;u ¶rt;m¶rt;a [1], m m a nuu nma uu , n¶rt;¶rt;uam nu m u u am, aum amu [2–4]. am m uu u m um a mn ¶rt;u a.

  相似文献