The structure and development of greater Lagos     

Dr. Klaus Grenzebach 《GeoJournal》1978,2(4):295-310

In the period between 1965 and 1976, when German geographers carried out their fieldwork for the Afrika-Kartenwerk under the sponsorship of the German Research Society, remarkable progress in urban development especially in Lagos could be observed. The cooperation with the Federal Survey Department of Nigeria gave the opportunity for collecting several series of aerial photographs which bring into focus some stages of the overwhelming urban expansion.The materials presented here have been selected to demonstrate some regional structures of the Nigerian capital. — In the geography of today the scientific evaluation of aerial photographs together with findings from local observation and historical as well as statistical data is still undervalued. Through this technique, the more classical and conservative method of geographical analysis, relying on subjective judgement, may regain some of its importance, which it once had in the age of exploration of new territories.Where data is scarce and written records of urban expansion are not available or difficult to extract, aerial photographs can give an impression of certain stages of urban growth. A functional analysis under geographical aspects has to be regarded by changes within spatial units in order to the factors of influence. Those factors are numerous, their influence will cause changes in a series of pushes arising from economic developments of the vast hinterland as well as from social conditions of certain groups of the population. In a metropolitan center, as Lagos, the highest ranking central place of Africa's most populous nation, heterogenous events and a confusing number of planning decisions must be taken into consideration. One consequence of nationwide regional interactions with the metropolis is migratory population dynamics. In pursuing lines of interaction, which originate from economic power, population density, and natural resources, one can hardly isolate a single element of influence because all factors are closely interrelated. For Lagos, there is only limited data available on the social and economic standard of the population, valid basic demographic figures of some value are not available.One still has to accept very rough estimates on population figures, number of industrial workers, the standards of housing and the social and economic hierarchy of the population. The present retrospective analysis of aerial photographs gives an interpretation of the regional structure of the town and indicate possible future development.  相似文献   

Radar measurements of wind and waves     

Klaus Hasselmann  W. Alpers  D. Barick  D. Crombie  C. Flachi  A. Fung  H. van Hutten  W. Jones  G. P. De Loor  B. Lipa  R. Long  D. Ross  C. Rufenach  W. Sandham  O. Shemdin  C. Teague  D. Trizna  G. Valenzuela  E. Walsh  F. Wentz  J. Wright 《Boundary-Layer Meteorology》1978,13(1-4):405-412

  相似文献   

Über Zusammenhänge zwischen der Eisführung des Ostgrönlandstroms und der atmosphärischen Zirkulation über dem Nordpolarmeer     

Klaus Strübing 《Ocean Dynamics》1967,20(6):257-265

  相似文献   

Mass occurance and sporadic distribution of Corynocera ambigua Zetterstedt (Diptera, Chironomidae) in Danish lakes. Neo- and palaeolimnological records     

Klaus Peter Brodersen  Claus Lindegaard 《Journal of Paleolimnology》1999,22(1):41-52

The chironomid Corynocera ambigua (Tanytarsini) is commonly reported as a cold-stenothermal species living in shallow lakes in arctic and subarctic regions. In palaeoecological studies of temperate lakes, larval remains of C. ambigua are usually found in late-glacial sediments from the Allerød and Younger Dryas periods, and often in association with subfossil Chara oospores. During a surface sampling program of chironomid head-capsules in 41 Danish temperate lakes, C. ambigua was found to comprise 25% of the chironomid assemblages in two lakes, and was sporadically found in 8 other lakes (0.5-10%). A 70 cm palaeo-stratigraphy from the shallow (max depth 1.2 m) and eutrophic (total phosphorus = 150 g P l^-1) Lake Stigsholm showed that C. ambigua has been abundant in the last 4-5 centuries. At a sediment level of 25 cm (~year 1925, ²¹⁰Pb dating), C. ambigua began to decrease in frequency while Chironomus plumosus, Procladius sp., Cladotanytarsus gr. mancus and Tanytarsus spp. increased, suggesting an increased nutrient loading and an approach to eutrophic conditions. In 1995 C. ambigua was still very abundant in Lake Stigsholm but in early March 1997 no living larvae were found. An extremely heavy growth of Elodea, Enteromorpha and filamentous algae in the summers of 1995 and 1996, with following degradation in the fall, might have influenced the invertebrate population dynamics. No significant distinguishing characteristics were found for the lakes supporting C. ambigua. Its occurrence in warm (~20°C) Danish lakes brings into question the perception of the species as being cold-stenothermal.  相似文献   

Sedimentation und Tektonik im mittleren Abschnitt des Rio Toro in der Ostkordillere NW-Argentiniens     

Prof. Dr. Klaus Schwab  Dr. Andreas Schäfer 《International Journal of Earth Sciences》1976,65(1):175-194

Zusammenfassung Die bis 5000 m mächtigen jungkänozoischen Sedimente im Hangenden der Grupo Salta wurden im Mittelabschnitt der Quebrada del Toro auskartiert und gegliedert, wobei ein vorwiegend aus Vulkanitkomponenten bestehendes Konglomerat als Leithorizont diente. Auf diese Sedimente sind von West und Ost ältere Gesteine aufgeschoben, so daß sie heute nur noch in dem Rio Toro-Keilgraben erhalten sind. Anhand der wechselnden Geröllführung und lokaler Diskordanzen läßt sich nachweisen, daß durch die Hebung der westlichen und östlichen Randschollen der kontinentale Sedimentationsraum zunehmend eingeengt wurde. Die terrestrischen Sedimente im Rio ToroKeilgraben wurden erst zu einem relativ späten Zeitpunkt der Schollenbewegungen gefaltet und verworfen.Die jüngsten Sedimente — Terrassen und Schuttfächerablagerungen — lassen sich dem heutigen Flußbett des Rio Toro zuordnen.

---

In the central part of the Quebrada del Toro up to 5000 m continental sediments of Upper Cenozoic age on top of the Salta Group have been mapped and divided into several units. A conglomerate, which is mainly composed of volcanic pebbles could be used as a marker. From west and east older rocks have been thrusted on these sediments, which therefore are preserved only in the Rio Toro-Keilgraben. By means of changing gravel associations and local unconformaties it can be shown, that the uplift of the western and eastern border made the basin of continental sedimentation narrower. The terrestrial sediments in the Rio Toro-Keilgraben have been folded and faulted only at a relatively late stage of the block movements.The youngest sediments, alluvial terraces and fan deposits, can be related to the recent bed of the Rio Toro.

---

Resumen En la parte central de la Quebrada del Toro hasta 5000 m de sedimentos continentales del Cenozico superior han sido levantados y subdividos en algunos unidades, usando coma estrato guía un conglomerado compuesto en la mayor parte de rodados volcanicos. Del oeste y del este rocas más viejas han sido corridas sobre estos sedimentos, los quales han sido conservados solamente en el Río Toro-Keilgraben. Considerando el cambio en la asociación de rodados y las discordancias locales se puede provar que por el levantamiento de los bordes occidentales y orientales la cuenca sedimentaria continental fue estrechada. En un momento relativamente tarde en el desarollo tectonico los sedimentos continentales en el Rio Toro-Keilgraben fueron plegados y fallados.Los depositos más recientes, terrazzas y conos de deyección pueden ser relacionados con el cauce del Río Toro.

---

Résumé Les sédiments d'âge cénozoïque supérieur, de près de 5000 m d'épaisseur qui se trouvent au-dessus du Groupe de Salta, ont fait l'objet de levés dans la partie centrale de la Quebrada del Toro. Un conglomérat se composant en majeure partie de galets volcaniques a servi de repère. Ces sédiments sont surmontés de roches plus anciennes, sous l'effet de chevauchements venant de l'Ouest et de l'Est, si bien que de nos jours on ne les trouve que dans le graben en coin du Rio Toro. On peut prouver, grâce au contenu variable des galets et à des discordances locales, que le soulèvement des bordures occidentale et orientale a causé un resserrement du bassin continental de sédimentation. Les sédiments terrestres dans le graben en coin du Rio Toro ont été plissés et disloqués seulement à une époque relativement tardive au cours des mouvements des blocs.Les sédiments les plus récents — terrasses d'accumulation et cônes d'alluvions — sont à mettre en liaison avec le lit actuel du Rio Toro.

---

- Grupo Salta Quebrada del , , . , -. , . - . — — -.

---

---

Geänderte Fassung eines auf der 64. Jahrestagung der Geologischen Vereinigung 1974 in Bochum gehaltenen Vortrages.  相似文献   

Contributions to the mineral chemistry of Hawaiian rocks     

R. V. Fodor  Klaus Keil  T. E. Bunch 《Contributions to Mineralogy and Petrology》1975,50(3):173-195

Phenocryst and groundmass pyroxenes in 24 rocks of the tholeiitic, alkalic, and nephelinic suites from Haleakala and West Maui volcanoes, Maui, Hawaii, were analyzed quantitatively by electron microprobe. Results and conclusions: i) Tholeiites contain augite, pigeonite, and bronzite; alkalic rocks contain salite, augite, and ferroaugite; and nephelinic rocks have salite, sometimes of Wo>50 mole %. ii) The three suites can be distinguished by Ca contents of pyroxenes: High-Ca pyroxenes of tholeiitic rocks have Wo_30–40; those of alkalic rocks have Wo_38–48; and those of the nephelinic rocks have Wo_47–51; i.e. Wo in clinopyroxene increases from tholeiitic, to alkalic, to nephelinic suites, iii). In the alkalic suite, rock types can be distinguished on the basis of clinopyroxene composition: Alkalic olivine and alkalic basalts have Wo_38–45, hawaiites and mugearites have Wo_45–48. Trachytes can be distinguished from both groups by higher Fe (Fs_22–30) and Ca contents (Wo_43–47). iv) Pyroxenes in tholeiitic rocks show higher intrarock variability (e.g. Fs₁₂Wo₄₀-Fs₃₇Wo₃₀) than those of the alkalic and nephelinic suites, v) Na₂O bulk-rock content affects Na₂O content of the precipitating high-Ca pyroxene; e.g. Na₂O in groundmass pyroxene increases from tholeiitic, to alkalic (mafic members only), to nephelinic suites; a similar relationship is present within the differentiated alkalic suite, vi) In tholeiites, changes in groundmass high-Ca pyroxene compositions are related to changes in bulk rock compositions, e.g. FeO/FeO+MgO+CaO in clinopyroxene increases as this ratio increases in the bulk rock; this is not true for alkalic and nephelinic rocks, vii) In groundmass high-Ca pyroxene, Al₂O₃, Na₂0, and TiO₂ contents increase and MnO content decreases with increasing Wo content from tholeiitic, to alkalic (mafic members only), to nephelinic suites, viii) Groundmass high-Ca pyroxenes are richer in MnO and Na₂O and poorer in Cr₂O₃ compared to coexisting phenocrysts. High-Ca pyroxene phenocrysts in nephelinic rocks and in one mugearite are depleted in SiO₂ and enriched in Al₂O₃ relative to coexisting groundmass clinopyroxene, indicating increased SiO₂ activity during crystallization. Some tholeiites show the reverse; this Si—Al relationship is not clear in other samples.  相似文献   

The development of the chlorinity/salinity concept in oceanography: William J. Wallace. Elsevier,Amsterdam, 1973, 227 pp., Dfl. 46.00     

Klaus Grasshoff 《Chemical Geology》1975,15(1):81-82

  相似文献   

Stochastic riming of plate-like and columnar ice crystals     

Klaus D. Beheng 《Pure and Applied Geophysics》1980,119(4):820-830

Riming growth of ice particles is simulated by numerically solving the stochastic collection equations, simultaneously considering coagulation of water droplets. By introducing a special criterion which defines the habit of a riming particle, the influence of this habit on the growth of several kinds of ice particles assumed to be formed during riming was investigated.It was found that (i) hexagonal rimed ice plates are growing more efficiently than lump graupel or rimed columns, (ii) the use of different collection kernels for the lump graupel evolution leads to widely differing results and that (iii) the time dependent decrease of liquid water substance and the size of the resulting ice particles were more strongly influenced by the initial ice crystal concentration than by the initial ice crystal size and the habit of the ice particles. By decreasing the number density of ice crystals gradually a critical ice crystal concentration was found at which the present liquid water was not completely consumed by the riming process even after 1800 s model time, causing large drops of radii >100 m to be formed in appreciable concentrations.  相似文献   

The genesis of the methane in Lake Kivu (Central Africa)     

Dr. Klaus Tietze  Dr. Mebus Geyh  Dr. Helmut Müller  Dr. Lothar Schröder  Dr. Wolfgang Stahl  Dr. Hermann Wehner 《International Journal of Earth Sciences》1980,69(2):452-472

Large amounts of methane and carbon dioxide, among other gases, are dissolved in the deep water of Lake Kivu. There is no dispute about the primarily magmatic origin of the carbon dioxide, but models of the genesis of the methane have been contradictory up to now. They have been based on too few and partly too inaccurate data.On the basis of new measurements obtained from gas and sediment samples, some of the old concepts have been further developed to a new model. According to this model, the methane is generated mainly by bacteria from the organic carbon of the sediment. It probably also contains minor amounts of thermocatalytic methane.About 70% of the organic carbon of the upper sediment is derived from mainly magmatic carbon dioxide (old carbon), which enters the biozone of the lake from the deep water by eddy diffusion and is assimilated there. The remaining 30% comes from atmospheric carbon dioxide (young carbon) assimilated in the biozone. But because methane also migrates into the lake from deeper sediment, the¹⁴C-content in the methane dissolved in the lake water is not 30% modern but only ca. 10% modern.More isotopic measurements on plankton, methane, carbon dioxide and sediment samples are necessary to support this model.

---

Zusammenfassung Im Tiefenwasser des Kivusees sind u. a. große Mengen an Methan und Kohlendioxid gelöst. Während über den hauptsächlich magmatischen Ursprung des Kohlendioxids weitgehend Einigkeit besteht, sind die bisherigen Modellvorstellungen zur Genese des Methans widersprüchlich. Sie beruhen auf zu wenigen und zum Teil zu ungenauen Meß-daten.Mit Hilfe neuer Meßergebnisse an Gas- und Sedimentproben des Kivusees wurden einige der alten Vorstellungen zu einem neuen Modell weiterentwickelt. Danach ist das Methan hauptsächlich bakteriell aus dem organischen Kohlenstoff des Sediments entstanden. Wahrscheinlich enthält es auch geringe Beimengungen thermokatalytischen Methans.Der organische Kohlenstoff des oberen Sediments stammt zu rd. 70% aus dem vorwiegend magmatischen Kohlendioxid (alter Kohlenstoff), das aus dem Tiefenwasser durch turbulenten Austausch in die Biozone des Sees gelangt und dort assimiliert wird. Die restlichen 30% stammen aus dem in der Biozone assimilierten atmosphärischen Kohlendioxid (junger Kohlenstoff). Weil jedoch auch Methan aus tieferen Sedimentschichten in den See wandert, beträgt der¹⁴C-Gehalt des im Seewasser gelösten Methans nicht 30% modern, sondern nur ca. 10% modern.Weitere Isotopenuntersuchungen an Plankton-, Methan-, Kohlendioxid- und Sedimentproben sind notwendig, um das Modell abzusichern.

---

Résumé De grandes quantités de méthane et d'oxyde carbonique sont dissoutes dans les eaux profondes du Lac Kicu. Alors qu'on est en général d'accord sur l'origine surtout magmatique de l'oxyde carbonique, les modèles devant représenter la genése du méthane sont contradictoires. Ils reposent sur des données trop peu nombreuses et en partie trop inexactes.A l'aide de nouveaux résultats de mesures faites sur des échantillons de gaz et du sédiment, on a développé un nouveau modèle, à partir des anciennes représentations. D'après celui-ci, le méthane provient pour sa plus grande part du carbone organique du sédiment, transformé par des bactéries. Il contient probablement des traces d'un méthane de thermocatalyse.Le carbone organique du sédiment supérieur provient pour 70% de l'oxyde carbonique surtout magmatique (carbone »ancien«), des eaux profondes parvenu, par échanges turbulents, dans la biozone du lac, où l'oxyde carbonique est assimilé. Les 30% restant proviennent de l'oxyde carbonique atmosphérique (carbone »jeune«) assimilé dans la biozone. Le méthane des couches profondes du sédiment migrant dans le lac, la teneur en¹⁴C de méthane dissous dans les eaux du lac n'est pas de 30% modernes, mais de 10% modernes.D'autres recherches sur les isotopes d'échantillons du plancton, du méthane, de l'oxyde carbonique et du sédiment du Lac Kivu seront nécessaires pour confirmer ce modéle.

---

. , , . , , . . , . 70 % ( ), , . 30% (). , , ¹⁴ 30% modern, 10 % modern. , , .

  相似文献   

The nature and origin of ureilites     

John L. Berkley  G.Jeffrey Taylor  Klaus Keil  George E. Harlow  Martin Prinz 《Geochimica et cosmochimica acta》1980,44(10):1579-1597

Ureilites are carbon-bearing olivine-pigeonite achondrites which constitute a unique achondrite type. We performed a comprehensive mineralogical and petrological study on eight ureilites (Kenna, Novo Urei, Goalpara, Haverö, Dingo Pup Donga, Dyalpur, North Haig, and ALHA77257) the results of which were used to construct a hypothesis for the origin of ureilites. This hypothesis suggests that ureilites are primarily olivine-pigeonite cumulates which crystallized from a silicate liquid that also contained suspended solid carbon phases, mainly graphite. This carbon caused reduction of the melt and influenced ureilite mineral compositions. Carbonaceous material was trapped by settling cumulus mafic silicates along with other intercumulus material to form the carbon-rich ‘veins’ common to ureilites. Petrofabric analyses show that mafic silicates are oriented in lineated and foliated patterns characteristic of cumulate rocks, specifically adcumulates. Strain state of silicates suggests that ureilites were deformed subsequent to lithification by mild tectonic stress as well as by moderate to severe shock. The latter event caused the formation of micron-sized diamonds and lonsdaleite from graphite and carbon-induced reduction of silicate grain margins during temporal shock-heating.  相似文献