El cretácico medio y superior de la parte meridional del Bloque Maya (Guatemala)     

F. Michaud  E. Fourcade  J. Azema  M.A. Carballo Hernandez  J.C.Franco Austin 《Journal of South American Earth Sciences》1992,5(3-4)

Study of the Cretaceous strata of the Altos Cuchumatanes (western Guatemala) and in Alta Verapáz (central Guatemala) has revealed a number of foraminifers never before reported from these areas. These data permit a similar nomenclature to be applied to both areas in regard to the division of the sequence into formations. Thus, we distinguish in both areas: a) the Cobán Formation, a shallow platform carbonate of early Aptian to early Senonian age; b) the Campur Formation, of Campanian age, composed of a lower carbonate member with rudists and large benthonic foraminifers, and an upper carbonate member with pelagic foraminifers; c) the Sepur Formation, of Maastrichtian age, with flysch-like sediments, including intercalated blocks of ophiolite complex obducted during the Maastrichtian. We conclude that in early Aptian time, a shallow carbonate platform developed along the southern margin of the Maya Block. The platform subsided and was drowned during the terminal Campanian. This subsidence led to the formation of a flysch-like basin that received turbiditic sedimentation from the carbonate platform to the north and fragments of serpentinite from the ophiolite complex to the south.  相似文献   

The determination of hourly values of total solar radiation from daily summations     

Austin Whillier 《Theoretical and Applied Climatology》1956,7(2):197-204

Summary Curves, based on measured total (direct plus sky) solar radiation data for several stations in the Union of South Africa, are presented which enable the hourly distribution of total solar radiation on a horizontal surface to be determined for any locality, and any time of year on a long-term basis. In addition a graph is given showing the fraction of the daily total radiation which is received between stated hours, together with curves for four stations for estimating the difference between morning and afternoon total radiation for hour-pairs symmetrical about noon.Although based on South African solar radiation data, the curves are presented in a form convenient for use, as a first approximation, for localities anywhere in the world, and for any time of year. They are applicable for long-term averages as well as for cloudless days.

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Zusammenfassung Es werden Kurven der Globalstrahlung von Sonne und Himmel abgeleitet, die auf langjährigen Meßwerten für gewisse Stationen in der Südafrikanischen Union beruhen und gestatten, die stündliche Verteilung der Globalstrahlung auf Horizontalfläche für einen beliebigen Ort und für jede Jahreszeit zu bestimmen. In einem Diagramm wird gezeigt, welcher Anteil der täglichen Strahlungssumme zwischen bestimmten Stunden einfällt, außerdem werden Kurven für vier Stationen aufgestellt, um den Unterschied zwischen Vormittags- und Nachmittags-Globalstrahlung für zum wahren Mittag symmetrisch gelegene Stundenpaare zu untersuchen. Obgleich diese Kurven auf südafrikanischen Strahlungsmessungen basieren, ermöglicht ihre Form in erster Annäherung auch die Anwendung auf beliebige Orte der Erde und auf alle Jahreszeiten; sie können sowohl auf langjährige Mittelwerte wie auch auf wolkenlose Tage Anwendung finden.

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Résumé A partir des moyennes de mesures portant sur un certain nombre d'années de plusieurs stations de l'Union Sud-Africaine, l'auteur déduit des courbes qui permettent de déterminer la répartition horaire du rayonnement global du soleil et du ciel sur une surface horizontale pour un lieu donné et pour chaque saison. Un diagramme indique quelle est la proportion de la somme diurne du rayonnement entre des heures déterminées. D'autre part il construit des courbes pour quatre stations afin d'examiner la différence entre la rayonnement global du matin et de l'après-midi et cela pour des couples d'heures situées symétriquement par rapport au midi vrai. Bien que ces courbes aient été faites à partir de mesures du rayonnement en Afrique du Sud, à première approximation leur forme permet de les employer également dans d'autres régions de la Terre et pour toutes les saisons. Elles peuvent être utilisées aussi bien pour des moyennes portant sur de nombreuses années que pour les jours sans nuages.

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With 3 Figures  相似文献   

The tilted forest: Glaciological-geologic implications of vegetated neoglacial ice at Lituya Bay,Alaska     

Austin Post  Gregory Streveler 《Quaternary Research》1976,6(1):111-117

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The geologic history of the passive margin off new england and the canadian maritime provinces     

Elazar Uchupi  James Albert Austin Jr.   《Tectonophysics》1979,59(1-4)

The geologic history of the passive continental margin off the east coast of North America from New England to Newfoundland is described using all available geological and geophysical information. “Rift” and “drift” phases of the margin's evolution are recognized, with rifting initiated in Late Triassic and completed by Early Jurassic. The plate decoupling process created a complex block-faulted terrain as a result of uplift and tensional fracturing. The approximate plane of continental separation is marked by a “hinge zone” characterized by a pronounced steepening of basement gradients. Since the Early Jurassic, the margin has undergone continual subsidence in response to cooling and sediment loading. This “drift” sequence attains its maximum thickness in the vicinity of the continental slope and thins both landward and seaward. On the shelf, this unit consists of Mesozoic evaporites, carbonates, and deltaic deposits. Overlying these sediments is a prograding wedge of Cenozoic elastics. On the rise, the Mesozoic sediments are evaporites, hemipelagic limestones and shales and carbonaceous clays. The Cenozoic is dominantly terrigenous material. Separating these two sedimentary provinces is the continental slope, a site of major facies changes and a Mesozoic reef complex.  相似文献   

Shasta ground sloth (Nothrotheriops shastense hoffstetter) at Shelter Cave, New Mexico: Environment, diet, and extinction     

Robert S. Thompson  Thomas R. Van Devender  Paul S. Martin  Theresa Foppe  Austin Long 《Quaternary Research》1980,14(3):360-376

Seven coprolites of the extinct Shasta ground sloth (Nothrotheriops shastense) were recently discovered in the Los Angeles County Museum collection from Shelter Cave, New Mexico. Three dung balls provided radiocarbon ages of 11,330, 12,330 and 12,430 yr B.P. Packrat (Neotoma) middens disclose a xeric juniper woodland at Shelter Cave during the sloth's occupation. Plant cuticles from the dung indicate that the ground sloth had a diet dominated by mormon tea (Ephedra) and other xerophytic shrubs. Pollen spectra from the coprolites have high representations of anemophilous plants and low representations of the dietary items shown in the cuticle analysis.Fifteen radiocarbon dates of sloth dung obtained since 1974 strengthen the hypothesis that sloth extinction occurred about 11,000 yr B.P. Paleoenvironmental studies indicate that ground sloths lived in juniper woodlands and montane conifer communities. Nothrotheriops commonly dined on shrubs that are still present in these habitats. It is difficult to explain the demise of the Shasta ground sloth by climatic change or dietary stress. Human predation remains as a possible explanation; ground sloth extinction appears to coincide with the time of Clovis mammoth hunters.  相似文献   

Dissolved Inorganic Carbon in the Tucson Basin Aquifer     

Seth Rose  Austin Long 《Ground water》1989,27(1):43-49

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Carbon content and carbonate ¹³C abundances in the Early Precambrian Swaziland sediments of South Africa     

Bartholomew Nagy  Steven M. Kunen  John E. Zumberge  Austin Long  Carleton B. Moore  Charles F. Lewis  Carl R. Anhaeusser  Desmond A. Pretorius 《Precambrian Research》1974,1(1):43-48

Carbon content (0.02–0.68% organic), carbonate content (0–69.7%) and carbonate ¹³C abundances (${}^{\mathrm{?}}\text{7.5?+2.3‰}$) were obtained on samples from the Swaziland sediments of South Africa, which are among the oldest known sedimentary rocks on earth (> 3·10⁹ years old). The carbon chemistry of these sediments may serve as evidence for early life and/or for products of chemical evolution. The variation of organic and carbonate carbon concentrations in different sedimentary horizons seems to be controlled by differences in depositional and diagenetic histories. The carbonate δ ¹³C values did not vary significantly from the ordinary range of Phanerozoic limestone values.  相似文献   

Comments on “Radiocarbon: Short-term variations” by M.S. Baxter and J.G. Farmer     

P.E. Damon  Austin Long  E.I. Wallick 《Earth and Planetary Science Letters》1973,20(3):311-314

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Mesoscale aspects of the Urban Heat Island around New York City   总被引：15，自引：1，他引：15  

S. D. Gedzelman  S. Austin  R. Cermak  N. Stefano  S. Partridge  S. Quesenberry  D. A. Robinson 《Theoretical and Applied Climatology》2003,75(1-2):29-42

Summary ?A mesoscale analysis of the Urban Heat Island (UHI) of New York City (NYC) is performed using a mesoscale network of weather stations. In all seasons the UHI switches on rapidly in late afternoon and shuts down even more rapidly shortly after dawn. It averages about 4 °C in summer and autumn and 3 °C in winter and spring. It is largest on nights with clear skies, low relative humidity through much of the troposphere, and weak northwest winds, when it may exceed 8 °C. The synoptic meteorological situation associated with the largest UHI occurs roughly two to three nights after cold front passages. During spring and summer, sea breezes commonly reduce and delay the UHI and displace it about 10 km to the west. Backdoor cold fronts, which occur most frequently in spring and early summer, reduce or even reverse the UHI, as cold air from the water to the northeast keeps NYC colder than the western suburbs. Cases documenting the sensitivity and rapidity of changes of the UHI to changes in parameters such as cloud cover, ceiling, and wind speed and direction are presented. Received August 16, 2001; revised October 6, 2002; accepted November 20, 2002 Published online March 17, 2003  相似文献   

Field meeting at Sevenoaks,Kent: 10th July, 1948     

G. Austin Browne  F.G.S. 《Proceedings of the Geologists' Association. Geologists' Association》1949,60(4):274

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