Calcareous nannofossil biostratigraphic study of forearc basin sediments: Lower to Upper Cretaceous Budden Canyon Formation (Great Valley Group), northern California,USA     

ALLAN GIL S. FERNANDO  HIROSHI NISHI  KAZUSHIGE TANABE  KAZUYOSHI MORIYA  YASUHIRO IBA  KAZUTO KODAMA  MICHAEL A. MURPHY  HISATAKE OKADA 《Island Arc》2011,20(3):346-370

The results of a calcareous nannofossil biostratigraphic investigation of the North Fork Cottonwood Creek section of the Budden Canyon Formation (BCF; Hauterivian–Turonian) in northern California are summarized using the Boreal – cosmopolitan Boreal Nannofossil Biostratigraphy (BC) – Upper Cretaceous Nannofossil Biostratigraphy (UC) nannofossil zonal schemes of Bown et al. and Burnett et al. Sixteen intervals, ranging from the BC15 to UC8 zones, were established in the section. Combined biostratigraphic and magnetostratigraphic studies suggest a Hauterivian to mid‐Turonian age for the studied sequence. The Hauterivian–Barremian, Barremian–Aptian, Aptian–Albian, Albian–Cenomanian, and Cenomanian–Turonian stage boundaries were delineated near the top of the Ogo Member, below the Huling Sandstone Member, within the upper Chickabally Member, in the upper portion of the Bald Hills Member and within the Gas Point Member, respectively. Unconformities probably exist at the base of the Huling Sandstone Member and the upper part of the upper Chickabally Member. The nannofossil assemblage in the North Fork Cottonwood Creek suggests that the study area was under the influence of cold‐water conditions during the Barremian to Lower Aptian interval, shifting to tropical/warm‐water conditions during the Albian to Turonian interval as a result of the mid‐Cretaceous global warming. Although oceanic anoxic events have not yet been reported in the BCF, preliminary total organic carbon, along with nannofossil data, suggest the presence of the global Cenomanian–Turonian boundary oceanic anoxic event 2.  相似文献   

The local geologist 1: Exporting your heritage?     

MICHAEL A. TAYLOR 《Geology Today》1991,7(1):32-36

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The Eemian and Weichselian stratigraphy of the Langelandselv area, Jameson Land, East Greenland     

JON Y. LANDVIK  ASTRID LYSÅ  SVEND FUNDER  MICHAEL KELLY 《Boreas: An International Journal of Quaternary Research》1994,23(4):412-423

Coastal Jameson Land is characterized by thick Quaternary deposits from the last interglacial/glacial cycle. The successions at the mouth of Langelandselv exhibit a key stratigraphy where sediments from the Langelandselv interglaciation (Eemian) are overlain by three till units interbedded with glacimarine and deltaic interstadial successions. Immediately after the retreat of glaciers after the extensive Scoresby Sund glaciation (Saalian). advection of warm Atlantic surface water surpassed what is known from the Holocene. The two lowermost Weichselian tills, deposited during the Aucellaelv and Jyllandselv stades (Early Weichselian), reflect short-lasting readvances of fjord glaciers. Luminescence dates and correlation with adjacent areas suggest ages of 110–80 ka and 70–60 ka for the Hugin Sø and the Møselv interstades, respectively.  相似文献   

DEDICATED PRINCIPAL PROPERTIES FOR PEPTIDE QSARS: THEORY AND APPLICATIONS     

BERTSKAGERBERG  MICHAEL  SVANTEWOLD 《地理学报(英文版)》1990,(3)

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Cordierite-bearing schists and gneisses from Timor, eastern Indonesia: P-T conditions of metamorphism and tectonic implications     

MICHAEL BROWN  MICHAEL M. EARLE 《Journal of Metamorphic Geology》1983,1(2):183-203

In the Boi Massif of Western Timor the Mutis Complex, which is equivalent to the Lolotoi Complex of East Timor, is composed of two lithostratigraphical components: various basement schists and gneisses; and the dismembered remnants of an ophiolite. Cordierite-bearing pelitic schists and gneisses carry an early mineral assemblage of biotite + garnet + plagioclase + Al-silicate, but contain no prograde muscovite; sillimanite occurs in a textural mode which suggests that it replaced and pseudomorphed kyanite at an early stage and some specimens of pelitic schist contain tiny kyanite relics in plagioclase. Textural relations between, and mineral chemistries of, ferro-magnesian phases in these pelitic chists and gneisses suggest that two discontinuous reactions and additional continuous compositional changes have been overstepped, possibly with concomitant anatexis, as a result of decrease in P_load during high temperature metamorphism. The simplified reactions are: garnet and/or biotite + sillimanite + quartz + cordierite + hercynite + ilmenite + excess components. P-T conditions during the development of the early mineral assemblage in the pelitic gneisses are estimated to have been P + 10 kbar and T > 750°C, based upon the plagioclase-garnet-Al-silicate-quartz geobarometer and the garnet-biotite geothermometer. P-T conditions during the subsequent development of cordierite-bearing mineral assemblages in the pelitic gneisses are estimated to have been P + 5 kbar and T + 700°C with X_H2O < 0.5, based upon the Fe content of cordierite occurring in the assemblage quartz + plagioclase + sillimanite + biotite + garnet + cordierite coexisting with melt. Final equilibration between some of the phases suggests that conditions dropped to P > 2.3 kbar and T > 600°C. A similar exhumation P-T path is suggested for the pelitic schists with early metamorphic conditions of P > 6.2 kbar and T > 745°C and subsequent development of cordierite under conditions in the range P = 3-4 kbar and T = 600-700°C. The tectonic implications of these P-T estimates are discussed and it is concluded that the P-T path followed by these rocks was caused by decompression during rifting and synmetamorphic ophiolite emplacement resulting from processes during the initiation and development of a convergent plate junction located in Southeast Asia during late Jurassic to Cretaceous time.  相似文献   

Soldier Settlement in New Zealand After World War I: Two Case Studies     

MICHAEL ROCHE 《New Zealand geographer》2002,58(1):23-32

Historians and geographers have variously explored the WWI discharged soldier settlement schemes in New Zealand. The shared orthodoxy has emphasised the widespread failure of many of these soldier settlers and settlements. Recently there have been signs of a revisionist interpretation of the scheme. This paper extends this critique by considering the meanings of failure and success in broader terms through two New Zealand case studies. The discussion suggests that there were subtle graduations of both administrative and settler success and failure.  相似文献   

Shear zone metamorphism: Introduction     

MICHAEL BROWN 《Journal of Metamorphic Geology》1984,2(2):75-75

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The surface CO₂ gradient and pore-space storage flux in a high-porosity litter layer     

ADAM I. HIRSCH †  SUSAN E. TRUMBORE  MICHAEL L. GOULDEN 《Tellus. Series B, Chemical and physical meteorology》2004,56(4):312-321

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Tidal variations in the Sundarbans Estuarine System, India   总被引：1，自引：0，他引：1  

MEENAKSHI CHATTERJEE  D SHANKAR  G K SEN  P SANYAL  D SUNDAR  G S MICHAEL  ABHISEK CHATTERJEE  P AMOL  DEBABRATA MUKHERJEE  K SUPRIT  A MUKHERJEE  V VIJITH  SIDDHARTHA CHATTERJEE  ANWESHA BASU  MADHUMITA DAS  SARANYA CHAKRABORTI  ARAVIND KALLA  SURJA KANTA MISRA  SOUMYA MUKHOPADHYAY  GOPAL MANDAL  KANKAN SARKAR 《Journal of Earth System Science》2013,122(4):899-933

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Modelling nitrogen dynamics for a mesoscale catchment using a minimum information requirement (MIR) concept / Modélisation des dynamiques de l'azote pour un bassin versant de taille moyenne,utilisant le concept de besoin minimum d'information     

MICHAEL EISELE  CHRIS LEIBUNDGUT 《水文科学杂志》2013,58(5):753-768

Abstract

Based on the water balance model LARSIM (Large Area Simulation Model), a model for the simulation of nitrogen transport was developed in a mesoscale catchment in southwest Germany. To meet the needs and constraints in river basin management, the nitrogen model was developed following the concept of minimum information requirement (MIR). The modelling concept uses only few calibration parameters and only easily accessible input data. Water balance, runoff generation and nitrogen transport were simulated on a 1-km² grid of sub-areas in which different land-use classes and soil characteristics were accounted. Temporal variability of the storage of mobile nitrogen were described using a monthly based mass balance. Nitrogen mobilization and transport was simulated using monthly values of different runoff components and data for soil properties, topography, hydrogeology and river network. The simulation was calibrated and validated using streamflow from two gauging stations and observed nitrogen concentrations at the catchment outlet, showing reasonable results for both streamflow and nitrogen dynamics. The results of the model application are discussed in the context of uncertainty problems and their implications for water management.  相似文献