نتایج جستجو برای: type flood basalts

تعداد نتایج: 1365507  

ژورنال: علوم آب و خاک 2020

Selection of the appropriate distribution function and estimation of its parameters are two fundamental steps in the accurate estimation of flood magnitude. This study relied on the concept of optimization by meta heuristic algorithms to improve the results obtained from the conventional methods of parameter estimation, such as maximum likelihood (ML), moments (MOM) and probability weighted mom...

2013
Hejiu Hui Clive R. Neal Chi-Yu Shih Laurence E. Nyquist

We report a new radiometric Rb–Sr age determination of 4.0370.04 Ga for high-Al basaltic clast 14321,1353, which is a Group B Apollo 14 high-Al basalt based on its whole-rock incompatible-traceelement chemistry. In addition, available literature Rb–Sr isotope data for Apollo 14 high-Al basalts were reprocessed using the same decay constant and data reduction protocol as used for sample 14321,13...

2006
Susan E. Humphris Geoffrey Thompson Tristan da Cunha

Deep Sea Drilling Project Leg 75 drilled into igneous basement in the Angola Basin at Site 530, located about 20 km north of the escarpment at the eastern end of the Walvis Ridge. Petrographic and geochemical characteristics of the basalts indicate that the basement is quite uniform, variations in chemical composition being related to weathering, crystal fractionation, and the modal abundances ...

2010
Alfred Edward Bence

The rubidium-strontium isotopic relationships in alkaline and subalkaline oceanic basalts have been determined by mass spectrometric techniques. The results are consistent with a complex model for the earth in which there is continuing convection. Sr87/Sr 8 6 ratios for all oceanic basalts fall in a narrow range from .702 to .705. This suggests that the oceanic upper mantle source regions are g...

2003
Victoria E. Hamilton Michelle E. Minitti

[1] We acquired new thermal emission spectra of oxidized synthetic Martian meteorite-like basalts for comparison to Martian surface spectra acquired by the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES). We find that true thermal emission spectra of the oxidized basalts do not provide good spectral matches to the Martian spectra. By contrast, previous biconical reflectance spectra...

Ahangari, Masoumeh, Asadpour, Manijeh, Cheraghi, Arezoo,

The exposed volcanic rocks in south west of the Khoy area consist of basalts with minor amounts of plagioclase-phyric basalts. These rocks are composed of clinopyroxene plus plagioclase and plagioclase phenocrysts, respectively. The basaltic rocks are highly altered and contains high amounts of secondary minerals mainly chlorite and epidote. According to mineral chemistry, the composition of cl...

2013
Jennifer L. Whitten James W. Head

Early extrusive volcanism from mantle melting marks the transition from primary to secondary crust formation. Detection of secondary crust is often obscured by the high impact flux early in solar system history. To recognize the relationship between heavily cratered terrain and volcanic resurfacing, this study documents how volcanic resurfacing alters the impact cratering record and models the ...

2006
G. Y. Kramer B. L. Jolliff

Introduction: Luna 16 landed on the northeastern corner of Mare Fecunditatis on September 20, 1970. The robotic mission returned to Earth with a drill core that sampled the regolith to a depth of 35cm. This core was replete with relatively high-Al mare basalts (11-20 wt% Al2O3 compared to typical mare basalts: 7-11 wt% Al2O3). The return of these samples raised two important questions: does Mar...

Journal: :Remote Sensing 2016
Yiwen Mei Efthymios I. Nikolopoulos Emmanouil N. Anagnostou Davide Zoccatelli Marco Borga

The error in satellite precipitation-driven complex terrain flood simulations is characterized in this study for eight different global satellite products and 128 flood events over the Eastern Italian Alps. The flood events are grouped according to two flood types: rain floods and flash floods. The satellite precipitation products and runoff simulations are evaluated based on systematic and ran...

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