منابع مشابه
Rocks of ages
There is an intangible quality of implausibility to Australia that is impossible to put into words. It has an ancient and fragile feel: it is almost a continental equivalent of a tree sprouting out of a seemingly solid rock; precarious and beautiful and not quite sustainable. It is a continent where the unexpected is usual, and yet it is always surprising and thrilling when the unexpected is fo...
متن کاملRadiometric ages for basement rocks from the Emperor
[1] The Hawaiian-Emperor seamount chain is the ‘‘type’’ example of an age-progressive, hot spotgenerated intraplate volcanic lineament. However, our current knowledge of the age distribution within this province is based largely on radiometric ages determined several decades ago. Improvements in instrumentation, sample preparation methods, and new material obtained by recent drilling warrant a ...
متن کاملU-Pb Isotopic Ages of Intrusive Rocks Related to Mineralization North of Terrace, British Columbia
In 2004, the BC Min is try of En ergy, Mines and Pe tro leum Re sources and Boot leg Ex plo ra tion Inc. en tered into a part ner ship agree ment aimed at the eval u a tion of the re gional po ten tial for in tru sive-re lated gold min er al iza tion near Ter race, Brit ish Co lum bia. Boot leg Ex plo ra tion Inc. is a wholly owned sub sid iary of Ea gle Plains Re sources Ltd., and their area o...
متن کاملThe case for a younger Imbrium basin: New 40Ar-39Ar ages of Apollo 14 rocks
Petrographically and chemically well-characterized rocks of the Apollo 14 landing site (12 impact melt breccias, 3 clast-free impact melt rocks, 2 granulitic rocks, 1 cataclastic noritic anorthosite, 1 shocked gabbronorite, 1 mare basalt, and 1 plagioclase single crystal) have been dated by the 40Ar-39Ar technique. The samples represent two different formations at the Apollo 14 site: (1) small ...
متن کاملU/Pb and Pb/Pb zircon ages from granitoid rocks of Wallagga area: constraints on magmatic and tectonic evolution of Precambrian rocks of western Ethiopia
The Precambrian rocks in western Ethiopia consist of highand low-grade terranes intruded by granitoids with a wide compositional spectrum. The formation ages of these granitoid rocks are, so far, poorly understood. Single-grain zircon Pb/Pb evaporation and conventional U/Pb dating conducted on four granitoids places time constraints on their emplacement and tectonothermal events. Three granitoi...
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ژورنال
عنوان ژورنال: Current Biology
سال: 2008
ISSN: 0960-9822
DOI: 10.1016/j.cub.2008.10.056