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pro vyhledávání: '"N.H. Gale"'
Autor:
N.H. Gale
Publikováno v:
Oxford Journal of Archaeology. 15:113-120
Summary. A considerable part of the paper on which I comment is devoted to criticisms of the trace element analyses made in Oxford and the authors argue that analytical problems exist at Oxford for at least the elements Co, Pb and Zn. A close examina
Publikováno v:
Proceedings of the Yorkshire Geological Society. 42:297-305
SUMMARY A Rb-Sr age of 394 ± 3 Ma has been determined from a 21–point isochron for the Shap Granite, which was probably emplaced in lower Devonian times. The determination provides a minimum age for the base of the Gedinnian Stage. K-Ar measuremen
Publikováno v:
Earth and Planetary Science Letters. 26:195-206
A well-defined internal Rb Sr isochron has been determined for the unbrecciated Nakhla achondrite, defining an age T = (1.24 ± 0.01) AE and an initial 87 Sr/ 86 Sr ratio of 0.70254 ± 0.00003. The excellence of fit to the isochron shows that a very
Publikováno v:
Earth and Planetary Science Letters. 51:9-17
In their paper on the Ordovician, Silurian and Devonian time scales McKerrow, Lambert and Chamberlain conclude that Rb Sr whole-rock isochron ages for acid volcanics always resetting events significantly later than extrusion. In contrast we cite here
Publikováno v:
Journal of the Geological Society. 136:235-242
The extrusion of the Stockdale Rhyolite, an upper Ordovician lava lying within Zone 2 of the Cautleyan Stage of the Ashgill, is dated by the Rb-Sr whole rock isochron method at 421 ± 3 Ma. This datum is more precise than any published Lower Palaeozo
Publikováno v:
Earth and Planetary Science Letters. 48:311-324
Measured Pb-Pb whole meteorite data for the Bruderheim L6 chondrite scatter slightly about a line passing above Can˜on Diablo lead and yielding an age of 4.482 + 0.017 Ga, using the terrestrial 238 U/ 235 U ratio of 137.88. The measured U isotopic c
Publikováno v:
Earth and Planetary Science Letters. 46:311-322
207 Pb/ 204 Pb- 206 Pb/ 204 Pb whole meteorite isochrons for Richardton (H5) and Farmington (L5) are presented and give Pb-Pb ages of 4.545 ± 0.010 and 4.620 ± 0.010 Ga respectively (errors ± 2σ). The Pb-Pb isochron for Farmington passes below th
Publikováno v:
Geochimica et Cosmochimica Acta. 41:335-339
Abundances of U and Th have been determined in 21 kimberlites from India by delayed fission neutron technique. Whole-rock U ranges from 1.87 to 3.93 ppm but Th shows wider variation from 14.02 to 60.44 ppm. Average Th/U ratios in three main diatremes
Publikováno v:
Journal of Archaeological Science. 15:57-72
The sources of gypsum, used as an interior building material in the Bronze Age palaces of Crete, some buildings at Akrotiri in Thera and in the mainland palaces at Mycenae and Tiryns, have been attributed by archaeologists to geological deposits in C
Autor:
R.D. Beckinsale, M.J. Crow, A. Macfarlane, Robert J. Pankhurst, J.W. Arthurs, N.H. Gale, A.F. Wilkinson
Publikováno v:
Precambrian Research. 13:63-76
Field mapping and structural studies in northern Sierra Leone by an I.G.S. team have established a stratigraphic sequence in this part of the Archaean of the West African Craton. An older “Leonian” granite-greenstone terrain is identified which e