修饰名词"impact crater"用形容词,所以用know的形容词known,意为"已知的"。故填known。(2)考查动词时态和语态。句意:陨石坑,顾名思义,是小行星撞击地球等天体时形成的。这里为本句谓语动词,根据从句时态可知,主句时态为一般现在时;主语"an impact crater",为名词单数,和动词form之间存在被动...
Magnetic imaging of the Vredefort impact crater, South Africa. Earth Planet. Sci. Lett. 261, 456-468.Muundjua, M., et al. (2007), Magnetic imaging of the Vredefort impact cra- ter, South Africa, Earth Planet. Sci. Lett., 261, 456-468, doi:10.1016/j. epsl.2007.07.044....
Previous investigations of the structure of this large impact crater, based on integrated geophysical modeling, have shown that the central rise structure is an upper crustal feature with a presently recognized uplift of some 12 km, decreasing to about 4 km at the depth of the Moho. This study...
old Vredefort Structure is considered to be a meteorite crater by some workers, but of endogenous origin by others. Petrologica... W.,SCHREYER - 《Journal of Petrology》 被引量: 76发表: 1983年 Deeply exhumed impact structures: A case study of the Vredefort structure, South Africa The main...
Vredefort Dome in Vredefort, Free State. The Vredefort dome is the oldest and largest meteorite impact site (Asrobleme) in the world. Formed an ...
Vredefort Crater cross-section: This cross-section shows the structure of the Vredefort Impact Crater at a time shortly after it was formed. The rocks of the Witwatersrand Basin, Ventersdorp Lava, Ghaap Dolomite, and Pretoria Subgroup were originally deposited in a nearly horizontal position but...
Lightning remagnetiza- tion of the Vredefort impact crater: no evidence for impact-generated magnetic fields. J. Geophys. Res. 117, 1-17.Carporzen, L., Weiss, B. P., Gilder, S. A., Pommier, A., and Hart, R. J. (2012). Lightning remagnetization of the Vredefort impact crater:...
(1998) Constraints on the size of the Vredefort impact crater from numerical modeling. Meteoritics and Planetary Science 33: pp. 483-490Turtle, E. P. & Pierazzo, E. , 1998 . Constraints on the size of the Vredefort impact structure from numerical modelling . Meteoritics and Planetary ...
They represent intrusive offshoots of the homogenized impact melt body that originally lay within the crater. U–Pb single zircon and Ar–Ar dating indicates that the Vredefort Granophyre and pseudotachylitic breccias, and the Witwatersrand pseudotachylites all formed at 2020±5Ma – the age ...
impact melt body that originally lay within the crater.U-Pb single zircon and Ar-Ar dating indicates that the Vredefort Granophyre and pseudotachylitic breccias,and the Witwatersrand pseudotachylites all formed at 2020 +-5 Ma -the age of the impact event,making the breccias a convenient ...