Alvarezn.

Brit.

/alˈvɑːrɛz/,

/ˈalvərɛz/, U.S.

/ˈælvəˌrɛz/

Origin: From proper names. Etymon: proper name Alvarez.

Etymology: < the names of Luis W. Alvarez (1911–88), United States physicist, and his son Walter Alvarez (b. 1940), United States geologist, who formulated the hypothesis together in 1980.

Geology.

attributive. Designating the hypothesis that the mass extinctions at the Cretaceous–Palaeogene (K-T) boundary were due to the environmental effects of the impact of a large asteroid or comet.The hypothesis brought together the known timing of the extinctions with the discovery that at a number of sites the clay layer at the K–T boundary contains a level of iridium that is very rare on Earth but common in asteroids (see also quot. 1994).

ΚΠ

1980 Christian Sci. Monitor 14 Apr. 23/2 According to the Alvarez theory, an asteroid about 10 kilometers in diameter struck our planet 65-million years ago with the force of 100 megatons of TNT.

1994 Nature 6 Jan. 33/1 The Alvarez hypothesis has become widely accepted since identification of the probable primary impact site in the Yucatan.

2006 D. H. Erwin Extinction ii. 32 Following the apparent success of the Alvarez hypothesis in explaining the end-Cretaceous mass extinction, the Permo-Triassic boundary was the obvious next place to look for iridium.

2009 New Yorker 25 May 59/3 The Alvarez hypothesis..was that everything—the clay layer from the scaglia rossa, the clay from Denmark, the spike in iridium, the shift in the fossils—could be explained by a single event.

This is a new entry (OED Third Edition, September 2012; most recently modified version published online December 2021).

单词	alvarez
释义	Alvarezn. Brit. /alˈvɑːrɛz/, /ˈalvərɛz/, U.S. /ˈælvəˌrɛz/ Origin: From proper names. Etymon: proper name Alvarez. Etymology: < the names of Luis W. Alvarez (1911–88), United States physicist, and his son Walter Alvarez (b. 1940), United States geologist, who formulated the hypothesis together in 1980. Geology. attributive. Designating the hypothesis that the mass extinctions at the Cretaceous–Palaeogene (K-T) boundary were due to the environmental effects of the impact of a large asteroid or comet.The hypothesis brought together the known timing of the extinctions with the discovery that at a number of sites the clay layer at the K–T boundary contains a level of iridium that is very rare on Earth but common in asteroids (see also quot. 1994). ΚΠ 1980 Christian Sci. Monitor 14 Apr. 23/2 According to the Alvarez theory, an asteroid about 10 kilometers in diameter struck our planet 65-million years ago with the force of 100 megatons of TNT. 1994 Nature 6 Jan. 33/1 The Alvarez hypothesis has become widely accepted since identification of the probable primary impact site in the Yucatan. 2006 D. H. Erwin Extinction ii. 32 Following the apparent success of the Alvarez hypothesis in explaining the end-Cretaceous mass extinction, the Permo-Triassic boundary was the obvious next place to look for iridium. 2009 New Yorker 25 May 59/3 The Alvarez hypothesis..was that everything—the clay layer from the scaglia rossa, the clay from Denmark, the spike in iridium, the shift in the fossils—could be explained by a single event. This is a new entry (OED Third Edition, September 2012; most recently modified version published online December 2021). < n.1980
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