ex1317: Dinosaur Extinctions---An Observational Study
Description
About 65 million years ago, the dinosaurs suffered a mass extinction
virtually overnight (in geologic time). Among many clues, one that
all scientists regard as crucial is a layer of iridium-rich dust that
was deposited over much of the earth at that time. The theory is that
an event like a volcanic eruption or meteor impact caused a massive
dust cloud that blanketed the earth for years killing off animals and
their food sources. Dataset has Iridium depths by type of deposit.
Usage
ex1317
Arguments
Format
A data frame with 28 observations on the following 3 variables.
Iridium
Iridium in samples (ppt)
Strata
a factor with levels "Limestone" and
"Shale"
DepthCat
a factor with six levels: "1", "2",
…, "6"
References
Alvarez, W. and Asaro, F. (1990). What Caused the Mass Extinction? An
Extraterrestrial Impact, Scientific American263(4): 76--84.
Courtillot, E. (1990). What Caused the Mass Extinction? A Volcanic
Eruption. Scientific American263(4): 85--92.