Rock On #10

Which is older:

Fault I.

Which correctly gives the order of the faults, from oldest (first) to youngest (last):

I, J, H

Which is younger:

The tree.

You are asked to assign as accurate a numerical age as possible (how many years old) to a sedimentary deposit. You would be wise to use:

Either counting of annual layers or radiometric techniques if the deposit is young (less than about 100,000 years), and radiometric techniques if the deposit is old (more than about 100,000 years).

One practical radioactive system used to date lava flows involves:

The solid potassium-40, which decays to the gas argon-40.

You start with 200 parent atoms of a particular radioactive type, which decays in a single step to give a stable offspring, and you start with none of those stable offspring. You wait just long enough for two half lives to pass. You should expect to have how many offspring atoms (on average)(remember that the number of parents and the number of offspring add up to 200, so if you have 10 parents, you have 190 offspring because 10 and 190 add up to 200, and if you have 20 parents you have 180 offspring, and so on):

150

Which is the correct age progression, from younger (first) to older (last)?

B, F, E, D, C

Using only uniformitarian calculations from the thickness of known sedimentary rocks, likely rates at which those rocks accumulated, and features in and under those sedimentary rocks, geologists working two to three hundred years ago estimated that the Earth:

Is more than about one-hundred-million years old.

Geological evidence based on several radiometric techniques has provided a scientifically well-accepted age for the Earth. Represent that age of the Earth as the 100-yard length of a football field, and any time interval can be represented as some distance on the field. (So something that lasted one-tenth of the age of the Earth would be ten yards, and something that lasted one-half of the age of the Earth would be fifty yards.) On this scale, how long is written history?

Just over the thickness of a sheet of paper.

What is accurate about the scientific results learned by counting annual layers in ice cores?

Many tests show that some ice cores have reliably preserved annual layers, and the longest record extends back more than 100,000 years.

The above photograph was taken in the Grand Canyon, and shows a cliff that is approximately 30 feet high.What are the rocks in the cliff?

Precambrian metamorphic rocks with some igneous rocks intruded; the folding was caused by mountain-building processes when the rocks were very hot deep in a mountain range.

In the two pictures above, I and II, show traces of former life in rocks from the Grand Canyon. Each is "typical";the rocks near sample I contain fossils similar to those shown in sample I, and the rocks near sample II contain fossils similar to those shown in sample II.It is likely that:

Sample I is from higher in the cliffs of the Grand Canyon, and sample II is from much lower, nearer to the river.

Which is NOT accurate about the Grand Canyon, in Arizona:

The canyon is wider at the top and narrower at the bottom because the river was wider when the region was wetter, and has narrowed as deserts spread recently.

The picture above shows a very hard piece of rock about six inches across, in the Grand Canyon.The surface of the rock looks rather different from the surfaces of many other rocks.What made this odd-looking surface?

The river, which blasted the rock with sand- and silt-laden water during floods; this shows that even hard rocks can be eroded by rivers.

John Wesley Powell, who led the first boat trip through the Grand Canyon, called the feature marked by the yellow lines "The Great _________". What did he put in the blank?

Unconformity