Earth Science: Geology, the Environment, and the Universe, New York

Section 3: Absolute-Age Dating of Rocks

Absolute-Age Dating of Rocks

1.		According to the table, what is the half-life of Thorium-234? Days Elapsed Grams Of Thorium – 234 Remaining 0 16 12 11 24 8 36 6 Need a Hint?
			A)	8 days
			B)	20 days
			C)	16 days
			D)	24 days
2.		What type of material is used in the dating technique of dendrochronology? Need a Hint?
			A)	tree leaves
			B)	sediment layers from lake beds
			C)	tree growth rings
			D)	key beds
3.		A gravel-sized particle in a conglomerate is __________ the conglomerate rock.
			A)	younger than
			B)	the same age as
			C)	always ten times older than
			D)	older than
4.		What method is used to determine the exact age of a rock or fossil? Need a Hint?
			A)	dendrochronology
			B)	radiometric dating
			C)	relative age dating
			D)	the principle of superposition
5.		According to the figure, after four half-lives (22,820 years), how much C-14 would be left? <a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0328664233/184123/135_adrocks_ss_211c.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (15.0K)</a> Need a Hint?
			A)	6.25%
			B)	25%
			C)	0%
			D)	10%
6.		What isotope is used for finding the age of materials that are organic in origin? Need a Hint?
			A)	carbon-14
			B)	thorium-232
			C)	uranium-238
			D)	potassium-40