Assume That Human Recorded History Can Be Stretched Back to 4600

Q56: Which rocks are most useful in unraveling

Q57: Examine the words and/or phrases for each

Q58: Give an example of a fossil type

Q60: The rare element iridium has been implicated

Q62: An unconformity is _.<br>A)an erosional (or non-depositional)surface

Q63: High concentrations of what rare mantle- or

Q64: Which geologic eon denotes the first 800

Q65: The ratio of parent to daughter isotopes

Q66: What kind of unconformity is produced when

Q87: The radioactive isotope,potassium-40,has argon-40 as a daughter