Exam 12: Deep Time: How Old Is Old

If the lithology and fossil content of two bodies of rock on opposite sides of a canyon are identical,then these remaining outcrops were likely physically connected at one time and formed part of an extensive,sheet-like layer of rock.This idea summarizes the principle of ________.

Accurate radiometric dating is possible only if a rock contains a measurable amount of ________.

If a sandstone lies on top of a shale,________.

Basaltic clasts within a conglomerate have been radiometrically dated to 50 million years ago.Is this a reliable age for the conglomerate?

If an igneous dike cuts across a sequence of sedimentary beds,________.

Radiometric dates applied to sedimentary rocks produce ages that ________.

The principle of ________ explains the occurrence of older rock within a newer igneous body.

If all of Earth's history were compressed into a single year,Homo sapiens would first appear on ________.

Buried erosional surfaces between parallel sedimentary strata are termed ________.

Which of the following is always the same for different isotopes of a single element?

Magnetostratigraphy takes advantage of the fact that Earth's magnetic field ________.

The surface below sedimentary rocks that overlie igneous or metamorphic rocks is termed a(n)________.

If the relative ages of two formations are known,what else about them can be inferred?

Dendrochronology involves dating of historic and geologic events through the study of ________.

Which principle of stratigraphy could be used to determine the relative ages of Layer 7 and Layer 3?

When an unstable parent isotope decays,which of these is true?

Basaltic clasts within the basal layers of a conglomerate imply which of the following statements?

Which eon of geologic time is represented by rocks containing abundant shelly fossils?

After one half-life has passed,what is the ratio of parent isotopes to daughter isotopes?

Can the age of Earth be reliably estimated from sediment thicknesses?