A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilised in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonised by life.
To assign absolute dates to fossils in this sediment core, it would be most helpful if ________.

Question

A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilised in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonised by life. 
To assign absolute dates to fossils in this sediment core, it would be most helpful if ________.

Quizplus · Accepted Answer

Volcanic ash layers provide a way to assign absolute dates to the fossils in the sediment core, as these layers can be radiometrically dated. Knowing the order in which the fossils occurred (choice A) may be helpful for interpreting the evolutionary history, but it does not provide absolute dates. The sediments being undisturbed by underwater currents (choice B) may help preserve the integrity of the fossils, but it does not provide a method for absolute dating. Fossils throughout the column being equally spaced apart (choice D) is not necessarily indicative of anything and does not provide a method for absolute dating.

A Sediment Core Is Removed from the Floor of an Inland