Question

based on uranium-235 dating, the zoroaster granite is approximately 1.8 billion years old, and the basalt (igneous sill) that intrudes into the base dolomite is approximately 1.1 billion years old. what can be said, then, about the age of the base dolomite?

Answer 1

The base dolomite must be older than 1.1 billion years and younger than 1.8 billion years. To determine the exact age, direct dating would be needed, but geologic principles provide this relative age estimate.

Step-by-step explanation:

Based on the provided information, the base dolomite is older than the age of the igneous sill basalt, which is approximately 1.1 billion years old, but younger than the Zoroaster Granite, which is approximately 1.8 billion years old. Thus, we can infer that the base dolomite must have formed sometime after the Zoroaster Granite but was in place before the basalt intruded into it.

The dating of rocks and minerals using radioactive isotopes, such as uranium-235 and rubidium-strontium, helps scientists establish a relative timeline for geological events. While the exact age of the base dolomite cannot be determined without direct dating, the principles of cross-cutting relationships in geology dictate that it must be between these two dates derived from surrounding rock formations. Therefore, the base dolomite should be older than 1.1 billion years but younger than 1.8 billion years.