- Which principle can be used to determine the relative age of an igneous intrusion called a dike?
- What gas was lacking in early Earth's atmosphere? Its absence played a strong role in the type of weathering and organisms on Earth's surface
- We categorize impact _______ as either simple or complex, depending on their size and features
- The discovery of _____ allowed geologists to use isotopes to finally determine the age of Earth with accuracy
- Relative dating is concerned with the ______ in which geologic units were formed, rather than with their age
- Isotopes are different forms of an element that have different ______
- A(n) _____ fossil is a very short-lived, geographically widespread fossil species known to exist during a specific period of geologic time
- When geologists assign actual numbers to the age of a rock unit, they determine the ______ age
- Early scientific attempts a determining Earth's age gave a number that was ______
- Relative dating _______ to determine the order in which geologic events occurred
- Which chapter of geologic history is the earliest and represents 90% of geologic time?
- The geologic timescale details and divides geologic time based upon ______
- The erosional surface observed by James Hutton at Siccar Point in Scotland is now called a(n) _____ because it represents a significant amount of missing time in the geologic record
- The geologic timescale is subdivided into three _____ since the end of the Precambrian
- The oldest known rock found on Earth is dated at _____ years old
- Name the method of preservation: fish with fins and scales
- James Hutton inferred that the rocks below the contact at Siccar Point were vertical gray sandstone and shale and the rocks above were gently dipping red sandstone and conglomerate. Therefore, the histories of these rocks were _____.
- When a geologist attempts to match up two different sections of rock according to time, he or she is ____ the rocks
- Determining the actual age of an event or object in years is called
- An _____ is a break in the geologic record that is made when rock layers are eroded or when sediment is not deposited for a long period of time