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EnglandGeologyQuick questions
Module 2 and 4: Fossils and time; Interpreting the past
Quick questions on The geological time scale and correlation: eras and periods, lithostratigraphy and biostratigraphy - OCR A-Level Geology
6short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is the geological time scale?Show answer
Geological time is divided into a nested hierarchy, from longest to shortest:
What is correlation?Show answer
Correlation matches rocks of the same age between separate areas, using two main methods:
What are marker horizons?Show answer
A marker horizon is a thin, distinctive, widespread bed used as a reference line. The best example is a volcanic ash band: it is deposited from a single eruption over a geologically instantaneous time, so it represents the same moment everywhere, is widespread and recognisable, and can even be radiometrically dated to give an absolute tie point. Matching an ash band between areas correlates the sequences precisely at that level.
What is q1?Show answer
List the geological time hierarchy from longest to shortest. [2 marks]
What is q2?Show answer
State the difference between a period and a system. [2 marks]
What is q3?Show answer
Explain why biostratigraphy can correlate areas with different rock types. [2 marks]
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