 Geologists are able to deduce the past environments and tectonic events by studying geological records like rocks and geological structures.The oldest components of the Eastern Block were first formed more than 4 billion years ago (the Hadean Eon).It later experienced numerous geological events between 3.8 and 1.85 billion years ago (the Eoarchean to Paleoproterozoic Era), including recurring volcanic eruptions and metamorphic events.