1. Metamorphism: Precambrian rocks are often highly metamorphosed. This means that they have been subjected to intense heat and pressure, changing their original composition and structure. The intense heat and pressure associated with plate tectonics and mountain building events during the Precambrian era often altered these early rocks.

2. Absence of Complex Fossils: While Precambrian rocks contain evidence of early life, they are generally lacking the complex fossils found in younger rocks. This is because early life forms were mostly single-celled organisms and soft-bodied, making fossilization less likely. The famous fossils known as stromatolites, layered structures formed by microbial mats, are a key indicator of early life in the Precambrian.

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