What characteristic differentiates relict features from contemporary features?

The characteristic that differentiates relict features from contemporary features is the firm to extremely firm texture. Relict features are remnants of past environmental conditions and processes that have become stabilized and have undergone significant weathering or alteration over time. These features often reflect the consolidated state of older sediments or materials that have not been actively changed by current environmental processes.

In contrast, contemporary features are shaped and influenced by current environmental factors and tend to exhibit more variability and less consolidation. The firm to extremely firm texture typically indicates that the material is less prone to erosion or alteration, which is a common characteristic of relict features. This texture helps in distinguishing them from contemporary features that may be softer or more susceptible to change due to current conditions.

The other characteristics, such as soft boundaries, presence of bright colors, and low organic carbon content, do not uniquely reflect the historical context or stability of relict features in the same way that texture does. Instead, they might reflect various other conditions that do not directly indicate whether a feature is contemporary or relict.