Here's a breakdown:

* Sedimentary rocks form from the accumulation and lithification of sediment. This sediment can be eroded from other rocks, formed by biological processes, or deposited from chemical precipitation.

* Many factors can prevent sedimentary rock formation:

* Erosion: Strong winds or water currents can remove sediment as quickly as it is deposited.

* Lack of deposition: Areas may experience little or no sediment accumulation due to their environment (e.g., deserts, high mountain peaks).

* Metamorphism: Existing sedimentary rocks can be transformed into metamorphic rocks by heat and pressure.

* Uplift and erosion: Sedimentary rocks can be uplifted and eroded away.

* The absence of sedimentary rocks does not indicate a complete lack of geological activity. It simply means that the conditions necessary for the formation and preservation of sedimentary rocks were not present.

In summary: The lack of sedimentary rocks is not a reliable indicator of time passage. It simply indicates that there was no accumulation, preservation, or survival of sediments in that specific location.

To understand the geological history of a region, it is important to consider all the factors that influence rock formation and analyze other geological data, such as:

* Geochronology: Radioactive dating methods can provide precise ages for rocks.

* Structural geology: Analyzing folds, faults, and other structures can reveal the history of deformation and uplift.

* Paleontological data: Fossils found in surrounding areas can provide clues about the age and environment of the region.