When rocks sit in a pool of salt water, the primary type of weathering occurring is chemical weathering.

Here's why:

* Salt Crystal Growth: Salt water evaporates, leaving behind salt crystals. These crystals grow inside the pores and cracks of the rock. As they grow, they exert pressure, causing the rock to break apart. This process is called haloclasty.

* Hydrolysis: Water molecules can react with certain minerals in the rock, breaking them down into new minerals. This process is particularly effective in rocks containing feldspar.

* Oxidation: The dissolved salts in the water can accelerate oxidation processes, especially in rocks containing iron. This leads to the formation of rust-like compounds, which can weaken the rock.

It's important to note: While salt water can cause physical weathering (e.g., the force of waves eroding the rock), the main contributor to weathering in this scenario is chemical weathering.