Final answer:
The chronological order starts with the deposition of the oldest sedimentary reddish-brown rocks, followed by shale with marine organisms, then gray clay with minerals. The final event is the intrusion of magma that solidifies into glasslike rocks.
Step-by-step explanation:
To determine the chronological order of the events based on the described rock layers, we use principles of geology such as the Law of Superposition and cross-cutting relationships. Here is the sequence:
- Reddish-brown rocks with sand-sized rock grains were deposited horizontally.
- Rocks made of shale and skeletons of marine organisms were deposited horizontally.
- Rocks composed of gray clay flakes with crystals of minerals were deposited horizontally.
- An intrusive layer of magma cut into the reddish-brown rocks and solidified to form glasslike rocks.
We start with the deposition of the oldest layer, the reddish-brown rocks, which are typically sedimentary and form from the accumulation and cementation of mineral or organic particles. Over time, additional layers of sediment form on top, with the shale and marine skeletons being next, indicating a marine environment. The uppermost layer of gray clay with minerals is the youngest sediment deposit. Finally, the intrusive layer of magma, which cuts through the reddish-brown rocks, solidifies last, indicating it is the most recent geological event, as per the principle of cross-cutting relationships.