Question

arrange from oldest to youngest using the letters provided. please tell what each letter represents
a. gneiss b. granite c. angular unconformity d. sandstone e. conglomerate f. basalt
a. gneiss b. granite d. sandstone c. angular disconformitye conglomerate f. basalt
a. gneiss b. granite c. angular unconformity f. basalt d. sandstone e. conglomerate
b. granite a. gneiss c. angular disconformity f. basalt d. sandstone e. conglomerate
b. granite a. gneiss c angular disconformity d. sandstone e. conglomerate f. basalt

Explanation:

Step1: Determine the oldest rock

Gneiss (A) is a metamorphic rock. Metamorphic rocks form deep - seated and are generally older in such geological cross - sections.

Step2: Consider the next - oldest rock

Granite (B) is an igneous rock. Igneous intrusions (like granite) occur after the formation of the surrounding rocks (in this case, the gneiss). But it is older than the overlying sedimentary rocks.

Step3: Analyze the angular unconformity

Angular unconformity (C) represents a period of erosion and non - deposition. It occurs after the underlying rocks (gneiss and granite) have been deformed (tilted) and eroded.

Step4: Look at the basalt (F)

Basalt is an igneous rock. If it is a lava flow (extrusive igneous rock), it can be a marker. But in the context of sedimentary rock layering, we first consider the sedimentary rock formation order.

Step5: Analyze the sedimentary rocks

Sandstone (D) is a sedimentary rock. After the angular unconformity, sedimentary rocks start to form. Sandstone is likely to form before conglomerate (E) in a typical sedimentary sequence (assuming normal deposition). Conglomerate (E) is a coarser - grained sedimentary rock. Basalt (F), if it is a lava flow, can be a later event (for example, if it is an inter - bedded lava flow or a capping lava flow). But in the absence of more information about the basalt's position (e.g., if it is intrusive into the sedimentary rocks or not), considering the sedimentary rock order first.

Answer:

A. gneiss B. granite C. angular unconformity F. basalt D. sandstone E. conglomerate