Authochthonous

Incorrect. This describes an allochthonous formation.

Incorrect. While authochthonous formations can be deformed, this doesn't define them. Deformation can occur both in-place and during transport.

Correct! This is the definition of an authochthonous formation.

Incorrect. While authochthonous formations are often source rocks, this characteristic isn't exclusive to them.

Incorrect. Authochthonous formations can be excellent source rocks.

Incorrect. Authochthonous formations can also serve as reservoir rocks.

Correct! Determining the age of formations is important, but it is not directly related to whether a formation is authochthonous or allochthonous.

Incorrect. Understanding authochthonous formations is crucial for interpreting these structures.

Incorrect. This would be an allochthonous formation.

Correct! Volcanic rocks formed in place are authochthonous.

Incorrect. Uplift and erosion suggest movement, making this an allochthonous formation.

Correct! Sedimentary layers deposited in a basin are typically authochthonous.

Incorrect. This is a crucial technique in determining authochthonous formations.

Incorrect. Seismic surveys provide important data for interpreting geological structures.

Incorrect. Examining the minerals and textures of rocks is essential for determining authochthonicity.

Correct! Structural analysis helps understand deformation and movement, but it's not the primary technique for determining if a formation is authochthonous.

Correct! Knowing the origin and movement of formations helps understand hydrocarbon processes.

Incorrect. While groundwater is important, this question focuses on oil and gas exploration.

Incorrect. While tectonic movement is related to earthquakes, the question focuses on oil and gas exploration.

Incorrect. Estimating the Earth's age is done through different methods.

**1. Analysis:** The tilted sandstone layer unconformably overlying granite raises questions because: - **Unconformity:** This suggests a significant gap in time and geological processes between the formation of the granite and the sandstone. - **Tilting:** Steep tilting indicates possible movement or deformation, potentially caused by tectonic forces. - **Potential for Transport:** The unusual position raises the possibility that the sandstone layer was transported from another location. **2. Possible Explanations:** - **Authochthonous Scenario:** The sandstone could have formed in its current location, but a later tectonic event uplifted and tilted the entire formation. The granite would have been present during the deposition of the sandstone but experienced deeper burial and subsequent uplift, exposing it at the surface. - **Allochthonous Scenario:** The sandstone layer could have been transported from a different location. It might have been eroded from a nearby mountain range and deposited over the granite during a period of marine transgression. This could explain the unconformity and tilting. **3. Research Needed:** - **Stratigraphic Analysis:** Carefully examine the rock layers above and below the sandstone layer for evidence of continuity or breaks, and compare their ages. - **Structural Analysis:** Map the orientation and deformation of the sandstone layer and the surrounding rocks to understand their relationship and potential movement. - **Petrographic Analysis:** Compare the mineral composition and textures of the sandstone with potential source rocks to see if they match, providing evidence of origin.