Question

A geologist is working in an area with exposed sedimentary rocks and finds a well exposed sequence of stratified rocks. As he works through a thick sequence of limestone, he sees abundant large clam fossils that produce an interlocking texture suggesting a reef, but within the limestone section these clams disappear and the overlying limestone is made up primarily of fragments of corals. He now moves 50 km away and finds limestones interbedded with shales, and the limestones contain the same clam fossils he had seen previously 50 km away. As he continues through this section, the rocks become entirely limestone, and the clams disappear again with coral fossils above forming a reef structure. He concludes:

Answer 1

Formation of an oil well.

Step-by-step explanation:

• As the geologist is working on an area that has exposed sedimentary rocks and finds the sequence of the ricks arranged in a stratified form he sees as a thick sequence of the limestone and an abundant amount of the fossil beds.

• The limestone made up of the corals is interbred with the presence of the shale that consists of the same fossils that he found about 50 km away. And thus he concludes that the sedimentary rock of shale may be involved in the formation of an oil well.

Answer 2

An oil well is formed

Step-by-step explanation:

Limestone is a kind of sedimentary rock that is rich in minerals, most of them work as nutrients for some living things like corals and clams, that is the reason why in the first point is quite common to find these living things.

In the case of the shale, is a kind of rock that is like compact sand, doesn`t have enough minerals to living things. even more, there are different colors depending the mineral that is the dominant in the rock.

If it is black is a signal of organic compounds, that is the reason why in the second point just the clams are present but not the coral.

And in the third point, both living things dissapear, because this shale turns into oil.