with one of the following is the most common method of improved recovery?

It is located in the Northern Territories, Canada. If location is what you mean by area.

To my knowledge it is the oldest rocks on Earth, formed at the end of the Hadean, some 4.01 Ga. It is highly deformed (20 km2) tonalite and granodiorite associated with amphibolite and ultra-mafic rocks, all lithologies are juxtaposed by high stress in banded rocks.

The discharge for a single stream should not change much from the headwater to the mouth. The exceptions to the mouth would be if another stream joined the main stream, which would increase the discharge or if you loose a significant amount of water to infilitration, which would decrease the discharge. The gradient should be high at the headwaters and gradually decrease downstream where it should be low at the mouth. Of course differences in lithologies or secondary streams can change the gradient for a short distance, thought the overall profile should fit the expected model.

The earth's crust is made up of several elements: Silica, Calcium, Oxygen, Iron, Sodium, Aluminium, Manganese and so on. These elements combine in some form or other to make salts like Silicon-oxide, Calcium carbonate, Iron-oxide for example which are known as minerals and several minerals combine to make rocks. The distribution of rocks and minerals across the different parts of the globe is different, and hence geologist study different rocks/lithologies across the globe. And also this distribution will changes with depth. The upper crust has different elemental composition with respect to the lower crust. For example, the upper crust has more of aluminum with respect to lower crust whereas the lower crust ahs more Magnesium with respect to upper crust.