The point of writing a scientific paper is to communicate the findings and significance of your research. No one will be obligated to read your paper, so you have to persuade them to start reading, and you have to write clearly enough that they keep reading. The purpose of the introduction is to tell the reader what the paper is about and, more importantly, to justify to the reader why the paper is significant. Such a sentence can, from the reader's perspective, be one of the most important in the whole paper, because the reader then knows what to expect as she or he proceeds. It may be an important sentence for the writer as well, because you're forced to decide what the focus of your paper really will be, and you may realize that you're covering either too many things or not enough things, or not using those things to help refine or increase scientific knowledge.
Geologists love to wax poetic about the geologic context of their work.
Often such a context is vital to understanding the paper. However, this section of a paper, if present, should not include every detail known about the region or rock unit. It should tell, and should only tell, the information needed to put the results and discussion in context. This section of a paper is always boring but almost always necessary. This section should answer those questions.