Wallace and Hobbs is definitely the go-to for most freshman and sophomore-level meteorology classes.
Even had a few upper-level courses that referenced it. Maybe a bit more advanced for what you're looking for, but still is an excellent textbook. Still have mine in my office.
The standard intro to atmospheric science I believe is Wallace & Hobbs; this book focused on the physical science and quantitative aspect of atmospheric science. I don't have anything for general geophysics however.
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I once heard from a guy having a physics PhD now working in weather forecasting said "Even the most theoretical ideas in meteorology is nowhere as sophisticated as in theoretical physics." Atmospheric science is more of an applied science much like engineering. So I think all the really high-level theoretical tools in GR, QFT, etc. will unlikely be used there, and I suspect this is the same for geophysics as well. The more immediately applicable background knowledge to have, I would say, is fluid dynamics.
You'll be hard-pressed to find a better introductory textbook than Wallace & Hobbs. It's a comprehensive and informative introductory tome that still manages to have lots of judiciously chosen pretty pictures.
There is an outstanding book on the mountain by Dick Thompson called <em>Volcano Cowboys</em>. It bounces around a bit, but a majority of the book detailing the USGS investigating the build up before the eruption and the aftermath. In addition to interviews, Thompson had full access to their field notes and reports. You get a great understanding of how hard it is to be predictive with what was then a largely observational science. And the description of what happened to Dave Johnson at Coldwater II is heartbreaking (exactly right place, exactly wrong time.)
Modern-day science creates many more problems than it solves. Otherwise, it just creates problems to solve. You shouldn't concern yourself too much with that.
https://www.amazon.com/The-Ion-Effect-Electricity-Health/dp/0553196863/ref=cm_cr_pr_product_top
So this book is part of the required readings for my petrophysics class, and it's literally like reading what that guy in the video was saying. I have to read it with either a dictionary or google near by because I don't understand a lot of the words in it. But hey, petrophysics!
Cool, I think those areas expose you to some of our oldest geologic features as well as Quaternary stuff in Langebaan. I assume the Ladysmith part is for venturing into the Drakensberg range, where you will see some spectacular structural geology features. Unless you're from around the active volcanic or swampy areas of the US, the stuff you will encounter (sedimentary and metamorphics) should be easy to recognize for you. Bachelor's field trips are such cool learning experiences. It's awesome you get to go to a different country too.
I highly recommend Stow's book as a guide to (mostly sedimentary) field work, if you don't have one already. It has great tips on setting up your field notes, beautiful color photos for examples, and a touch of good geologist humor (and timeless geologist fashion).
There tends to be a bit of a divide between mineral/metal exploration and oil & gas, but for minerals I'd definitely recommend this:
Try to find some of the old MIT text books (http://www.amazon.co.uk/Special-Relativity-MIT-Introductory-Physics/dp/0748764224) They're out of print but really very helpful. Also Young's and Freedmann is the core text of most of my courses =]