I recommend you to study "Paleoclimatology: Reconstructing Climates of the Quaternary" By: Raymond S Bradley. Reading this book helps you get familiar with different paleoclimate proxies. For more information you can see Prof. Bradley's publications in below link:
there are many textbooks about paleoclimatology. A good reference book on Quaternary paleoclimates is Raymond Bradley's "Paleoclimatology. Reconstructing Climates of the Quaternary", published by Elsevier.
Being an archaeologist, you could be interested in historical climatology.... The old text by the French Historian Emmanuel LeRoy Ladurie ("Time of feast, time of famine", 1973) is allways full of interesting data...