Until now, geography teaching has only touched upon the way in which students write argumentations focused on geographical topics, and the challenges of doing this. In order to shed light on this process, this study considers the problems and challenges students face when using material-based written argumentation in geography lessons. The results from 19 evaluated text products and sound thinking protocols, which were collected in the 8th grade of a comprehensive school, are presented and analyzed. These results show that simultaneously handling several materials at once is a challenge for the students in material-based writing due to a lack of processing techniques.