Many fundamental processes evolve over months and years, including 1) the strengthening of fault zones in the interseismic period between earthquakes, 2) the sequestration of carbon-bearing minerals in subsurface geologic reservoirs, 3) charge cycling in batteries, 4) the reactions between mixing magmas preceding volcanic eruptions, and 5) the degradation of fossils. Characterizing these processes in experiments typically requires unnatural methods of increasing the rates of reactions, or periodically removing the material from the apparatus or host material. Organization of a group of experts focused on these processes into a BAG will provide significant advances in our understanding of these processes. The BAG will enable far longer experiments than achieved previously that reveal the 4D evolution in situ, without significant perturbation of the sample, and without unnatural acceleration of the rates of the processes.