Final answer:
TEX86 and GDGTs are climate proxies used in geology to estimate past temperatures and pH levels based on lipid analysis in sediments.
Step-by-step explanation:
TEX86 and GDGTs are both used as climate proxies in the field of geology. TEX86, which stands for TetraEther indeX of tetraethers forming 86 carbon rings, is a proxy used to estimate sea surface temperature in the past. It is based on the analysis of certain lipids produced by marine microorganisms called archaea.
GDGTs, or Glycol Dialkyl Glycerol Tetraethers, are another type of lipid compound found in sediments. They can be used to reconstruct past temperature and pH conditions. Certain ratios of GDGTs can indicate changes in temperature, and the presence of specific GDGTs can be linked to pH levels.