Pollen analysis a means of obtaining information on the composition and extent of past floras and environments by examining fossil pollen grains , spores , and similar structures in peat and sedimentary deposits .
The author of the 1996 study remarked , " the temporal-spatial distribution of cenozoic faunas and floras on the plateau not only shows the climatic conditions in various periods of time , but it also indirectly indicates changes in elevation of the plateau in various periods . "