The Initial Eocene Thermal Maximum(IETM) has seriously affected the water quality and biological activities of sea and lake.Based on the experimental results of drilling cores

elemental analysis

organic carbon isotope and TOC

the lakewater oxidation-reduction conditions and paleoproductivity of Dongying terrestrial fault basin during early Eocene has been studied in this paper.It turned out that the lacustrine was strongly reductive but resumed oxidation environment afterward.The fluctuations of redox interface caused by the extreme climate events changed the lacustrine redox pattern

which resulted in the "disharmony" of the oxidation-reduction variation along the water depth.The productivity of the lacustrine was high in the early time

followed by a rapid decrease but increased progressively again.The lowest productivity period is basically consistent with the IETM.It has confirmed that the Initial Eocene Thermal Maximum (IETM) has affected the spatial and temporal fluctuation of the lacustrine.This event has obvious sedimentary record and biogeochemical response

which determines water oxidation-reduction and the bio-mass activities of the original basin.The hypoxia of lacustrine caused by thermal maximum resulted in the temporary decrease in productivity.However

productivity has been greatly restored with the sufficient oxygen supply after the event.This is especially demonstrated in the No.four section of Shahejie Formation with the higher TOC content and the productivity

and thus becomes the main reservoir of tight oil and gas production.