Abstract: Cyclic sediment records contain rich geological information.Taking the Paleogene Kongdian Formation in Wangjiagang area in Jiyang Depression as an example,this paper studied the characteristics of material response in the cyclic sediment records of continental clastic rocks.Three kinds of cycles including color,lithology and grain size were identified in the continental clastic deposits accumulated during the gradual shrinking of lake level in Wangjiagang area and the genetic mechanism of these cycles is intermittent fluctuation of the Salt Lake level.Vertically from gray to red strata,the mineral cycle features in progressively increasing contents of quartz and potassium feldspar,decreasing contents of plagioclasite and calcite,and increasing content of anhydrite.The mineral cycles and color cycles have a good coupling relationship.The cycles also have a certain coupling relationship with element enrichment.Vertically,the contents of major elements such as Al,Ca,Fe and Mg have an increasing trend;while the contents of trace element Sr,Ba,Ga and Co have an increasing trend.The cycles also have a certain coupling relationship with element ratios,especially Fe/Mn and V/Ni ratios,which show multiple cycles.It is confirmed that sedimentary cycles of the continental clastic rocks in Wangjiagang area have relatively significant coupling relationship with mineral contents and element enrichment,and the former directly control the latter.Late diagenetic fluid modification influences material response and coupling patterns of the cycles through material exchange.

Key words: cyclic sedimentation, clastic rock, Kongdian Formation, Paleogene, Jiyang Depression