Abstract:Chlorophyll-a concentration of Huguangyan Maar Lake sediments were determined by diffuse reflectance spectroscopy. Through comparison with TOC, Sr intensity and magnetic susceptibility we concluded that chlorophyll-a can be taken as a reliable proxy of primary production, higher chlorophyll-a absorption reflects stronger monsoon intensity and higher precipitation, and vice versa. Holocene environment evolution at Zhanjiang area reconstructed by chlorophyll-a, TOC, Sr intensity and magnetic susceptibility of Huguangyan Maar Lake sediments demonstrated that the monsoon intensity in Zhanjiang area was strong in the early Holocene and declined dramatically since 6000 a BP. Holocene climate evolutional pattern at Zhanjiang area is similar with many other records from the monsoonal areas of the North hemisphere and summer isolation at 30°N, implying that solar isolation is the driving force of millennial-scale Holocene monsoon evolution at Zhanjiang area. However, monsoonal evolution lags behind solar isolation by about 2200 a. Monsoon strengthen demonstrated by chlorophyll-a declined significantly since 6000 a BP. Nonetheless, all the other records display gradual weakening process. Negative feedback of vegetation-atmosphere induced by solar isolation might have caused quick droughty trend, on the other hand, dilution effect led by increased sedimentary rate may amplify declining trend of chlorophyll-a around 6000 a BP. Sedimentary environment since 3600 a BP could be impacted by human activities.