：基于全球地质记录的比对，国际人类世工作组建议20 世纪中期（约1950 年）为人类世的起始时间，四海龙湾沉积物曾被列为“人类世界线层型剖面”的候选地质体之一。但在1950 年以前，人类已较深刻地影响了四海龙湾周围地区的环境。通过重建四海龙湾沉积物900 年以来的总有机碳、总有机碳和总氮的摩尔比（C/N）、δ¹³C_org和Ca/Ti，以及硅酸盐矿物主要元素Si、Al 和K含量的历 史序列，平均分辨率约为10 年，以气候变化为背景，探究该地区人类活动的历史。发现人类活动从1850 年开始显著增强，在此之前的中世纪暖期和小冰期指标变化大体符合自然规律。1850—1950年指标的变化反映出快速增长的人口破坏了植被，导致风化加剧，地表环境的演变脱离了自然轨道，表明人类活动开始成为一种重要的地质营力，但这段时期的变化只是局地信号；1950 年后，C/N 持续下降及δ¹³C_org持续负移，反映出在新政府和先进生产力的条件下，四海龙湾周围地区的环境状态再次发生改变，这与全球地质环境的加速变化同步，可以支持国际人类世工作组所提出的“20 世纪中期是人类世的起始时间”。

Abstract： Based on global comparison of geological records, the international Anthropocene Working Group (AWG) suggested that the mid-20th century (~1950 CE) be the onset of the Anthropocene, the Sihailongwan maar Lake sediment had been listed as one of the candidates for Global Stratotype Section and Point (GSSP) for Anthropocene. However, human had put a profound impact on the environment of areas around the Sihailongwan maar Lake before 1950 CE. Historical sequences of TOC contents, C/N ratios, δ¹³C_org values, Ca/Ti ratios and concentrations of silicate major elements Si, Al, K since 900 CE were reconstructed, the average resolution is ~10 a, to explore the history of human activities in this region, with the background of climate change. It was found that human activities had significantly increased since 1850 CE, but the changes in the measured proxies during the Medieval Warm Period and Little Ice Age before 1850 CE generally followed natural laws. The changes in the measured proxies during 1850–1950 CE reflected the rapid population growth, which damaged vegetation, and thus resulted in intensified weathering, and deviation of the surface environment evolution from natural state, these indicate that human had started to be an important force for geological environment, but the changes during this period were only local signals; after 1950 CE, C/N ratios and δ¹³C_org values decreased continuously, which reflected that the environmental status of the area around Sihailongwan maar Lake changed once again, under the new government and advanced productivity, this was in sync with the Great Acceleration of global geological environment, and can support that “the mid-20th century is the onset time of the Anthropocene” proposed by the AWG.