Complex sentence: Anomalously high levels of mercury in the area of the tomb mound have been detected, which gives credence to the Sima Qian's account that mercury was used to simulate waterways and the seas in the Mausoleum of the First Qin Emperor.
Split into simpler sentences: Anomalously high levels of mercury in the area of the tomb mound were found. This gives credence to the Sima Qian's account that mercury was used to simulate waterways and the seas in the Mausoleum of the First Qin Emperor.