The Huoluochaideng ancient city, located in the northern Ordos Plateau, once was a prosperous metropolis in Han Dynasty. However, the city suddenly disappeared at ~2.0 ka and the reason for the disappearance is still a mystery. In this article, detailed analysis on the Holocene stratigraphic sequences and active tectonics in the area of northern Ordos Plateau are presented to reveal the reasons for the Huoluochaideng ancient city's disappearance. Our results show that the Huoluochaideng ancient cities were filled with the flood deposits and buried on a group scale. The Holocene flood deposits were widely distributed in the ancient city and adjacent areas. The ¹⁴C dating results of the flood deposits demonstrated the ancient city experienced at least three palaeoflood events (~2.05, ~1.99, and ~1.85 ka) during the Late Holocene, which are consistent with the occurrence time of the most recent palaeoearthquake events (~2.08–1.85 ka) on the Langshan Mountain piedmont fault. Therefore, it is suggested that the palaeoearthquake events and their secondary damages led to the outbreak of extensive floods in the northern Ordos Plateau. After the last flood event (~1.85 ka), the Huoluochaideng ancient city was buried again by the northward moving Kubuqi Desert due to the arid climate and desertification. In summary, the disappearance of Huoluochaideng ancient city is suggested to relate with the great flood events that was triggered by the palaeoearthquake on the Langshan Mountain piedmont fault, such as the levees break of the Yellow River.

中文翻译：

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鄂尔多斯高原北部全新世地层序列及其对汉霍洛柴登古城消失的启示。

霍洛柴灯古城位于鄂尔多斯高原北部，曾经是汉代繁荣的大都市。但是，这座城市突然在2.0 ka时消失了，消失的原因仍然是个谜。本文对鄂尔多斯高原北部地区全新世地层序列和活跃构造进行了详细分析，揭示了霍洛猜灯古城消失的原因。我们的研究结果表明，霍洛柴灯古城充斥着洪水，被成群地埋葬。全新世洪水沉积物广泛分布在古城及邻近地区。在¹⁴洪水沉积物的C测年结果表明，古城在全新世晚期经历了至少3次古洪水事件（〜2.05，〜1.99和〜1.85 ka），这与最近的古地震事件的发生时间一致（〜2.08） –1.85 ka）在Lang山山前断裂上。因此，建议古地震事件及其次生破坏导致了鄂尔多斯高原北部大规模洪水的爆发。在最后一次洪水事件（〜1.85 ka）之后，由于干旱的气候和沙漠化，霍洛柴登古城再次被北移的库布其沙漠掩埋。综上所述，霍洛柴灯古城的消失被认为与Lang山山前断层古地震引发的大洪水事件有关，