Seabed erosion and deposition related to the typhoon activity of the past millennium on the southeast coast of China

Abstract

Catastrophic events often interrupt long‐term Earth surface processes. In coastal areas, although millennial‐scale trends of climatic and sea‐level changes determine the trajectory of sedimentary landform evolution, storm and/or tsunami activity can cause abrupt changes in depositional conditions that may alter the long‐term sedimentary processes. Here, we report a sedimentary hiatus that is widely observed from the late Holocene sedimentary sequence at the seabed along the southeast China coast. This hiatus was discovered by close temporal sedimentary and radiocarbon dating analyses of a seabed sedimentary sequence in the mouth area of the Pearl River estuary. The results suggest that a couple of metres in the middle to late Holocene sediment at the seabed were eroded by a catastrophic event happening c. 1000–800 cal. Years BP. In theory, a mega‐tsunami generated from the Manila Trench could have caused such erosion at the seabed, but there is a lack of direct geological and historical evidence to support such a hypothesis. Much more likely, a super‐typhoon struck the coast and caused the erosion. This hypothesis is strongly supported by the region's historical and geological records, which suggest a period characteristic of intense typhoons ranging from the Medieval Warm Period to the climate transition phase (c. 1000–600 cal. Years BP). During the subsequent Little Ice Age, deposition of sandy sediment continued, suggesting frequent but weaker typhoon activity. Over the past two centuries the deposition of sandy sediment and gravels began, implying the beginning of a phase of intensifying typhoon conditions, possibly a result of the recent warming climate. © 2020 John Wiley & Sons, Ltd.

A preliminary study on sediment records of possible typhoon in the northern South China Sea during the past 6500 years

“…Due to the disturbed sediments found in both cores of the same lagoon, Yue et al (2019) inferred possible tsunami-induced events. However, distinguishing typhoon and tsunami deposits is very difficult, therefore we cannot confirm the tsunami occurrence recorded in Layer 6 (Xiong et al, 2020). The confirmation of tsunami needs further studies on land, as the differentiation criteria (e.g.…”

“…This is supported by previous studies. For instance, due to the huge typhoons in history, the seabed erosion occurred for the cores out of the PRE, which results in the post-eroded deposits filled with shell fragments and coarsened fractions (Xiong et al, 2020).…”

“…Coincidentally, the 1-3 kyr BP span the duration of "cultural gap" in a site of Hong Kong (Yang et al, 2018). It seems that there is a relation between the coastal change documented in the YJ core and the ruin of ancient human culture because Xiong et al (2020) proposed that typhoon (or tsunami) could cause the hiatus (seabed erosion) in three cores close to Hong Kong, on the east of the PRE. More paleo-typhoon records from sediments are needed to validate the relation between typhoon activities and ancient humans' settlements.…”

Poleward Shift in Tropical Cyclone Tracks in the Northwest Pacific During Warm Periods: Past and Future

“…Previous studies (e.g., Ramos et al., 2017; Sun et al., 2013; Yang et al., 2019) have suggested that one paleo‐tsunami affected the central to northern parts of the SCS around AD 1000, and the earthquake was originated from the Manila Trench (Lau et al., 2010; Mak & Chan, 2007; Ramos et al., 2017; Sun et al., 2013; Xiong et al., 2020). On the other hand, some other studies (Goff et al., 2020; Qiu et al., 2019) suspected that no paleo‐tsunami affected the SCS in the past millennium, and no sedimentary evidence of paleo‐tsunami event affecting the Xisha Islands area has been recorded since that time (Sun et al., 2013; Yan et al., 2011; Yue et al., 2019).…”

“…The historical documentary record in the Hainan and parts of Guangdong (Chu et al., 2002); 7 . HKUV10 (Xiong et al., 2020); 8. The historical documentary record of Hainan and Guangdong (Liu et al., 2001); 9.…”