The abyssal giant sinkholes of the Blake Bahama Escarpment: evidence of focused deep-ocean carbonate dissolution

Channel inception through bottom‐current erosion of pockmarks revealed by numerical simulation

“…In the present study, we focus on the interaction between bottom currents and depressions formed by fluid escape, but similar results could apply to other kind of negative-relief bedforms formed by other factors, such as faulting (Berndt et al, 2012;Gay et al, 2021) and sediment dissolution (Cavailhes et al, 2022;Kluesner et al, 2022). On a nearly aclinal seafloor, the bottom-current erosion would be stronger at the downstream flanks (or reaches), shown as the erosion of single pockmark (Figure 6) or pockmark train (Figure 7), which is consistent with the current erosion mainly occurred at the downstream of an arc-shaped and elongated depression (with a length of 30 km), at the northern Argentine continental margin (Warnke et al, 2023).…”

“…In the Grenada Basin (Gay et al, 2021) and the Hatton Basin (Berndt et al, 2012), the wide development of giant polygonal faults on the seabed may induce a stronger bottom‐current erosion between the neighbouring polygons, forming seafloor furrows with a flat bottom. Moreover, large number of mega‐depressions (i.e., sinkholes) can be formed by the dissolution of carbonate‐rich sediments and surface collapse (Cavailhes et al, 2022; Kluesner et al, 2022), while their interaction between bottom currents is still a poorly known processes, and the difference in the impacts from sinkholes and pockmarks on bottom‐current actions are also worthy of thorough investigation. In addition, the development of subsurface structures, that is, faults, diapir, gas chimney and buried channels, determines the distribution of pockmarks and other heterogeneities on the seafloor, subsequently controlling the inception and development of pockmark‐related channels (Cartwright & Santamarina, 2015; Chen et al, 2018; Pilcher & Argent, 2007; Sun et al, 2011).…”

First Documentation of Large Submarine Sinkholes on the Ganquan Carbonate Platform in the Xisha Islands, South China Sea

“…Among them, submarine sinkholes have unique karstic features that are different from inland and coastal sinkholes or caves. They are located in deep waters, which makes detailed study difficult [7]. Their unusual positions and unique geomorphological features with steep biogeochemical gradients and distinct microbial communities provide natural laboratories to study marine karst processes, climate-related issues, marine ecology, and carbonate geochemistry.…”

“…They formed during low sea levels during the last glacial period and later experienced carbonate accretion along the sinkhole margins during the Holocene based on side-scan sonar, seismic surveys, and radiocarbon dating. Recently, more submarine sinkholes have been reported in the Bahamas and Caribbean Sea [7]. Seismic reflection and bathymetric data show that 29 sinkholes are located at the toe of the Bahamian carbonate platform and have been corroded by the circulation of saltwater.…”

“…Seismic reflection and bathymetric data show that 29 sinkholes are located at the toe of the Bahamian carbonate platform and have been corroded by the circulation of saltwater. Their water depths range from 4584 to 4967 m, and their diameters range from 255 to 1819 m, with vertical depths from 30 to 185 m [7]. In addition, more than 21 submarine sinkholes have been discovered on Luymes Bank, which is a part of Saba Bank in the Caribbean Netherlands, and their water depths range from 93 to 187 m. These submarine sinkholes were formed via carbonate platform dissolution caused by acidic seawater from a submerged lake, which is a novel mechanism for submarine sinkhole formation and growth [14].…”