Reconstruction of Middle to Late Quaternary sea level using submerged speleothems from the northeastern Yucatán Peninsula

Abstract

We examined 14 subaerially deposited speleothems retrieved from submerged caves in the northeastern Yucatán Peninsula (Mexico). These speleothems grew during the Middle to Late Quaternary and were dated by 230Th‐U techniques to provide upper depth limits for past sea levels. We report the first relative sea‐level limits for Marine Isotope Stages (MIS) 11 and 6, and present new evidence for sea‐level oscillations during MIS 5 and early MIS 1. For the latter periods, the origin of growth interruptions is evaluated by combining petrographic methods with trace element analyses. The MIS 5c sea‐level highstand probably occurred between 103.94 ± 0.58 ka and 96.82 ± 0.42 ka and must have exceeded ‐10.8 m (relative to present‐day local sea level). The minimum average rate of sea‐level fall over a 9.4 ka‐long period during the MIS 5e/5d transition is calculated from stalagmite and published coral data at 1.74 ± 0.37 m/ka. For the early Holocene, previous discrepancies with respect to a potential multimetre oscillation of local sea level were found to be challenging to reconcile with the existing speleothem data from the area.

Holocene sea-level rise evidenced in Hells Bells 234U/238U ratio and geochemical composition

“…Under these premises, Hells Bells formation places constrains on the minimum height of the redoxcline and halocline (reflecting the competition of sea level and freshwater layer thickness). This is opposite to the water level constraints obtained from submerged speleothems, which grow in dry caves and therefore provide an upper limit for past water level elevation (sea level) 11,52 .…”

“…The Yucatán Karst Aquifer (YKA) hosts the largest known network of underwater caves in the world 16,18 . Climate driven sea-level fall and rise by >100 m 19 caused large parts of the cave system to fall dry and submerge, respectively 11,18,20,21 . Modern water levels were reached around 4.5-3.8 ky ago 20,22,23 .…”

“…The δ 234 U0 value is influenced by several processes, such as the alpha-recoil process, host rock dissolution, and redox-behavior of Uranium [7][8][9][10] . In general, the δ 234 U0 value of secondary carbonates from the northern YP is close to secular equilibrium [11][12][13] and hence lower than the δ 234 U0 value of seawater (146.8±0.1‰ 14 ). In a recent study from southwest Nevada, it was suggested that even under dry conditions (e.g., during periods of a low water table), alpha-recoil causes excess 234 U to accumulate in damaged crystal lattice sites and/or on fractured surfaces of the bedrock and sediments, which may then be 'captured' as the water table returns 15 .…”

“…The measured δ 234 U values vary from 15.1 ± 1.2 to 59.9 ± 4.4‰, and the 230 Th/U ages range from recent to as old as 96 ky. To estimate the potential influence of initial (either detrital or freshwater derived) excess 230 Thxs on the 230 Th/U age, a first order correction was applied. Here, we assume one single source of contamination with a moderately elevated detrital ( 230 Th/ 232 Th) activity ratio of 2 ± 1, which is based on previous observations from speleothems of cave sites on the YP and the Caribbean realm 11,12,[30][31][32][33][34] . When using this correction model, the corrected ages for the measured Hells Bells samples range from 95.81 ± 0.52 ky to modern.…”

The World Atlas of Last Interglacial Shorelines (Version 1.0)

“…Two manuscripts for which data is available in WALIS 1.0 are only available as preprints. At the same time, data from one paper published outside the Special Issue were submitted by the lead author to WALIS (Steidle et al, 2021). In one case (not shown in Table 2), the WALIS U-series structure was used to report on Last Interglacial coral and speleothem ages in the Mediterranean Sea, adding more samples to those currently in WALIS for that region (Pasquetti et al, 2021).…”