Assessing vermetid reefs as indicators of past sea levels in the Mediterranean

TY - JOUR

T1 - Assessing vermetid reefs as indicators of past sea levels in the Mediterranean

AU - Sisma-Ventura, G.

AU - Antonioli, F.

AU - Silenzi, S.

AU - Devoti, S.

AU - Montagna, P.

AU - Chemello, R.

AU - Shemesh, A.

AU - Yam, R.

AU - Gehrels, R.

AU - Dean, S.

AU - Rilov, G.

AU - Sivan, D.

N1 - © 2020 Published by Elsevier B.V. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy.

PY - 2020/11

Y1 - 2020/11

N2 - The endemic Mediterranean reef building vermetid gastropods Dendropoma petraeum complex (Dendropoma spp) and Vermetus triquetrus develop bio-constructions (rims) on rocky shorelines at about Mean Sea Level (MSL) and are therefore commonly used as relative sea-level (RSL) markers. In this study, we use elevations and age data of vermetid reefs to (1) re-assess the vertical uncertainties of these biological RSL indicators, and (2) evaluate the vertical growth rates along a Mediterranean east-west transect, in attempt to explain the differences found in both growth rates and uncertainties. In Israel, Differential Global Positioning System (DGPS) and laser measurements relative to the local datum show that the reef surfaces mainly occupy the upper intertidal zone with variations in elevation from +0.51 ± 0.07 m to +0.13 ± 0.05 m along the coast. However, in specific sites the vertical uncertainty exceeds the tidal range. In some places the local vermetid species D. anguliferum and V. triquetrus appear to alternate along the vertical rim profiles. This study documents a spatial variability of vertical growth rates, ranging from ~1 mm yr−1 in Israel and Crete, to ~0.1–0.2 mm yr−1 in NW Sicily and Spain. The order of magnitude of the difference in growth rates correlates with the east-west spatial thermal gradient of Sea-Surface Temperature (SST). Preferential skeleton deposition of D. petraeum and V. triquetrus measured by growth axis δ18O analysis shows that most calcification occurs at SST above the mean annual value. These findings indicate that vermetid reefs are a site-specific RSL indicator, displaying various vertical uncertainties and inner-structure complexities. Local data on the indicative range of vermetids are required when reconstructing relative sea-level changes using fossil vermetids.

AB - The endemic Mediterranean reef building vermetid gastropods Dendropoma petraeum complex (Dendropoma spp) and Vermetus triquetrus develop bio-constructions (rims) on rocky shorelines at about Mean Sea Level (MSL) and are therefore commonly used as relative sea-level (RSL) markers. In this study, we use elevations and age data of vermetid reefs to (1) re-assess the vertical uncertainties of these biological RSL indicators, and (2) evaluate the vertical growth rates along a Mediterranean east-west transect, in attempt to explain the differences found in both growth rates and uncertainties. In Israel, Differential Global Positioning System (DGPS) and laser measurements relative to the local datum show that the reef surfaces mainly occupy the upper intertidal zone with variations in elevation from +0.51 ± 0.07 m to +0.13 ± 0.05 m along the coast. However, in specific sites the vertical uncertainty exceeds the tidal range. In some places the local vermetid species D. anguliferum and V. triquetrus appear to alternate along the vertical rim profiles. This study documents a spatial variability of vertical growth rates, ranging from ~1 mm yr−1 in Israel and Crete, to ~0.1–0.2 mm yr−1 in NW Sicily and Spain. The order of magnitude of the difference in growth rates correlates with the east-west spatial thermal gradient of Sea-Surface Temperature (SST). Preferential skeleton deposition of D. petraeum and V. triquetrus measured by growth axis δ18O analysis shows that most calcification occurs at SST above the mean annual value. These findings indicate that vermetid reefs are a site-specific RSL indicator, displaying various vertical uncertainties and inner-structure complexities. Local data on the indicative range of vermetids are required when reconstructing relative sea-level changes using fossil vermetids.

KW - Bio-markers

KW - Growth rates

KW - Mediterranean Sea

KW - Past sea-level

KW - Vermetid reefs

UR - http://www.scopus.com/inward/record.url?scp=85089223534&partnerID=8YFLogxK

U2 - 10.1016/j.margeo.2020.106313

DO - 10.1016/j.margeo.2020.106313

M3 - Article

AN - SCOPUS:85089223534

SN - 0025-3227

VL - 429

JO - Marine Geology

JF - Marine Geology

M1 - 106313

ER -