GLOBAL TRAVERTINE DEPOSITION MODULATED BY OSCILLATIONS IN CLIMATE

Travertine deposits are important records of past fluid flow in Earth’s crust, and document fluid migration through both tectonic activity and changes in climate. While many studies hint at possible relationships between travertine formation and global climate, none have investigated these connections at a global scale. Here we compile 1649 published travertine ages from six continents to test the hypothesis that global and/or regional changes in climate regulate travertine deposition. A kernel density estimation (KDE) of these data contains three main clusters of ages. The youngest cluster contains four peaks at 9, 24, 40, and 54 ka. A second cluster of ages contains three peaks at 96, 107, and 127 ka. The oldest cluster contains two peaks at 200 and 221 ka. Peaks in bedded travertine ages occur with main frequencies that correspond to 100 kyr changes in global climate, where most peaks occur during glacial terminations or interglacial periods. The largest peak in the global dataset is centered at 9 ka, which occurs during the 10-7.5 ka Early Holocene climatic optimum and lags behind the Younger Dryas event by 2 kyr. Time series analysis also suggests a possible connection with 41 kyr obliquity cycles. Alternatively, banded travertine deposits that typically form vertical veins have age peaks that occur during times of dry climate.

The global travertine age dataset is subdivided into North America, Europe, the Black Sea, the Mediterranean, the Arabian-Sahara Deserts, and Australia regions. KDEs of these regional datasets also contain multiple peaks that correspond with local times of high precipitation or wet conditions. This can be attributed to higher groundwater recharge rates, providing the necessary water to form travertine. Many bedded travertine-depositing systems may therefore be water-limiting and sufficient CO₂ may be present even during times of no travertine deposition. In contrast, banded vein travertine deposits that have peaks corresponding to times of dry climate may form through an alternative process involving an upward injection of CO₂-rich fluids from a depressed water table.