Geochemical Constraints on Carbonate Platform Evolution in the Paleo-Tethys Region

The Paleo-Tethys Ocean represented one of the most dynamic marine realms of the late Paleozoic, characterized by complex tectonic reorganization, fluctuating sea levels, and profound biotic and geochemical transformations. Carbonate platforms that developed along its continental margins preserve detailed geochemical signatures that constrain their depositional evolution, diagenetic overprint, and paleoenvironmental conditions. This study synthesizes major, trace, and rare earth element (REE) geochemistry, along with stable isotope data (δ¹³C and δ¹⁸O), to evaluate controls on carbonate platform growth and decline in the Paleo-Tethys region. Elemental ratios such as Sr/Ca, Mg/Ca, Mn/Sr, and Fe content indicate varying degrees of diagenetic alteration and water–rock interaction, distinguishing primary marine signatures from burial modification. Positive δ¹³C excursions correspond to enhanced organic carbon burial and periods of increased platform productivity, whereas negative excursions align with regional anoxia and environmental instability associated with Late Paleozoic tectonic convergence. REE patterns, including Ce and Eu anomalies, further constrain redox conditions and hydrothermal influence during carbonate deposition. The integration of geochemical proxies reveals a strong coupling between tectonic subsidence, eustatic oscillations, and oceanic circulation in governing platform architecture and facies distribution.