Time-equivalent Early Permian sedimentary successions from high-latitude Gondwana basins and from equatorial accumulations in North China, covering the glacial to postglacial transition, display correlatable trends in continental weathering intensity based on chemical index of alteration (CIA) values. The successions display a pattern of CIA values that varies with latitude, similar to modern estuarine suspended sediments. Based on the modern-day CIA-temperature correlation, the glacial Early Permian low-to high-latitude land surface temperature gradient is estimated as ~20°C, slightly higher than the calculated values for the contemporaneous sea-surface temperature gradient.
- CIA values
- Tectonic setting