Carbon isotope stratigraphy - Themed article collection GFF

GFF

Over the last few decades the concept of carbon isotope stratigraphy has evolved from the pioneering stage to become a standard tool for long-distance examination of marine sedimentary rocks.

The method helps us to understand the evolution of marine depositional environments through time and the processes that account for changes to these environments. The method is a proxy for changes to the global carbon cycle, revealing important information about the relative tempo and magnitude of climate change.

The underlying principle of carbon isotope stratigraphy is the fact that the relative abundance of stable carbon isotopes (C12 and C13) in the ocean-atmosphere system varies over geological timescales and that the carbon in precipitated marine carbonates reflect this variation relatively well. The exact variation of carbon isotopes is mainly influenced by changes in the primary productivity and carbon burial on a global scale, and this relates to changes in global climate.

By analysing marine carbonate rocks through sedimentary successions, it is possible to map out the changes in carbon isotope composition over time and define time intervals of unusually rapid changes (spikes) that reflect changes to the ocean-atmosphere system and that can be correlated across or between basins or even on a global scale. The lower Palaeozoic successions of northern Europe, particularly the flat-lying Ordovician and Silurian strata of Scandinavia, the East Baltic area and the British Isles, are classical. These strata formed in shallow intracratonic basins that subsequently underwent little burial and – for most areas – only minor tectonism.

The rocks therefore show comparably little diagenetic change and yield not only excellently preserved fossils but, importantly, also a well-preserved carbon isotopic signal. A substantial number of studies on this topic have been published in GFF over the years and in this virtual special issue, we have collated ten of the most important papers published between 2012 and 2018. Together they help to increase our understanding of how contemporaneous marine environments evolved and to constrain the timing of important biotic or climatic events and to enable correlation of these events globally.