{'fraction_non_alphanumeric': 0.014854111405835544, 'fraction_numerical': 0.010610079575596816, 'mean_word_length': 5.784172661870503, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
High resolution stratigraphy in modern and ancient marine sequences: ocean sediment cores to Palaeozoic outcrop

The Deep Sea Drilling Project (DSDP), over its initial ten years of operations, relied almost entirely on a developing biostratigraphy based on microfossil groups for its stratigraphic control. During that same period, high resolution stratigraphic methods were developed for Quaternary marine cores through combination of microfossil biostratigraphy and paleomagnetic reversal sequences. The introduction of the hydraulic piston corer in 1982 provided the means to extend the surface core studies to depth and a major impulse to paleoceanographic studies. By the end of the DSDP programme in 1984, an integrated high resolution stratigraphy for the North Atlantic had emerged, based on microbiostratigraphy, magnetostratigraphy and isotope stratigraphy which had extended the identification of Milankovitch cycles to the Pliocene. Through the Ocean Drilling Program’s operations since 1986, integrated Cenozoic stratigraphies have been extended to all the major oceans and emphasis is now placed on extending these to land sections. Resolution in pre-Cenozoic marine sequences has begun to benefit from the same integrated approach along with emerging techniques such as strontium isotope stratigraphy and ‘cyclostratigraphy’. The deciphering of geological events from the sedimentary record requires increasingly precise stratigraphic resolution if we are to advance our understanding of the Earth’s system and its processes. An important development of the 1980s was the recognition that the record of orbitally-modulated late Cenozoic and Quaternary climatic fluctuations might provide a key to improving resolution further back in the stratigraphic record (e.g. Imbrie 1985). It is important to improve stratigraphic resolution on these longer in order to explore the