Disrupted continental environments around the Devonian-Carboniferous Boundary: introduction of the tener event

Abstract

1. Introduction The Devonian-Carboniferous Boundary (DCB) is associated with one of the most severe biocrises through the Phanereozoic, namely the Hangenberg Event or Hangenberg Biocrisis. Long considered as a second-order extinction event, this biocrisis is now regarded as equally severe as the global Late Frasnian Kellwasser Biocrisis as it led c. 45% of marine genera to extinction and wiped out entire ecosystems at the end of the Famennian Age (Becker et al., 2016 and references within). Research traditionally focused on the Devonian-Carboniferous Boundary, i.e. for the search for a basal Carboniferous GSSP and a biostratigraphic scheme, but high resolution data on extinctions all through the Hangenberg Biocrisis are still a work in progress, and mainly concern the marine realm (see the synopsis by Kaiser et al., 2015 and references within). What happened on continents is less clear. The latest Famennian flora is traditionally seen as a homogeneous cover of “Archaeopteridalean forests” (Fairon-Demaret, 1986; Jarvis, 1990) that is associated to the homogeneous “lepidophyta palynoflora” (Streel et al., 2000) typical of that interval. This assemblage suffered from the biocrisis but did not become extinct before the DCB (Streel & Marshall, 2006). Consequently, there is a marked time shift between the main extinction events in the marine and terrestrial realms, which points to clear differences on the effects of the biocrisis between both realms (e.g. McGhee, 2013). Timing of t