Reef recovery following the Late Devonian mass extinction: evidence from the Dugway Range, west-central Utah

The biotic crisis of the Late Devonian Period involved three distinct peaks of extinction intensity and preferentially eliminated reef taxa. By the end of the second peak, the Frasnian-Famennian (F-F) boundary, the dominant constructor guild member of the mid-Paleozoic, the stromatoporoids, had ceased reef construction in most parts of the world. An undescribed stromatoporoid bioherm in the Dugway Range, west-central Utah, is one of the few locations where stromatoporoids continued building reefs into the mid-Famennian. The sections are well-constrained biostratigraphically using both conodonts and stromatoporoids and range from the latest Frasnian to the Early Carboniferous. The reefal faunas are depauperate and dominated by labechiids and stylostromids, as is characteristic of most Famennian bioconstructions. In this region, reefal development was episodic with reefal units interbedded with units lacking reef taxa. The stromatoporoid survivors belong to long-ranging clades, and may represent extinction-resistant taxa. Both were fairly minor constituents of Frasnian reef communities