The Geological Society of America’s (GSA) 2015 Annual Meeting was an international meeting bringing together professionals, students, teachers and affiliates from 58 countries to communicate their research in geology. With over 7,400 geologists walking through the doors, the variety of sessions was unrivalled, with 342 technical sessions taking place during the Conference. Palaeontologists were in for a treat this year, with over 25 technical sessions and 20 poster sessions, addressing many new and varied strands of palaeontological research. How biotic fauna has evolved over geological time is a vital aspect to understanding past life on Earth, and despite countless studies of and major advances in understanding faunal trends over the last 500 million years, our record is still very much incomplete. So, it comes as no surprise that the themes of evolution, extinction and assessing bias in the fossil record were well-covered topics at the meeting.
A series of talks relating to extinction events explored the causes and subsequent recoveries from these major biotic crises. A session on ‘Mass Extinction Causality’ began with a talk from Steve Holland on the stratigraphy of mass extinction, which highlighted that there is a potential stratigraphic architectural control on the last occurrences of fossils. Steve argued that with the possible exception of the end-Cretaceous (K–Pg), mass extinctions in the fossil record are characterized by clusters of last occurrences at sequence stratigraphical horizons. This may have a significant impact on how we currently infer the tempo and timing of these events. The role of flood basalt volcanism as the ultimate cause of major extinction events was widely discussed during the session. Talks on Deccan volcanism, a controversial contender for the K–Pg mass extinction event, were given by Loyc Vanderkluysen, Paula Mateo, Jahnavi Punekar, Thierry Adatte, Thomas Tobin and Gerta Keller, covering topics including the lava emplacement record and palaeoenvironmental changes associated with the volcanism. James Witts assessed the nature and timing of the K–Pg extinction in Antarctica, and the likely contribution of volcanism versus extraterrestrial impact as a causative mechanism. Steve Stanley closed the session with a talk on the true intensity of the end‑Permian mass extinction.
With a momentary lull in palaeontological-facing talks and the onset of jet-lag fast outpacing the high caffeine intake of the day, a trip to the aquarium was in order. Baltimore’s National Aquarium, situated a few minutes from the conference centre in the harbour area, provided unexpected thrills for us palaeontologists. A 4D showing of ‘pre-historic sea monsters’ allowed us to assuage the fear that we would spend the morning in a palaeontology-free world.
Towards the end of the conference, there was an interesting session on the recovery of biota following the devastating end-Permian mass extinction, the largest loss of taxonomic diversity in Earth history. Talks were aimed at redefining “restructuring” intervals by characterizing chaotic palaeoenvironmental conditions, and comparing these to changes in community diversity and ecological complexity. Margaret Fraiser challenged current paradigms about hypothesized Early Triassic marine conditions as a control on low ecological complexity, and showed an absence of environmental degradation even when ecological complexity remained low. William Foster used a quantitative approach to investigate if marine benthos were impacted by events at sub-stage boundaries during the Early Triassic, and showed that benthic ecosystems were only interrupted by additional crises in the Late Indian (Dinerian) and mid-Olenkian (Smithian/Spathian). Elizabeth Petsios suggested that outgassing from Siberian Traps volcanism may have stalled recovery in environments susceptible to temperature rise, particularly in shallow marine settings. Tracy Thomson proposed that the rich trace fossil record in deltaic deposits from Utah reveal a ‘hidden diversity’ in the aftermath of the end-Permian extinction. In another session on broad-scale controls on biodiversity through time, Richard Twitchett provided evidence that bioturbation may be a key control on marine diversification following the end-Triassic extinction event.
A change in focus to ‘Ancient Life in Deep Time’ gave insights into ancient faunas during stratigraphically important time periods. Work by John L. Moore showed how small shelly faunas (‘SSFs’) can be used to help refine a critical interval of metazoan history during the Cambrian, and Jan Ove R. Ebbstad presented work on the stratigraphy of the Ediacaran–Cambrian transition, identified by the trace fossil Treptichnus pedum.
In addition to the talks, poster sessions allowed the chance to grab a free beer (of which, over 100 kegs were consumed through the course of the Conference) and peruse posters. Poster sessions covered topics including ichnology, palynology, trends in morphology and body size, as well as palaeoecology modern analogues. A huge amount of non-technical sessions were continuously held throughout the day at the conference centre and included courses and seminars on applied biostratigraphy, the concept of the Anthropocene, and Geo-Education. GSA provided a great opportunity to appreciate the numerous ways in which palaeontology is helping to answer major questions about how life and our planet have evolved through time.