Thomas Cronin, Ph.D.
Thomas Cronin is a Senior Geologist at the Florence Bascom Geoscience Center.
Dr. Cronin received his BA from Colgate University in Geology in 1972 and MA and PhD in Geology from Harvard University in 1974 and 1977.
Positions: National Research Council Post-doc at the USGS at the Museum of Natural History, Washington DC 1977-1978, research scientist USGS since 1978. NSF-sponsored visiting researcher at Shizuoka University, Japan (1991), lecturer Urbino (Italy) Summer School for Paleoclimatology Faculty (2009-2016), adjunct faculty Georgetown University’s Walsh School of Foreign Service (2005-present), White House Office of Science, Technology and Policy (OSTP) (1996-97).
US Geological Survey research in paleoclimatology, sea-level change, biostratigraphy, geochemistry and ecosystems; more than co-authored 200 scientific articles, more than 60 journals including Science, Nature, Nature Geoscience, Proceedings National Academy of Sciences, Geology, Geophysical Research Letters, Trends in Ecology and Evolution, and Quaternary Science Reviews. Numerous invited articles to proceedings volumes, handbooks & encyclopedias. Written two books, former co-editor of Global & Planetary Change, editorial boards for Journal of Micropaleontology, Marine Micropaleontology, Journal of Paleontology. Frequent manuscript reviews for international journals, proposals to National Science Foundation and other agencies.
In addition to work at OSTP, served on numerous USGS and interagency scientific committees and panels, contributing to USGS program development and informing decision-makers and the public. Published influential studies in the fields of micropaleontology, sea level and climate change, paleoceanography, and ecosystem history. Honors: Brady Medal (TMS London), Duke of Montefeltro Medal (USSP Urbino), Fellow, American Association for Advancement of Science, Wilmot H. Bradley lecture (Geological Society Washington), US Coast Guard Service Medal, AGU Citation for Excellence Reviewing, Bolin Climate Center Annual Lecturer (Stockholm), USGS Leadership, Meritorious Service, and Excellence Awards. Research widely reported in media including NY Times, National Geographic Society, New Scientist, Chesapeake Bay Journal, BBC, NPR, AP, and Fox News. Collaboration with major research institutions across the US, Europe and Asia, mentored numerous bachelors, masters and PhD students.
Current research focused on Land-Sea Linkages in the Arctic, Arctic paleoclimatology and sea-level change. Participated in four Arctic icebreaker research expeditions recovering sediment cores of the last million years of Arctic Ocean history. Work has influenced US Department of Homeland Security, US Coast Guard icebreaker planning, NOAA’s Arctic Program, and the International Ocean Drilling Program deep-sea coring program.
Science and Products
Enhanced Arctic amplification began at the Mid-Brunhes Event 430,000 years ago
Central Arctic Ocean paleoceanography from ∼50 ka to present, on the basis of ostracode faunal assemblages from the SWERUS 2014 expedition
Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins
Post-glacial flooding of the Bering Land Bridge dated to 11 cal ka BP based on new geophysical and sediment records
The 3.6 ka Aniakchak tephra in the Arctic Ocean: A constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea
Biological response to climate change in the Arctic Ocean: The view from the past
An Arctic and Subarctic ostracode database: Biogeographic and paleoceanographic applications
Calcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean
Calcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean
Climate change
Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation
On the reconstruction of palaeo-ice sheets: Recent advances and future challenges
Science and Products
- Science
- Multimedia
- Publications
Filter Total Items: 128
Enhanced Arctic amplification began at the Mid-Brunhes Event 430,000 years ago
Arctic Ocean temperatures influence ecosystems, sea ice, species diversity, biogeochemical cycling, seafloor methane stability, deep-sea circulation, and CO2 cycling. Today's Arctic Ocean and surrounding regions are undergoing climatic changes often attributed to "Arctic amplification" - that is, amplified warming in Arctic regions due to sea-ice loss and other processes, relative to global mean tAuthorsThomas M. Cronin, Gary S. Dwyer, Emma Caverly, Jesse Farmer, Lauren H. DeNinno, Julio Rodriguez-Lazaro, Laura GemeryCentral Arctic Ocean paleoceanography from ∼50 ka to present, on the basis of ostracode faunal assemblages from the SWERUS 2014 expedition
Late Quaternary paleoceanographic changes at the Lomonosov Ridge, central Arctic Ocean, were reconstructed from a multicore and gravity core recovered during the 2014 SWERUS-C3 Expedition. Ostracode assemblages dated by accelerator mass spectrometry (AMS) indicate changing sea-ice conditions and warm Atlantic Water (AW)inflow to the Arctic Ocean from ∼50 ka to present. Key taxa used as environmentAuthorsLaura Gemery, Thomas M. Cronin, Robert K. Poirier, Christof Pearce, Natalia Barrientos, Matt O'Regan, Carina Johansson, Andrey Koshurnikov, Martin JakobssonDeglacial sea level history of the East Siberian Sea and Chukchi Sea margins
Deglacial (12.8–10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East SiberiAuthorsThomas M. Cronin, Matt O'Regan, Christof Pearce, Laura Gemery, Michael Toomey, Igor SemiletovPost-glacial flooding of the Bering Land Bridge dated to 11 cal ka BP based on new geophysical and sediment records
The Bering Strait connects the Arctic and Pacific oceans and separates the North American and Asian landmasses. The presently shallow ( ∼ 53 m) strait was exposed during the sea level lowstand of the last glacial period, which permitted human migration across a land bridge today referred to as the Bering Land Bridge. Proxy studies (stable isotope composition of foraminifera, whale migration intoAuthorsMartin Jakobsson, Christof Pearce, Thomas M. Cronin, Jan Backman, Leif G. Anderson, Natalia Barrientos, Goran Bjork, Helen Coxhall, Agatha de Boer, Larry Mayer, Carl-Magnus Morth, Johan Nilsson, Jayne Rattray, Christian Sranne, Igor Semiletov, Matt O'ReganThe 3.6 ka Aniakchak tephra in the Arctic Ocean: A constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea
The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is relatively wellAuthorsChristof Pearce, Aron Varhelyi, Stefan Wastegård, Francesco Muschitiello, Natalia Barrientos Macho, Matt O'Regan, Thomas M. Cronin, Laura Gemery, Igor Semiletov, Jan Backman, Martin JakobssonBiological response to climate change in the Arctic Ocean: The view from the past
The Arctic Ocean is undergoing rapid climatic changes including higher ocean temperatures, reduced sea ice, glacier and Greenland Ice Sheet melting, greater marine productivity, and altered carbon cycling. Until recently, the relationship between climate and Arctic biological systems was poorly known, but this has changed substantially as advances in paleoclimatology, micropaleontology, vertebrateAuthorsThomas M. Cronin, Matthew A. CroninAn Arctic and Subarctic ostracode database: Biogeographic and paleoceanographic applications
A new Arctic Ostracode Database-2015 (AOD-2015) provides census data for 96 species of benthic marine Ostracoda from 1340 modern surface sediments from the Arctic Ocean and subarctic seas. Ostracoda is a meiofaunal, Crustacea group that secretes a bivalved calcareous (CaCO3) shell commonly preserved in sediments. Arctic and subarctic ostracode species have ecological limits controlled by temperatuAuthorsLaura Gemery, Thomas M. Cronin, William M. Briggs, Elisabeth M. Brouwers, Eugene I. Schornikov, Anna Stepanova, Adrian M. Wood, Moriaki YasuharaCalcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean
Microfaunal and geochemical proxies from marine sediment records from central Arctic Ocean (CAO) submarine ridges suggest a close relationship over the last 550 thousand years (kyr) between orbital-scale climatic oscillations, sea-ice cover, marine biological productivity and other parameters. Multiple paleoclimate proxies record glacial to interglacial cycles. To understand the climate-cryosphereAuthorsR. E. Marzen, Lauren H. DeNinno, Thomas M. CroninCalcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean
Microfaunal and geochemical proxies from marine sediment records from central Arctic Ocean (CAO) submarine ridges suggest a close relationship over the last 550 thousand years (kyr) between orbital-scale climatic oscillations, sea-ice cover, marine biological productivity and other parameters. Multiple paleoclimate proxies record glacial to interglacial cycles. To understand the climate-cryosphereAuthorsRachel Marzen, Lauren H. DeNinno, Thomas M. CroninClimate change
Climate change (including climate variability) refers to regional or global changes in mean climate state or in patterns of climate variability over decades to millions of years often identified using statistical methods and sometimes referred to as changes in long-term weather conditions (IPCC, 2012). Climate is influenced by changes in continent-ocean configurations due to plate tectonic processAuthorsThomas M. CroninEvidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation
The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice-shelf groundiAuthorsMartin Jakobsson, Johan Nilsson, Leif G. Anderson, Jan Backman, Goran Bjork, Thomas M. Cronin, Nina Kirchner, Andrey Koshurnikov, Larry Mayer, Riko Noormets, Matthew O'Regan, Christian Stranne, Roman Ananiev, Natalia Barrientos Macho, Dennis Cherniykh, Helen Coxall, Bjorn Eriksson, Tom Floden, Laura Gemery, Orjan Gustafsson, Kevin Jerram, Carina Johansson, Alexey Khortov, Rezwan Mohammad, Igor SemiletovOn the reconstruction of palaeo-ice sheets: Recent advances and future challenges
Reconstructing the growth and decay of palaeo-ice sheets is critical to understanding mechanisms of global climate change and associated sea-level fluctuations in the past, present and future. The significance of palaeo-ice sheets is further underlined by the broad range of disciplines concerned with reconstructing their behaviour, many of which have undergone a rapid expansion since the 1980s. InAuthorsChris R. Stokes, Lev Tarasov, Robin Blomdin, Thomas M. Cronin, Timothy G. Fisher, Richard Gyllencreutz, Clas Hattestrand, Jakob Heyman, Richard C. A. Hindmarsh, Anna L. C. Hughes, Martin Jakobsson, Nina Kirchner, Stephen J. Livingstone, Martin Margold, Julian B. Murton, Riko Noormets, W. Richard Peltier, Dorothy M. Peteet, David J. W. Piper, Frank Preusser, Hans Renssen, David H. Roberts, Didier M. Roche, Francky Saint-Ange, Arjen P. Stroeven, James T. Teller - News