Position: Professor

Address: 4202 E. Fowler Ave., NES 107

Tampa FL 33620

Phone: +1-(813) 974-1067

Fax: +1-(813) 974-4808

Email: bonac@usf.edu

Specialty: Karst Geology, Quaternary paleoclimatology, Cave mineralogy & Geochemistry

Research interests: Paleoclimate and sea-level changes based on cave deposits;
Mineralogy and geochemistry of cave minerals, carbonate geology and karst protection


1999 Postdoctoral Fellow, University of Lund, Sweden (Quaternary paleoclimate)

1998 Postdoctoral Fellow, The Pennsylvania State University, USA (Paleoclimate)

1996 PhD Geology, Babes-Bolyai University, Cluj, Romania

1987 BSc Geology, Babes-Bolyai University Cluj, Romania

Selected recent publications

(italic = student author; * corresponding author)

Dumitru, O.A., Austermann, J., Polyak, V.J., Fornos, J.J., Asmerom, Y., Gines, J., Gines, A., Onac, B.P.* 2019: Constraints on global mean sea level during Pliocene warmth. Nature, 574: 233-236; http://dx.doi.org/10.1038/s41586-019-1543-2

Polyak, V.J., Onac, B.P., Fornos, J.J., Asmerom, Y., Hay, C., Dorale, J.A., Gines, J. Tuccimei, P., Gines, A. 2018: A highly resolved record of relative sea-level in the western Mediterranean Sea during the Last Interglacial period. Nature Geoscience, 11: 860-864; https://doi.org/10.1038/s41561-018-0222-5

Cleary, D.M., Onac, B.P., Tantau, I., Wynn, J.G., Forray, F.L., Ionita, M., Tamas, T. 2018: A guano-derived d13C and d15N record of climate since the Medieval Warm Period in NW. Journal of Quaternary Science, 33 (6): 677-688.

Staubwasser, M., Dragusin, V., Onac, B.P., Assanov, S., Ersek, V., Hoffmann, D.L., Veres, D. 2018: Climate change impact on the transition of Neanderthals to modern humans in Europe. PNAS, https://doi.org/10.1073/pnas.1808647115

Dumitru, O.A., Forray, F.L., Fornos, J.J., Ersek, V., Onac, B.P. 2017: An assessment of stable isotopes variability in precipitation, cave drip, and groundwater from Mallorca Island, Western Mediterranean. Hydrological Processes, 31: 104-116; doi: 10.1002/hyp.10978

Cleary, D.M., Wynn, J.G., Ionita, M., Forray, F.L., Onac, B.P. 2017: Evidence of long-term NAO influence on East-Central Europe winter precipitation from a guano-derived δ15N record. Scientific Reports, 7, 14095

Persoiu, A., Onac, B.P., Wynn, J.G. Blaauw, M., Ionita, M., Hansson, M. 2017: Holocene winter climate variability in Central and Eastern Europe. Scientific Reports, 7: 1196 DOI:10.1038/s41598-017-01397-w

Onac, B.P., Hutchison, S.M., Geanta, A., Forray, F.L., Wynn, J.G., Giurgiu, A.C., Coroiu, I. 2015: A 2500-year Late Holocene multi-proxy record of vegetation and hydrologic changes from a cave guano-clay sequence in SW Romania. Quaternary Research, 83: 437-448; doi:10.1016/j.yqres.2015.01.007

Onac, B.P., Forray, F.L., Wynn, J.G., Giurgiu, A.M. 2014: Guano-derived d13C--based paleo-hydroclimate record from Gaura cu Musca Cave, SW Romania. Environment Earth Sciences, 71 (9): 4061-4071;
DOI: 10.1007/s12665-013-2789-x

Onac, B.P., Effenberger, H.S., Wynn, J.G., Povara, I. 2013: Rapidcreekite in the sulfuric acid weathering environment of Diana Cave, Romania. American Mineralogist, 98: 1302-1309.

Onac, B.P., Wynn, J.G., Sumrall, J. 2011: Tracing the sources of cave sulfates: a unique case from Cerna Valley, Romania. Chemical Geology 288: 105-114; DOI: 10.1016/j.chemgeo.2011.07.006

Dorale, J.A., Onac, B.P., Fornos, J.J., Gines, J., Gines, A., Tuccimei, P., Peate, D.W. 2010: Sea-level highstand 81,000 years ago in Mallorca. Science, 327: 860-863.


Ponta, G., Onac, B.P. (Eds.) 2019: Caves and karst systems of Romania. Springer International, Cham, 544 p.

Gines, A., Gines, J., Gomez-Pujol, L., Onac, B.P., Fornos, J.J. (Eds.) 2012: Mallorca: a Mediterranean benchmark for Quaternary studies. Monografies de la Societat d’Història Natural de les Balears, 18, 220 p.

Racovita, G., Onac, B.P. 2000: Scarisoara Glacier Cave. Monographic study. Ed. Carpatica, Cluj-Napoca, 140 p.


2016 - 2019: A 5-million-year record of western Mediterranean Sea level variability; National Science Foundation P2C2 program (PI).

2016 - 2018: Climate and vegetation reconstruction using ice and guano cores in lava tubes at El Malpais, NM;  National Park Service (PI)

Synergetic activities

Editor in Chief: International Journal of Speleology

President: Cave Minerals Commission (UIS)

Organizer: Sea level changes into MIS 5: from observations to predictions NSF workshop, Palma de Mallorca (April 10-14, 2012)

Research collaborations

Sea level changes based on cave deposits from Mallorca, Spain

collaboration with J. Fornos, A. Gines, J. Gines (Univ. Palma de Mallorca), J. A. Dorale (Univ. Iowa),  V. Polyak & Y. Asmerom (Univ. New Mexico), & P. Tuccimei (Univ. Rome 3).

Paleoenvironmental reconstructions based on cave bat guano

collaboration with F.L. Forray (Babes-Bolyai University, Cluj, Romania), J.G. Wynn (NSF)

Mineralogy of mine caves in Sardinia, Italy

collaboration with J. De Waele, A. Naseddu, F. Sauro, P. Forti (Univ. Bologna)

Colorado River incision history of Grand Canyon from speleothems

collaboration with V. Polyak, C.A. Hill, A.N. Palmer, Y. Asmerom (UNM)

Paleoclimatic reconstructions based on ice deposits from Scarisoara Cave, Romania
collaboration with A. Persoiu (Speleo Institute Cluj),  J.G. Wynn (USF),  M. Ionita & N. Rimbu (Alfred Wegener Institute, Germany).

Holocene climate patterns in NW Romania based on speleothems

collaboration with V. Ersek (Northumbria University, UK) , V. Dragusin (Speleo Institute Bucharest), D. Fleitmann (Univ. Basel, Switzerland).

Created: March 23, 2008

Modified: September 16, 2021