Indiana University Bloomington

Simon Brassell

Simon C. Brassell

Professor of Geological Sciences

Biogeochemistry and Molecular Organic Geochemistry

Office:   MSBII 404
Phone:   812-855-3786

Educational Background

  • Ph.D., 1980, Organic Geochemistry, University of Bristol, U.K.
  • B.Sc., 1976, Chemistry & Geology (Class I), University of Bristol, U.K.

Research Interests

Determination, assessment, and interpretation of molecular and isotopic characteristics of organic matter to identify biogeochemical processes associated with carbon cycling in modern and ancient natural systems.

Activities focused on the exploration and application of biomarkers, and their isotopic signatures, as environmental, paleoclimatic, stratigraphic and geochemical tools to better understand:

  • Environmental and climatic signals recorded in the temporal and spatial variations of the molecular and isotopic characteristics of sedimentary organic matter.
  • The capacity of molecular and isotopic signals to reflect controls on primary production and factors that affect the survival of organic matter in sediments, particularly microbial processes.
  • The evolutionary progression of life through time, especially biosynthetic responses preserved in the biogeochemical carbon cycle that are related to global perturbations of the ocean and atmosphere.
  • Depositional controls on the formation of petroleum source rocks and influences on the generation, composition, and biodegradation of petroleums, and the fate of hydrocarbons in the environment

Courses Taught

Undergraduate classes involving interactive learning, which have been aided by development and assessment grants, and recognized by teaching awards in each of the past four years:

  • G131: “Oceans and Our Global Environment.” An introductory oceanography course for non-science majors with on-line web-based exercises (
  • G302: “Development of the Global Environment.” An exploration of Earth history focused on its development, its atmosphere, oceans and continents, the evolution of life, catastrophic events and climate change (

Graduate classes in aspects of biogeochemistry, supplemented by training in analytical techniques and seminars in topical areas of interdisciplinary research:

  • G587: “Organic Geochemistry.” A comprehensive exploration of measurement and applications of molecular and isotopic characteristics of organic matter focused on principles and processes.
  • G690: “Biogeochemistry.” An interdisciplinary examination of the characteristics of biogeochemical processes involved in the global carbon cycle and affecting Earth’s climate history.
Graduate seminars in aspects of biogeochemistry:
  • G690: “Organic Geochemical Stratigraphy.” Examination of temporal changes in biogeochemical records and the causes of their variability through exploration and evaluation of records from marine and lacustrine settings, and from modern and ancient systems.
  • G690: “Petroleum Geochemistry” Examination of the chemistry of petroleum, with a focus on the origins and fate of molecular constituents, especially controls on their occurrence and abundance and assessment of their applications in petroleum geoscience.
  • G690: "Paleoclimatology" Exploration of the principles and application of tools used to measure, assess, interpret, and explain patterns and processes of climate change throughout Earth history.
Teaching Publications:
  • Newsletters about the IU Bloomington Course Portfolio Initiative within the Scholarship of Teaching and Learning (SOTL) Program. (Fall01) (Spring03)
  • Abstracts on development of web-based exercises for teaching introductory oceanography (pdf) and use of discussion group in an earth history class. (pdf)
  • Course Portfolio for G131 as fully illustrated (pdf) and compact (pdf) versions.

Recent Research Projects

Projects representative of opportunities for research, including collaborative activities, which are, or have been, supported by NSF, NOAA, JOI/USSSP and other funding agencies:

  • Evolution of temperature controls on alkenone biosynthesis: did variations in alkenone unsaturation, the basis for the paleotemperature proxy UK 37, developed in calcareous nannoplankton as a biological response to global cooling during the Paleogene?
  • Biogeochemistry of Lower Aptian organic-rich sediments (ODP 198): a high-resolution stratigraphic study of variations in molecular and isotopic (13C, 2H, 15N) characteristics to explore depositional conditions and global influences on sequestration of organic matter during oceanic anoxic events.
  • Molecular diversity in the sedimentary record: an assessment of compositional variations in biomarkers as a measure of biocomplexity through geological time.
  • Monterey Bay particulate organic matter: a study to assess the seasonality of alkenone production and temperature signals within an upwelling system (Bac et al., 2003; PDF).

Other current and exploratory projects include several collaborative ventures with colleagues at Indiana University, Lisa Pratt, Arndt Schimmelmann, and Peter Sauer, and their students and post-docs.

Representative Publications

Brassell S.C. (submitted) Biomarker evidence for environmental constraints on ancient cyanobacterial assemblages. North-Central Section, Geol. Soc. Amer. 43rd Ann. Mtg., Rockford, IL.

Brassell S.C. (submitted) Origin of steroidal ketones in Cretaceous marine sediments. 24th Intl. Mtg. Org. Geochem., Bremen, Germany.

Dumitrescu M. & Brassell S.C. (submitted) Paleoceanographic and environmental controls on enrichment of major and trace elements in Early Aptian organic-rich sediments corresponding to Oceanic Anoxic Event-1a at Shatsky Rise (Site 1207). Paleoceanography.

Jaraula C.B., Brassell S.C., (submitted) Kenig F., & Doran P.T. Novel Penta-Unsaturated Alkenones From Lake Fryxell, Antarctica. Organic Geochemistry.

Dumitrescu M. and Brassell S.C. (submitted) Biogeochemical assessment of paleoproductivity during the Early Aptian Oceanic Anoxic Event at Shatsky Rise, ODP Leg 198. Organic Geochemistry (pdf)

Finkelstein D.B., Brassell S.C., Pratt L.M. (in review) Microbial biosynthesis of wax esters during desiccation: an adaptation for colonization of the earliest terrestrial environments? Geology

Brassell S.C. (in review) Steryl ethers in a Valanginian claystone: molecular evidence for cooler waters in the central Pacific during the Early Cretaceous? Palaeogeog., Palaeoclimatol., Palaeoecol.

Jaraula C.B., Brassell S.C., Kenig F., Doran P.T., Hopmans E. & Schouten S. (2008) Applicability of biomarker temperature proxies in cold end-member lakes in Taylor Valley, Antarctica. Gordon Conf. Org. Geochem., Plymouth, NH.

Harvey M.C. & Brassell, S.C. (2008) Combustion of fossil organic matter associated with the Cretaceous/ Paleogene (K/P) boundary. Gordon Conf. Org. Geochem., Plymouth, NH.

Finkelstein D.B. & Brassell S.C. (2008) Biosynthesis of wax esters during desiccation: an adaptation for survival on the early Earth? Gordon Conf. Org. Geochem., Plymouth, NH.

Brassell, S.C. (2008) Sedimentary records of biomarkers as milestones for evolutionary innovations. Geol. Soc. Amer. Ann. Mtg., Houston, TX.

Finkelstein D.B., Brassell S.C. & Pratt L.M. (2008) Evolution of Wax Esters as Storage Lipids in Microbial Mats. Geol. Soc. Amer. Ann. Mtg., Houston, TX.

Brassell S.C. & Dumitrescu M. (2008) Biogeochemical evidence for environmental constraints on cyanobacterial populations during an Oceanic Anoxic Event. Amer. Geophys. Union Fall Mtg., San Francisco, CA.

Finkelstein D.B. & Brassell S.C. (2008) Biosynthesis of wax esters during desiccation: an adaptation for survival on the early Earth? Amer. Geophys. Union Fall Mtg., San Francisco, CA.

Harvey M.C., Brassell S.C., Belcher C.M., Montanari, A. (2008) Combustion of fossil organic matter at the K/P boundary. Geology 36, 355-358. doi: 10.1130/G24646A.1 Villinski J.C., Hayes J.M., Brassell S.C., Riggert V.L. & Dunbar R.B. (2008) Sedimentary sterols as biogeochemical indicators in the Southern Ocean. Org. Geochem. 39, 567-588. doi:10.1016/j.orggeochem.2008.01.009

Wang R.L., Zhang S.C., Brassell S.C., Tomasi D., Scarpitta S.C., Zhang G., Sheng G.Y., Wang S.M. & Fu J.M. (2008) Geochemical signals and paleoclimate changes in a 16,000 14C year sedimentary record from Lake Gucheng, eastern China. In Geochemistry Research Advances, (ed. Stefánsson O.) pp. 143-161. Nova Science.

Brassell S.C. et al. (2004) Recognition of alkenones in a lower Aptian porcellanite from the west-central Pacific. Organic Geochemistry 35, 181-188. (pdf)

Wang et al., (2004) Steroids in sediments from Zabuye Salt Lake, western Tibet: diagenetic, ecological or climatic signals? Organic Geochemistry 35, 157-168. (pdf)

Bac M.G. et al. (2003) Seasonal variation in alkenones, bulk suspended POM, plankton and temperature in Monterey Bay, California: implications for carbon cycling and climate assessment. Organic Geochemistry 34 (6), 837-855. (pdf)

Bralower T.J. et al. (2002). New Evidence for abrupt climate change in the Cretaceous and Paleogene: an Ocean Drilling Program expedition to Shatsky Rise, northwest Pacific, GSA Today, 12(11) 4-10. (pdf)

Bralower T.J. et al. (2002). Proceedings of the ODP: Initial Reports ODP Leg 198 [CD-ROM and online at ODP link].

Bian L. et al. (2001) Algal and archaeal polyisoprenoids in a recent marine sediment: molecular isotopic evidence for anaerobic oxidation of methane. Geochemistry, Geophysics, Geosystems, G3, 2, 2000GC000112. (pdf)

Prahl F. et al. (2000) Status of alkenone paleothermometer calibration: report from working group 3. Geochemistry, Geophysics, Geosystems, G3, 1, 2000GC000058. (pdf)

Awards and Honors

Royal Society University Research Fellowship

David and Lucile Packard Fellowship for Science & Engineering


Roles on major committees within the Department and University, and aspects of professional service:

  • Department: Graduate Studies Committee Chair since 1996; Currently Policy Committee Member; Recently Computer Committee Chair; Acting Chair for part of 2000; Member or Chair of seven faculty search committees since 1993.
  • University: Member of the Advisory Council for SOTL; Chair of Course Portfolio Initiative, a vehicle enabling peer review of teaching sponsored by the Dean of Faculties; Member of the IU SOTL Academy; Member, Bloomington Faculty Council 2003-2005.
  • Professional: Review panelist for Geology and Paleontology, NSF; Reviewer for national and international interdisciplinary journals and funding programs; Previously Associate Editor for Geochimica et Cosmochimica Acta and Organic Geochemistry. Former member, Council of the European Association of Organic Geochemists.

Laboratory Facilities

The Biogeochemical Laboratories are well equipped for investigations of the molecular and isotopic compositions of organic matter. The analytical instrumentation includes:

  • Molecular mass spectrometers: Finnigan TSQ700 and Incos XL for biomarker analysis.
  • Isotopic mass spectrometers: Two Finnigan MAT 252 instruments with continuous flow for analysis of 13C and 34S in gases and biomarkers; A Delta Plus XP with multiple periferals including Costech elemental analyzer, for continuous flow analysis of 2H, 13C, 15N and 18O.
  • Gas chromatographs (FID, FID/FPD) for biomarker analyses.
  • Accelerated solvent extractor (ASE-200) for automated extractions of sedimentary biomarkers.
  • Analytical geochemistry laboratories with cold and freezer storage.