Amino Acid Geochronology Research Articles

Amino acid racemization in lacustrine ostracodes, part I: effect of oxidizing pre-treatments on amino acid composition

Bleaching biominerals reduces the concentration of amino acids to a residual fraction which is thought to be preserved within intra-crystalline proteins. Intra-crystalline amino acids represent a relatively closed-system and may be superior for amino acid geochronological and paleothermometry investigations. Here we quantify the effects of extended bleaching (to 144 h) on amino acid concentrations and d/ l values in the valves of seven modern ostracode species. Then we compare the effects of increasingly aggressive pre-treatments (sonication, exposure to 3% hydrogen peroxide for 2 h, and exposure to 10% bleach for 48 h) on amino acid concentrations and d/ l values in fossil ostracode ( Candona) valves from numerous locations throughout the western United States and northern Mexico. Bleaching modern ostracode valves results in a rapid order-of-magnitude reduction in amino acid concentrations and a slight increase in d/ l values. Amino acid concentrations in five of the seven modern species increased slightly after prolonged exposure to bleach, suggesting that bleaching weakens a resistant protein source within the ostracode valves. Increasingly aggressive pre-treatments had virtually no effect on amino acid concentrations, d/ l values, or inter-sample variability in fossil Candona valves older than about 1 ka. Candona valves younger than about 1 ka showed a progressive decrease in amino acid concentrations with more aggressive oxidizing pre-treatments. Valves older than 1 ka generally had amino acid concentrations < 10 nM mg −1. A delayed increase in amino acid concentrations (15–30 nM mg −1), followed by a gradual decrease to residual concentrations consistently < 10 nM mg −1, was observed in both outcrop and core samples. We propose that a large amount of weakly bound proteins is leached geologically instantaneously from Candona valves. Long-term (10’s of ka) diagenesis gradually weakens and then destroys a secondary pool of tightly bound proteins contained within the valves. Residual amino acid concentrations are likely derived from intra-crystalline proteins and resistant inter-crystalline proteins that are essentially immune to leaching. Candona valves deposited in pluvial Lake Chewaucan and exposed in sediments that crop out along the Ana River, Oregon, have unexpectedly well-preserved proteins and lower d/ l values compared to fossil Candona valves of similar age from other locations. The Ana River results argue for developing site-specific calibrations for amino acid geochronology or paleothermometry studies that utilize ostracodes.

Amino acid geochronology of the type Cromerian of West Runton, Norfolk, UK

Aminostratigraphic studies of continental deposits in the UK have hitherto relied almost exclusively on data from the aragonitic shells of non-marine molluscs for dating Pleistocene sequences. This is usually based on the d/l value of a single amino acid, d-alloisoleucine/l-isoleucine (A/I), in the total shell proteins. Two genera of freshwater gastropods (Valvata and Bithynia) are used to explore the value of using multiple amino acids from the intra-crystalline fraction, which should be more protected from the effects of diagenesis than the inter-crystalline component. Results are compared from both the aragonitic shells and opercula composed of calcite, a more stable form of calcium carbonate. In order to put the amino acid data from the West Runton Freshwater Bed into perspective, statistical analyses are used to compare them with results from the Hoxnian (MIS 11) site at Clacton-on-Sea, Essex. Twelve protein decomposition indicators revealed that the results from the shells were not as clear-cut as those from the opercula. Five indicators from the Valvata shell suggest that West Runton is older than Clacton (at a 95% significance level), but two actually suggested a younger age. Seven indicators show that the Bithynia shells from West Runton are older than congeneric shells from Clacton. In marked contrast, all 12 indicators isolated from the opercula demonstrate that West Runton is significantly older than Clacton. The data are also compared with results from Waverley Wood, an important archaeological site in the English Midlands falling within the ‘Cromerian Complex’. Contrary to earlier interpretations, the new amino acid data from Bithynia opercula indicate that West Runton is older than Waverley Wood, a relationship now consistent with the available biostratigraphy.

Aspartic acid geochronology of sediments from the ocean margin off of India

Aspartic acid racemization was studied in the clay and coarse fractions of sediments from southwestern Bay of Bengal (Core 1) in order to understand the role of terrestrial organic matter in the amino acid geochronology of Indian marginal sediments. Conventional radiocarbon ages were determined for the coarse carbonate fraction (>25 μm) of sediments, the core covering an age back to ∼40 kyr BP. Aspartic acid racemization rate constants ( k asp) were calculated for clay and coarse fractions of bulk sediments using a first order kinetic model and three horizons with constant k asp values were identified, corresponding to the periods from 0 to 5.5 kyr, 5.5 to 19 kyr and >19 kyr. Best fit models of high significance were derived from the relationship between aspartic acid D/ L ratio and calibrated radiocarbon ages as an alternative to racemization rate constants. To test the applicability of these first order kinetic and logarithmic models derived for Core 1, they were used to calculate ages for another sediment core (Core 2), calculated aspartic acid ages being consistent with radiocarbon ages. However, the logarithmic model gave better results than the first order kinetic model for older samples, suggesting that the logarithmic model is a better choice for the amino acid geochronology of Indian margin sediments. For both sediment fractions, aspartic acid ages based on the logarithmic model gave similar ages, consistent with radiocarbon ages and suggesting that there is no significant difference in aspartic acid racemization between both fractions of bulk sediment. As a result, the clay fraction can also be used for amino acid dating of Indian margin sediments.

Amino acid geochronology: its impact on our understanding of the Quaternary stratigraphy of the British Isles

AbstractThis review aims to act as a brief primer to amino acid racemization and protein breakdown, as well as to document the major applications and results of amino acid dating on British Quaternary sediments. Amino acid results from fossil shells have had far‐reaching effects in developing our current understanding of British Quaternary stratigraphy and its links to continental Europe and the marine record. To appreciate the potential for amino acid geochronology, the technique's limitations and recent developments are discussed, as well as the future of the field. Copyright © 2009 John Wiley &amp; Sons, Ltd.

Ice-free conditions in Novaya Zemlya 35 000–30 000 cal years B.P., as indicated by radiocarbon ages and amino acid racemization evidence from marine molluscs

Novaya Zemlya was covered by the eastern part of the Barents–Kara ice sheet during the glacial maximum of marine isotope stage 2 (MIS 2). We obtained 14C ages on 37 samples of mollusc shells from various sites on the islands. Most samples yielded ages in the range of 48–26 14C Ky. Such old samples are sensitive to contamination by young 14C, and therefore their reliability was assessed using replicate analyses and amino acid geochronology. The extent of aspartic acid racemization (Asp D/L) indicates that many of the 14C ages are correct, whereas some are minimum ages only. The results indicate that a substantial part of Novaya Zemlya was ice-free about 35–27 14C Kya, and probably even earlier. Corresponding shorelines up to >140 m a.s.l. indicate a large Barents–Kara ice sheet during early MIS 3. These results are consistent with findings from Svalbard and northern Russia: in both places a large MIS 4/3 Barents–Kara ice sheet is postulated to have retreated about 50 Kya, followed by an ice-free interstadial that lasted until up to ca. 25 Kya. The duration of the MIS 2 glaciation in Novaya Zemlya was calculated by applying the D/L values to a kinetic equation for Asp racemization. This indicates that the islands were ice covered for less than 3000 years if the basal temperature was 0oC, and for less than 10 000 years if it was -5oC.

Ice-free conditions in Novaya Zemlya 35 000-30 000 cal years B.P., as indicated by radiocarbon ages and amino acid racemization evidence from marine molluscs

Novaya Zemlya was covered by the eastern part of the Barents–Kara ice sheet during the glacial maximum of marine isotope stage 2 (MIS 2). We obtained 14 C ages on 37 samples of mollusc shells from various sites on the islands. Most samples yielded ages in the range of 48–26 14 C Ky. Such old samples are sensitive to contamination by young 14 C, and therefore their reliability was assessed using replicate analyses and amino acid geochronology. The extent of aspartic acid racemization (Asp D/L) indicates that many of the 14 C ages are correct, whereas some are minimum ages only. The results indicate that a substantial part of Novaya Zemlya was ice-free about 35–27 14

Malacological and sedimentological evidence for “warm” glacial climate from the Irig loess sequence, Vojvodina, Serbia

Four loess units and three paleosol layers are preserved in the Irig brickyard, Vojvodina, Serbia. Amino acid geochronology provides stratigraphic correlations between loess units V‐L1 and V‐L2 at the Irig section with loess of glacial cycles B and C, respectively, described from other central European localities. Luminescence dating results for the upper loess layers V‐L1L1 and V‐L1S1L1 confirm the geological interpretations, although in samples below paleosol V‐L1S1S2, the age increase with depth is less than in our proposed age model. Magnetic susceptibility and sedimentological evidence from the Irig loess‐paleosol sequence show general similarities with the MIS 6‐1 pattern of the SPECMAP oxygen‐isotope curve. Malacogical investigations at the Irig site reveal the continuous presence of the Chondrula tridens and Helicopsis striata faunal assemblages throughout the last glacial and final part of the penultimate glacial loess. The loess snail fauna, which is characterized by the complete absence of cold‐resistant species, suggests a stable, dry, and relatively warm glacial climate, compared with other central European loess localities. Furthermore, these data suggest that the southern slope of Fruška Gora was a refugium for warm‐loving and xerophilus mollusc taxa during the otherwise unfavorable glacial climates of the Late Pleistocene.

Closed-system behaviour of the intra-crystalline fraction of amino acids in mollusc shells

When mollusc shells are analysed conventionally for amino acid geochronology, the entire population of amino acids is included, both inter- and intra-crystalline. This study investigates the utility of removing the amino acids that are most susceptible to environmental effects by isolating the fraction of amino acids encapsulated within mineral crystals of mollusc shells (intra-crystalline fraction). Bleaching, heating and leaching (diffusive loss) experiments were undertaken on modern and fossil Corbicula fluminalis, Margaritifera falcata, Bithynia tentaculata and Valvata piscinalis shells. Exposure of powdered mollusc shells to concentrated NaOCl for 48h effectively reduced the amino acid content of the four taxa to a residual level, assumed to represent the intra-crystalline fraction. When heated in water at 140°C for 24h, only 1% of amino acids were leached from the intra-crystalline fraction of modern shells compared with 40% from whole shell. Free amino acids were more effectively retained in the intra-crystalline fraction, comprising 55% (compared with 18%) of the whole shell after 24h at 140°C. For fossil gastropods, the inter-shell variability in D/L values for the intra-crystalline fraction of a single-age population was reduced by 50% compared with conventionally analysed shells. In contrast, analysis of the intra-crystalline fraction of C. fluminalis does not appear to improve the results for this taxon, possibly due to variability in shell ultrastructure. Nonetheless, the intra-crystalline fraction in gastropods approximates a closed system of amino acids and appears to provide a superior subset of amino acids for geochronological applications.

An introduction to the Middle and Upper Pleistocene loess–paleosol sequence at Ruma brickyard, Vojvodina, Serbia

Six Loess units and five paleosols are preserved in the 20 m thick exposure of Middle and Late Pleistocene sediments at Ruma brickyard, Vojvodina, Serbia. Amino acid geochronology provides stratigraphic correlations between Loess–Paleosol units SL L1-S1, SL L2-S2, SL L3-S3 and SL L4 at Ruma with loess of Glacial cycles B, C and D, and E, respectively, at other central and southeastern European localities. The profile represents one of the best potential sections in the region for reconstructing detailed paleoclimates and paleoenvironments of the last ca. 350,000 yr. Initial sedimentological, magnetic and malacological evidence indicate many episodes of drier conditions in the region than in other parts of central and southeastern Europe during the later part of the Middle and Late Pleistocene.

The earliest record of human activity in northern Europe

The colonization of Eurasia by early humans is a key event after their spread out of Africa, but the nature, timing and ecological context of the earliest human occupation of northwest Europe is uncertain and has been the subject of intense debate. The southern Caucasus was occupied about 1.8 million years (Myr) ago, whereas human remains from Atapuerca-TD6, Spain (more than 780 kyr ago) and Ceprano, Italy (about 800 kyr ago) show that early Homo had dispersed to the Mediterranean hinterland before the Brunhes-Matuyama magnetic polarity reversal (780 kyr ago). Until now, the earliest uncontested artefacts from northern Europe were much younger, suggesting that humans were unable to colonize northern latitudes until about 500 kyr ago. Here we report flint artefacts from the Cromer Forest-bed Formation at Pakefield (52 degrees N), Suffolk, UK, from an interglacial sequence yielding a diverse range of plant and animal fossils. Event and lithostratigraphy, palaeomagnetism, amino acid geochronology and biostratigraphy indicate that the artefacts date to the early part of the Brunhes Chron (about 700 kyr ago) and thus represent the earliest unequivocal evidence for human presence north of the Alps.

Amino acid geochronology of individual foraminifer (Pulleniatina obliquiloculata) tests, north Queensland margin, Australia: A new approach to correlating and dating Quaternary tropical marine sediment cores

In this study, we demonstrate the utility of amino acid geochronology based on single‐foraminiferal tests in Quaternary sediment cores from the Queensland margin, Australia. The large planktonic foraminifer Pulleniatina obliquiloculata is ubiquitous in shelf, slope, and basin sediments of north Queensland as well as pantropical oceans. Fossil tests are resistant to dissolution, and retain substantial concentrations of amino acids (2–4 nmol mg−1 of shell) over hundreds of thousands of years. Amino acid D and L isomers of aspartic acid (Asp) and glutamic acid (Glu) were separated using reverse phase chromatography, which is sensitive enough to analyze individual foraminifera tests. In all, 462 Pulleniatina tests from 80 horizons in 11 cores exhibit a systematic increase in D/L ratios down core. D/L ratios were determined in 32 samples whose ages are known from AMS 14C analyses. In all cases, the Asp and Glu D/L ratios are concordant with 14C age. D/L ratios of equal‐age samples are slightly lower for cores taken from deeper water sites, reflecting the sensitivity of the rate of racemization to bottom water temperature. Beyond the range of 14C dating, previously identified marine oxygen‐isotope stage boundaries provide approximate ages of the sediments up to about 500,000 years. For this longer time frame, D/L ratios also vary systematically with isotope‐correlated ages. The rate of racemization for Glu and Asp was modeled using power functions. These equations can be used to estimate ages of samples from the Queensland margin extending back at least 500,000 years. This analytical approach provides new opportunities for geochronological control necessary to understand fundamental sedimentary processes affecting a wide range of marine environments.

River terrace sequences: templates for Quaternary geochronology and marine–terrestrial correlation

AbstractFluvial sequences, particularly terrace staircases, represent archives of Quaternary palaeoclimatic fluctuation and can serve as stratigraphical frameworks for geochronology and for correlation with other depositional environments, in particular, the global marine oxygen isotope record. Fluvial lithostratigraphical frameworks also provide contexts for records, from fossils and artefacts, of faunal evolution and human occupation; conversely, both records can be means of relative dating of riverine sequences.Three fluvial sequences are examined as case studies. First is the Severn–Avon system in the English Midlands, which has biostratgraphical evidence and an amino acid geochronology, together with marker inputs from three different glaciations. The Somme sequence of northern France, famous for its Palaeolithic artefact assemblages, again has biostratigraphy and an amino acid geochronology and has also been dated with reference to overlying loess/palaeosols sequences. The fluvial terraces of the River Arun, the final case study, lack dating evidence but are interspersed within the Sussex raised beach staircase. Although various lines of evidence suggest that the rivers discussed have formed terraces in response to climatic fluctuation, an intriguing difference is that interglacial sediments occur at the bases of terrace formations in the Severn–Avon, whereas in the Somme they occur at the tops of sequences, beneath loessic overburden. Copyright © 2004 John Wiley &amp; Sons, Ltd.

Reconstructing estuarine conditions: oyster shells as recorders of environmental change, Southwest Florida

Live-collected shells of the oyster, Crassostrea virginica, contain geochemical records of modern temperature and salinity, so records of prehistoric conditions may be obtained from subfossil shells. Restoration of channelized watersheds in Florida is receiving much attention, and plans for targeted watersheds require information about estuarine conditions before channelization. Lack of historical records necessitates alternative methods to understand pre-disturbance conditions. A 14C-calibrated, amino-acid geochronology based on racemization of glutamic acid yielded ages ranging from 190–1220 AD and from 1270–1860 AD for subfossil oysters from Blackwater River (near-natural watershed) and for Faka-Union Bay (channelized watershed), respectively. δ 18O and δ 13C values of subfossil shells from Blackwater River indicate salinity and summer temperatures similar to present. Winter temperatures recorded in shells from 190, 590, 720, and 1050 AD appear 1–5 °C colder than present winter temperatures, whereas the shell from 1220 AD records winter temperatures similar to modern winter temperatures. These temperature shifts may indicate change in climate or natural seasonal variation of winter temperature from year to year. Subfossils from Faka-Union Bay may reflect a complicated hydrology, which cannot be evaluated by isotopic compositions alone and demonstrates the need for development of independent elemental proxies for temperature and salinity. Decreases in δ 13C from subfossil to modern shells may in part result from CO 2 added to the atmosphere from fossil fuel burning (the Suess effect). Subfossil δ 13C that is >1‰ more positive than modern shells suggest a change in the dominant carbon sources from terrestrial C 4 or aquatic plants to C 3 plants (mangroves).

Pleistocene raised marine deposits on Wrangel Island, northeast Siberia and implications for the presence of an East Siberian ice sheet

Two previously undocumented Pleistocene marine transgressions on Wrangel Island, northeastern Siberia, question the presence of an East Siberian or Beringian ice sheet during the last glacial maximum (LGM). The Tundrovayan Transgression (459,000–780,000 yr B.P.) is represented by raised marine deposits and landforms 15–41 m asl located up to 18 km inland. The presence of high sea level 64,000–73,000 yr ago (the Krasny Flagian Transgression) is preserved in deposits and landforms 4–7 m asl in the Krasny Flag valley. These deposits and landforms were mapped, dated, and described using amino acid geochronology, radiocarbon, optically stimulated luminescence, electron spin resonance, oxygen isotopes, micropaleontology, paleomagnetism, and grain sizes. The marine deposits are eustatic and not isostatic in origin. All marine deposits on Wrangel Island predate the LGM, indicating that neither Wrangel Island nor the East Siberian or Chukchi Seas experienced extensive glaciation over the last 64,000 yr.

Quaternary highstands in Bear Lake Valley, Utah and Idaho

Surficial deposits in Bear Lake Valley, Utah and Idaho, demonstrate that Bear Lake and its surrounding wetlands expanded and contracted several times during the Quaternary Period. Deposits in 40 outcrops and the geomorphology of the valley were studied to reconstruct the water-level history. Temporal control was provided by amino acid geochronology on 29 samples of aquatic mollusks, calibrated by 14 C dating and tephrochronology. Samples of three molluscan genera were heated and analyzed to determine intergeneric differences in aspartic (Asp) and glutamic (Glu) acid racemization. The covariance of Asp and Glu racemization in these genera was used to identify aberrant amino acid analyses. The rate of Glu racemization was calibrated by using a parabolic model that was used to estimate sample ages. Although the paucity of exposures, uncertainty of the depositional setting, and postdepositional uplift of deposits hamper an accurate reconstruction of water level in Bear Lake Valley, several conclusions can be drawn. During the middle Pleistocene, lacustrine or wetland environments in northern Bear Lake Valley may have extended up to 1830 masl (meters above sea level; ∼6000 ft) twice between ca. 1000–100 ka (Bear Hollow phase). During the late Pleistocene, the shoreline of Bear Lake transgressed at least three times: (1) to 1817 masl (∼5960 ft) at 47–39 cal. (calendar-year-corrected) ka (Jensen Spring phase); (2) to 1814 masl (5950 ft) at ca. 16–15 cal. ka (Raspberry Square phase); and (3) to 1814 masl at ca. 9 cal. ka (Willis Ranch phase). Bear River currently bypasses Bear Lake, but flowed into the lake during highstands and allowed the water level to rise to the valley threshold at Nounan narrows. Water levels have lowered to 1806 masl (5923 ft) since the middle Pleistocene, likely because of downcutting by Bear River at Nounan narrows. Because downcutting at Nounan narrows controls the maximum attainable water level in Bear Lake Valley, effects of climate change on lake level are limited, and Bear Lake may actually have been smaller than today when Lake Bonneville transgressed to its maximum shoreline during the Last Glacial Maximum.

Amino acid paleothermometry of Quaternary ostracodes from the Bonneville Basin, Utah

Unlike many other proxy climate recorders, temperature-dependent chemical reactions that take place in fossils are independent of paleoprecipitation changes, and therefore allow paleotemperatures to be calculated uniquely. In this study, I use the extent of amino acid racemization in fossil ostracode shells to reconstruct the temperature history of the Bonneville Basin, Utah. The enantiomeric composition ( D/ L ratios) of 64 ostracode samples, each comprising an average of 18 subsamples, from 25 sites were analyzed by reverse phase HPLC. The effective diagenetic temperature (EDT) for five intervals of the Quaternary, including the last full-glacial period, was calculated for two amino acids (aspartic and glutamic acids). Errors associated with the EDT calculations were derived using a Monte Carlo procedure. Age control was provided by both new and previously published AMS 14C, luminescence, tephra, and amino acid geochronology. The EDT for the southern Bonneville Basin during the middle Pleistocene interval from 620–150 ka (oxygen-isotope stages (OIS) 16–6) was 5.7±1.5°C. This compares with an EDT of 10.9±1.3°C for the late Holocene (last 5.8 cal ka), and a current mean annual temperature of about 9.4°C at nearby sites (40°N latitude). The EDT then decreased to 3.3±1.3°C for the interval from OIS 6–2 (150–12 cal ka). During the last full-glacial period (24–12 cal ka=OIS 2), the EDT was 1.1±2.5°C, or about 10±3°C lower than during the late Holocene. Paleotemperatures this low suggest that reduced evaporation rather than increased precipitation could have accounted for the increased effective moisture and the growth of Lake Bonneville.

Late Quaternary Spring-Fed Deposits of the Grand Canyon and Their Implication for Deep Lava-Dammed Lakes

One of the most intriguing episodes in the Quaternary evolution of the Grand Canyon of the Colorado River, Arizona, was the development of vast lakes that are thought to have backed up behind lava erupted into the gorge. Stratigraphic evidence for these deep lava-dammed lakes is expectedly sparse. Possible lacustrine deposits at six areas in the eastern canyon yielded no compelling evidence for sediment deposited in a deep lake. At two of the sites the sediment was associated with late Quaternary spring-fed pools and marshes. Water-lain silt and sand at lower Havasu Creek was deposited ∼3000 cal yr ago. The deposit contains an ostracode assemblage similar to that living in the modern travertine-dammed pools adjacent to the outcrop. The second deposit, at Lees Ferry, formed in a spring-fed marsh ∼43,000 cal yr ago, as determined by 14C and amino acid geochronology. It contains abundant ostracode and mollusk fossils, the richest assemblages reported from the Grand Canyon to date. Our interpretation of these sediments as spring-fed deposits, and their relative youth, provides an alternative to the conventional view that deposits like these were formed in deep lava-dammed lakes that filled the Grand Canyon.

Amino‐acid geochronology and the British Pleistocene: secure stratigraphical framework or a case of circular reasoning?

AbstractAminostratigraphy is central to the recently revised correlation of Quaternary deposits in the British Isles, providing a link between terrestrial deposits and marine Oxygen Isotope Stages. The central tenet of British aminostratigraphy, however, that shells from the same interglacial yield very similar ratios, so that the characteristic ratios from different interglacials are distinct, remains uncertain. The data available suggest that amino‐acid ratios from different interglacials do not fall into discrete groups, but overlap considerably. It is therefore not valid to assign individual shells to Oxygen Isotope Stages simply on the basis of their amino‐acid ratios, which means that filtering data to remove high or low values, on the assumption that they represent reworked shells, is unacceptable. The range of ‘characteristic ratios’ assigned to British warm stages may have been underestimated and the degree of separation between them overestimated. Amino‐acid ratios should be treated as sample data that are naturally variable. Copyright © 2002 John Wiley &amp; Sons, Ltd.

Age of the Cutler Dam Alloformation (Late Pleistocene), Bonneville Basin, Utah

Luminescence geochronology, especially infrared stimulated luminescence analyses on marsh mud, shows that a relatively deep lake reached its peak (∼1340 m above sea level) in the Bonneville basin 59,000±5000 yr ago. The age is consistent with nonfinite 14C ages and with amino acid geochronology on ostracodes. The Cutler Dam Alloformation was deposited during this lake cycle, which, like the subsequent Bonneville lake cycle, appears to have reached its maximum highstand following the peak of a global glacial stage (marine oxygen-isotope stage 4) but at a time when other records from North America show evidence for cold climate and expanded glacier ice.

Applied Marine Paleoecology: An Oxymoron or Reality?

Other| August 01, 2001 Applied Marine Paleoecology: An Oxymoron or Reality? MICHAŁ KOWALEWSKI MICHAŁ KOWALEWSKI 1Michał Kowalewski, an eclectic geobiologist, literature scavenger, and data-free paleontologist, has worked on research topics including morphometrics, predation, taphonomy, amino-acid geochronology, stable isotope geochemistry, and computer modeling. He has no fear on tackling on any new project in any discipline—he simply doesn't know enough about any thing to be afraid of it. Michal obtained his M.S. in geology (stratigraphy and exploration) from the University of Warsaw and his Ph.D. in geosciences from the University of Arizona. His mentors, Antoni Hoffman in Warsaw and Karl Flessa in Tucson, tried very hard to teach him how to do science and clearly succeeded, sort of. Michal held a series of research positions on various continents doing an assortment of projects ranging from Cambrian trace fossils to Recent mollusks. He was a post-doctoral researcher in Tucson, Arizona, a research scientist in Warsaw, Poland, a visiting scientist in Botucatu, Brazil, and a Humboldt Fellow in Tübingen, Germany. He is currently an assistant professor of geobiology in the Department of Geological Sciences of the Virginia Polytechnic Institute and State University where he successfully harassed Richard Bambach into retirement. Here, he is pictured doing what he does best: exhaustive fieldwork. Search for other works by this author on: GSW Google Scholar Author and Article Information MICHAŁ KOWALEWSKI 1Michał Kowalewski, an eclectic geobiologist, literature scavenger, and data-free paleontologist, has worked on research topics including morphometrics, predation, taphonomy, amino-acid geochronology, stable isotope geochemistry, and computer modeling. He has no fear on tackling on any new project in any discipline—he simply doesn't know enough about any thing to be afraid of it. Michal obtained his M.S. in geology (stratigraphy and exploration) from the University of Warsaw and his Ph.D. in geosciences from the University of Arizona. His mentors, Antoni Hoffman in Warsaw and Karl Flessa in Tucson, tried very hard to teach him how to do science and clearly succeeded, sort of. Michal held a series of research positions on various continents doing an assortment of projects ranging from Cambrian trace fossils to Recent mollusks. He was a post-doctoral researcher in Tucson, Arizona, a research scientist in Warsaw, Poland, a visiting scientist in Botucatu, Brazil, and a Humboldt Fellow in Tübingen, Germany. He is currently an assistant professor of geobiology in the Department of Geological Sciences of the Virginia Polytechnic Institute and State University where he successfully harassed Richard Bambach into retirement. Here, he is pictured doing what he does best: exhaustive fieldwork. Publisher: SEPM Society for Sedimentary Geology First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print ISSN: 0883-1351 Society for Sedimentary Geology PALAIOS (2001) 16 (4): 309–310. https://doi.org/10.1669/0883-1351(2001)016<0309:AMPAOO>2.0.CO;2 Article history First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation MICHAŁ KOWALEWSKI; Applied Marine Paleoecology: An Oxymoron or Reality?. PALAIOS 2001;; 16 (4): 309–310. doi: https://doi.org/10.1669/0883-1351(2001)016<0309:AMPAOO>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyPALAIOS Search Advanced Search As a rabid marine paleoecologist by spirit and a non-applied scientist by training, I have pursued obscure truths about dead things from a dusty past for over a decade now. And, I have found paleoecology everything I hoped for, and more. It is a discipline that is intellectually challenging, offers intriguing historical questions, and, above all, has a certain methodological, shall we say, flexibility that makes it a true art among sciences. We walk a thin line between what is creative but still scientifically acceptable and what is speculative and of dubious value. After all, we hope to understand the... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.