Paleoenvironmental Applications Research Articles

Paleoenvironmental application of Taxodium macrofossil biomarkers from the Bobov dol coal formation, Bulgaria

This study correlates paleobotanical observations with chemical tracers and geological interpretation for Bulgarian coals. Two samples were studied, i.e. clay sediment with embedded twigs paleobotanically assigned to Taxodium dubium and plant material scraped off from the leaf imprint of a macrofossil. An assignment of the geological age is presented by considering the biomarker assemblage and paleobotanical data in comparison with information already available for Taxodium dubium. The geochemical data with paleobotanical and geological observations indicate a Late Oligocene geological age for the Bobov dol coal. The following points support this assignment: (i) triterpenoids were completely altered to des-A-lupane or chrysene derivatives, and (ii) diterpenoids were diagenetically converted to their aromatized end products.

Live and dead benthic foraminiferal faunas from Whittard Canyon (NE Atlantic): Focus on taphonomic processes and paleo-environmental applications

Abstract Dead benthic foraminiferal assemblages were studied in the > 150 μm fraction of 4–5 cm deep sediment levels at 18 stations in the Whittard Canyon area in June 2007. This sediment layer is composed of fairly recent sediment ( In both canyon branches, the population dynamics, such as seasonal response to phytodetritus deposition, certainly contribute to differences between live and dead faunas. For instance, Bulimina marginata , which is usually considered as an opportunistic species is over-represented in the dead assemblage. The fragility of the tests of some species can explain their total absence in the thanatocoenoses. This concerns many organic cemented arenaceous tests, miliolid tests sensitive to dissolution and perforate taxa with thin tests. Furthermore, transport (e.g. sediment gravity flows), active in both canyon branches, leads to an increasing relative contribution of allochthonous individuals, originating from outer shelf and upper canyon sites, towards the deeper canyon stations. Consequently the dead faunas do no reflect local environmental conditions. The high abundance of transported dead foraminifera in both canyon branches leads to important biases in the foraminiferal assemblage composition, but may also significantly bias the interpretation of δ 13 C, δ 18 O, trace-elements and 14 C concentration in foraminiferal shells. It may therefore strongly complicate the reconstruction of environmental parameters such as bottom water temperature or exported paleoproductivity, and radiocarbon dating of the foraminiferal assemblages. Therefore, in both canyon axes, the use of dead foraminiferal faunas to reconstruct paleoenvironmental in situ conditions is precluded. However, the study of dead assemblages in the canyon branches, in particular the quantity of allochthonous foraminifera, can give important clues about the downslope sedimentary dynamics. On both open slopes, despite taphonomic (test destruction) and biological processes (population dynamics), the distribution and the composition of the live fauna resemble those of the dead assemblage. In these areas, dead foraminiferal faunas include much less material derived from downslope transport. Consequently, on the open slope, dead assemblages appear to better reflect local conditions. Therefore, the ecological information obtained from fossil open slope samples can be more reliably used to reconstruct paleoenvironmental conditions.

Core and intact polar glycerol dialkyl glycerol tetraethers (GDGTs) in Sand Pond, Warwick, Rhode Island (USA): Insights into the origin of lacustrine GDGTs

Branched and isoprenoidal glycerol dialkyl glycerol tetraethers (GDGTs) are abundant in lake sediments and have potential use for determining past changes in climate and limnology. However, emerging evidence suggests that both classes of GDGTs can be associated with both allochthonous soil organic matter and in situ production, potentially complicating interpretation of these compounds in lacustrine sedimentary environments. Here, we investigate the “dual source” issue surrounding lacustrine GDGTs – with an emphasis on the branched GDGTs – by studying both core and intact polar GDGTs within a pond and its watershed in Warwick, RI. Significant differences in both absolute concentrations of branched GDGTs and the percent of branched GDGTs present as IPLs between the soils and shallow lake sediments suggests in situ production of these compounds within the lake environment. Principal components analysis of GDGT lipid concentrations and environmental parameters in Sand Pond sediments and soils highlights two prominent trends in the data, one related to the absolute concentrations of “type I” branched GDGTs (brGDGT-I, Ib, Ic) and the majority of the isoprenoidal GDGTs, and another related to the concentration of the more methylated “type III” branched GDGTs (brGDGT-III, IIIb, IIIc) and isoprenoidal GDGT-0. The latter trend exhibits a subsurface maximum in the sediment column, potentially indicating in situ production of more highly methylated branched GDGTs and GDGT-0 within the lacustrine sediment column. Trends in the distributions of branched GDGTs (as reflected by the MBT and CBT indices) imply mixing of two distinct sources of branched GDGTs (soil-derived and in situ), or alternatively, two or more different microbial producers. Both possibilities present a challenge to the application of brGDGT-based paleoenvironmental proxies in lakes. This study highlights the importance of determining the sources of GDGTs to the lacustrine environment prior to paleoenvironmental application.

Effect of temperature and rhizosphere processes on pedogenic carbonate recrystallization: Relevance for paleoenvironmental applications

In soils of arid and semiarid climates, dissolution of primary (lithogenic) carbonate and recrystallization with CO 2 from soil air leads to precipitation of pedogenic carbonates and formation of calcic horizons. Thus, their carbon isotope composition represents the conditions prevailing during their formation. However, the widespread use of the isotopic signature (δ 13C, δ 18O, Δ 14C) of pedogenic carbonates for reconstruction of local paleovegetation, paleoprecipitation and other environmental conditions lacks knowledge of the time frame of pedogenic carbonate formation, which depends on climatic factors. We hypothesized that temperature-dependent biotic processes like plant growth and root and rhizomicrobial respiration have stronger influence on soil CaCO 3 recrystallization than abiotic temperature-dependent solubility of CO 2 and CaCO 3. To assess the effect of temperature on initial CaCO 3 recrystallization rates, loess with primary CaCO 3 was exposed to 14CO 2 from root and rhizomicrobial respiration of plants labeled in 14CO 2 atmosphere at 10, 20 or 30 °C. 14C recovered in recrystallized CaCO 3 was quantified to calculate amounts of secondary CaCO 3 and corresponding recrystallization rates, which were in the range of 10 −6–10 −4 day −1, meaning that 10 −4–10 −2% of total loess CaCO 3 were recrystallized per day. Increasing rates with increasing temperature showed the major role of biological activities like enhanced water uptake by roots and respiration. The abiotic effect of lower solubility of CO 2 in water by increasing temperature was completely overcompensated by biotic processes. Based on initial recrystallization rates, periods necessary for complete recrystallization were estimated for different temperatures, presuming that CaCO 3 recrystallization in soil takes place mainly during the growing season. Taking into account the shortening effect of increasing temperature on the length of growing season, the contrast between low and high temperature was diminished, yielding recrystallization periods of 5740 years, 4330 years and 1060 years at 10, 20 and 30 °C, respectively. In summary, increasing CaCO 3 recrystallization rates with increasing temperature demonstrated the important role of vegetation for pedogenic CaCO 3 formation and the predominantly biotic effects of growing season temperature. Considering the long periods of pedogenic carbonate formation lasting to some millennia, we conclude that methodological resolution of paleoenvironmental studies based on isotope composition of pedogenic carbonates is limited not by instrumental precision but by the time frame of pedogenic carbonate formation and hence cannot be better than thousands of years.

Modern pollen data from North America and Greenland for multi-scale paleoenvironmental applications

The modern pollen network in North America and Greenland is presented as a database for use in quantitative calibration studies and paleoenvironmental reconstructions. The georeferenced database includes 4634 samples from all regions of the continent and 134 pollen taxa that range from ubiquitous to regionally diagnostic taxa. Climate data and vegetation characteristics were assigned to every site. Automated and manual procedures were used to verify the accuracy of geographic coordinates and identify duplicate records among datasets, incomplete pollen sums, and other potential errors. Data are currently available for almost all of North America, with variable density. Pollen taxonomic diversity, as measured by the Shannon–Weiner coefficient, varies as a function of location, as some vegetation regions are dominated by one or two major pollen producers, while other regions have a more even composition of pollen taxa. Squared-chord distances computed between samples show that most modern pollen samples find analogues within their own vegetation zone. Both temperature and precipitation inferred from best analogues are highly correlated with observed values but temperature exhibits the strongest relation. Maps of the contemporary distribution of several pollen types in relation to the range of the plant taxon illustrate the correspondence between plant and pollen ranges.

Future Trends and Goals in Ostracode Research

In recent decades, research on ostracodes has grown dramatically. While many aspects of the group have been investigated, this review focuses on the paleoenvironmental applications of ostracodes from marine and nonmarine environments. It is argued that while ostracodes have great potential as paleoenvironmental tools, much of that potential has not yet been fully realized because of our imperfect understanding of ostracode biology, taxonomy, systematics and ecology. Future developments will be sure to result from additional studies in these areas, and will also be effected by exchange of ideas with scientists working on related proxies. However, the flow of ideas should not be one-way; workers in other disciplines can also learn from the study of ostracodes.

Using Stable Isotopic Data to Resolve Rate and Duration of Growth throughout Ontogeny: An Example from the Surf Clam, Spisula solidissima

Other| April 01, 2003 Using Stable Isotopic Data to Resolve Rate and Duration of Growth throughout Ontogeny: An Example from the Surf Clam, Spisula solidissima LINDA C. IVANY; LINDA C. IVANY 1Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, lcivany@syr.edu Search for other works by this author on: GSW Google Scholar BRUCE H. WILKINSON; BRUCE H. WILKINSON 2Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48130 Search for other works by this author on: GSW Google Scholar DOUGLAS S. JONES DOUGLAS S. JONES 3Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 Search for other works by this author on: GSW Google Scholar Author and Article Information LINDA C. IVANY 1Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, lcivany@syr.edu BRUCE H. WILKINSON 2Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48130 DOUGLAS S. JONES 3Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 Publisher: SEPM Society for Sedimentary Geology Accepted: 31 Jul 2002 First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print ISSN: 0883-1351 Society for Sedimentary Geology PALAIOS (2003) 18 (2): 126–137. https://doi.org/10.1669/0883-1351(2003)18<126:USIDTR>2.0.CO;2 Article history Accepted: 31 Jul 2002 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 LINDA C. IVANY, BRUCE H. WILKINSON, DOUGLAS S. JONES; Using Stable Isotopic Data to Resolve Rate and Duration of Growth throughout Ontogeny: An Example from the Surf Clam, Spisula solidissima. PALAIOS 2003;; 18 (2): 126–137. doi: https://doi.org/10.1669/0883-1351(2003)18<126:USIDTR>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 Abstract Examination of ontogenetic variation in the stable isotopic composition of accretionary biogenic hard parts is becoming a commonplace technique for gaining insights into organism age, changes in growth rate through ontogeny, and environmental conditions under which organisms lived. However, the application of isotopic data to life-history studies often is impeded by the noisy nature of environmental signals, as well as by seasonal cessation of hardpart accretion. A computational approach is presented that quantitatively resolves secular (seasonal) change in environmental parameters such as temperature and salinity with spatial (hard part) variation in isotopic composition. Output consists of determinations of mean annual isotopic composition, seasonal range in isotopic composition, and variation in hard-part growth rate for any interval of data in an accretionary transect. Quantitative estimates of absolute growth rates, as well as the proportion of each season represented by hard-part accretion, are derived for every season of the organism's life recorded in their hard parts.This methodology is applied to δ18O data from a valve of the surf clam, Spisula solidissima, collected live from the New Jersey shelf. Based on the saw-toothed pattern of δ18O variation in this clam, and on the fact that observed amplitudes of δ18O variation are only a fraction of those anticipated from measurements of ambient water salinity and temperature, it is apparent that growth cessation occurred during each of the dozen summers and dozen winters of ontogeny. Determination of best-fit sinusoids for each season of growth reveals that: (1) rate of growth decreased exponentially during the ontogeny of this individual; (2) net spring season accretion was initially twice that in the fall; and (3) ontogenetic decrease in net accretion was accomplished in part by reduction in rate of accretion, and in part by reduction in the number of spring and fall days during which growth occurred. Isotope thermometry suggests that all growth intervals span an optimum temperature; shorter (or longer) durations of seasonal shell accretion occur over narrower (or wider) temperature ranges centered on about 11°C.Beyond the obvious paleoenvironmental applications, the advantage of this method for biologists and paleontologists is that rate and duration of growth can be approximated at seasonal to subseasonal levels of resolution for any living or fossil organism. Such information from a suite of individuals can reveal how growth within a species is affected by changes in latitude, depth, productivity, anthropogenic influence, and other environmental gradients. In addition, because changes in rate and timing of growth within a lineage are the mainstay of heterochrony studies, quantitative methods for assessing such variables through time in fossil specimens will allow more rigorous testing of evolutionary hypotheses. 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Fossil diatom assemblages from pre-historical and historical deposits and their paleoenvironmental applications

Fossil diatom assemblages from pre-historical and historical deposits and their paleoenvironmental applications

Stable isotopes in modern ostrich eggshell: a calibration for paleoenvironmental applications in semi-arid regions of southern Africa

An isotopic study of modern ostrich eggshell (OES) is presented as a calibration for terrestrial paleoenvironmental applications. The stable carbon and nitrogen isotope fractionations of OES were determined for various organic fractions of eggshell by measuring the isotopic ratios of modern OES samples collected from controlled settings (i.e., zoos and farms) and corresponding ostrich diet. These fractionations were used to evaluate the relationship between the isotope composition of OES laid by free-range birds living in South Africa and their environment. The carbon isotope composition of the total organic and inorganic fractions of OES were enriched by 2 and 16‰, respectively, relative to the diet. In natural settings, the δ 13C values of both the organic and inorganic fractions of OES reflected that of ambient vegetation, with a noted dietary preference for C 3 plants. The nitrogen isotope composition of the total organic fraction of OES was 3‰ enriched relative to the diet, and varied inversely with mean annual precipitation (MAP) in natural settings. A decrease in MAP of 100 mm was accompanied by an increase in δ 15N values of approximately 1‰. The oxygen isotope composition of the inorganic fraction of the OES varied linearly with that of the drinking water in controlled settings. However, in natural settings, the δ 18O of OES values were highly variable and are thought to be controlled primarily by the δ 18O of ingested plant leaf-water. The stability of the isotopic signal in the organic fraction of OES through geologic time was evaluated through a series of heating experiments. The δ 13C and δ 15N values of the total organic fraction of heated OES increased by less than 0.6 and 0.2‰ for carbon and nitrogen, respectively, in spite of extensive diagenetic alteration and changes in the amino acid composition of the samples. The results of this study indicate that the stable carbon and nitrogen isotope composition of OES is relatively stable under the experimental conditions used and may be used to derive a plethora of paleoenvironmental information, including changes in C 3 and C 4 vegetation and paleorainfall estimates. Additionally, carbon isotopic analysis of individual amino acids (IAA) in the OES and corresponding diet were determined to elucidate information on isotopic fractionation during OES protein synthesis. The δ 13C values of IAA in OES range over 12‰ and provide valuable information for future studies of (1) diagenesis in fossil OES samples and (2) comparative animal physiology, including the determination of digestive and feeding strategies of extant and extinct animals.

Time resolution and the study of Late Cretaceous and Early Tertiary megafloras

In this paper, I discuss issues of time resolution and time-averaging in fossil megafloras from Late Cretaceous (Cenomanian) to Oligocene age. The sites are predominantly from North America with some examples from other continents. The purpose of this paper is to explicate the methods used to resolve the age and duration of fossil floras and to discuss the uncertainties associated with these methods. The age of floras is most important for their evolutionary, paleoclimatic and paleoaltitudinal applications, while the duration of floras (here defined as the time represented by individual assemblages, florules, or quarries) is critical for paleoecological and paleoenvironmental applications. Levels of time resolution of both the age and the duration of fossil floras are subject to time-averaging. Behrensmeyer et al. (1992, p. 75) have defined two types of time-averaging: analytical time-averaging which is artificial and results from techniques of analysis and taphonomic time-averaging which is natural and results from the taphonomic history of the assemblage.

Application of Image Analysis to Neogene Planktonic Foraminiferal Bioseries

The morphological characteristics of fossil foraminiferal tests are the basis for making phylogenetic and taxonomic, as well as paleoecological inferences about fossil species. A complete understanding of the taxonomic and paleoenvironmental information contained in morphology of foraminifera depends heavily on quantitative methods to describe phenotypic and ecophenotypic variation. Automated image analysis is used to quantify the shape characteristics of planktonic and benthic foraminifera. There are three main components to the authors' quantitative image analysis system: (1) computer based image digitizer; (2) Fourier series analysis in closed form; and (3) multivariate statistical analysis. The advantages of such a system are that shape characteristics can be objectively determined and that large numbers of specimens can be analyzed. The focus of their research has been to improve the utility of foraminifera in paleoenvironmental and biostratigraphic application. The Globorotalia menardii/Globorotalia tumida group and the Globigerinoides obliquus/Globigerinoides extremus complex from Neogene sediments from DSDP Site 502 in the Caribbean have been examined via image analysis. In both groups they were able to determine distinct morphotypes that change relative proportion with time. This information is utilized to define morphotypes within each group that are independent of taxonomically defined zones. Changes in the proportions of each endmore » member are also correlated with paleoceanographic events of the Neogene such as the initiation of Northern Hemisphere glaciation and the Messinian event. Signal processing techniques, such as cross correlation, spectral analysis, and cross spectral analysis are also used in their investigations. Applying these techniques to the data in conjunction with stable isotope record for Site 502 allows them to determine correlations with the isotopic record and the similarities in the frequencies in the morphological records.« less