Difference between revisions of "RECENT PUBLICATIONS ON FORAMINIFERA"
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| + | ==EVALUATION OF ∂<sup>13</sup> STRATIGRAPHY AND BIOSTRATIGRAPHIC IMPLICATIONS FOR LATE CRETACEOUS GLOBAL CORRELATION== | ||
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| + | [[Image:EarthScienceReview_front.gif |left|80px|]]<font size="2"> | ||
| + | ...... To better assess the global versus local contribution in a δ<sup>13</sup>C record it is necessary to compare numerous isotopic records on a global scale. As a contribution to this objective, this paper reviews bulk sediment δ13Ccarb records from the Late Cretaceous in order to identify differences and similarities in secular δ<sup>13</sup>C trends that help establish a global reference δ<sup>13</sup>C record for this period. The study presents a global-scale comparison of twenty δ<sup>13</sup>C records from sections representing various palaeo-latitudes in both hemispheres and different oceanic settings from the Boreal, Tethys, Western Interior, Indian Ocean and Pacific Ocean, and with various diagenetic overprinting. The isotopic patterns are correlated based on independent dating with biostratigraphic and paleomagnetic data and reveal good agreement of the major isotope events despite offsets in absolute δ<sup>13</sup>C values and variation in amplitude between the sites. ...... The combination of chemostratigraphy with biostratigraphy and magnetostratigraphy substantially increases the precision and temporal resolution of inter-regional correlations and helps overcome problems that arise from differences in biostratigraphic schemes, facies or provincialism of key fossils. By using an iterative approach to stepwise increase precision of the correlations, isochroneity of first and last occurrences of marker species versus chemostratigraphy is tested, which helps to improve biostratigraphic zonations, to assess zonal boundary ages and to identify useful criteria for defining Late Cretaceous stage boundaries, many of which are still not formally defined. The presented correlations indicate a consistent position for most planktic foraminifer zonal boundaries relative to corresponding isotope shifts during the mid-Cretaceous sea-level high, whereas diachroneity appears to be more pronounced during the Late Campanian and Maastrichtian global sea-level fall. A similar pattern is observed for trans-continental consistency in the δ<sup>13</sup>C shifts. Graphic correlation of isotopic shifts, magnetostratigraphic and biostratigraphic events among the compared sections is used to detect hiatuses or relative changes sediment accumulation rates and visualizes consistency or offsets of individual biostratigraphic markers relative to chemo- and magnetostratigraphy. Finally, an attempt of a global average δ<sup>13</sup>C stack is presented for the Turonian through Maastrichtian. | ||
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| + | <font size="2">([http://www.sciencedirect.com/science/article/pii/S0012825213001293# ABSTRACT]) | ||
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| + | ----Wendler, I., 2013. [http://www.sciencedirect.com/science/article/pii/S0012825213001293# A critical evaluation of carbon isotope stratigraphy and biostratigraphic implications for Late Cretaceous global correlation]. Earth-Sciences Review 126, 116-146. | ||
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==ASSESSMENT OF SEAWATER Nd ISOTOPE SIGNATURES AND AUTHIGENIC PHASES OF GULF OF GUINEA SEDIMENTS== | ==ASSESSMENT OF SEAWATER Nd ISOTOPE SIGNATURES AND AUTHIGENIC PHASES OF GULF OF GUINEA SEDIMENTS== | ||
