1; An integrated paleomagnetic analysis program for stratigraphy labs and research projects; 2; Aptian-Albian carbon and oxygen isotope stratigraphy of the Ontong Java Plateau

Author(s): Zhang, Chunfu
Source: 118p. Institution: Purdue University, West Lafayette, IN, United States
Note: In English. 98 refs. Master's thesis
Summary: 1. This section describes the enhanced Windows-based Paleomagnetic Analysis Program written by the author for stratigraphy labs and the paleomagnetic community to quickly get the big picture of paleomagnetic feature. This program integrates on-screen visualization and analysis of paleomagnetic data and printing graphic outputs. With graphic user interface, it is easy to understand and use. It can accept flexible data file format: either fixed length or delimited data files. Each data file can contain up to 500 samples with a variable number of demagnetization steps (up to 50). The integrated toolboxes accept keyboard or copy-and-paste data input, and allow the user to calculate paleolatitudes, convert between spherical and Cartesian coordinates, and perform many functions of the main program. A synopsis of the program operation and capabilities is also presented. 2. Carbon and oxygen isotope data were obtained from the fine fraction and planktonic and benthic foraminifers from the Aptian-Albian sediments of the Ocean Drilling Program (ODP) Leg 192 at the Ontong Java Plateau (western equatorial Pacific). The δ13C curves of these Ontong Java sections can be correlated to the composite δ13C curve compiled from two sections in Italy. The difference in δ13C between shallow and benthic carbonate was used in conjunction with the calcite compensation depth to estimate the atmospheric CO2 level during the Aptian-Albian interval according to Berger and Spitzy's (1988) method, and the CO2 estimated was ∼8120 ppm for the Early Aptian, and ∼1570 to 730 ppm for the Late Albian. The increase in atmospheric CO2 content as a result of the Ontong Java Plateau eruption (∼1800 ppm) was also estimated from the degassing of basalt magma erupted. The δ18O data were internally consistent in most cases, and were used to derive the average paleotemperatures during the Aptian-Albian (sea surface temperature: ∼15-24°C after latitudinal correction). The relatively low paleo-temperature estimates suggested that minor alteration might have occurred. Nevertheless, the temperature evolution trend had been largely preserved.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Albian; Aptian; Atmosphere; C-13/C-12; Carbon; Carbon dioxide; Chemostratigraphy; Computer programs; Cretaceous; Data processing; Foraminifera; Invertebrata; Isotope ratios; Isotopes; Leg 192; Lower Cretaceous; Mesozoic; Microfossils; O-18/O-16; Ocean Drilling Program; Ontong Java Plateau; Oxygen; Pacific Ocean; Paleoclimatology; Paleoenvironment; Paleomagnetic Analysis Program; Paleomagnetism; Paleotemperature; Protista; Stable isotopes; West Pacific
Coordinates: S050100 N010000 E1643000 E1570000
Record ID: 2005069925
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