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A combined methodological approach using visual and geochemical methods is introduced and preliminary results of a study illustrating its effectiveness to determine chert source provenance are presented. This study focuses on lithic debitage and raw chert samples collected from the interior of southern Baffin Island, Arctic Canada. Chert is abundant throughout this region yet it occurs as small, scattered surface nodules that are highly variable in color. Prior to this study, little was known about the provenance of this local toolstone and whether it derived from local outcrops, glacial till sheets, or both. Given the pronounced variability exhibited by this chert, we use individual attribute analysis and petrography to impose some kind of analytical order upon an otherwise random aggregation of rocks. Thereafter, inductively coupled plasma mass spectrometry and secondary ion mass spectrometry are used to test the validity of these color categories to determine from how many geochemically distinct sources they derive. Using a standard that measures Al to a ratio of Ga/Zr, our results indicate that all of the raw chert samples derive from a single local source, while the debitage derives from four different sources, including the one that is local. We are confident that this combined methodological approach can be applied in other regions where chert variability is pronounced and source provenance is unknown. © 2009 Wiley Periodicals, Inc. 相似文献
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Karim Nassar Wael Elham Mahmod Hassan Fath Ali Masria Kazuo Nadaoka Abdelazim Negm 《Marine Georesources & Geotechnology》2019,37(1):81-95
This study focuses on the shoreline change detection along the North Sinai coast in Egypt using geographic information system and digital shoreline analysis system (DSAS) during the elapsed period from 1989 to 2016. The measurement of shoreline variation is mainly described for three zones: zone I, El-Tinah plain bay; zone II, El-Bardawil Lake; zone III, El-Arish valley. The rates of shoreline changes in the form of erosion and accretion patterns are automatically quantified by four statistical parameters functioned in DSAS namely endpoint rate, net shoreline movement, linear regression rate (LRR), and least median of squares. LRR results elucidate that the western seaside of El-Tinah plain bay has experienced an extremely dynamic feature with an average erosion rate of ?8.17?m/year. The littoral drifts have been driven by eastward alongshore currents toward the east side of the bay to be accreted with an average rate of +4.28?m/year. Moreover, the shoreline has progressed west of El-Bardawil inlet (1), El-Bardawil inlet (2), and El-Arish harbor. Subsequently, the corresponding average beach growth rates are found to be +2.7, +8.5, and +6.5?m/year, respectively. In contrast, the shoreline on the down-drift side to the east has negatively retreated, and the corresponding beaches have regressed at rates of ?4.5, ?8.65, and ?2.9?m/year, respectively. 相似文献