کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4719236 1639175 2008 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Depositional environments of the Mediterranean “Lower Evaporites” of the Messinian salinity crisis: Constraints from quantitative analyses
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Depositional environments of the Mediterranean “Lower Evaporites” of the Messinian salinity crisis: Constraints from quantitative analyses
چکیده انگلیسی
We use simple quantitative analyses to evaluate controversial water level scenarios for the Mediterranean “Lower Evaporites” of the Messinian salinity crisis. Our results indicate that a shallow-water scenario for the Lower Gypsum units - with Mediterranean water level lower than the sill at Gibraltar - would imply unrealistic salt thicknesses on the order of 3 km. Some outflow to the open ocean must have persisted, implying that the Mediterranean was a deep-water basin during Lower Gypsum formation. Since glacio-eustatic fluctuations do not seem to have had a major influence on Lower Gypsum deposits, Mediterranean water level was even substantially higher than the Gibraltar sill. Our analyses furthermore show that precessional changes in the freshwater budget may explain the observed cyclic lithological changes of gypsum and non-evaporitic sediments. Potential precipitation of gypsum in the deep Mediterranean basins would have critically depended on the availability of oxygen and thus on the stratification of the water column. Finally, our results indicate that the deep Mediterranean halite units could have been deposited under shallow conditions, assuming that they correspond to the ~ 70 kyr time interval between glacials TG12 and TG14, when Mediterranean outflow to the Atlantic was blocked.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Marine Geology - Volume 253, Issues 3–4, 7 August 2008, Pages 73-81
نویسندگان
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