کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9526045 | 1636196 | 2005 | 22 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Aragonite dissolution, sedimentation rates and carbon isotopes in deep-water hemipelagites (Livinallongo Formation, Middle Triassic, northern Italy)
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Hemipelagic nodular limestones are a widespread facies in the Triassic of the Tethys, often considered as being deposited at rather constant sedimentation rates. The aim of this paper is to investigate the sedimentation rate variability in a case-study from the Middle Triassic of the Dolomites, northern Italy, and to suggest possible causes. The nodular cherty limestones of the Livinallongo Fm. and correlated units were studied in four stratigraphic sections and compared to classical successions from the literature. Correlations between sections are based on ammonoid biostratigraphy and tephra stratigraphy. Correlation highlighted conspicuous changes in sedimentation rates through time and between sections, associated with sedimentological evidence of deep-water aragonite dissolution. Deep-water dissolution is believed to have resulted in small hiatuses and in a bias of ammonoid assemblages towards taxa with more resistant shells. Carbonate petrography and geochemistry provide evidence of differential diagenesis of the Livinallongo Fm. Carbonate nodules were lithified at the water-sediment interface, and their C isotope composition is regarded as a proxy of the δ13C of Middle Triassic bottom seawater. The onset of nodular cherty limestones, occurring contemporaneously at the basin scale, and the coeval carbonate platform drowning events are tentatively explained by the inflow and local upwelling of cool deep water from Panthalassa into the western Tethys.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Sedimentary Geology - Volume 181, Issues 3â4, 15 November 2005, Pages 173-194
Journal: Sedimentary Geology - Volume 181, Issues 3â4, 15 November 2005, Pages 173-194
نویسندگان
Nereo Preto, Christoph Spötl, Paolo Mietto, Piero Gianolla, Alberto Riva, Stefano Manfrin,