کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8868133 | 1622088 | 2018 | 72 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Late Cretaceous climate in the Canadian Arctic: Multi-proxy constraints from Devon Island
ترجمه فارسی عنوان
آب و هوای کرتاسه بعدا در قطب شمال کانادا: محدودیت چند پروکسی از جزیره دون
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
چکیده انگلیسی
Arctic climate in the Late Cretaceous has long been recognized to have been warm and wet relative to the present, but quantitative assessments of paleoclimate have been challenging due, in part, to disagreements between proxies in marine and terrestrial environments. This study provides a first multiproxy evaluation of Late Cretaceous (~93-90â¯Ma to 73-72â¯Ma) paleoclimate and paleohydrology from Devon Island in the Canadian High Arctic (modern location: 76°17â²N, 91°12â²W; Late Cretaceous location: ~71°30â²N, ~24°30â²W). Surface temperatures are reconstructed at ~12.6 to 20.6â¯Â°C for the ocean and 11.7 to 16.9â¯Â°C over land, using glycerol dialkyl glycerol tetraether (GDGT) based proxies measured from marine (TEX86) and terrestrial samples (MBTâ²5ME). These proxies are likely skewed toward warm month temperatures, based on novel analysis and interpretation of biomarkers in sediment and co-occurring marine vertebrate coprolites. The hydrogen isotopic composition (δ2H) of precipitation is constrained to have varied from â123â° to â82â° (VSMOW) using evidence from n-alkanes likely derived from higher plants. δ18O of shelfal marine surface water is constrained to have been between â10.5â° to â3.4â°, using phosphate oxygen isotopes of marine vertebrate teeth and coprolites. From these, marine salinity is modeled to have varied from 10 PSU and 30 PSU, indicative of periodic freshwater influx. These estimates indicate that large marine vertebrates lived and fed, at least intermittently, in near-shore brackish waters. Finally, the Arctic was similarly warm in both the Late Cretaceous and Paleocene/Eocene, but the Late Cretaceous isotopic composition of precipitation at Devon Island was enriched in the heavy isotope of hydrogen by up to +60 to +70â° relative to Arctic Eocene sites. The combination of techniques used here reduces uncertainties related to the application of proxies to an environment without a modern analogue, providing novel paleoclimatic constraints on the Late Cretaceous Arctic region.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Palaeogeography, Palaeoclimatology, Palaeoecology - Volume 504, 1 September 2018, Pages 1-22
Journal: Palaeogeography, Palaeoclimatology, Palaeoecology - Volume 504, 1 September 2018, Pages 1-22
نویسندگان
James R. Super, Karen Chin, Mark Pagani, Hui Li, Clay Tabor, David M. Harwood, Pincelli M. Hull,