کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9524362 1348966 2005 21 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Basin evolution during the transition from continental rifting to subduction: Evidence from the lithofacies and modal petrology of the Jurassic Latady Group, Antarctic Peninsula
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Basin evolution during the transition from continental rifting to subduction: Evidence from the lithofacies and modal petrology of the Jurassic Latady Group, Antarctic Peninsula
چکیده انگلیسی
The Jurassic Latady Basin (southern Antarctic Peninsula) developed in a broad rift zone associated with the early stages of Gondwana extension. Early Jurassic sedimentation (∼185 Ma) occurred in small, isolated terrestrial to lacustrine rift basins in the present-day northwest and west and became shallow marine by the early Middle Jurassic. Quantitative modal analysis reveals a high proportion of mature, quartzose sandstone derived from cratonic and quartzose recycled-orogen provenances, most likely in the direction of the Ellsworth-Whitmore Mountains in the Gondwana interior. Sandstones with a more volcanolithic provenance probably represent an influx of sands from a Permian volcanic source in West Antarctica. The Early Jurassic Latady sequence contains abundant volcanic quartz and rhyodacite grains, locally derived from the nearby ignimbrites of the rift-related Mount Poster Formation (∼185 Ma). Between the Middle and Late Jurassic (?160-150 Ma), there was a dramatic change throughout the Latady Basin to higher-energy conditions with marked lateral facies variations. Sandstones contain abundant fresh volcanic detritus and plot in the transitional arc field. Their source was a nearby, active continental margin arc, but there is no outcrop of arc material on the Antarctic Peninsula from this time. A possible source area is preserved on the Thurston Island block to the southwest. However, some fluvial systems still had access to areas of uplifted metamorphic/plutonic basement and quartzose, cratonic sources. Evidence of mixing of fluvial systems from different provenances and the lack of mixing of other fluvial systems suggest a complex topography of variably uplifted fault blocks with fluvial systems constrained in narrow valleys. The change from continental rift- to arc-related sources illustrates the shift from plume- (continental provenances) to continental margin arc-dominated tectonics. Thermal relaxation in the Late Jurassic led to the final phase of deposition in anoxic, deep-water conditions in a sediment-starved marine basin stretching from Ellsworth northward into southern South America.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of South American Earth Sciences - Volume 20, Issue 3, December 2005, Pages 171-191
نویسندگان
, ,