کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5787259 1641468 2017 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Formation of a metastable hollandite phase from amorphous plagioclase: A possible origin of lingunite in shocked chondritic meteorites
ترجمه فارسی عنوان
تشکیل یک فاز هولاندیتی متاستاز از پلاژیوکلاز آمورف: منشاء احتمالی لینگنیت در شهاب سنگ های تنگی کاندید
کلمات کلیدی
Lingunite؛ Hollandite؛ فاز شبه؛ شهاب سنگین
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فیزیک زمین (ژئو فیزیک)
چکیده انگلیسی


- Lingunite was found first to crystallize from amorphous oligoclase as a metastable phase.
- This process might account for the origin of lingunite found along with maskelynite in shocked chondritic meteorites.
- Metastable lingunite appeared at ∼20-24 GPa and ∼1100-1300 °C in laboratory timescales.
- It might also form at the higher temperatures and shorter time periods of shock events.
- The hollandite phase was not observed when using albite or labradorite as starting materials.

We conducted high-pressure experiments in plagioclase with different anorthite contents at 18-27 GPa and 25-1750 °C using both a laser-heated diamond anvil cell and a Kawai-type multi-anvil apparatus to clarify the formation conditions of the hollandite phase in shocked chondritic and Martian meteorites. Lingunite (NaAlSi3O8-rich hollandite) was found first to crystallize from amorphous oligoclase as a metastable phase before decomposing into the final stable state. This process might account for the origin of lingunite found along with maskelynite in shocked chondritic meteorites. Metastable lingunite appeared at ∼20-24 GPa and ∼1100-1300 °C in laboratory tests lasting tens of minutes; however, it might also form at the higher temperatures and shorter time periods of shock events. In contrast, the hollandite phase was not observed during any stage of crystallization when using albite or labradorite as starting materials. The formation process of (Ca,Na)-hollandite in the labradorite composition found in Martian shergottites remains unresolved. The orthoclase contents of the hollandite phase both in shocked meteorites (2.4-8.2 mol%) and our oligoclase sample (3.9 mol%) are relatively high compared to the albite and labradorite samples (0.6 and 1.9 mol%, respectively). This might critically affect the crystallization kinetics of hollandite phase.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics of the Earth and Planetary Interiors - Volume 272, November 2017, Pages 50-57
نویسندگان
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