نشریه علوم زمین خوارزمی

نشریه علوم زمین خوارزمی

بازنگری موقعیت چینه‌نگاری رسوبات قرمز منتسب به نئوژن در شمال اشتهارد، جنوب غرب استان البرز

نویسندگان
معصومه ظاهری
بهروز رفیعی
رضا علی پور
دانشگاه بوعلی سینا
10.22034/KJES.2023.8.2.105991
چکیده
نهشته‌­های منتسب به نئوژن در منطقه اشتهارد گسترش زیاد دارند اما به دلیل فقدان داده‌­های کافی جایگاه چینه­‌شناسی مشخص ندارند. به همین منظور، ویژگی­‌های تکتونیکی و رسوب­‌شناسی این نهشته­‌های قاره‌­ای در چهار برش شمال اشتهارد، مردآباد، معدن نمک و رود شور بررسی شده است. مطالعه این رخساره‌­ها منجر به شناخت و تفکیک پنج واحد رسوبی M1 تا M5 گردید. مطالعات سنگ­‌شناسی و کانی­‌شناسی کنگلومراها، ماسه‌­سنگ‌­ها و کانی­‌های رسی نشان داد که ترکیب رسوبات واحدهای M1 تا M4 با واحد M5 تفاوت­‌های زیادی دارد. مشاهدات میدانی نیز یک ناپیوستگی فرسایشی و گنبد نمکی در مرز بین واحدهای M4 و M5 را آشکار کرده است. مقایسه واحدهای نئوژن منطقه اشتهارد با نهشته‌­های رسوبی معادل آن­ها در منطقه آوج نشان می­‌دهد که نهشته­‌های واحدهای M1 تا M4 معادل سازند قرمز بالایی بوده و واحد M5 مربوط به پلیوسن می­‌باشد. از این رو پیشنهاد می­‌شود که واحد M5 تحت عنوان سازند جدیدی در نظر گرفته شود.
کلیدواژه‌ها
کانی‌شناسی
نهشته‌های قرمز نئوژن
میوسن
منطقه اشتهارد
ایران مرکزی

عنوان مقاله English

Revision of the stratigraphic position of red deposits attributed to the Neogene in the north of Eshtehard, southwest of Alborz Province

نویسندگان English

Masoomeh Zaheri
Behrouz Rafiei
Reza Alipoor
Bu-Ali Sina University
چکیده English

Based on tectonic and sedimentological characteristics, Neogene deposits were chosen to review due to their high extent in the Eshtehard area (Alborz Province) and lack of previous information. These sediments were not determined in the area due to an indistinct lower boundary and the absence of the Qom Formation, and they were attributed to the Neogene. The clastic-evaporitic continental deposits in the north of Eshtehard, Mard Abad, Salt Mine and Rud Shur sections were divided into five sedimentary units (M1 to M5) based on facies and lithological characteristics. Lithological studies showed that the composition of the sediments of the M1 to M4 units is very different from that of the M5 unit. Field observations reveal an erosional unconformity between M4 and M5 units, and the salt dome has pierced M4 but has no effect on unit M5. Comparing the Neogene units of the Eshtehard area with equivalent sedimentary deposits in the Avaj area, it seems that the deposits of the M1 to M4 units in the Eshtehard area are equivalent to the Upper Red Formation, and the M5 unit belongs to the Pliocene and suggests that it should be considered as a new formation.

کلیدواژه‌ها English

mineralogy
Neogene red deposits
Miocene
Eshtehard area
Central Iran
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