Dolomitization and dolomite cementation of upper Triassic limestones, Wadi Sha'am- Ras Al Khaimah

الموضوعات

علوم تطبيقية وتكنولوجية

الملخص

The outcropped Upper Triassic carbonates in Wadi Sha'am, Ras Al Khaimah, have been subjected to pervasive dolomitization and dolomite cementation, which occur along and in the vicinity of faults and associated fractures. Field observations, petrographic, stable and strontium isotope analyses have been combined to constrain the timing of dolomitization episode(s), as well as the origin and evolution of dolomitizing fluids. Associated with fracturing and brecciation, saddle dolomite and host dolostones have similar δ 13CVPDB (+0.52‰ to +1.78‰ and +0.21‰ to +1.78‰, respectively) and δ18OVPDB (-9.98‰ to -8.03‰ and -9.40‰ to -5.30‰, respectively) stable isotope data and high strontium isotope ratios (0.708858 to 0.708864 and 0.709256, respectively). The precipitation of saddle dolomite was followed by the precipitation of coarse-crystalline equant calcite (δ 13CVPDB = -1.03‰ to +0.38‰, δ 18OVPDB = -7.10‰ to -4.68‰) and minor amounts of prismatic quartz. Two regional orogenic events (i.e. the obduction of Oman-UAE ophiolites and the Cenozoic thrusting phase) make it possible for hot basinal brines (referred to as hydrothermal fluids in literature) to flow through active faults and fractures. Assuming that saddle dolomite and equant calcite were precipitated from evolved basinal brines with calculated δ 18OSMOW more than +2‰, the estimated temperatures (91°C to 107°C for saddle dolomite and 49°C to 64°C for calcite) indicate a cooling phase, which was probably related to obduction of Oman ophiolites. Calcite cement filling fractures that cut across the dolostones and saddle dolomite have low δ13CVPDB (-10.81‰ to -8.43‰) and δ18OVPDB (-11.93‰ to -11.80‰) isotope values and low strontium isotope ratio (0.708393), indicating the involvement of meteoric water during the uplift and erosion phase. This study thus elucidates the influence of regional tectonic history and related basinal fluids on the diagenetic evolution of carbonate succession. The formation of large vugs might have been caused by the under-saturation of hot basinal brines in terms of calcite. Low porosity in the dolostones should be attributed to the extensive carbonate cementation.

روابط وملفات

التعريف والنوع

رقم الوثيقة

07588856-76a5-446b-8aac-d3099fe90a54

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

رسائل ماجيستير

نوع الملف

pdf text

أسماء الملفات

2283576_1.pdf

بيانات النشر

ألقاب المؤلفين

[{"name_ar":"Jun Lei","title_ar":"اعداد","title_en":"Preparation"},{"name_ar":"Sadoon Morad ","title_ar":"اشراف","title_en":"Supervision"}]

اللغة

English

المصدر والدورية

اسم المصدر

Dolomitization and dolomite cementation of upper Triassic limestones, Wadi Sha'am- Ras Al Khaimah

المحتوى والصفحات

عدد الصفحات

0

كلمات الباحثين

Applied sciences Dolomitization Saddle dolomite Wadi sha'am Petroleum engineering 0765:Petroleum engineering

إشراف وإعداد

الإشراف

Sadoon Morad

الإعداد

Jun Lei

الاقتباسات الببليوغرافية