Microfacies and Diagenetic Analysis of Lockhart Limestone, Shah Alla Ditta Area Islamabad, Pakistan

Abstract

The Larger Foraminifera made a major contribution to Paleocene and Eocene biota. The microfacies and diagenetic setting of the Paleocene Lockhart Formation were analyzed in Shah Alla Ditta area, Islamabad. The Lockhart Formation is highly fossiliferous, comprising of thin nodular limestone with interbedded shale/ marl. The lower contact is unconformable with Jurassic Samansuk formation while the upper contact is conformable with Margalla Hill Limestone. Rock samples were collected from the field and thin sections were prepared and analyzed under the microscope and on the basis of detailed petrographic study three types of microfacies were identified and interpreted based on Dunham's textural classification, allochem type, fossil content and sedimentary structures. The microfacies include: LH-MF 1: Foraminiferal Wackestone/ Biomicrite Microfacies, LH-MF 2: Algal Foraminiferal Wackestone Microfacies, LH-MF 3: Mixed Bioclastic Mudstone Microfacies. A number of larger benthic foraminifera, and the lack of Planktonic foraminifera in the Lockhart Limestone, indicate shallow to deep water of restricted inner to middle shelf environment of deposition. Larger foraminifera and dasycladacena algae are the two major fossil contents present in the Lockhart Formation. Larger foraminiferal species like Lockhartia hameii and Lockhartia conditi present in the formation confirm the age of Lockhart Limestone as Paleocene. The main diagenetic fabric recognized in the limestone reveals mechanical and chemical compaction, deep burial water pressure, pressure solution and tectonics-related fracturing. The nodularity in the limestone is credited to pressure solution.

Investigation of reservoir characteristics, depositional setting and T–R sequences of the Lockhart Limestone of Meyal Oil Field, Pakistan: a petrophysical approach

“…According to Bilal and Khan (2017), the Lockhart Limestone, outcropped in Azad Kashmir, has experienced micritization, dolomitization, neomorphism, cementation, compaction and fracturing. In Islamabad, Khattak et al (2017) reported different diagenetic features in the Lockhart Limestone such as mechanical and chemical compaction, deep burial water pressure, pressure solution and tectonics-related fracturing. In the Kohat area, the diagenetic alterations of the Lockhart Limestone include tight packing, stylolitization, dolomitization, neomorphism (aragonite to calcite transformation) and sparfilled fractures (Fig.…”

“…In the Hazara and Kala-Chitta areas, the Lockhart Limestone is comprised of dark-colored nodular and massive limestone and intercalations of shale and marl (Shah 2009;Awais et al 2012 and. The Lockhart Limestone has been studied extensively by earlier investigators (e.g., Afzal et al 2005;Sameeni et al 2009;Yaseen et al 2011;Hanif et al 2013;Sameeni et al 2013;Ahmad et al 2014;Malik and Ahmed 2014;Khan et al 2016;Bilal and Khan 2017;Khattak et al 2017) in the context of sedimentology, biostratigraphy Fig. 1 Regional map showing location and tectonic setting of the Meyal Oil Field (marked by blue ellipse).…”

“…Modified after Kazmi and Rana (1982) and Hasany and Saleem (2012) and sequence stratigraphy. Similarly, different researchers have investigated the diagenetic fabric of the Paleocene Lockhart Limestone exposed in the Kohat-Potwar sub-basins, Islamabad, Salt Range (central and western), Margalla Hill Range and Azad Kashmir (Ali et al 2014;Khan et al 2016;Bilal and Khan 2017;Khattak et al 2017;Khan et al 2018). However, no published work is available on reservoir characterization, sequence stratigraphy (T-R sequences) and depositional environment of the Lockhart Limestone penetrated in the Meyal-05P and Meyal-10P wells.…”

Reservoir Potential Evaluation of the Middle Paleocene Lockhart Limestone of the Kohat Basin, Pakistan: Petrophysical Analyses

“…The Lockhart Limestone was studied extensively by the geoscientists (Sameeni et al, 2009;Hasany and Saleem, 2012;Hanif et al, 2013;Ahmad et al, 2014;Ali et al, 2014;Nawaz et al, 2015;Khan et al, 2016;Saddique et al, 2016;Ahsan and Shah, 2017;Khattak et al, 2017;Khan et al, 2018;Siyar et al, 2018;Awais et al, 2019). According to Hasany and Saleem (2012), Lockhart Limestone is comprised of massive, argillaceous limestone in the Meyal Oil Field, Potwar sub-basin, Pakistan.…”

The Dynamics of the Developing Calcarenite Member of Pamutuan Formation In Cintaratu Area, Pangandaran, West Java

“…Microscopic observation on texture, composition (percentage of fragmented and/or non-fragmented shells, the percentage of micrite and terrigenous material, grain size composition), allochem type, diagenetic and microfossils content provide guidance on finding carbonate facies, index energy, sequence stratigraphy and depositional environment [9]- [11]. Field investigation and microscopic observation have been applied to facies and depositional interpretation of ancient carbonate several basins in Asia [8]- [10], [12], [13], including Indonesia [14].…”