A Trip to Rohtas Fort

السلام علیکم ۔
Geo-archaeology of Eastern most Salt Range.
One day event of GeoHikingClub.
Dated: 10/12/2023.
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Resource person: Muneer Ahmad Khan, Dr. Syed Kamran Ali, Tariq Mahmood, Dr. Abdul jabbar Khan, Dr. Qazi Suhail Imran.
The easternmost stretch of the Salt Range is influenced by both the Jehlum Fault and the Salt Range thrust. Elevated hillocks composed of Cambrian and Siwalik sedimentary rocks dominate the landscape, with the ridge primarily formed by the Jutana Formation.
This region holds significant historical importance, having been declared a primary habitat by both Central Asian invaders such as the Mughals and Hindu pilgrims, particularly the jogis. Over the centuries, notable figures including Alexander, Mahmood Ghaznavi, Al-Bairuni, Mughals, and the British emperors visited the area, leaving behind constructed buildings. Rohtas Fort (Sher Shah Suri), Tilla Jogian, and Nandana stand out as well-known landmarks.
During a recent event, participants embarked on a hike to Tilla Jogian, covering a distance of 3.5 km one way. They received a briefing on the Nagri sandstone, a key material used in constructing the fort. The majority of structures at Tilla Jogian are crafted from the Jutana, Baghanwala, and Nagri formations.
Participants were informed about Al-Bairuni's method for calculating the ridge's height. This involved determining the angle from two points at the foothills of the ridge. Subsequently, considering the height of the ridge and the angle of the horizon (ufaq) from its summit, Al-Bairuni calculated the Earth's radius. Remarkably, this calculation, performed over a millennium ago, relied on 🌎 an astrolabe and trigonometry 📐📏. The participants even engaged in a practical demonstration using a self-made astrolabe, highlighting the enduring scientific legacy of Al-Bairuni's work.
Through these intricate calculations, Al-Bairuni laid the foundation for modern GIS and geodesy, marking a significant milestone in the field.
20 participants were served with Russian salad 🥗, dahi bhally, chicken 🐔 karahi, Kashmiri chaiy, kashmiri kulchy, and lunch/breakfast. Total amount of 47,000/- rupees was utilized.
We express our gratitude to the organizers.