Field Guide To The Geology of Oman
Volume 1: Western Hajar Mountains & Musandam
By Samir S. Hanna
Historical Association of Oman 2006
Book Review by Aaron Noah M.
“It is recognized worldwide that Oman has a geological heritage so unique and so accessible that it is almost unrivalled anywhere on Earth.”
Today Oman is mostly desert, but throughout its geological history it has witnessed dramatic climatic changes. At least twice in the past the Arabian landscape featured glaciers, at other times there were lush forests, and for approximately 190 million years most of terrain was drowned under an ocean.
“At the summit of Jabal Shams (Oman’s highest mountain) there are marine fossils that once lived in a shallow tropical ocean.”
Evidence of Oman’s rich geological history can be found everywhere. Unlike other places in the world where rock structures are normally hidden beneath soil and vegetation, Oman’s layers of the past are exposed for study. Millions of years and a variety of features are chronicled, including fossils and rare glimpses of rocks from the upper mantle.
In the first section of the book Samir explains geological time scale, plate tectonics, the geological history of Oman, and the main rock sequences found in the region. Part two is dedicated to field trips, inviting the reader to explore the geography firsthand.
The text is geared for both armchair-geologists and professionals. Many years have passed since my last Geology 101 class, but I managed a smooth tour of the material, admittedly having to grab for the dictionary on words like “autochtonous” and “ophiolite.”
Despite my “rocky” vocabulary, the book makes an interesting read. It’s amazing to imagine all of the transformations the region has experienced over a mind-boggling stretch of years. To put the geological time scale into perspective, the author asks the reader to think of the last 3.8 billion years (as far back as the oldest known rocks) as equivalent to one calendar year, with each day representing roughly ten million years. Early life doesn’t appear until July or August, dinosaurs flourish on the 10th and then go extinct by the 25th of December, and then humanity arrives on the scene just a few minutes before the stroke of midnight on New Year’s Eve.
The field trips are thorough, including maps, photos, and diagrams. Samir uses landmarks and odometer indicators to guide you through each route, with plenty of details on the rock formations and even a few suggestions on camp or picnic sites. I’d like to see GPS coordinates as well, but I think the kilometer markings would probably work well enough. The print quality is low budget, but the photos are still enticing enough that I look forward to trying out a few of these routes soon.
I haven’t seen this field guide in the stores, but I was able to secure a copy from the Dubai Natural History Group. You can also get one direct from the publisher, the Historical Association of Oman.
Field trips: Wadi Bani Kharus, Wadi Hajir, Nakhl, Tawaiyah Chromite Quarry, Wadi Mistal & Ghubra Bowl, Wadi Abyad, Wadi Bani Awf & Snake Gorge, Wadi Sahtan, Wadi Hawasina, Wadi Bani Ghafir, Buwah, the Semial Gap, Wadi Muaiydin, Wadi Ghul & Jabal Shams, Sharfat Al Alamayn viewpoint, Nizwa area, and Musandam.