I have been thinking about doing a field trip along the Jurassic Coast in Dorset, England. For those who do know know about the South West Coast Path, it is a continuous coastal path that runs for about 630 miles from Minehead to Poole in south west coast of England. There is no preferred direction, but traditionally, and especially among geoscientists, it is typically walked counterclockwise, because if you do that, you progressively encounter younger rocks. That is the preferred way to looking and studying geology, from old to new if possible.
The 95 mile easternmost segment of the South West Coast Path is known as the Jurassic Coastal Path, between the towns of Exemouth and Poole. There are numerous books, papers, web pages dedicated to the path, and in terms of the science of Paleontology, Stratigraphy and Structural Geology, there are volumes, literally 300 years of research on this topic and area.
This is also an UNESCO World Heritage Site, the only one such natural site in Great Britain. The path is important geologically because it covered 185 million years of geologic history with fairly continuous exposure of rocks along the sea cliffs. Also it includes several type section of Jurassic stratigraphy along the very path.
According to the SW Path Trail Association, the path can be walked in 9 days, but shorter walks are possible, and there is hotels and easy access to food, drink and road as need be almost all along the way.
Suggested Itinerary
Day 1: Exmouth to Sidmouth (12.5 miles)
Day 2: Sidmouth to Seaton (10.3 miles)
Day 3: Seaton to Seatown (14.2 miles)
Day 4: Seatown to Abbotsbury (12.4 miles)
Day 5: Abbotsbury to Ferrybridge (10.9 miles)
Day 6: Isle of Portland Circuit (13 miles)
Day 7: Ferrybridge to Lulworth Cove (14.5 miles)
Day 8: Lulworth Cove to Worth Matravers (13 miles)
Day 9: Worth Matravers to Studland (12.3 miles)
As you can see, these are hard days, of 10-15 miles of walk over variable terrain, plus I will have to make frequent stops to look at the rocks. I have decided to give it a go and perhaps organize a proper field trip out of this.
The Dorset coast isn’t just a scenic getaway; it is a global gold standard for Jurassic geology. Because the rocks dip gently to the east, walking from Lyme Regis toward Swanage is effectively like walking forward through of Earth's history.
I am particularly interested in the Weymouth Anticline area, which covers Day 6-9. Technically a full week won't be enough to visit all the outcrop just in this segment, but I think I can get a good understanding of the outcrop in say about 5 to 7 days.
Above is the basic stratigraphic column of the area that goes with the map. Basically the Upper Triassic to Lower Cretaceous section is exposed here. This are is the type section for the Jurassic. Especially the Kimmeridge Clay, hence the stage name Kimmeridgian is an world class source rock, globally. Meaning during this time about 152-157 Million Years ago one of the most prolific source rock for hydrocarbon were deposited, I can't wait to see the type section.
The trail follows the western edge of the Wessex Basin, which was a major area of sediment accumulation during the Jurassic. Near Lyme Regis, the cliffs are dominated by the Blue Lias—rhythmic layers of limestone and shale—and the organic-rich Black Ven Marls. As you move east toward West Bay and Burton Bradstock, the scenery changes to the golden Bridport Sands, capped by the highly condensed limestones of the Inferior Oolite. Areas like the Fleet and Herbury Peninsula expose the Fuller’s Earth and Forest Marble, reflecting a move from deeper sea clays to shallow marine environments.
The ammonites, most common invertebrate fossils of the Jurassic, found along these cliffs are used as precise biological "clocks" to date the rocks into specific zones and subzones. During this time, the area sat at about 35 degrees N latitude, acting as a crossroads where warm-water marine life from the south met cooler-water species from the north. This area is widely considered the Global hotspots for Lower Jurassic fossils, including ammonites and marine reptiles. Today marine reptiles (dinosaurs) are rather hard to find, but ammonites can still be widely observed.
So bottomline, I am trying to put together a detailed plan for this trip. I am not sure if it is going to be in the summer or the Fall. It is likely going to be multiple trips. Frist a short trip for planning and then the main trip at a later time.
