Summer Field Programme - 10 August 2013

The Lower Jurassic from Staithes to Port Mulgrave

Paul Wignall

The excursion will focus on the Lower Jurassic marine sediments from the Staithes Sandstone Formation to the Whitby Mudstone Formation, including the Cleveland Ironstone Formation and the ‘Jet Rock’.

Meet on the promenade at Staithes, next to the Cod and Lobster pub (NZ 782 188) at 11.00 am. Parking may be a problem due to the holiday period so please give due time to walk down to the meeting point from the higher levels of the village. Please bring a packed lunch as we will be out on the rocks for the remainder of the day.  Toilets are available only at Staithes. Hard hats are required for key exposures, especially near the cliff faces.  Stout walking boots with ankle protection are better than wellington boots or any other footwear on the foreshores. The path up the cliff at Port Mulgrave may be slippery if the day is wet but walking distances are low (total 4-6 km in the day).

The plan is to spend the day walking along the foreshore, as the tide recedes, and examining one of the best displayed Early Jurassic successions in the country. The going is mostly over wave-cut platforms but will involve some scrambling over boulders. On reaching Port Mulgrave there will be a steep ascent of the cliff followed by a cliff top walk back to Staithes. The geology to be seen includes the Staithes Sandstone Formation (shallow marine sandstones with abundant and diverse trace fossils and storm sedimentation), the Cleveland Ironstone Formation (small scale sedimentary cycles capped by ironstones showing iron ooliths, abundant bivalve fossils and exceptionally well seen storm gutters), the Grey Shale (offshore mudstone with common concretion bands and ammonites) and the Jet Rock (a black shale packed with large and odd-shaped concretions and lots of ammonites, it is the regional manifestation of a major climatic and oceanic event that saw the oceans warm and stagnate). 

The ascent is 90 m to the cliff top at Port Mulgrave. 

Low tide is at 13:15 pm (Scarborough) and high tides at 06:45 am and 19:12 pm.  The tides at Staithes are approximately 20 minutes earlier.  The excursion will finish at approximately 5 pm but there is an option to leave earlier if people wish to.