9/2/064/0030

The density of sites in a small stretch of coastline, and the inter‐digitations of the archaeological,palaeontological, and geological sites, makes it impossible to draw firm lines between individualsites and single out one or a few to the exclusion of others. Rather, the near‐continuousdistribution, and its novel ability to represent a swathe of human settlement variation throughtime and space, warrants the entire locality to be designated as a Provincial Heritage Site. Forthis reason we recognize the Pinnacle Point Site Complex (PPSC) that spans the coastal areabelow the cliffs from PP1 in the east to PP21 (caves) and to PP18, 19, 22, 31 (shell middens) inthe west. The area and several of these sites have been described in publications, and here weprovide an abbreviated summary. The sites are mostly caves and rockshelters, but there are awide variety of open‐air sites and shell middens as well. The caves and rockshelters were cut byhigh sea levels into fault breccias that occur at the bedding planes in the Table MountainSandstone (TMS). Caves and rockshelters form typically where the folds have a dip that is nottoo vertical. If it is too vertical, erosion occurs throughout the fault breccia almost like flowingdown a chimney and a roof cannot form to the cave or rockshelter. The bedding planes atPinnacle Point are perfect for cave and rockshelter formation. Many of the caves androckshelters are more than +10 m above sea level, assuring that the sediments escaped beingwashed out 123,000 years ago by the +5 m high sea level.Fortunately, capping the TMS is a calcrete bed throughout the area. TMS is normally acidic,resulting in poor preservation of fossil bone. But the calcrete buffers the water, raising itsalkalinity as it flows through the TMS, and into the sediments in the caves and rockshelters,resulting in outstanding bone preservation. An added benefit is that at Pinnacle Point we havea rare situation where the caves were sealed in the past by dunes. When the caves weresealed, speleothems (stalagmites, stalactites, and flowstones) formed. Speleothems canpreserve long sequences of climate and environmental change that can be reconstructedthrough the study of carbon and oxygen isotopes (and dated precisely with uranium‐thoriumdating) but only when the cave is closed during their formation. The special conditions of caveclosure by ancient dunes at the PPSC means that the precious archives of climate andenvironmental change are present. These caves and rockshelters drew human and animaloccupants over a significant period of time from at least 170,000 years ago to several hundredyears ago. This regular occupation along with the erosion of fault breccia and aeolian depositionof primarily beach‐derived sands formed stacks of sediments in the caves and rockshelters.These stacks have been well‐preserved and protected in various contexts (PP9) to the pointwhere they are untouched, which in other contexts (PP13B) they have been partially eroded andreveal to the visitor the stratigraphy of the site. In an extreme case (PP5‐6) there is over 14 m ofstacked sediments (likely far more) that at the contact of the cliff and sediment was erodedaway, leaving a natural erosion face of the entire stratigraphy. Imagine a multi‐layered cakebeing sliced, top to bottom, in half with the cut now revealed and showing all the layers. We arecurrently excavating into this naturally eroded cut, and this has the potential to be conserved(much like the much shorter section at Nelson Bay Cave) as a living museum of extraordinarycultural and environmental change through time.