Lazurite ( (Na,Ca)8 (Al,Si)12O24(S,SO)4 ), is one of a number of related feldspathoid minerals, which occur in silica-poor igneous rocks collectively termed the Sodalite Group. Also part of the group are nosean (or noselite) along with a clacium-bearing type named Haüyne.
Sample of Haüyne from Mayen, Eifel Mountains, Rhineland-Palatinate, Germany. Attribution: Rob Lavinsky, iRocks.com
Lazurite is a [...]
Plants growing on land are rarely preserved fossils because continental conditions may not be very favourable for the process of fossilisation.
Fossil wood is not usually found associated with the rest of the tree (leaves and roots) and identification can be difficult, in these cases the specimens are given a special botanical name. These [...]
When starting out on preparation most hobbyist collectors will find the use of a rotary tool kit with interchangeable heads immensely versatile. Along with an electric engraver, steel probes and craft knives, these can be helpful for carefully picking away and removing the surrounding sediments. Fortunately the tools just mentioned do not take up much space and can be purchased at very little expense to the user.
The cliffs for about 2 km to the west of Cowbar Nab are capped by glacial till, bedrock being at 40 to 50m O.D. Staithes Beck has cut a deep channel through the till in to the solid strata. On the coast, several landslips and rockfalls can be seen and, in contrast, examples of slow, gradual marine erosion. The marine erosion has been the subject of detailed studies by Agar (1960) and by Durham University in recent years.
Make your way across the beck and follow the Cleveland Way up the steep, stepped path and then eastwards where there is a view of the Old Gut dock (marked 1 on the plan). Pass the path down to the shore at NZ 725 198 and North Warren Cottage (Tile Sheds). (2 cisterns (2) are missed unless one deviates along the coastal path). At NZ 735 197 fork left off the Cleveland Way to go down the track in to the quarries.
Frosterley Marble is a dark grey to black limestone which has been used as an ornamental stone locally and internationally in churches and buildings such as Durham Cathedral.
The alum works was started in the mid-17th century and closed in about 1860. There was a major redevelopment about 1800 when a new alum house was constructed by Hummersea beach. The history and industrial archaeology of the alum works has received much attention in recent years and, in particular, there is the major survey by English Heritage (Hunt et al. 2004). The main sites are included in the mini-geotrail.
View the geomorphology of this area (much of which has now been donated to Tees Valley Wildlife Trust. The scarp line of Saltwick Sandstone is set back from the coast and is paralleled underground by the subcrop of the Cleveland Ironstone Formation (see the geological map). The, therefore, deep embayment is infilled by till that is much landslipped on the seawards side. The Snailah Ponds, still shown on modern maps, are said to have been infilled by material from Boulby Potash Mine development.
Boulby Quarry and the sea cliffs beneath (making use of the tracks down to the shore) are where several 19th century and, more recently, geologists such as Chowns made measured sections. That by Lewis Hunton (1836) is the most notable as he independently recognized the importance of collecting fossils in-situ, and relating the fossils found to the beds in which they occur bolstering the emerging concept of biostratigraphy.
Welcome to the latest offering in the TVRIGS Rock of the Month series of articles. This month I thought that we might examine a broad group of deposits known as argillaceous rocks, collectively referred to as argillites (clay rocks), as opposed to arenites (sandstones) and rudites (conglomerates, tillites and breccias).
Derived from the Latin Argilla – [...]