Most cave systems are through limestone bedrock. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. Limestone makes up about 10% of the total volume of all sedimentary rocks. Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera. Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Typically, if the clast, or rock particle, contains anything else besides sand, then it is either a conglomerate or a breccia, another sedimentary rock that is very similar to conglomerates. The interior of the rock is held together by a cement-like process that comes from the high pressure of the environment. This gives the exterior a rather uneven appearance. They occur when the sediment material consists of rock grains of many different sizes. Typically, conglomerates have large grains but vary according to their rounding and sorting properties.Ĭonglomerate rocks form from special conditions. This is because, as a sedimentary rock, it forms from other rock particles. Unlike other rock types, which are classified due to their chemical composition and minerals, conglomerates are classified based on the size of their grains. Both conglomerates and breccias are characterized by clasts larger than sand (>2 mm).Ĭonglomerate rocks are a type of sedimentary rock. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts. Talus slopes might become buried and the talus cemented in a similar manner.Ĭonglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Breccias indicate accumulation in a juvenile stream channel or accumulations because of gravity erosion. The angular shape of the fragments indicates that the material has not been transported far from its source. Both breccias and conglomerates are composed of fragments averaging greater than 2 millimetres (0.079 in) in size. Sedimentary breccias can be described as rudaceous.Ī conglomerate, by contrast, is a sedimentary rock composed of rounded fragments or clasts of pre-existing rocks. Sedimentary breccias are an integral host rock for many SEDEX ore deposits. In the field, it may at times be difficult to distinguish between a debris flow sedimentary breccia and a colluvial breccia, especially if one is working entirely from drilling information. Thick sequences of sedimentary (colluvial) breccias are generally formed next to fault scarps in grabens. These are, in essence, lithified colluvium. The other derivation of sedimentary breccia is as angular, poorly sorted, immature fragments of rocks in a finer grained groundmass which are produced by mass wasting.
Technically, turbidites are a form of debris flow deposit and are a fine-grained peripheral deposit to a sedimentary breccia flow. They are formed by either submarine debris flows, avalanches, mud flow or mass flow in an aqueous medium. Sedimentary breccias are a type of clastic sedimentary rock which are made of angular to subangular, randomly oriented clasts of other sedimentary rocks. It usually takes about 15 to 20 working days for delivery, and it may take a bit longer to Central and South America.īreccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments. We send the goods to other countries by registered airmail through Hong Kong Post. It usually takes about 8 to 12 working days for delivery. We send the goods to USA, UK and Australia buyers by E-express, a kind of postal express service set up by Hong Kong Post.
It is an ideal learning aid for students and kids and also a very good collectible item for everybody.
The pictures in the listing are just for reference as we are selling multiple pieces with same pictures. Each one will be a bit different (specimen size, color and weight) even in the same production batch. Weight of each piece is about 6 to 13 g, total weight with packing box is about 140 g. Size of each piece is about 23x17x15 mm (about 0.9x0.7x0.6 inch). (similar to picture, stock of more than 100 boxes): 10 different sendimentary stone specimen in clear plastic box