Chalk

picture info	Chalk Chalk ( /ˈtʃɔːk/) is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO₃. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert) is very common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint). Chalk as seen in Cretaceous deposits of Western Europe is unusual among sedimentary limestones in the thickness of the beds [...More Info...] [...Related Items...]
picture info	Germany Germany (German: Deutschland, German pronunciation: [ˈdɔʏtʃlant]), officially the Federal Republic of Germany (German: Bundesrepublik Deutschland, listen (help·info)), is a country in Central and Western Europe, lying between the Baltic and North Seas to the north and the Alps, Lake Constance, and the High Rhine to the south. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, France to the southwest, and Luxembourg, Belgium, and the Netherlands to the west. Germany includes 16 constituent states, covers an area of 357,386 square kilometres (137,988 sq mi), and has a largely temperate seasonal climate [...More Info...] [...Related Items...]
picture info	Ground Water Groundwater is the water present beneath Earth's surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the surface naturally; natural discharge often occurs at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells [...More Info...] [...Related Items...]
picture info	Silicification In geology, petrifaction or petrification is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals. Petrified wood typifies this process, but all organisms, from bacteria to vertebrates, can become petrified (although harder, more durable matter such as bone, beaks, and shells survive the process better than softer remains such as muscle tissue, feathers, or skin). Petrifaction takes place through a combination of two similar processes: permineralization and replacement [...More Info...] [...Related Items...]
picture info	Negev The Negev (Hebrew: הַנֶּגֶב‬, Tiberian vocalization: han-Néḡeḇ ; Arabic: النقب‎ an-Naqab) is a desert and semidesert region of southern Israel. The region's largest city and administrative capital is Beersheba (pop. 205,810), in the north. At its southern end is the Gulf of Aqaba and the resort city of Eilat. It contains several development towns, including Dimona, Arad and Mitzpe Ramon, as well as a number of small Bedouin cities, including Rahat and Tel as-Sabi and Lakyah [...More Info...] [...Related Items...]
picture info	Israel Israel (/ˈɪzriəl, -reɪəl/; Hebrew: יִשְׂרָאֵל‬; Arabic: إِسْرَائِيل‎), officially the State of Israel, is a country in the Middle East, on the southeastern shore of the Mediterranean Sea and the northern shore of the Red Sea. It has land borders with Lebanon to the north, Syria to the northeast, Jordan on the east, the Palestinian territories of the West Bank and Gaza Strip to the east and west, respectively, and Egypt to the southwest [...More Info...] [...Related Items...]
picture info	Mesozoic The Mesozoic Era ( /ˌmɛsəˈzoʊɪk, ˌmiː-, -soʊ-/ or /ˌmɛzəˈzoʊɪk, ˌmiː-, -soʊ-/) is an interval of geological time from about 252 to 66 million years ago. It is also called the Age of Reptiles, a phrase introduced by the 19th century paleontologist Gideon Mantell who viewed it as dominated by diapsids such as Iguanodon, Megalosaurus, Plesiosaurus and Pterodactylus. This Era is also called from a paleobotanist view the Age of Conifers. Mesozoic means "middle life", deriving from the Greek prefix meso-/μεσο- for "between" and zōon/ζῷον meaning "animal" or "living being". It is one of three geologic eras of the Phanerozoic Eon, preceded by the Paleozoic ("ancient life") and succeeded by the Cenozoic ("new life") [...More Info...] [...Related Items...]
picture info	Clay Clay is a finely-grained natural rock or soil material that combines one or more clay minerals with possible traces of quartz (SiO₄), metal oxides (Al₂O₃ , MgO etc.) and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are plastic due to particle size and geometry as well as water content, and become hard, brittle and non–plastic upon drying or firing. Depending on the soil's content in which it is found, clay can appear in various colours from white to dull grey or brown to deep orange-red. Electron microscope photograph of smectite clay – magnification 23,500 Although many naturally occurring deposits include both silts and clay, clays are distinguished from other fine-grained soils by differences in size and mineralogy [...More Info...] [...Related Items...]
picture info	Hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit, although in areas with scarp/dip topography a hill may refer to a particular section of flat terrain without a massive summit (e.g [...More Info...] [...Related Items...]
picture info	Meudon 1---> French Land Register data, which excludes lakes, ponds, glaciers > 1 km2---> (0.386 sq mi or 247 acres) and river estuaries. 2---> Population without double counting: residents of multiple communes (e.g., students and military personnel) only counted once.

Meudon (French pronunciation: [mø.dɔ̃]) is a municipality in the southwestern suburbs of Paris, France. It is in the département of Hauts-de-Seine
[...More Info...] [...Related Items...]