North Pennines — Area of Outstanding Natural Beauty and European Geopark: a geodiversity audit. North Pennines Natural Landscape, 2010.
Glossary
| Adit | Horizontal, or nearly horizontal tunnel or mine entrance |
| Ammonoid | A subclass of molluscs with coiled shells belonging to the class Cephalopoda |
| Anticline | Arch-shaped fold of rocks, closing upwards |
| Armour-stone | Large stone block used in coastal defence and other engineering works |
| Aureole | Area surrounding an igneous intrusion affected by metamorphic changes |
| Batholith | A large body of intrusive igneous rock with no visible floor |
| Bituminous | Rich in hydrocarbons or bitumen |
| Bivalve | Aquatic molluscs of the class Bivalvia, characterised by paired shell valves. |
| Blanket bog | An extensive area of peat bog |
| Bouguer anomaly | A gravity anomoly calculated after corrections for latitude, elevationand terrain. |
| Brachiopod | A phylum of solitary marine shelled invertebrates |
| Braided rivers | A river consisting of a number of small channels separated by bars |
| Breccia | Coarse-grained clastic sedimentary rock consisting of angular fragments of pre-existing rocks |
| Brockram | A term used in NW England for breccias and conglomerates of Permo-Triassic age |
| Calc-silicate | A group of minerals consisting of calcium silicates |
| Chert | A dense, very hard rock composed of extremely fine-grained silica. |
| Chronostratigraphy | The standard hierarchical definition of geological time units |
| Conglomerate | Coarse-grained clastic sedimentary rock composed of rounded or subrounded fragments of pre-existing rocks |
| Conodonts | An extinct group of microscopic marine animal fossils, composed mainly of calcium phosphate, and which commonly resemble fish teeth and worm jaws. |
| Continental shelf | The gently sloping offshore zone, extending usually to about 200 metres depth |
| Crinoid | Crinoids, or 'sea lillies', are marine animals composed of calcareous plates, belonging to the phylum Echinodermata |
| Cross-bedding | Internally inclined layers in a rock related to the original direction of current flow |
| Cupola | A dome-shaped offshoot rising from the top of a major igneous intrusion |
| Desiccation cracks | Polygonal cracks formed in a sediment as it dries out in a terrestrial environment, also known as shrinkage cracks |
| Displacement | The relative movement on either side of a fault plane |
| Doline | A steep-sided enclosed depression in a limestone region |
| Dolomitic limestone | A limestone containing a high concentration of the mineral dolomite |
| Dry valley | A valley produced by running water but which is presently streamless |
| Dyke | Discordant, sheet-like bodies of intrusive igneous rock in a vertical, or near-vertical orientation |
| Evaporites | Sedimentary deposit of minerals formed by natural evaporation |
| Fault | A fracture in rocks along which some displacement has taken place |
| Feldspar | A group of rock-forming minerals consisting of silicates of aluminium, sodium, potassium, calcium and more rarely barium |
| Felsite | A general term used to denote fine-grained igneous rocks |
| Gangue | Generally valueless mineral or rock which accompanies an ore |
| Gastropod | Molluscs belonging to the class Gastropoda, usually with coiled shells |
| Gouge | Broken rock, often shale or clay, in a mineral vein or between fault planes |
| Graptolite | A group of extinct colonial marine organisms. Generally placed in the phylum Chordata, but sometimes regarded as Coelenterata. They consist of one or more branches or stipes in which individuals in the colony occur in rows |
| Greywackes | A sandstone containing a high proportion of silt, clay and rock fragments in addition to quartz grains |
| Hornfels | A fine-grained rock that has been partly or completely recrystallised by contact metamorphism |
| Inlier | An outcrop of older rocks surrounded by those of younger age |
| Joints | A fracture, or potential fracture, in a rock adjacent to which there has been no displacement |
| Lamprophyre | A group of intrusive igneous rocks characterised by abnormally high contents of silicate minerals such as biotite, hornblende and augite, with generally small amounts of feldspar |
| Lapilli-tuff | A compact rock composed of small pieces of lava rounded during eruption |
| Lithology | The character of a rock expressed in terms of its mineral composition, structure, grain size and arrangement of its constituents |
| Magma | Molten rock |
| Magnetic anomaly | The value of the local magnetic field remaining after the subtraction of the dipole portion of the Earth's field |
| Metamorphism | Change in the mineralogy and structure of a rock as a result of the effects of heat and/or pressure |
| Monocline | A one-limbed flexure on either side of which the strata are horizontal or dip at only low angles |
| Mountain building | The complex series of geological processes which create mountains |
| Nunataks | An isolated mountain peak projecting from an ice sheet |
| Ostracod | Small arthropods belonging to the subclass Ostracoda, having a twin shell |
| Outlier | A remnant of a younger rock surrounded by older strata |
| Palaeomagnetic | The magnetic characteristics of a rock formed in the geological past |
| Pegmatite | Igneous rocks of especially coarse grain size |
| Phenocryst | Large crystals, usually of near perfect shape, embedded in a fine- grained matrix in igneous rocks |
| Phreatic | Volcanic eruptions generated by the interaction between hot magma and surface or ground water |
| Porphyritic | The term applied to igneous rocks which contain isolated crystals, or phenocrysts, larger than those forming the main body of the rock |
| Radiometric dating | The method of determining the geological age by measuring the relative abundance of parent and daughter isotopes in rocks |
| Rendzina | A brown earth soil of humid or semi-arid grassland that has formed over calcareous parent material. |
| Rottenstone | Any highly decomposed but still coherent rock |
| Sedimentary rocks | Those rocks formed by the accumulation of fragments from the wasting of previous rocks or organic materials, deposited as layers of sediment |
| Sill | A tabular igneous intrusion with concordant contacts with the surrounding wall rocks |
| Sink hole | see doline |
| Statigraphy | The definition and description of the stratified rocks of the Earth's crust |
| Streak | The name given to the colour of the powder of a mineral or rock |
| Supergene | Alteration formed near the surface |
| Syncline | A concave-upwards fold with the youngest rocks in the centre |
| Tailings | Fine-grained waste from mineral processing operations |
| Throw | The amount of displacement on a fault |
| Tonstein | A rock, composed mainly of the mineral kaolinite, typically found as thin lasyers in coal-bearing sequences of rocks. Tonsteins may have been formed by the decomposition of volcanic ash-falls. |
| Trilobite | Extinct marine arthropods characterised by having a segmented oval body divided into three segments |
| Tufa | A porous or cellular deposit of calcium carbonate deposited from lime-rich springs |
| Tuff | A rock formed of compacted volcanic fragments |
| Turbidity current | A dense sub-marine flow of mixed water and sediment, capable of very rapid movement |
| Unconformity | A substantial break in the succession of stratified sedimentary rocks following a period when no deposition was taking place |
| Volcaniclastic | A rock containing volcanic fragments in varying proportions |
| Xenolith | A foreign inclusion in an igneous rock |