| TAFONI | Roughly hemispherical hollows weathered in rock at the surface. Not common in caves, but some hollows in Nullarbor caves may well be tafoni. Karst - Depression Features of. Ref JJ |
| TAGGING | Affixing a tag bearing a cave number near its entrance, either by glue or by means of rock drill and a small nail or screw. Survey & Mapping term. Ref JJ |
| TALWEG | Also Thalweg. The line of lowest points along a valley floor, normally the stream channel. Geology. Ref KG |
| TAPE | Strips of woven synthetic fibre used for slings to support ladders or as a handline. Short lengths can be worn as a waist band. Climbing and SRT. Ref JJ |
| TAPE | In survey, a graduated tape of steel, plastic, wire-reinforced cloth, or fiberglass, used for measuring distance. Survey & Mapping term. Ref JJ |
| TAXON | (Plu Taxa) In biology, the name of a rank in a system of Taxonomy. From highest to lowest: Kingdom, Phylum, Class, Order, Family, Genus, Species. See Species. Biology - Flora & Fauna. Ref MM |
| TECTONIC | Pertaining to large scale movements of the earth's crusts, such as Folding and faulting. Geology. Ref KG |
| TERRA ROSSA | Reddish residual clay soil developed on limestone. Speleology term. Ref JJ |
| TERRESTRIAL | Living or active on the land surfaces, either Epigean, Endogean or Hypogean.. cf Amphibious, Aquatic, Arboreal. Fauna. Ref AC |
| TERRIGENOUS | Shallow marine sediments consisting of material derived from the land surface. Geology. Ref KG |
| TERTIARY | Tertiary climates in Australia were mainly warm and humid, with aridity first appearing towards the end of the Miocene and becoming widespread in the Pliocene. Geology. Ref KG |
| TERTIARY | The geological time between Cretaceous and Quaternary, from about 65 to 1.6 million years ago. It occupies the bulk of the Cainozoic era. From oldest to youngest, the subdivisions are Palaeocene, Eocene, Oligocene, Miocene, and Pliocene. Geology. Ref KG |
| THEODOLITE | Survey instrument that measures both horizontal and vertical angles, as well as horizontal distances using a telescope and a stadia. Survey & Mapping term. Ref MM |
| THREAD | A natural hole in a rock mass through which a rope, tape or wire can be passed to create an anchor. Climbing and SRT. Ref RW |
| THRESHOLD | Slope or cliff facing up a blind or half-blind valley below a present or former streamsink. Geology. Ref JJ |
| THRESHOLD | That part of a cave near the entrance where surface climatic conditions rapidly grade into cave climatic conditions. Not necessarily identical with twilight zone. Cave - Parts of. Ref JJ |
| THROUGH CAVE | A cave which may be followed from entrance to exit along a stream course or along a passage which formerly carried a stream. Cave - Kinds of. Ref JJ |
| TIDEMARK | A horizontal bench or a marking on a wall of a lava tube which indicates a prior lava level. Lava Cave term. Ref KG |
| TOPOFIL | A mechanical cave survey device that uses a roll of thread and a distance counter, a protractor to measure inclination and a compass to measure the bearing. Survey & Mapping term. Ref RW |
| TOWER KARST | The ultimate development of Cockpit karst through Cone karst to Tower karst, in which the residual hills have very steep to overhanging lower slopes. There may be alluvial plains between the towers and flat-floored depressions within them. Syn Fenglin. Karst - Hill Features of. Ref JJ |
| TRACE | A length of wire rope with clips at each end to fasten a wire ladder to a belay point. Climbing and SRT. Ref JJ |
| TRACER | (1) A material introduced into surface or underground water where it disappears or into soil to determine drainage interconnections and travel time. (2) A material introduced into cave air to determine cave interconnections. Survey & Mapping term. Ref JJ |
| TRANSGRESSION | An advance of the sea across the land, due to subsidence of the land, or a eustatic rise in sea level. Opposite of Regression (qv). Geology. Ref KG |
| TRANSITION ZONE | Initial region of the Dark zone beyond the Twilight zone where there is no visible light. But some external factors from the entrance environment may still be apparent, eg seasonally fluctuating air temperatures. Cave - Parts of. Ref AC |
| TRANSPIRATION | Loss of water by plants, usually by evaporation from leaves. Cf. evaportranspiration. Fauna. Ref MM |
| TRAVERSE | (1) A route along ledges above the floor of a cave, (2) to travel in a cave along such a route. Speleology term. Ref JJ |
| TRAVERSE | The commonest form of cave survey in which direction, distance and vertical angle between successive points are measured. Survey & Mapping term. Ref JJ |
| TRAVERTINE | Compact calcium carbonate deposit, often banded, precipitated from spring, river or lake water. It is often at least partly of biogenic origin with algae or invertebrate animals involved. Cf. tufa. Karst - Kinds of. Ref JJ |
| TREE ROOT | Tree roots often penetrate down into caves and can form dense mats of fine rootlets, or thick tap roots which can completely block a passage. The breakdown of the tree roots forms food for cavernicoles. Speleology term. Ref MM |
| TRI-CAM | A metallic device placed in holes or cracks for use as an anchor Cf. Chock. Climbing and SRT. Ref RW |
| TROG | A caver. The act of caving. Short for troglodyte. Speleology term. Ref MM |
| TROG UP | To dress in suitable clothing and to gather lighting and other gear before going caving. Speleology term. Ref MM |
| TROGLOBITE | An animal (an obligate cavernicole) that lives in a cave and is unable to live outside of it. Troglobites usually have troglomorphic adaptions. Aquatics now referred to as Stygobites but may be referred to as aquatic troglobites. Speleology term. Ref JJ |
| TROGLODYTE | A human cave dweller. Speleology term. Ref JJ |
| TROGLOMORPHIC ADAPTION | Adaptions to the cave environment, eg loss of pigment, for species living in the dark zone. eg long antennae and legs, partial or complete loss of eyes, reduced metabolic rate. Speleology term. Ref AC |
| TROGLOMORPHIES | Syn. troglomorphic adaptations. (N.B. Troglomorphies do not necessarily equate to level of adaptation to dark zone environment.) Speleology term. Ref MM |
| TROGLOPHILE | A terrestrial cavernicole which frequently completes its life cycle in caves but is not confined to this habitat. Speleology term. Ref JJ |
| TROGLOXENE | A terrestrial Cavernicole which spends only part of its life cycle in caves and returns periodically to the epigean domain for food. Speleology term. Ref JJ |
| TRUE NORTH | The direction of the geographical north pole at a place. Survey & Mapping term. Ref JJ |
| TUBE | A cave passage of smooth surface, and elliptical or nearly circular in cross-section. Cf. phreatic tube Cave - Parts of. Ref JJ |
| TUFA | Spongy or vesicular calcium carbonate deposited from spring, river or lake waters. Cf. travertine. Speleology term. Ref JJ |
| TUFF | A consolidated form of volcanic ash or lapilli. Lava Cave term. Ref KG |
| TUMULUS | A rounded, sharply convex, mound of lava, frequently with radial or polygonal cracks, where a semi-solid crust has been pushed up by pressure from below. Applied to small mounds on a lava tube floor. See 'Puddings'. Lava Cave term. Ref KG |
| TUNNEL | A nearly horizontal cave open at both ends, fairly straight and uniform in cross-section. Cave - Parts of. Ref JJ |
| TURBIDITY | The muddiness, cloudiness or milkiness of water. Related to the amount of suspended sediment in the water. Hydrology terms. Ref AC |
| TWILIGHT ZONE | The part of a cave in which some daylight penetrates (but not direct sun light) and gradually diminishes to zero light. See Transition zone. Cave - Parts of. Ref JJ |