NZLRI rock reclassification
-
-
Rock class Rock type reclass Rock type definition Ng Ngauruhoe tephra Volcanic airfall deposits from Ngauruhoe maunga (dark, iron and magnesium-rich sediments) Kt Kaharoa and Taupo ashes Volcanic airfall deposits from Kaharoa and Taupomoana (white, droughty, nutrient poor sediments) Rm Rotomahana mud Volcanic airfall deposits from Rotomahana maunga (dark, iron and magnesium-rich sediments) Mo Ashes older than Taupo ash Volcanic airfall deposits older than the Taupo ash layer Ta Tarawera tephra Volcanic airfall deposits from Tarawera maunga (dark, iron and magnesium-rich sediments) La Lahar deposits Volcanic deposits from lahars from andesitic maunga (dark, iron and magnesium-rich sediments) Sc Scoria Volcanic deposits from scoria from andesitic or basaltic maunga (dark, iron and magnesium-rich stones with holes in them) Vu Extremely weak altered volcanics Volcanic rocks that have been altered (e.g. by hydrothermal activity) thereby weakening the rocks Tp Taupo and Kaharoa breccia and pumiceous alluvium River deposits originally derived from volcanic airfall deposits from Kaharoa and Taupo maunga (white, droughty, nutrient poor sediments). Silt, sand and angular shaped pebble sized grains. Ft Quaternary breccias older than Taupo breccia A formation containing many angular pebble shaped grains composed of pumice from eruptions older than the eruption from Taupomoana in approximately 232AD Lp Pumiceous lapilli White bits of porous pumice from volcanoes like Taupo or Rotorua ranging in size from 2 to 64mm in diameter Vo Lavas and welded ignimbrites Hard volcanic rocks In Ancient volcanics Hard volcanic rocks Vb Indurated volcanic breccias Hard volcanic rocks containing sharp fragments Gn Plutonics Hard volcanic rocks containing big crystals Tb Indurated fine-grained pyroclastics Hard volcanic rocks with small crystals Um Ultramafics Dark coloured volcanic rocks high in iron and magnesium. Fertile. Pt Peat Organic-rich soil material. Spongy to walk on Cl Coarse slope deposits Landslide debris Lo Loess Wind-blown silt from wave-cut marine benches or braided riverbeds exposed by uplift by earthquakes and/or by lower sea levels during ice-ages when winds are stronger Gl Glacial till Fine sediment from glaciers pulverising rocks Wb Windblown sand Sand blown by wind to form sand foredunes parallel to the coast, parabolic dunes and sand flats. (Sand is gritty feeling and raspy sounding). Uf Unconsolidated clays and silts Fine sediment that has not been consolidated or cemented into rock. Clay is sticky. Silt is silky and pops when rubbed between fingers Af Fine alluvium Alluvium is sediment from streams and rivers. Fine alluvium is silt or clay sized. Clay is sticky. Silt is silky and pops when rubbed between fingers Us Unconsolidated sands and gravels Loose sands and gravels. (Sand is gritty feeling and raspy sounding) Gr Alluvial gravels River gravels Mm Massive mudstone Rock with no joints or bands that is made of silt or clay. (Clay is sticky. Silt is silky and pops when rubbed between fingers). Sb Bedded sandstone Rock that is mostly sandy and has bands. (Sand is gritty feeling and raspy sounding) Mb Bedded mudstone Rock that is mostly composed of clay or silt and has bands. (Clay is sticky. Silt is silky and pops when rubbed between fingers) Cw Weakly consolidated conglomerate Gravels contained in a rock that not very hard ("weakly consolidated") Mf Frittered mudstone Rock made of silt or clay that shatters into small pieces when exposed to weathering, a process called "frittering" Mx Sheared mixed lithologies A mixture of rocks in an area where there is a lot of movement of rocks because of earthquakes and plate tectonics Me Bentonitic mudstone Rock composed of bentonitic clay (a swelling clay). Landforms on this rock tends to have earthflows at very low slope angles but are fertile Ac Crushed argillite association of rocks Crushed argillite rocks are unstable fine-grained clay rocks. Landforms containing these rocks tend to have earthflows at very low slope angles but are fertile Sm Massive sandstone Rock is gritty feeling and raspy sounding. It is hard and often forms stable landform. Tends to be less fertile and can be more derought-prone unless there are deep soils that hold moisture on top of the rocks (eg from volcanic ash). Ar Argillite Fine-grained mudstone. Fertile. Erodible. Droughty. Cg Conglomerate or breccia Gravels or sharp stones amongst finer materials in a sedimentary rock layer Si Indurated sandstone A very hard rock made of sand. Typically not very fertile and typically quite stable. Li Limestone Limestone. There are a wide range of sorts of limestones, from hard to soft limestones, shelly, and sandy to muddy limestones. Many limestones are amazing aquifers but not all. Gw Greywacke association of rocks Hard old sandstone and argillite rocks from the formation of Aotearoa, often found in the axial ranges/maunga e.g. Alps, Tararua, Ruahine, Kaweka etc Sx Semi-schist Rock where the chemicals have started to align under pressure to become like schist Gs Gneiss Highly altered metamorphic rock. Only found in places like Fiordland Sy Schist Greywacke changed by burial and pressure. Metamorphic rock. Ma Marble Hard limestone I Perrenial ice and snow Perrenial ice and snow
-
-
ShareYour PDF is processing
Your PDF will download to this device shortly. It can take up to a minute on a slow connection. Please do not close your browser.