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Norsk versjon | ||||
| THE NATURAL STONE DATABASE | |||||
| Deposit Area 1648 - 602 | |||||
| (Last updated 08.sep.2021) | |||||
Name of Deposit Area : Follstad |
| (Object Id : 1648,602,00,00) |
| Location |
| County : | Sør-Trøndelag (16) | Municipality : | Midtre Gauldal (1648) |
| Map 1:50000: | Støren (1621-3) | Map 1:250000: | Trondheim |
| Marking point: | Longitude: | 10.3212540 | Latitude: | 63.0311780 |
| EU89-UTM Zone 32 | (Coordinates IS confirmed) |
| X-coord: | 566850 m. | Y-coord: | 6989749 m. |
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| Commodity |
| Main Type: | Granite and other igneous rocks | Sub Type: | Trondhjemite | |
| Brickstone(Y/N): | N |
| Production |
| Activity: | Stone quarrying | Reserves: | ||
| Prod. method: | Open pit mining | Production: | ||
| Prod. status: | Active | Volume of dump: |
| Importance |
| Public: | National Importance (reg. 28.05.2017) |
| Economical: | Very significant , (Confirmed 04.jul.2001 by Tom Heldal) |
| Historical: | No , (Confirmed 04.jul.2001 by Tom Heldal) |
Products |
| Commercial Name | Product description |
| Støren | Classification :Massive blocks | Colour :White | |
| Play of colours : | Uniformity :Medium good | ||
| Lithology :Trondhjemite | Grain size :Fine - medium grained (<1mm - 3 mm) |
Mineralogy: |
| Quartz | Major mineral (>10%) | ||
| Plagioclase | Major mineral (>10%) | ||
| Epidote | Subordinate mineral (1-10%) | ||
| Potassic feldspar | Subordinate mineral (1-10%) | ||
| Muscovite | Subordinate mineral (1-10%) | ||
| Biotite | Subordinate mineral (1-10%) | ||
| Titanite | Accessory mineral (<1%) | ||
| Zircon | Accessory mineral (<1%) | ||
| Chlorite | Accessory mineral (<1%) | ||
| Calcite | Accessory mineral (<1%) | ||
| Apatite | Accessory mineral (<1%) | ||
| Magnetite | Accessory mineral (<1%) |
Test of Physical Properties: |
| Type of test | Standard | Test value | ||
| Specific gravity | DIN 52102 | 27,24 g/cm3 | ||
| Compressive strength | DIN 52105 | 230 N/mm2 | ||
| Bending strength | DIN 52112 | 14,5 N/mm2 | ||
| Water absorption (weight %) | DIN 52103 | ,34 % | ||
| Wearing coefficient | ASTM C241-85 | 2,2 mm | ||
| Thermal expansion coeffisient | NBE-89 | 6 10/ C |
|
Operations |
| From - To | Activity | Comments | |
| 1890 | Regular production | Antatt drevet av jernbanen fra siste del av 1800-tallet. | |
| 1956 - 1958 | Regular production | Company/Institution :AS Norsk Labrador | |
| 1974 - 1979 | Regular production | Company/Institution :AS Norsk Labrador | |
| 1979 | Regular production | Company/Institution :bl.a. Trøndergranitt AS | |
| Drevet av flere firma i perioden, de siste årene under navnet Trøndergranitt AS. 2010: 3 mann arbeider full tid i bruddet. Årlig uttak: 5-600 m3. | |||
| 2011 | Regular production | Company/Institution :Trøndergranitt AS / Norblock AS | |
| Trøndergranitt AS ble en del av Norblock-gruppen. |
Deposit rock |
| Lithology: | Trondhjemite | Weathering colour: | Yellow/brown staining | |
| Era: | Paleozoic | Period: | Silurian | |
| Dating: | 432 (-3\+3) million year | Method: | U/Pb | |
| Genesis: | Magmatic | Form: | Dyke | |
| Main texture: | Structureless |
| Main grain size: | Fine - medium grained (<1mm - 3 mm) | Main alteration: | Epidotisation |
| Strike/Dip: | 200 / 68 | Direction: | ||
| Plunge: |
| Stratigraphic classification of host rock |
| Era: | Paleozoic | Period: | Silurian |
| Province: | Caledonides | |
| Geotec.unit: | Trondheim Nappe Complex | |
| Tectonic complex: | Størendekket | |
| Igneous complex: |
| Group: | Formation: |
Structures |
| Location: | Type: | Orientation(360 gr.): | Relation to min.: | |
| Not defined | Joints/Fractures | Strike/Dip :190 / 45 |
Information(s) in free text format |
| Description |
| Forekomsten har vært drevet mer eller mindre kontinuerlig siden jernbanedriften for rundt 100 år siden. I dag drives bruddet av Trøndergranitt AS med to mann. Bergarten er en hvit tonalitt, som også kalles trondhjemitt. Forekomsten har form av en steiltstående gang, rundt 375 meter mektig, hvorav rundt 80 meter drives. Den fortsetter under dyrket mark i nordlig retning, ovenfor bruddet. Driften har foregått fra dalbunnen og oppover åssiden, frem til dyrket mark. Mye av de nedre delene av bruddområdet er nedskrotet og vanskelig å kvalitetsvurdere. Driften i dag foregår oppe i åssiden. I dette finnes det godt rom for fremtidig drift i nordlig retning. Blokkstørrelsen er normalt i gjennomsnitt mindre enn det som kreves for eksportformål. Dette skyldes steile sprekker, terrengparallelle sprekker og spenninger i fjellet. Det er mulig dette bildet kan forbedres ved dypere drift og inndrift mot nord. Centimetertykke, sorte (biotittrike) bånd som er orientert parallelt med trondhjemittgangen opptrer i deler av forekomsten. På polerte plater har disse karakter av en diffus stripning. Forekomsten må regnes som viktig i nasjonal sammenheng; bergarten pryder en rekke bygninger og uteanlegg rundt om i landet. I forekomsten finnes tilstrekkelige reserver for lang tids småskala drift. |
| Examples |
| Trondhjemitten fra Støren brukes til monumenter, gulvflis, fasadeplater, kantstein/brostein og massive steinarbeider. I likhet med andre trondhjemitter og lyse granitter kan gul misfarging ved utsatt bruk (eks. tynne, bakstøpte fasadeplater) forekomme ved utluting av jern fra biotitt. Det er særlig når fukt står i steinen over lang tid at slik misfarging skjer. For øvrig regnes Støren trondhjemitten som holdbar og egnet til alle formål. Brukseksempler: * Scandinavium, Stockholm (gulvflis) * NRK, Oslo (fasadeplater) * Konserthuset, Oslo (fasadeplater) * Norges Banks nybygg, Oslo (gulv og trapper) * Grand Hotell (tilbygg), Oslo (fasadeplater) * Cecil Hotell, Oslo (gulvflis) * Fellesbanken, (Karl Johans gt.) Oslo (fasadeplater) * Hovedpostkontoret, Bergen (fasadeplater, innvendig gulvflis og veggplater) * Vetrlidsalmenningen, Bergen (kantstein, brostein) * Tinghuset, Trondheim (fasadeplater) * Gjensidige NOR Forsikrings nybygg, Trondheim (fasadeplater) * Trondheim Torg, (?) * Electrosenteret, Stavanger (fasadeplater) |
| Location |
| Forekomsten ligger ved Follstad, ca. 3 km nordøst for Støren.Bruddet er lett tilgjengelig. |
| Photo(s) from the Deposit area: |
|
Bibliography: |
| From NGU's Reference Archive: |
| Size, William B. , 1979 |
| Petrology, geochemistry and genesis of the type area trondhjemite in the Trondheim Region, Central Norwegian Caledonides. |
| ;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU; No.351;51-76 pages |
| Abstract: | |
| Trondhjemite from the Follstad district of the Trondheim region is present within allochthonous Lower Paleozoic eugenosynclinal and partly miogeosynclinal rocks of the Caledonide orogen. Four periods of trondhjemite intrusive activity have been recognized, with the main Follstad trondhjemite a product of late tectonism and metamorphism in the upper greenschist facies. Field relations, mineralogy and major and trace element abundances all attest to the high degree of homogeneity of the trondhjemite, which is of the high-Al203 type (average 16.2 %). Trondhjemites of the district average 71.5% SiO2, 5.3% Na2O3, but only 1.3%K2O. The REE abundances are depleted and highly fractionated. Barium greatly exceeds rubidium in abundance. Distinctive compositional characteristics of the Follstad trondhjemite support designation of the district as a type locality for trondhjemite. Petrogenetic models for the origin of the Follstad district trondhjemite that are based on anatexis of granitic crust or partial melting of greywacke are unlikely. Distinctive compositional gaps in the gabbro-trondhjemite suite, when compared with the other associated magmatic rocks in the Follstad district, cannot easily be explained by a fractional crystallization model. The petrogenetic model that best fits the data from the Follstad trondhjemite is based on equilibrium melting of a low-K2O tholeiitic basalt during anatexis in an orogenic zone. |
| Dunning, Greg ; Grenne, Tor , 2000 |
| U-Pb age dating and paleotectonic significance of trondhjemite from the type locality in the Central Norwegian Caledonides |
| ;Norges geologiske undersøkelse;TIDSSKRIFTARTIKKEL;NGU Bulletin; No.437;57-65 pages |
| Abstract: | |
| Zircon and titanite U-Pb data are reported from the trondhjemite type locality at Follstad, near Støren in Central Norway. A concordant fraction of aricular zircon and an overlapping fraction of titanite give an age of 432+- 3Ma for the intrusion of the pluton. Fractions of prismatic zircon display inheritance. The Follstad trondhjemite represents a suite of similar intrusions occurring in metasedimentary and metavolcanic rocks of the Upper Allochthon in the Scandinavian Caledonides. Trondhjemite emplacement commonly with associated mafic magmatism, was broadly coeval with metamorphism and deformation during the climatic Caledonian (Scandian) orogenic event, immediately before rapid uplift and cooling in Late Silurian and Early Devonian times. A possible scenario for the formation of the Follstad and equivalent trondhjemites is that of partial melting of crustal rocks at garnet-amphibolite grade, facilitated by the emplacement of rift-related, mantle-derived mafic intrusions. The latter could have formed, in Early Silurian time, in a paleotectonic setting characterised by the development of extensional segments within a predominantly transpressional regime, due to highly oblique collision between the convergin margins of Baltica and Laurentia. |
Fieldsamples |
| Sample No. | Sample type | Miscellanrous | |||
| 24005 | Block |
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| 24055 | Block |
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| 24150 | Block |
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| The fact sheet was created on 20.03.2023 |
| Questions or comments regarding the fact sheet can be emailed to: ressursdatabaser@ngu.no |
| Copyright © 2023 Geological Survey of Norway |