DescrizioneNorth america and scandinavia basement rocks.png
North Americancratons and basement rocks. As radiometric ages were determined for the shield-like rocks on the continents which were either exposed at the surface, underlay the flat rocks, or were within the interior of the mountain belts, patterns of age intervals were determined. These old rocks have been called the "basement". This has been interpreted to mean that the continents had somehow grown by development of rock assemblages with these characteristic age parameters. The expanding continental nuclei are part of the "craton" which consist of both exposed and buried basement rocks.
Questa è una immagine ritoccata, il che significa che è stata modificata digitalmente dalla sua versione originale. Modifiche: Change of colours to match some geological map colour templates. La versione originale può essere vista qui: North america basement rocks.png. Le modifiche sono di Bjoertvedt.
di condividere – di copiare, distribuire e trasmettere quest'opera
di modificare – di adattare l'opera
Alle seguenti condizioni:
attribuzione – Devi fornire i crediti appropriati, un collegamento alla licenza e indicare se sono state apportate modifiche. Puoi farlo in qualsiasi modo ragionevole, ma non in alcun modo che suggerisca che il licenziante approvi te o il tuo uso.
condividi allo stesso modo – Se remixi, trasformi o sviluppi il materiale, devi distribuire i tuoi contributi in base alla stessa licenza o compatibile all'originale.
2005-09-16T15:47:59Z Saperaud 484x429 (13371 Bytes) [[North America]]n [[craton]]s and basement rocks. As radiometric ages were determined for the shield-like rocks on the continents which were either exposed at the surface, underlay the flat rocks, or were within the interio
{{Information |Description=North Americancratons and basement rocks. As radiometric ages were determined for the shield-like rocks on the continents which were either exposed at the surface, underlay the flat rocks, or were within the interior o