geological maps

A geological map provides a graphic representation of selected geological features within a desired surface topographic or subsurface area. The size and relative position of each feature on the map corresponds to its correct geographic situation according to an established scale and projection. Mapped features included in the map key include geologic units, stratigraphic contour lines, fault lines, strike and dip lines, and other symbols. Information can be extrapolated from surface mapping in order to postulate the distribution of geological features in the subsurface. Resulting hypothetical structural models can provide the basis for exploring the landmass in search of its resources.

Commonly, geological features cannot be measured continuously over large areas, so other forms of evidence are employed to infer the delineation of large or hidden features. Surface geological features may be traceable in bedrock outcroppings (ground surveys), from air photographs (photogeological reconnaissance) and/or from satellite images. Subsurface geological features may be traceable in boreholes using cores, cuttings and/or geophysical logs. Geophysical surveys (measuring the magnetic, gravitational, or seismic properties) provide information that helps delineate geological features in the subsurface.

A Geographic Information System (GIS) is an efficient way to manage, analyse and display spatial data. Data from a variety of different sources can be rapidly computer-overlaid for viewing and analysis.

[links: images: LANDSAT image gallery, Geology - Oman; Seafloor Mapping, Bahia, Brazil; websites: Geological Map of Canada : Structural Geology (animations) : Geologic Maps from USGS National Park Service : Geological Maps, UWisc : USGS National Geologic Map Database : USGS Geology in the Parks : Animations : Plate Tectonics : Rocks & Minerals : Geologic Time : Glossary : Geomorphic Provinces : Sand Dunes : Caves : Glaciers : Coasts : NPS Park Geology Tour home]

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Geological terms, as applied to paleogeology, paleontology, and evolution.

Geological Terms: Alphabetic Sections
▪ A ▪ B ▪ C ▪ D ▪ E ▪ F ▪ G ▪ H ▪ I ▪ J ▪ K ▪ L ▪ M ▪ N ▪ O ▪ P ▪ Q ▪ R ▪ S ▪ T ▪ U ▪ V ▪ W ▪ X ▪ Y ▪ Z ▪ animations ▪ diagrams ▪ tables

Rocks & Minerals: ◙ Alphabetic Sections ◙ ◊ A ◊ B ◊ C ◊ D ◊ E ◊ F ◊ G ◊ H ◊ I ◊ J ◊ K ◊ L ◊ M ◊ N ◊ O ◊ P ◊ Q ◊ R ◊ S ◊ T ◊ U ◊ V ◊ W ◊ X ◊ Y ◊ Z ◊ elements of periodic table ◊◊◊ Mineral Index ◙◙ Rock Index: alphabetic ◙◙ Rock Index: Igneous Rocks ◙◙ Rock Index: Metamorphic Rocks ◙◙ Rock Index: Sedimentary Rocks ◙◙

Landmasses:
Ancient continents ▪ Baltica
Cratons ▪ Laurentian Craton
Supercontinents ▪ Gondwana ▪ Rodinia

Geological Time:
Late Precambrian-early Cambrian ▪ Gondwana ▪ Laurentia
Late Proterozoic ▪ Baltica
Neoproterozoic ▪ Rodinia

Geological structures ▪ accretionary prism/wedge ▪ akmoliths ▪ allochthonous nappe ▪ anticline ▪ antiformal stacks ▪ autochthonous ▪ back-arc basin ▪ batholith ▪ boudin ▪ bysmalith ▪ cactoliths ▪ chonoliths ▪ concordant ▪ conformable ▪ cratons ▪ décollement folds ▪ diapir ▪ diatreme ▪ dike ▪ discordant ▪ ductoliths ▪ duplex ▪ enclaves ▪ en echelon ▪ ethmoliths ▪ fault attributes (heave, throw, slip ; normal, reverse, strike-slip) ▪ faulting ▪ forearc basin ▪ harpoliths ▪ horse ▪ hypabassal ▪ klippes ▪ laccoliths ▪ lopoliths ▪ mélange ▪ monocline ▪ nappe (allocthonous) ▪ olistostrome ▪ overturned fold ▪ phacoliths ▪ platforms ▪ pluton ▪ recumbent fold ▪ shear zones ▪ shields ▪ sills ▪ slump ▪ sphenoliths ▪ stocks ▪ strata ▪ syncline ▪ thrust fault ▪ Toreva block (listric fault, slumping) ▪ unconformity ▪ volcano ▪ vein ▪ window ▪

Structural geology: ▪ allochthonous, autochthonous : attitude of fold structures: ▪ axial plane ▪ deformation ▪ dip ▪ dip direction ▪ en echelon ▪ fault attributes ▪ faulting (duplex) ▪ fold anatomy ▪ fold axis ▪ fold limb ▪ fold hinge ▪ fold nose ▪ folding ▪ geological maps ▪ horst & graben ▪ klippes ▪ listric fault ▪ mapping ▪ nappe ▪ normal fault ▪ plunge ▪ plunge direction ▪ reverse fault ▪ shear zones ▪ slump ▪ strike ▪ strike-slip fault ▪ thrust fault ▪ transform fault ▪ window (thrust) ▪ wrench fault

Geological phenomena ▪ assimiliation ▪ cryoseism ▪ deformation ▪ exchange of volatiles ▪ faulting ▪ fold anatomy ▪ folding ▪ fractional crystallization ▪ frost quake ▪ magmatic differentiation ▪ magmatic mixing ▪ shear zones ▪ unconformity ▪ slumping ▪ volcanism ▪

Rocks/Rock Formations: ◙◙ Rock Index: alphabetical ◙◙ Rock Index: Igneous Rocks ◙◙ Rock Index: Metamorphic Rocks ◙◙ Rock Index: Sedimentary Rocks ◙ amphibolites ◙ aplites ▪ aplite dike ▪ argillaceous ▪ basalt ▪ breccia ▪ Bowen's Reaction Series ◙ cement ◙ clast ▪ cumulates ▪ enclaves ◙ gneisses ▪ granite ◙ granodiorite ▪ greenstone belts ◙ groundmass ◘ hornfels ▪ hypabassal ▪ ophiolites ◙ pegmatites ▪ pegmatite dike ▪ peridotite ▪ plutonic ▪ porphyry ◙ schists ▪ schlieren ▪ texture ▪ xenoliths ▪

Minerals/Crystals: ◊◊◊ Mineral Index ▪ argillic, argillaceous ▪ overgrowth ◊ paleoblasts ▪ phenocryst ◊ porphyroblasts ◊ porphyroclasts ◊ xenocrysts ◊

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