Structural Measurement Atlas
Atlas / States / Maine

Maine strike and dip data

26,897 structural measurements in Maine, digitized from 137 published geologic maps across 5 sources. Every row carries its azimuth, inclination, measurement type, location confidence and the citation of the map it came from.

Open Maine on the map

What kinds of measurement

The Atlas separates planar structures, recorded as a strike and dip, from linear ones, recorded as a trend and plunge. This is what Maine holds:

Measurement typeGeometryMeasurementsShare
Foliation Planar — strike and dip 8,86133%
Bedding Planar — strike and dip 6,33424%
Other Planar — strike and dip 3,74414%
Joint Planar — strike and dip 2,73110%
Lineation (mineral, stretching) Linear — trend and plunge 2,0698%
Fold hinge / axis Linear — trend and plunge 1,2255%
Cleavage Planar — strike and dip 1,0544%
Vein / dike Planar — strike and dip 6973%
Fault plane Planar — strike and dip 180<1%
Slickenline Linear — trend and plunge 2<1%

Where the data comes from

Each source is a survey, agency or program whose published mapping was harvested and reconciled into one schema. Rows are published only where the source's terms permit redistribution.

SourceMeasurementsShare
USGS NGMDB GeMS 18,19068%
Maine Geol. Survey 6,78625%
NPS GRI parks 1,5206%
NGMDB legacy quads 3991%
USGS data releases · MRDS 2<1%

Most-measured published maps

The individual quadrangles and data releases contributing the most measurements in Maine. The full citation for every map behind a selection ships in the sources.csv of any export.

Published mapYearScaleMeasurements
Ludman, A., 2024, Bedrock geology of the Lincoln 1:100,000 quadrangle, Maine: Maine Geological Survey, Geologic Map 24-11, scale 1:100,000.2024 1:100,0001,700
Digitized points from H. Berry mylar; structure data from Osberg spreadsheet: Submitted to MGS 2003-07-082020 1:24,0001,618
Field Work, June 1963 - September 1993: Submitted to MGS 2022-03-162022 1:24,0001,479
Arthur M. Hussey II, Bowdoin College emeritus, original data 1:24,0001,386
Stephen G. Pollock, University of Southern Maine, 2004 original data2004 1:24,0001,378
Field work: Submitted to MGS 2003-07-282020 1:24,0001,051
David P. West, Jr., Middlebury College, 2022, original data2023 1:24,0001,011
Field Work by Arthur M. Hussey, II: Submitted to MGS 2022-02-242022 1:24,000994
Stephen G. Pollock, original data, collected 20102010 1:24,000727
Locations digitized off georeferenced 24k topo basemaps.: Submitted to MGS 2021-12-062022 1:24,000641
Field Work; Locations digitized off georeferenced 24k topo basemaps.: Submitted to MGS 2021-12-082022 1:24,000610
Sidle, William C., 1991, Reconnaissance bedrock geology of the Waldoboro Pluton Complex and other intrusive rocks in coastal Lincoln and Knox Counties, Maine: Maine Geological Survey, Open-File Report 91-3, 11 p., 2 maps, scale 1:24,000.2024 1:24,000569
adapted from: Gilman, Richard A., and Chapman, Carleton A., 1988, Bedrock Geology of Mount Desert Island, in The Geology of Mount Desert Island: Maine Geological Survey, Bulletin B-38, scale 1:50,0002025 50000461
David P. West, Jr., Middlebury College, 2021, original data2022 1:24,000445
Christopher Koteas, Norwich University, 2020-2021, original field work2022 1:24,000403

Most-measured map units

Where a source recorded the geologic unit a measurement was taken on, the Atlas keeps it. These are the units carrying the most measurements in Maine.

Map unitAgeLithologyMeasurements
Cape Elizabeth Formation of the Casco Bay Group Oce OrdovicianSchist and gneiss, of sedimentary-rock origin2,225
Bucksport Formation of the Kingsclear Group Sb Silurian(?)Schist and gneiss, of sedimentary-rock origin1,490
Megunticook Formation of the Cookson Group Cm CambrianSchist and gneiss, of sedimentary-rock origin1,071
Bucksport Formation Sb SilurianSchist and gneiss, of sedimentary-rock origin634
Penobscot Formation of the Cookson Group OCp Ordovician-CambrianSchist and gneiss, of sedimentary-rock origin458
Benner Hill Formation of the Benner Hill Sequence Obh OrdovicianSchist and gneiss, of sedimentary-rock origin441
Smyrna Mills Formation Ssm SilurianSlate and phyllite, of sedimentary-rock origin370
Carys Mills Formation SOcm Silurian-OrdovicianMostly carbonate rock296
Amphibolite of the Cape Elizabeth Formation of the Casco Bay Group Ocea OrdovicianMedium and high-grade regional metamorphic rock, of unspecified origin290
Vassalboro Group, undifferentiated SOvu Silurian-OrdovicianSchist and gneiss, of sedimentary-rock origin289
Cross River Formation OCcr Ordovician-Cambrian(?)Medium and high-grade regional metamorphic rock, of unspecified origin275
Patch Mountain Member of the Sangerville Formation Ssp SilurianMeta-carbonate rock236

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