Item talk:Q271429

{

 "USGS Publications Warehouse": {
   "@context": "https://schema.org",
   "@type": "Article",
   "additionalType": "Journal Article",
   "name": "40Ar/39Ar dating of Silurian and late Devonian cleavages in lower greenschist-facies rocks in the Westminster terrane, Maryland, USA",
   "identifier": [
     {
       "@type": "PropertyValue",
       "propertyID": "USGS Publications Warehouse IndexID",
       "value": "70207676",
       "url": "https://pubs.usgs.gov/publication/70207676"
     },
     {
       "@type": "PropertyValue",
       "propertyID": "USGS Publications Warehouse Internal ID",
       "value": 70207676
     },
     {
       "@type": "PropertyValue",
       "propertyID": "DOI",
       "value": "10.1130/B30030.1",
       "url": "https://doi.org/10.1130/B30030.1"
     }
   ],
   "journal": {
     "@type": "Periodical",
     "name": "GSA Bulletin",
     "volumeNumber": "122",
     "issueNumber": "5-6"
   },
   "inLanguage": "en",
   "isPartOf": [
     {
       "@type": "CreativeWorkSeries",
       "name": "GSA Bulletin"
     }
   ],
   "datePublished": "2010",
   "dateModified": "2020-01-03",
   "abstract": "40Ar/39Ar dating of muscovite, biotite, and K-feldspar combined with microstructural analysis of lower greenschist-facies, polymetamorphic, phyllitic rocks, and marbles were successfully used to decipher the thermal and tectonic histories of the Westminster and adjacent terranes in western Maryland. The presence of unreset detrital muscovite in some samples demonstrates that temperatures in these rocks never exceeded the closure temperature for argon diffusion in muscovite, \u223c350 \u00b1 50 \u00b0C. Minor biotite in some arkoses constrains the minimum metamorphic temperatures to \u2265\u223c320 \u00b0C. These data show an Early Silurian (ca. 430 Ma) cleavage in the western part of the Westminster terrane and a Late Devonian event (ca. 370 Ma) in the eastern Westminster and adjacent Potomac terranes. These two cleavage domains are separated by the NE-trending, newly identified Parrs Ridge fault zone. We propose that the sinistral transpressive collision of the Carolina terrane with Laurentia emplaced the western portion of the Westminster terrane in the Pennsylvania embayment along the Martic fault where it was folded and cleaved at ca. 430 Ma but otherwise largely sheltered from later deformation. The later Late Devonian dextral transpressive accretion of the outboard Potomac terrane thrust rocks of the eastern Westminster and Potomac terranes to the west, causing Late Devonian (360\u2013370 Ma) S2\u00a0cleavage in these rocks, but only minimal discrete overprinting S3\u00a0cleavages in rocks farther west. Final juxtaposition and thermal convergence of these terranes occurred along reactivated dextral strike-slip faults in the Alleghanian at ca. 300 Ma.",
   "description": "20 p.",
   "publisher": {
     "@type": "Organization",
     "name": "GSA"
   },
   "author": [
     {
       "@type": "Person",
       "name": "Wintsch, R. P.",
       "givenName": "R. P.",
       "familyName": "Wintsch"
     },
     {
       "@type": "Person",
       "name": "Kunk, Michael J. mkunk@usgs.gov",
       "givenName": "Michael J.",
       "familyName": "Kunk",
       "email": "mkunk@usgs.gov",
       "identifier": {
         "@type": "PropertyValue",
         "propertyID": "ORCID",
         "value": "0000-0003-4424-7825",
         "url": "https://orcid.org/0000-0003-4424-7825"
       },
       "affiliation": [
         {
           "@type": "Organization",
           "name": "Florence Bascom Geoscience Center",
           "url": "https://www.usgs.gov/centers/florence-bascom-geoscience-center"
         },
         {
           "@type": "Organization",
           "name": "Eastern Geology and Paleoclimate Science Center",
           "url": "https://www.usgs.gov/centers/florence-bascom-geoscience-center"
         }
       ]
     },
     {
       "@type": "Person",
       "name": "Mulvey, Brian",
       "givenName": "Brian",
       "familyName": "Mulvey"
     },
     {
       "@type": "Person",
       "name": "Southworth, C. Scott ssouthwo@usgs.gov",
       "givenName": "C. Scott",
       "familyName": "Southworth",
       "email": "ssouthwo@usgs.gov",
       "identifier": {
         "@type": "PropertyValue",
         "propertyID": "ORCID",
         "value": "0000-0002-7976-7807",
         "url": "https://orcid.org/0000-0002-7976-7807"
       },
       "affiliation": [
         {
           "@type": "Organization",
           "name": "Florence Bascom Geoscience Center",
           "url": "https://www.usgs.gov/centers/florence-bascom-geoscience-center"
         },
         {
           "@type": "Organization",
           "name": "Eastern Geology and Paleoclimate Science Center",
           "url": "https://www.usgs.gov/centers/florence-bascom-geoscience-center"
         }
       ]
     }
   ],
   "funder": [
     {
       "@type": "Organization",
       "name": "Eastern Geology and Paleoclimate Science Center",
       "url": "https://www.usgs.gov/centers/florence-bascom-geoscience-center"
     }
   ],
   "spatialCoverage": [
     {
       "@type": "Place",
       "additionalType": "country",
       "name": "United States",
       "url": "https://geonames.org/4074035"
     },
     {
       "@type": "Place",
       "additionalType": "state",
       "name": "Maryland"
     },
     {
       "@type": "Place",
       "additionalType": "unknown",
       "name": "Westminster terrane"
     },
     {
       "@type": "Place",
       "geo": [
         {
           "@type": "GeoShape",
           "additionalProperty": {
             "@type": "PropertyValue",
             "name": "GeoJSON",
             "value": {
               "type": "FeatureCollection",
               "features": [
                 {
                   "type": "Feature",
                   "properties": {},
                   "geometry": {
                     "type": "Polygon",
                     "coordinates": [
                       [
                         [
                           -76.2451171875,
                           38.13455657705411
                         ],
                         [
                           -76.22314453125,
                           38.12591462924157
                         ],
                         [
                           -75.93200683593749,
                           39.48284540453334
                         ],
                         [
                           -76.57470703125,
                           39.58452390500424
                         ],
                         [
                           -77.0361328125,
                           38.86109762182888
                         ],
                         [
                           -76.2451171875,
                           38.13455657705411
                         ]
                       ]
                     ]
                   }
                 }
               ]
             }
           }
         },
         {
           "@type": "GeoCoordinates",
           "latitude": 38.95644174777863,
           "longitude": -76.43024492366774
         }
       ]
     }
   ]
 }

}