Petrology and structure of the Franconia quadrangle, New Hampshire

Research Article| July 01, 1938 Petrology and structure of the Franconia quadrangle, New Hampshire CHARLES R. WILLIAMS; CHARLES R. WILLIAMS Search for other works by this author on: GSW Google Scholar MARLAND P. BILLINGS MARLAND P. BILLINGS Search for other works by this author on: GSW Google Scholar Author and Article Information CHARLES R. WILLIAMS MARLAND P. BILLINGS Publisher: Geological Society of America Received: 18 Feb 1938 First Online: 02 Mar 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 1938 Geological Society of America GSA Bulletin (1938) 49 (7): 1011–1044. https://doi.org/10.1130/GSAB-49-1011 Article history Received: 18 Feb 1938 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation CHARLES R. WILLIAMS, MARLAND P. BILLINGS; Petrology and structure of the Franconia quadrangle, New Hampshire. GSA Bulletin 1938;; 49 (7): 1011–1044. doi: https://doi.org/10.1130/GSAB-49-1011 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Franconia quadrangle of New Hampshire supplements the geology of the Littleton and Moosilauke quadrangles in such a way that a very representative picture of the geology of western and central New Hampshire may be obtained by a knowledge of these three quadrangles.Three groups of rocks occupy the Franconia quadrangle. The oldest group contains highly deformed metamorphic rocks of Ordovician (?) and Devonian age. The second group consists of plutonic rocks of the New Hampshire magma series. This is a subalkaline series, in part syntectonic, and is probably late Devonian. The chief dark mineral is biotite, and the rocks are more or less foliated. The third group is the White Mountain magma series, which is alkaline and probably Mississippian. Such minerals as hedenbergite, fayalite, hastingsite, fluorite, and allanite are characteristic, and biotite is subordinate. The rocks of this group are massive.The structure reflects the genetic differences of the three groups. The metamorphic rocks are thrown into closed, isoclinal folds which trend northeasterly. The New Hampshire magma series occurs as great sheets and lenses, which have forcefully injected the older metamorphic rocks. The White Mountain magma series is represented by both extrusive and intrusive members, the latter occurring in ring-dikes and stocks. The space occupied by the ring-dikes was attained by piece-meal stoping along essentially vertical arcuate fracture zones. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.