Magmatic contrasts in the Winnipesaukee region, New Hampshire

Abstract

Research Article| April 01, 1944 Magmatic contrasts in the Winnipesaukee region, New Hampshire ALONZO QUINN ALONZO QUINN Search for other works by this author on: GSW Google Scholar Author and Article Information ALONZO QUINN Publisher: Geological Society of America Received: 23 Feb 1943 First Online: 02 Mar 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 1944 Geological Society of America GSA Bulletin (1944) 55 (4): 473–496. https://doi.org/10.1130/GSAB-55-473 Article history Received: 23 Feb 1943 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 ALONZO QUINN; Magmatic contrasts in the Winnipesaukee region, New Hampshire. GSA Bulletin 1944;; 55 (4): 473–496. doi: https://doi.org/10.1130/GSAB-55-473 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 In the Winnipesaukee area of central New Hampshire two groups of igneous rocks are strikingly different. The New Hampshire magma series is probably late Devonian, and the White Mountain magma series is probably Mississippian. The contrasting characteristics of these two magma series are tabulated.The New Hampshire magma series here consists of large partially concordant intrusions of Meredith porphyritic granite and Winnipesaukee quartz diorite and small intrusions of hornblende gabbro and Concord granite. Conclusive evidence of the origin of this series is lacking, but some evidence indicates that it has been derived by melting of sial.The White Mountain magma series includes a great variety of extrusive and intrusive rocks in the Ossipee Mountains, the Belknap Mountains, and Red Hill. Cauldron subsidence is an important method of intrusion. The order of intrusion, from oldest to youngest, is generally gabbro, diorite, monzodiorite, syenite, quartz syenite, granite. Calculations indicate the nature of the materials which could be subtracted or added, to cause the changes shown by this sequence. These calculations suggest that neither subtraction, in the form of crystal fractionation, nor addition, in the form of assimilation or pure melting, is the sole explanation, but that both played a part. Crystal fractionation probably dominated up to the stage of syenite, and assimilation probably assumed increased importance in the change from syenite to granite. 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.