U. Mass Lowell Prof. Nelson Eby Department of Environmental, Earth, & Atmospheric Sciences




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Ossipee Ring Complex, New Hampshire (NEIGC 2004)

NEIGC field trip A-5, October 8, 2004, investigated the geology of the Ossipee ring complex, central New Hampshire. The Ossipee complex is a member of the Younger White Mountain Igneous Province and has an age of ca 121 Ma. The geologic map is shown to the right. The field trip visited outcrops of the various ring-dike facies, basalt outcrops showing evidence of magma mixing and mingling, rhyolite outcrops rich in enclaves and also showing features of magma mingling and mixing, and the coarse-grained "Conway" granite that forms the central portion of the complex. A stop was also made peripheral to the complex to investigate the country rocks. The images below show some of the field trip stops and the field trip participants. The field trip guide (Ossipee NEIGC) is available as a pdf file.

Ossipee 1.jpg (47419 bytes) Ossipee 2.jpg (48671 bytes) Ossipee 3.jpg (35661 bytes) Ossipee 4.jpg (37126 bytes)
Stop 1. Mafic enclaves in the fine- to medium-grained granite facies of the ring dike. Stop 2. Mafic dike cutting pegmatite and tonalite.  Close-up of mafic dike.
Ossipee 11.jpg (29838 bytes) Ossipee 12.jpg (27210 bytes) Ossipee 13.jpg (38192 bytes) Ossipee 14.jpg (42764 bytes)
Field trip participants scrutinizing the Stop 2 outcrops. Stop 2. Outcrops above bridge crossing Coldbrook Outcrops just below bridge crossing Coldbrook.
Ossipee 15.jpg (47625 bytes) Ossipee 16.jpg (41053 bytes) Ossipee 5.jpg (34456 bytes) Ossipee 6.jpg (42196 bytes)
Outcrop in Coldbrook. Examining outcrop in Coldbook. Margin of Ossipee complex inroute to Stop 5. Stop 5. Outcrop of rhyolite at the margin of the complex.
Ossipee 10.jpg (26794 bytes) Ossipee 7.jpg (48550 bytes) Ossipee 8.jpg (38006 bytes) Ossipee 9.jpg (50728 bytes)
View from Stop 5. Enclaves in rhyolite at Stop 5.
Ossipee 17.jpg (53614 bytes) Ossipee 18.jpg (48327 bytes)    
Field trip participants at Stop 5.    

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