link to project
Penn State Abington College
J. Alcock Professor of Environmental SciencesCollege of Earth and Mineral Sciences Division of Science and Engineering Abington College
Virtual Geology of Wissahickon Creek, Fairmount Park:
Teaching and learning are active processes. Because the majority of my students are not science majors, I have the opportunity to create courses that stress methods of thinking and investigation through a combination of lecture, field trips, and laboratory activities. I want to challenge students to change their world view as they master new skills that increase their power as thinkers and questioners.
Telephone: (215) 881-7356
Fax: (215) 881-7623
I have also become interested in the use of systems and graphical analysis to predict the behavior of Earth Systems. A recent paper in the on-line journal Earth Interactions (http://www.earthinteractions.org/) looks at feedback and its potential to cause catastrophic environmental change in the Amazon Basin in response to deforestation.
Alcock, J., and Wagner, M. E., 1995, Metamorphic discontinuities in the Pennsylvania-Delaware Piedmont: evidence for early Paleozoic assembly, Canadian Journal of Earth Science, v. 32, p. 686-698.
Alcock, J., 1996, Effect of grossular on garnet-biotite Fe-Mg exchange, evidence from natural garnet with mixed growth and diffusion zoning, Contributions to Mineralogy and Petrology, v. 124, p. 209-215.
Alcock, J. and Muller, P. D. 1999a, Very high temperature, moderate pressure metamorphism in the New Russia gneiss complex, northeastern Adirondack Highlands, metamorphic aureole of the Marcy anorthosite. Canadian Journal of Earth Science, v. 36, p. 1-13.
Alcock, J., Myer, K., and Muller, P. D. 1999b, Three-dimensional model of heat flow in the aureole of the Marcy anorthosite, Adirondack Highlands, New York: Implications for depth of emplacement. Geological Materials Research, v.1, n. 4, p. 1-27 .
Alcock, J. and Muller, Peter, 2000, Anatexis at 700 to 1000 MPa in the aureole of the Marcy anorthosite, Adirondack Highlands, New York. Contributions to Mineralogy and Petrology, v.139, p. 643-654.
Alcock, J., Isachsen, C., Livi, K., and Muller, P., 2004,
Unraveling complex growth histories of zircon in anatectites,
constraints on model PTt paths for the NE Adirondack Highlands, NY. in
Tollo, R.P., Corriveau, L., McLelland, J. , and. Bartholomew, M.J.,
eds., Proterozoic Tectonic Evolution of the Grenville Orogen in North
America, Boulder, CO, Geological Society of America Memoir 197, p.
Alcock, J; Arenas, R; Martinez Catalan, J R, 2005, Shear
stress in subducting continental margin from high-pressure,
moderate-temperature metamorphism in the Ordenes Complex, Galicia, NW
Spain. Tectonophysics, V. 397, p. 181-194.
Alcock J, 2005, An algorithm for computation of the steady-state
thermal structure of mature subduction zones,
Computers & Geosciences, V. 31,
Alcock, J. and Muller, P., 1996, Very high-temperature, moderate to high-pressure metamorphism, eastern Adirondack Highlands: Evidence for deep emplacement of massif anorthosite. Geological Society of America, Abstracts with Programs, Northeastern Section, Vol. 28, No. 1, p. (Buffalo, NY.)
Muller, P. and Alcock, J., 1996, Contrasting absolute and relative ages, Adirondack Highlands, northeastern U. S., does the granulite uncertainty principle extend to U-Pb metamorphic ages? Presented at the 12th International Conference on Basement Tectonics. (Goosebay, Labrador).
Alcock, J. and Muller, P., 1998, The Marcy anorthosite emplaced at a depth of 30 km, geobarometric evidence from its aureole, NE Adirondack Highlands, NY. Geological Society of America, Abstracts with Programs, Vol. 30, No. 7, p. 229 (Toronto, Ont).
Alcock, J., Isachsen, C., Livi, K., and Muller, P., 2000,
High-resolution thermal history for migmatites from integrated electron
microbeam, cathode luminescence, and isotopic dilution analyses.
15th International Conference on Basement Tectonics, Programs and
Abstracts, p. 35 (A Coruña, Spain).
Alcock, J., Isachsen, C., and Muller, P., 2001, Conditions and timing of emplacement of the Marcy anorthosite, NE Adirondack Highlands, inferred from anatectites in its aureole: Part 1, Field relationships and P-T estimates. Geological Society of America, Abstracts with Programs, Vol. 33, No. 6, p. 292 (Boston, MA).
Alcock, J., 2001, Stable and unstable states in a system
controlled by positive feedback, implications for the tropical
rainforest ecosystem. GSA-GSL Earth System Processes Meeting,
Alcock, J., 2002, Multiple steady states created by positive feedback and their effects on system response to perturbation. Geological Society of America, Abstracts with Programs, Vol. 34, No. 6, p. 241 (Denver, CO).
Alcock, J. 2003, Milankovitch cycles, positive feedback and
system switching between stable states, a model for glacial –
interglacial repetitions. Geological Society of America, Abstracts with
Programs, Vol. 34, No. 7, p. 481 (Seattle, WA).
Alcock, J., Arenas, R., and Martínez Catalán, J.R.,
2004, Shear stress and negative feedback in subducting continental
margin, impact on high-pressure, moderate-temperature metamorphism, in
the Ordenes Complex, Galicia, NW Spain. Northeastern Section,
Geological Society of America, Tysons Corner, VA.
Alcock, J; Muller, Peter D; Haugh, Joshua, 2005, Contact metamorphism in pelitic gneiss adjacent to Wolf Creek ultramafic body, Ruby Range, SW Montana, evidence for hot emplacement Geological Society of America, Abstracts with Programs, vol.37, no.6, p. 42, Apr 2005.