Title: gg-dstng
1First-order Plan of Appalachian Orogen (Hibbard
and Waldron, 2009)
- Appalachians orogen
- Fossil regimes complementary
- Exposed accreted terranes
- Cryptic terrane suturing
- Laurentian-Paleozoic transition
- Upper mantle modification
- GeoPrisms focus site
Iapetus
Grenville
Peri-Gondwanan
Alleghanian
Taconic/Acadian
lt
Atlantic
mod from Hatcher (2002)
USGS Circ. 1264 (2004)
2S. Appalachians Suturing and Upper Mantle
Modification (Wannamaker, 2005, Surv. Geop.)
MT can Clarify continental assembly through
suture zone mapping Assess mantle modification
by purging of volatiles, ICEs Augment active
tectonic models through their fossil aftermath
3Geomagnetic Induction Arrows, 3867 s
Geomagnetic Induction Sites (Mareschal et al.,
1983)
Luque et al. (AJS, 1998) Fluid remobilized
graphite
Deep Crustal Conductivity In Fossil
Regimes Graphite, Sulphide Fluid Remobilization,
Shearing
Jones et al. (JGG,1997) Sulphide Stringers
4Northern Appalachians regional conductor,
stronger than in South (Greenhouse and Bailey,
1981)
Depression of Appalachian coast
response indicates compensating interior conductor
Geomagnetic induction arrows corrected for coast
effect
Broadscale 2D forward models suggest main
conductivity lies in lower crust, but hard to
resolve from GMV alone
Seismicity avoids conductor
5Fischer et al. (2010)
- Mantle receiver functions often imply sharp LAB
along eastern seaboard - Can conductivity confirm based on hydration or
melting?