Page 340 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

for the
Province. Intersections of the
mehing
Basin
partial
of the
depth
the
323
where partial
the
beneath
base
150 km
(Fig. 2.7). Notice
gradients with
the
Flow
encountered
about
region suggest
45 km)
Heat
craton, 250 km
at
geothermal
lithosphere
Range
peridotite
and
(=
may be
depth
melt
Tectonics
and
(@dW) e@inssetd =
§
§
g
2
2
8 8 , 88
@
8
&
a) Granite Dry P/T Diagram 3 10.15 FIGURE Geothermal gradients a) from Table 10.3, superimposed phase on Temperature T= (°C) for dry granite. Note diagram that fe temperatures are enough high about at ° ° ° 20 km Basin the in depth Range and initiate partial to Province melting: earthquakes occurring within 0 brittle the thus terminate above upper crust that depth. b) Geothermal
z= Depth (km)

Flow Map, in values Rift) and at region of and the
XS ~# Heat 107? W/m’). High W/m*). The (near the coast) Nevada
-- Muah
? ‘ ---A.---->) Regions of high and low values. expressed Province: Rio Grande 0.09 of the Sierra
i. rks of Mexico U. S. Department of Energy x 4.2 = — forearc region years ago. Low values are also observed in
American sp 2 a Pt Nef oa bagel fe je Continental) 4 py ‘ jan ; \ Coast ne eS oe Gulf from 1991). HFU flow units (1 Range and values (0.05 by normal the in 0.05 W/m") low marks the region Mountains).
y
i
North MARS osaiatee. a t S oe Marathon’. Gu a? \.< (simplified al., et Blackwell heat rifting (Basin is dominated low (< about 20 million (Appalachian
2) 0.09 wate a aa United States Mountains). A prominent East
(W/m 0.09 - ‘<0.05 rencmcag i t f * Steele. 1989, and highlighted. Older maps may show values in observed in areas of continental continental craton Pacific Northwest shows a the zone in
i
Flow > 0.05 Pi i i 4, 3 Heat flow map of the and hotspot. The the (Cascade plate convergence ceased collision
Heat [es] [_] Eeq an i: << i be) 10.14 Blackwell 0.09 W/m’) are in volcanic arc the Paleozoic continental
Who,
FIGURE 1996: sce also W/m‘. are the Yellowstone ongoing subduction at high Mountains. where
ukzaIQ OB (> a