Blue Ridge Country - January/February 2020 - 22

MOUNTAIN CURIOS

THE HEAVY-DUTY SCIENCE CURIO

New Eye

for
the

Blue Ridge

ANNE FULTON

We at Blue Ridge Country got a note in the email awhile back, about a new scientific study looking at "the electrical
conductivity of Earth's crust and mantle below the mountain chain," and such. We wanted to understand it better than we did
after several tries, so we contacted the study's lead author. He was kind enough to take it a bit toward better understanding
for the rest of us.
By BENJAMIN MURPHY

SHARP DROP: The falloff from the
mountains of South Carolina's Caesars Head
(foreground) and Table Rock (on the horizon)
state parks onto the Piedmont is starkly
illustrative of the unique character of the Blue
Ridge Escarpment.
INSET: Grandfather Mountain's Linn Cove
Viaduct is also a good place to appreciate the
escarpment.

22

BLUERIDGECOUNTRY.COM

A

lthough the last major tectonic event
to affect eastern North America ended
more than 100 million years ago, the
Southern Appalachian Mountains remain
surprisingly sharp and steep.
And because the conventional scientific
understanding of how topography evolves
over time would suggest that these mountains should be much broader and smoother,
geoscientists have for decades debated the
reasons for this unusually sharp contemporary relief. Our recent scientific study offers
a new take on this problem in the context
of the impressively sharp break at the southeastern edge of the range-the Blue Ridge
Escarpment.
This work, entitled "Insights into Intraplate Stresses and Geomorphology in the
Southeastern United States," by me (while
a PhD student at Oregon State University),

Lijun Liu (University of Illinois) and Gary
Egbert (Oregon State University), finds that
the steep escarpment between the Appalachians and the adjacent Piedmont could be
the result of zones of weakness within the
underlying crust.
How and why? Isostasy is the key. Isostasy
essentially describes the buoyancy of the
rigid crust sitting on top of the quasi-liquid
mantle. The physics of this are very much like
those that describe how one would float in
a pool on a pool float: the underlying liquid
pushes upwards and thereby supports the individual on the float.
A similar situation exists beneath the
Southern Appalachians; the mountains here
appear to be isostatically compensated,
meaning that they are buoyantly supported
by the Earth's underlying structure.
However, a traditional analysis of isostatic


http://www.BLUERIDGECOUNTRY.COM

Blue Ridge Country - January/February 2020

Table of Contents for the Digital Edition of Blue Ridge Country - January/February 2020

Blue Ridge Country - January/February 2020 - Intro
Blue Ridge Country - January/February 2020 - Cover1
Blue Ridge Country - January/February 2020 - Cover2
Blue Ridge Country - January/February 2020 - 3
Blue Ridge Country - January/February 2020 - 4
Blue Ridge Country - January/February 2020 - 5
Blue Ridge Country - January/February 2020 - 6
Blue Ridge Country - January/February 2020 - 7
Blue Ridge Country - January/February 2020 - 8
Blue Ridge Country - January/February 2020 - 9
Blue Ridge Country - January/February 2020 - 10
Blue Ridge Country - January/February 2020 - 11
Blue Ridge Country - January/February 2020 - 12
Blue Ridge Country - January/February 2020 - 13
Blue Ridge Country - January/February 2020 - 14
Blue Ridge Country - January/February 2020 - 15
Blue Ridge Country - January/February 2020 - 16
Blue Ridge Country - January/February 2020 - 17
Blue Ridge Country - January/February 2020 - 18
Blue Ridge Country - January/February 2020 - 19
Blue Ridge Country - January/February 2020 - 20
Blue Ridge Country - January/February 2020 - 21
Blue Ridge Country - January/February 2020 - 22
Blue Ridge Country - January/February 2020 - 23
Blue Ridge Country - January/February 2020 - 24
Blue Ridge Country - January/February 2020 - 25
Blue Ridge Country - January/February 2020 - 26
Blue Ridge Country - January/February 2020 - 27
Blue Ridge Country - January/February 2020 - 28
Blue Ridge Country - January/February 2020 - 29
Blue Ridge Country - January/February 2020 - 30
Blue Ridge Country - January/February 2020 - 31
Blue Ridge Country - January/February 2020 - 32
Blue Ridge Country - January/February 2020 - 33
Blue Ridge Country - January/February 2020 - 34
Blue Ridge Country - January/February 2020 - 35
Blue Ridge Country - January/February 2020 - 36
Blue Ridge Country - January/February 2020 - 37
Blue Ridge Country - January/February 2020 - 38
Blue Ridge Country - January/February 2020 - 39
Blue Ridge Country - January/February 2020 - 40
Blue Ridge Country - January/February 2020 - 41
Blue Ridge Country - January/February 2020 - 42
Blue Ridge Country - January/February 2020 - 43
Blue Ridge Country - January/February 2020 - 44
Blue Ridge Country - January/February 2020 - 45
Blue Ridge Country - January/February 2020 - 46
Blue Ridge Country - January/February 2020 - 47
Blue Ridge Country - January/February 2020 - 48
Blue Ridge Country - January/February 2020 - 49
Blue Ridge Country - January/February 2020 - 50
Blue Ridge Country - January/February 2020 - 51
Blue Ridge Country - January/February 2020 - 52
Blue Ridge Country - January/February 2020 - 53
Blue Ridge Country - January/February 2020 - 54
Blue Ridge Country - January/February 2020 - 55
Blue Ridge Country - January/February 2020 - 56
Blue Ridge Country - January/February 2020 - 57
Blue Ridge Country - January/February 2020 - 58
Blue Ridge Country - January/February 2020 - 59
Blue Ridge Country - January/February 2020 - 60
Blue Ridge Country - January/February 2020 - 61
Blue Ridge Country - January/February 2020 - 62
Blue Ridge Country - January/February 2020 - 63
Blue Ridge Country - January/February 2020 - 64
Blue Ridge Country - January/February 2020 - 65
Blue Ridge Country - January/February 2020 - 66
Blue Ridge Country - January/February 2020 - Cover3
Blue Ridge Country - January/February 2020 - Cover4
https://www.nxtbook.com/nxtbooks/leisure/BRCSO21
https://www.nxtbook.com/nxtbooks/leisure/brcja21
https://www.nxtbook.com/nxtbooks/leisure/brc_2021_0506
https://www.nxtbook.com/nxtbooks/leisure/brc_2021_0304
https://www.nxtbook.com/nxtbooks/leisure/brc_2021_0102
https://www.nxtbook.com/nxtbooks/leisure/brc_2020_11_12
https://www.nxtbook.com/nxtbooks/leisure/brc_2020_0910
https://www.nxtbook.com/nxtbooks/leisure/brc_2020_0708
https://www.nxtbook.com/nxtbooks/leisure/brc_2020_0506
https://www.nxtbook.com/nxtbooks/leisure/brc_2020_0304
https://www.nxtbook.com/nxtbooks/leisure/brc_2020_0102
https://www.nxtbook.com/nxtbooks/leisure/brc_2019_1112
https://www.nxtbook.com/nxtbooks/leisure/brc_2019_0910
https://www.nxtbook.com/nxtbooks/leisure/brc_2019_0708
https://www.nxtbook.com/nxtbooks/leisure/brc_2019_0506
https://www.nxtbook.com/nxtbooks/leisure/brc_2019_0304
https://www.nxtbook.com/nxtbooks/leisure/brc_2019_0102
https://www.nxtbook.com/nxtbooks/leisure/brc_2018_1112
https://www.nxtbook.com/nxtbooks/leisure/brc_2018_0910
https://www.nxtbook.com/nxtbooks/leisure/brc_2018_0708
https://www.nxtbook.com/nxtbooks/leisure/brc_2018_0506
https://www.nxtbook.com/nxtbooks/leisure/brc_2018_0304
https://www.nxtbook.com/nxtbooks/leisure/brc_2018_0102
https://www.nxtbook.com/nxtbooks/leisure/brc_2017_1112
https://www.nxtbook.com/nxtbooks/leisure/brc_2017_0910
https://www.nxtbook.com/nxtbooks/leisure/brc_2017_0708
https://www.nxtbook.com/nxtbooks/leisure/brc_2017_0506
https://www.nxtbook.com/nxtbooks/leisure/brc_2017_0304
https://www.nxtbook.com/nxtbooks/leisure/brc_20170102
https://www.nxtbook.com/nxtbooks/leisure/brc_201612
https://www.nxtbook.com/nxtbooks/leisure/brc_20160910
https://www.nxtbook.com/nxtbooks/leisure/brc_20160708
https://www.nxtbook.com/nxtbooks/leisure/brc_20160506
https://www.nxtbook.com/nxtbooks/leisure/brc_20160304
https://www.nxtbook.com/nxtbooks/leisure/brc_20160102
https://www.nxtbook.com/nxtbooks/leisure/brc_20151112
https://www.nxtbook.com/nxtbooks/leisure/brc_20150910
https://www.nxtbook.com/nxtbooks/leisure/brc_20150708
https://www.nxtbook.com/nxtbooks/leisure/brc_20150506
https://www.nxtbook.com/nxtbooks/leisure/brc_20150304
https://www.nxtbook.com/nxtbooks/leisure/brc_20150102
https://www.nxtbook.com/nxtbooks/leisure/brc_20141112
https://www.nxtbook.com/nxtbooks/leisure/brc_20140910
https://www.nxtbook.com/nxtbooks/leisure/brc_20140708
https://www.nxtbook.com/nxtbooks/leisure/brc_20140506
https://www.nxtbook.com/nxtbooks/leisure/brc_20140304
https://www.nxtbook.com/nxtbooks/leisure/brc_20140102
https://www.nxtbook.com/nxtbooks/leisure/brc_20131112
https://www.nxtbook.com/nxtbooks/leisure/brc_20130910
https://www.nxtbook.com/nxtbooks/leisure/brc_20130708
https://www.nxtbookmedia.com