VOL. 83, NO. B9
JOURNAL OF GEOPHYSICAL RESEARCH
SEPTEMBER 10, 1978
Paleomagnetism
of the DevonianCatskillRed Beds'
Evidencefor Motion of the CoastalNew England-CanadianMaritime
RegionRelativeto CratonicNorth America
DENNIS V. KENT AND NEIL D. OPDYKE
Lamont-DohertyGeologicalObseroatory
of ColumbiaUnioersity
Palisades, New York 10964
The naturalremanent
magnetizations
of reddishclaystones,
siltstones,
andsandstones
fromthenearly
flat lyingMiddleto UpperDevonian
Catskillsequence
of southeastern
NewYork wereanalyzed
with
thermal,alternating
field,and chemicaldemagnetization
techniques.
After removalof a low blocking
temperature
component
alongthepresent
geomagnetic
fielddirection
a characteristic
direction
of magnetizationwasisolated:D = 172.3ø,I = 1.0ø, k = 116,andag8= 4.7ø for N = 9 sites(43 samples),
giving
a paleomagnetic
northpoleat 46.8øN,116.7øE,
dp = 2.4ø,anddm= 4.7ø.Thecombined
demagnetization analyses
showthisto be theonlystablecomponent
of magnetization
presentin theserocks.The
derivedpoleposition
agrees
wellwiththepolesreported
forsomeDevonian
limestones
in Ohio,all falling
nearthePermianpolesfor NorthAmerica,but disagrees
withDevonianresultsfromeasternMaine-New
Brunswickand easternMassachusetts
whichgivepolesat lowerlatitudes.A similargeographical
group-
ingwithsimilardirections
isalsoapparent
for LowerCarboniferous
(Mississippian)
paleomagnetic
poles
for North America.We interprettheseand otherlate Paleozoic
paleomagnetic
datato showthat the
coastalCanadianMaritime-NewEnglandregionwasnot an integralpart of cratonicNorth America
until aboutthe Late Carboniferous,
Geologicalconsiderations
suggest
that the Carboniferous
relative
motion was along transcurrentshearzones.
INTRODUCTION
The Devonianpaleomagnetic
fieldfor North Americais not
well known; there are few publisheddata, and thosethat are
available show considerablescatter.Consequently,the position of North Americawith respectto the earth'srotationaxis
and to the othercontinentslacksadequatedefinitionfor paleogeographicreconstructions
and plate tectonicanalysisin the
mid-Paleozoic.
Until recently,resultsconsidered
to be representative
of the
Devonianof North Americacamefrom paleomagneticstudies
chieflyof lavasand red bedsof the Upper DevonianPerry
Formation of Maine and New Brunswick[Black, 1964;PhillipsandHeroy, 1966;Robertson
et al., 1968].However,a recent
investigationof Lower to Middle Devonianlimestonesfrom
Ohio [Martin, 1975]gavea paleomagnetic
polenearto the late
Paleozoicpolepositionfor North Americaand some15ø away
from the meanPerrypole.It is difficultto attributethe differencein the pole positionto a particularcause,suchas apparentpolarwanderwith respectto North Americain the Devonian, without additional data.
This reportdescribes
a paleomagnetic
studyof reddishsiltstonesand sandstoneswithin the Middle to Upper Devonian
Catskilldepositsof New York. The resultsof thisstudyenable
us to proposea resolutionto the apparentdiscrepancy
in
North AmericanDevonianpalcomagnetic
data on the basisof
paleogeography
andto discuss
therelevance
of theseandother
late Paleozoicpaleomagneticdata to the formation of the
conglomeratesknown collectivelyas 'Catskill.' These predominantlynonmarineterrigenoussedimentsof Middle and
Upper Devonianage extendto Pennsylvania
and the Virginias, while they thin to the westand gradeto marineequivalents. The semilenticularform of the deposit and its great
thickness reflect accumulation in a progressivelysubsiding
foredeepor exogeosyncline
within the border of the early
Paleozoic craton; the sediment was evidently eroded from
source lands to the east and southeast raised in the Acadian
orogeny.
The complexintertonguingand intergradingof Catskill
strata make regional stratigraphicrelationshipsdifficult to
unravel, and various interpretationsof the detailed stratigraphyhavebeenproposed.We followherethesubdivision
of
the clastic rocks at the Catskill front usedby Fletcher [1967]
and essentiallyfollowedin the geologicalmap of New York
[D. W. Fisheret al., 1970].Thisinterpretationrecognizes
cyclic
sedimentation
alternatingbetweenred bedunitsand dark gray
shalesand sandstones.The red beds form large tonguesthat
are thickestto the east at the Catskill front and which pinch
out progressively
farther to the westgoingup the section.
A total of 46 oriented drill core samplesdistributedover
nine sites was collected from within three red siltstone and red
sandstone units in the Catskill beds: seven sites were in the
Upper DevonianWaltolaFormation,and a sitewastakenin
both the Plattekill Formation and the Manorkill Formation,
which are of Middle Devonian age (Figure 1 and Table Al)
[Fletcher,1967].Generally,two specimens
(2.5 cm in diameter
Euramericansupercontinent.
and 2.0 cm high)wereobtainedfrom eachsamplefor magnetic
measurements.
The stratasampledwerenearlyflat lying,with
GEOLOGIC SETTING AND SAMPLING
beddingdips of lessthan 5ø; structuralcomplications
of the
The Catskill area of New York has beenregardedfor over a late PaleozoicAppalachianorogeny,whichresultedin folding
in northernPennsylvania,
centuryas a classicregion in which to study the Devonian of similarbedsjust to the southwest
systemof North America.Within the Devonianrocksof are apparentlynot presentin thisarea.On theotherhandit
southeastern
New York, there are approximately
5000 feet wasnotpossible
to do a foldtest[Graham,1949]to delimitthe
(1524m) of interbedded
redandgraysandstones,
shales,and ageof theremanentmagnetization
of theserocks,anddetailed
laboratory analysesof the magnetizationsare necessaryto
Copyright
¸ 1978by theAmerican
Geophysical
Union.
Papernumber8B0574.
0148-0227/78/098B-0574501.00
assess
theirsignificance.
4441
4442
KENT AND OPDYKE' PALEOMAGNETISM
OF DEVONIANCATSKILLRED BEDS
L,4KE'
ONT,4RIO
.41 ø
I0 0 I0 20 30 .4._.•50
MILES
'• •-w•
IOO
z'o 40
60.80
KM
Fig.I. Location
of paleomagnetic
sampling
sites
intheMiddleto UpperDevonian
Catskill
sequence.
Thehatched
area
showsthe outcropof Middle to Upper Devoniansediments
in New York. Lower Devonianand older formationsare
typically
foldedandfaulted
totheeastofthestructural
frontinNewYork,whileDevonian
stratatothewestareessentially
flat lying.
MEASUREMENTAND DEMAGNETIZATIONANALYSIS
The
NRM
directions
show considerable scatter but are
dominantlydippingdown and to the south,away from the
Thedirection
andintensity
of thenaturalremanent
magnet- presentgeomagneticfield direction(Figure 2a). Progressive
ization(NRM) of eachsamplespecimen
weremeasured
witha thermal,alternatingfield(AF), andchemicaldemagnetization
computerized
7-Hz spinnermagnetometer
[Molyneux,1972]. experimentswere performed to establishthe nature of the
TheNRM intensi•ies
rangebetween
5 X l0-8 and2 X l0-5
magnetizations and to isolate a characteristic direction for
emu/gbutaretypicallyneartheaverage
of2.2 X l0-8 emu/g.
these rocks.
N
N
ß
NRM
DIRECTIONS
+
CHARACTERISTIC
N
+
DIRECTIONS
Fig.2. (a) Plotsof NRM directions
and(b, c) characteristic
directions
basedon thermaldemagnetization
for Catskill
redbeds.Solid(open)circlesareonthelower(upper)hemisphere.
Pluses
represent
thepresent
geomagnetic
fielddirection
in the samplingarea.Squaresrepresentsamplesin whichthe characteristic
directioncouldnot be determined.
KENTANDOPDYKE.'
PALEOMAGNETISM
OFDEVONIAN
CATSKILL
REDBEDS
NYD3-4A
250' $50'
4443
W,uP
ponentwhich dips down and toward the north (Figures3a3c). Althoughthe directionsof thislow blockingtemperature
magnetizationare not very well defined,they generallycon600%
i
form to the presentgeomagneticfield direction, and these
588%\ 670' I
55 '
655'
componentscan be assumedto be of recent origin. Above
temperaturesof 150ø-350øC the trajectory of further demagnetizationtendsto be linear toward the origin until little
magnetizationremainsafter 670øC (Figure 3a). The high
blocking temperaturesuggeststhat the carrier of the stable
remanence
is hematitewhichoccursassmallaggregates
andas
a coatingand cementaroundthe grains.However,mostof the
samplesstudieddid not show this continuedlinear decayto
2xIO'%mu/Qrn
nearthe originin the highertemperaturerangeof demagnetizationbut ratherfollowedoneof two othertypesof behavior.
E, DOWN
In the firsttype,thereis little furtherchangein direction,but
a
substantial
fractionof the NRM still remainsup to temperw UP
aturesof 650ø-670øC;treatmentat slightly higher temperaturesresultsin what we interpretas spuriousmagnetizations
for the reasonsdiscussed
below(Figure3b). We attributethis
behaviorto a thermallydiscretecomponentof magnetization
[Irvingand Opdyke,1965]in whichthe spectrumof blocking
Ix I0'sernu/gm
temperaturesis concentratedin a small range below about
Iiø•
•
5062
*
S,'
NYD I-
5A
350 ø
450ø
o 631øo
,
I
NRM
E, DOWN
W,UP
670øC, near to the Curie temperatureof hematite.The second
type showsthe onsetof scattereddirectionsand largefluctuationsin magnetization
intensityat temperatures
varyingfrom
500øC to over 620øC from sample to sample as the intermediate temperaturerange trajectoryapproachesthe origin
(Figure3c). Thiserraticbehaviorat hightemperatures
appears
to be associated
with a markedphysicochemical
changein the
original magnetic mineralogythat occurredas the result of
heatingthe samplesin the laboratory.
A clear indicationof magneticmineral changeis givenby
the remeasurement
(at roomtemperature)of magneticsusceptibilityof specimens
aftertheyhavebeenheatedto successively
600 ø
127
NYD4-4B
•
141
IO
I x IO-•emu/gm
9
- N
=30
samples
•'
8
S•
N
7
6
E, DOWN
4
Fig.3. Vectordiagrams
ofprogressive
thermal
demagnetization
of
Catskill red bed samples.Opensymbolsrepresentprojectionson the
north-southplane, and solid symbolsthoseon the horizontalplane.
3
The numbers next to the symbolsare the thermal demagnetization
temperatures(degreesCelsius).
2
ThermalDemagnetizationStudies
I
Figure3 showsthechangein directionandintensityof the
NRM of representative
specimens
with progressive
thermal
demagnetization,
plottedaccording
to the Zijderveld[1967]
method.Thesediagrams
illustratetherangeof behaviorexhibited by theserocksas the resultof heating,particularly
to
highertemperatures.
The low and intermediatetemperaturecharacteristics
are
nearlythe samefor all samples.Initial heatingsproducea
changein direction,oftenaccompanied
by an increasein intensity,resultingfrom the removalof a magnetization
cam-
•
0
I
400
I
500
TEMPERATURE
I
6 00
700
(øC)
Fig. 4. Changein room temperatureinitial susceptibility
expressed
asthe ratio to the originalvalue(kt/ko) asthe resultof heatingCatskill
red bed samplesin air. The susceptibilitywassometimesnot measured
after everyheatingof eachsample.For clarity,linesconnectingto the
initial value(kt/ko = 1) have not beendrawn. The opencirclesshow
samplesusceptibilities
remeasuredonly after thermaldemagnetization
analysiswas completed.
4444
KENT AND OPDYKE: PALEOMAGNETISM
OF DEVONIAN CATSKILLRED BI..'DS
DWB - 2
W,.D.
OWN
NRM
SI
5 xI0'?emu/gm
E, UP
W, UP
NYD $-4B
heating (e.g., the lowest curve in Figure 4). Nevertheless,the
production of a large, dominant soft componentof magnetization which is likely to be affectedby stray magneticfields
presentin the laboratoryduringthermaldemagnetization
and
measurementis the probablecausefor the confuseddemagnetization resultsobservedat highertemperaturesin many samples of the Catskill red beds. Apparently, either hematiteor
some nonmagnetic,iron-bearing mineral in the rock has been
converted during thermal treatment to a highly magnetic
phase,suchas magnetite[H. P. Johnsonet al., 1972;Dunlop,
1972].
The introduction of spuriousmagnetizationsdue to phys-
icochemicalchangesat varioustemperaturesprohibitedblanket thermal cleaningat a singletemperatureof all samples.
Consequently,each samplewas thermally demagnetizedat a
minimum of four temperature steps, typically in the range
350ø-650øC, and a characteristic direction was obtained from
the demagnetizationtrajectory which was linear toward the
origin. The directions of the sample characteristicmagnetizations
1200oe
- 2000o
50oe80••'••O•oe
I :"
could be determined
NRM
for all but three
IRM
(10'•'emu/gm)
SAMPLE
•6
NYD4-1
2xI0'• emu/9m
in this manner
unstablesamplesand are shownin Figure 2b. Thesedirections
clusterwell with the exceptionof one samplefrom siteDPA
5
AF•
_
It•
HEATED
TO
680øC
4
E, DOWN
:-$
Fig. 5. Comparisonof reinanenthysteresis
of Catskill red bed samples before and after heatingin air.
highertemperatures(Figure 4). The susceptibilities
are generally near or slightly lessthan their initial valuesafter 400øC,
appear to increasegradually at temperaturesof up to about
620øC, and then show a rapid increasewith higher temperatures, at which the susceptibilities
can becomean order of
-2
I
-I
I
i
2
i
5
H (10•' Oe)
i
4
i
5
i
6
i
7
,-I
magnitudegreaterthan they wereoriginally.Besides
suscepti-
bility the reinanentmagneticpropertiesalsochangeafter thermal treatment,as is indicatedby comparisonof acquisitionof
IRM
isothermalremanenceand of remanentcoercivityof heated
(10'• emu/9m)
and unheatedcompanionspecimens.
The unheatedspecimens
all showa gradualincreasein remanencewith appliedfield but
SAMPLE
NYD $-4
do not reach saturationby 7 kOe, the highestfield used.There
is a smoothdecreasein remanencewith field appliedin the
reversedirection,and remanentcoercivitiesare typicallyabout
3 kOe (Figures5a and 5b). The heatedspecimens,
however,are
generallycharacterizedby a large initial increasein reinanent
intensityat relativelylow fields,and althoughsaturationagain
is not reachedby 7 kOe, the much reducedvalue of reinanent
coercivityshowsthat the low coercivityfraction now dominatesthe magnetizationof mostof the heatedsamples(Figure
5a). Althoughchangesin magneticpropertiesat elevatedtemperaturescommonlyoccurred,the effectsof heatingwere less
drasticin somesamples.For example,a samplefrom site3 was
H (10• Oe)
only partially affectedby heating, and much of its original
reinanent magneticpropertiesremained;two coercivityfracFig. 6. Vectordiagramsof progressive
alternatingfielddemagnetitions can be readily distinguishedby the kink in the remanent
zationof Catskillredbedsamples.The opensymbolsrepresent
projeccoercivitycurve(Figure 5b). Samplesfrom this site had good tions on the north-southplane, and the solid symbolsthoseon the
thermaldemagnetization
characteristics
(e.g., Figure 3a) and horizontalplane.The numbersnextto the symbolsare the demagneshowedonly relatively small changesin susceptibilityafter tizing fieldsin peak ocrsteals.
I'
.
'P'
UNHEATED
,I •
HEATED
TO
685'C
KENT AND OPDYKE: PALEOMAGNET!SM
OF DEVONIAN CATSKILL RED BEDS
4445
whose direction is almost exactly antiparallel to that of the
othersand which may representa paleomagneticreversal.
A F Demagnetization
The NRM of a suite of specimensfrom the nine siteswas
treatedin progressively
higheralternatingfields.All specimens
behaved similarly, and representativedemagnetizationdiagramsare shownin Figure 6. It is evident that fieldsof only
50-200 Oe are effectivein removinga componentnear to the
directionof the presentfield (Figure 6a). Thus the secondary
magnetizationin theserocks is characterizedas being of low
coercivityas well as of low blockingtemperature.In contrast,
the componentwith a trajectorytendingtowardthe originis of
high coercivity,stableagainstalternatingfieldsas high as are
available (2000 Oe), which is consistentwith a hematiteremanence carrier as inferred from the thermal experiments.The
directionof this high-stabilitycomponentis similar to that of
the characteristicmagnetizationisolatedin thermal demagnetization of companionspecimens
(i.e., compareFigures6b and
3a, and seeFigure 7).
0.5
i
i
i
'
5
I0
Iõ
20
TIME IN ACID (DAYS)
Oß
ChemicalDemagnetization
Disks, 1 cm thick, were cut from severalspecimensand were
leachedin l0 N hydrochloricacidat roomtemperature(andin
s
the earth'smagneticfield) over a periodof up to 25 days.The
Fig. 8. Plots of (a) the changein the intensityand (b) the corrediskswere removedfrom the acid periodicallyfor remeasure- spondingchangein directionsof the NRM of two Catskill red bed
ment of their magnetizationsat which timesthe acid bath was sampleswith time in l0 N hydrochloricacid. The crossedsymbolsin
replenished.Typical effectsof the acid treatmenton the mag- Figure 8b refer to the direction after 150 Oe of AF demagnetization
netizations
are illustratedin Figure8. All the specimenswas applied after 25 days in acid; the numbersnext to the symbols
showeda decreasein remanentintensitywith duration in acid
until between 10% and 40% of the original magnetization
remainedafter 25 days.However, the decreasewas uniformin
some samplesand more erratic in others(Figure 8a). Samples
showinguniform decreaseusuallyshowedonly a smallchange
in direction in the first l0 days, after which the directions
stayedconstant,with shallowdipstoward the south.The lack
of significantdirectional changewith chemicaldemagnetization in theseparticular samplesmay be due to the fact that
they had acquiredlittle secondarymagnetization.
In contrast,the remanentdirectionsof the specimenswith
the erratic intensitydecaycurvescontinuedto changeover the
refer to time in acid in days.
course of the experiment in a rather haphazard fashion but
with a tendencyto move toward the present magnetic field
direction. Interestingly, subsequentAF demagnetizationat
relatively low fields brings the directionsto closeagreement
with those of the better-behavedsamples(Figure 8b) which
togetherare nearto the characteristicdirectionsobtainedfrom
thermal and AF demagnetizationanalyses.Evidently,the acid
leachingpreferentiallyremovesthe high coercivityand high
blockingtemperaturemagnetizationtherebyallowingthe soft,
secondarycomponentto dominate. If this interpretationis
correct, chemical demagnetization (of the type performed
here) cannotbe consideredan effectivemethodof 'cleaning'in
these rocks.
'
RESULTS
ANDPALEOMAGNETIC
POLE
poSITION
The site mean directions are summarized in Table 1 and are
shownin Figure2c. There is no significantdifferencebetween
directions
of the Middl e Devonian
sites and those of the
Upper Devonian sites.The mean directionobtainedfrom all
nine site meansis declination, 172.3ø and inclination, 1.0ø {,a0•
= 4.7ø), whichgivesa paleomagnetic
polepositionat 46.8øN,
116.7øE(dp = 2.4ø, dm= 4.7ø). Sincewe canfind no evidence
of any other consistent
stablemagnetizationdirectionin these
rocks, we tentativelyassumethat this direction representsa
recordof the Middle to Late Devonianpaleomagneticfield for
NRM
300 oe
North America. The generally higher within-site dispersion
comparedto between-sitedispersionin characteristicdirecFig. 7. Directionsof N RM beforeand after the demagnetization
that secularvariation is effectively
to 300 Oe of 12 samplesof Catskillred beds.Mean directionafter300 tions (Table l) suggests
Oe (invertingthe directionof the northerly pointing sample)is D =
averaged
bysampling
overseveral
mete
rsof section
at each
167.8ø, I = 2.7 ø, and a•5 = 8.8 ø.
site.
4446
KENT AND OPDYKE.'PALEOMAGNETISM
OF DEVONIANCATSKILLRED BEDS
TABLE 1. Site Mean Directions of Characteristic Magnetization
Site
DWA
DWB
DMA
DPA*
NYD
NYD
NYD
NYD
NYD
1
2
3
4
5
Declination,
Inclination,
Age
Rs
deg
deg
Du
Du
Dm
Dm
Du
Du
Du
Du
Du
5/5
4/5
5/5
6/6
5/5
5/5
4/5
5/5
4/5
167.5
164.0
180.6
161.2
172.3
179.3
173.6
174.7
177.2
1.5
-2.5
4.3
-1.9
5.1
3.7
5.1
-2.4
- 1.4
43/46
172.0
1.2
3.8
9/9
172.3
1.0
4.7
All samples
All sites
a95
k
5.4
13.4
ll.4
7.4
16.8
15.1
15.7
13.9
22.3
198
47
46
82
22
26
35
31
18
33
l l6
Sites collectedfrom Upper Devonian (Du) and Middle Devonian (Dm) formations(seeTable A l).
Rs is the ratio of samplesor sitesusedin calculatingmeandirectionto the numberof samplesor sites
collected(rejectedsampleswere thermally unstable);a95is the radius(in degrees)of the circle of 95%
confidenceabout the mean direction[R. ,4. Fisher, 1953];k is the best estimateof Fisher'sprecision
parameter;the polar errors (dp and dm) are the semiaxesof the oval of 95% confidenceabout the
pole, dp being alongthe paleomeridiandirectionand dm perpendicularto it. The mean pole position
from nine sitepolesin 46.8øN, 116.6øE,,4• = 4.4ø, and K = 136.The meanpole positionfrom the mean
directionof nine sitesis 46.8øN, l l6.7øE, dp = 2.4ø, and dm = 4.7ø.
*One samplefrom this sitegavea direction(inclination,-6.5ø; declination,338.0ø) antiparallelto all
other samples;this direction was inverted to calculatethe site mean.
ComparisonWith Other Data
the BarnettFormation of Mississippian
age[Howelland Martinez, 1957](not listedin Table 2) werebasedon unclemagnetized N RM, which is apt to be contaminatedby secondary
Table 2 contains a summary of reported Devonian and magnetization,and thereforeare not consideredfurther here.
Early Carboniferous(Mississippian)paleomagneticpole posiComparison of the Catskill pole with the other middle to
tions for North America; included also are the mean Late late Paleozoic paleomagneticpoles from North America
Carboniferous(Pennsylvanian),Early Permian,and Late Per- shows(l) that it is nearthe Permianpolepositionand(2) that
mian pole positionscalculatedby I/an der goo and French it agreeswell with certain Devonian polesbut disagreesby
[1974] from what they consideredthe best available data. about 15ø with others. Becauseof the few experimentally
These poles are plotted in Figure 9. Older resultsfrom the reliableDevonianpolesavailableit is possibleto averageall
Middle Devonian Onondaga limestone[Graham, 1954] and the Devonianpolesto obtain a betterestimateof the paleo-
TABLE 2. Middle to Late PaleozoicPaleomagnetic
Polesfor North America
Identification
DI
D2
D3
RockUnit
Location
Age
D4
D5
D6
D7
ClamBankGroup
Newfoundland
PerryFormationvolcanics
NewBrunswick
PerryFormationredbeds
New Brunswick
PerryFormation
volcanics
Maine
PerryFormation
redbeds
NewBrunswick
!ow-grade
metavolcanics
Massachusetts
Columbus
limestone(reversedOhio
D8
D9
C!l
C!2
C! 3
CI 4
C! 5
Cu I
Delaware
limestone
Catskillredbeds
CodroyGroup
Maringoin
Formation
pre-Pictou
sandstone
Hopewell
Group
MauchChunkFormation
MaroonFormation
PolePosition
Reference
D!
Du
Du
Du
Du
D
D!
28øN,146øE
26øN,109øE
35øN,121øE
24øN,128øE
32øN,118øE
26øN,122øE
45øN,120øE
Black[1964]
Black[1964]
Black[1964]
Dm
Dm-Du
CI
C!(u)
CI (u)-Cu(!)
C!(u)-Cu(1)
C!(u)
Cu
48øN,118øE Martin[1975]
47øN,117øE thisstudy
30øN,127øE Black[1964]
34øN,117øE RoyandRobertson
[1968]
24øN,133øE Black[1964]
34øN,118øE RoyandPark[1969]
43øN,127øE Knowles
andOpdyl,
e [1968]
41øN,133øE Christense.
andth'lsh'v[1974]
Phillips
andHerov[1966]
Robertson
etal. [1968]
Brecheret
al. [1974]
Martin[1975]
directions)
Identification
CU
PL
PU
Ohio
NewYork
Newfoundland
NewBrunswick
NewBrunswick
NewBrunswick
Pennsylvania
Colorado
Geologic Series
Number of Poles in Mean
Pole Position
Upper Carboniferous
Lower Permian
Upper Permian
8
5
4
40øN, 130øE
43øN, 125øE
49øN, 113øE
Rel'ercnce
Vander VooandFrench[19741
Vander VooamtFrem'h[19741
Vander VooandFrench[19741
D is Devonian;
Cl andCu areLowerandUpperCarboniferous,
respectively.
Lower,middle,andupperdivisions
areindicated
by I, m, and
u, respectively.
KENTANDOPDYKE.'
PALEOMAGNETISM
OFDEVONIAN
CATSKILL
RED BEDS
tively,thoseDevonianresultswhichgivepolesnear the Per-
50 ø
s:©
PALEOMAGNETIC
POLES mian position could be consideredto reflecta late Paleozoic
FOR NORTH AMERICA
remagnetization[e.g., Creer, 19.70]and should not be in-
PL
cu
•3 40 ø
o
4447
•0 ø
z
cluded.It is difficultto envisage,
however,themechanism
by
whichsuchdifferenttypesof rocks(gray-colored
limestones
(D7 and D8) and the red bedsfrom the Catskills)situated
some 1000 km apart in differentgeologicalsettingsshould
both havebecomeremagnetized
in the Permian.In addition,
thelackof experimental
evidence
pointingto laterremagneti-
zation of theserockssuggests
that someother reasonshould
be soughtfor the apparentdiscordance
in the North American
Devonianpaleomagneticdata.
20 ø
I
I
I
I
I10ø
120ø
130ø
140ø
We note that thereappearsto be a geographicdistinction
EAST
LONGITUDE
betweenthe two setsof Devoniandata. That is, the Devonian
resultswhichgive polesat lower latitudeswereobtainedfrom
Fig. 9. Plot of middleto late Paleozoicpolepositionsfrom North localitiesfrom the coastalMaritime provinces
of Canadaand
America.The solidcirclesrepresent
Devonian,andthe adjacentnumfrom
eastern
New
England
(poles
D1,
D2,
D3,
D4, D5, and
bersreferto the poleswith a D prefixin Table2. The solidtriangles
20
60
representLower Carboniferous,and the adjacent numbersrefer to
D6 (Table2)), whereas
thosewhichgivean apparentposition
poleswith a Cl prefixin Table2. The locationsof samplinglocalities near the Permian pole are from farther west, from within the
for thesepolesare shownin Figure10.The opentrianglesrepresent continentalinterior(polesD7, D8, and D9 (Figure 10)). A
mean Upper Carboniferous(CU) and Lower (PL) and Upper (PU) similargrouping
andsimilardirections
seemto occurfor Early
Permian pole positionsfor North America listed in Table 2 from Van
der Vooand French [1974].
magnetic field relative to North America for this time. For
Carboniferous(Mississippian)
paleomagnetic
data:the available poles(Cl 1, C! 2, C! 3, and Cl 4 (Table 2)) from the
CanadianMaritimesgroupnearto the Devonianpolesfrom
validitythiswouldneedto assume
that the largescatterin the the sameareas,but the pole from the Mauch Chunk Formapolepositions
reflects
randomerrors,suchasunaveraged
secu- tion of Pennsylvania,
on thewestsideof theAppalachians
(C!
lar variation,for which there is little justification.A!terna- 5), plotsagainat higherlatitude,nearthe Permianpoleposi-
NORTHAMERICA
70 ø
80 ø
Fig. 10. Geographiclocationsof Devonianand LowerCarboniferous
paleomagnetic
samplinglocalitiesin North
America.Thesolidcirclesrepresent
Devonian,andtheadjacentnumbers
referto poleswitha D prefixin Table2. Thesolid
trianglesrepresentLower Carboniferous,
and the adjacentnumbersrefer to poleswith a CI pretixin Table 2. The
corresponding
polepositions
areplottedin Figure9. Horizontalhatching
andverticalhatching
areschematic
representationsof Old WorldandAppalachian
brachiopod
provinces,
respectively,
for theEarlyDevonian[fromJ. G.Johnson
and,4.
J. Boucot,1973].The dot-dashedlineis the approximatepositionof the Appalachianstructuralfront. The dashedlineis the
political boundary betweenCanada and the United States.
4448
KENT ANDOPDYKE:PALCOMAGNETISM
OF DEVONIANCATSKIl,l,RED BEDS
55,•
CRATONIC
•_
ERICA
45 ø
o
cu /
/.
,,•"
•,•'•
•,' CL
MARITIME
-
NEW
ENGLAND
D
25 o
I
I10ø
I
120 ø
I
130 ø
41
I0 ø
LONGITUDE (,EAST)
magneticpole (Cu I (Table 2)) reportedfor the Upper Carboniferouspart of the Maroon Formation of Colorado[ChristensenandHelsely, 1974], suggestto usan apparentpolar shift
for eratonicNorth America during the Carboniferousto near
the Upper Carboniferouspole positionfor the Maritime-New
England region(Figure !! ). The apparent polar wander path
for eratonicNorth America thus appearsto make a tight loop
or hairpin in the late Palcozoicwith the Maritime-New England path joining it at the switch in direction in the Late
Carboniferous. Clearly, though, additional palcomagnetic
data are required to definethe Carboniferoussegmentof the
apparent polar wander path for eratonic North America.
DIscussIoN
Assuminga geocentricaxial dipolefield, dissimilarapparent
polar wander path segmentsobtained from differentregions
within a continentimply that theseregionswere onceseparate
and moved in relation to each other. There may be other
reasonsfor discordantpalcomagneticpoles,suchas local tectonic rotations,but when suchdiscordancesoccurconsistently
on a regionalscale,they stronglysuggestthat continentaldrift
Fig. 11. Preferredapparentpolarwanderpathsfor eratonicNorth
America (solid curve) and for the Canadian Maritime-coastalNew
Englandregion (dot-dashedcurve) in the middle to late Palcozoic,
showingconvergence
to a commonpath in the Late Carboniferous.
Data from Table 2 were usedto obtain the meanpalcomagneticpole
positionsfor eratonicNorth America(squares:Devonian(D), poles
DT-D9, latitude= 46.6øN, longitude= 118.3øE,andA• = 2.8; Lower is responsible.
Thereforethe time at whichthe apparentpolar
Carboniferous(CL), pole Cl 5; Upper Carboniferous(CU), poleCu 1'
Lower
Permian
(PL);andUpper
Permian
(PU)[Van
derVooand wander
paths
converge
andgivea common
pathindicates
French,
1974])
andfortheMaritime-New
England
region
(solidcir- joiningof theonceseparate
regions
to forma single
landmass.
clcs:Devonian(D), polesD2-D6, latitude= 28.7øN,longitude=
Wilson [1966] has suggestedon geologicgroundsthat a
119.6øE,
andA• = 7.3ø);
Lower
Carboniferous
(CL),poles
CI2-C14, proto-Atlantic
Ocean
existed
in approximately
thesame
loca-
latitude = 30.8øN, longitude = 122.9øE,and A• = 14.8ø;and Upper
Carboniferous
(CU)[Van
derVoo
and
French,
1974]).
Poles
fromtionasthepresent
North
Atlantic
during
theearly
Palcozoic
Newfoundland
(DIandCI 1inTable2) were
notused
incalculating
whichthenclosed
bystages
duringthemiddleandlatePalcomeanpolepositions
because
of possible
additional
tectonic
complexity.zoic, bringing together the surrounding continents. Subsequently,the supercontinentthus formed again broke apart
and the presentAtlantic Oceanbeganto form sometimein the
Mesozoic. However, he suggeststhat the reopeningdid not
follow exactly the line of sutureformed by the closingof the
proto-Atlantic with the result that somecoastalregionshave
tion for North America (Figure 10). We thereforeconsideron beentransposed.This history wasproposedlargelyto account
the basis of these consistentrelationshipsthat the coastal for the present geographic distribution of early Paleozoic
Canadian Maritime and New England regiondid not sharea faunal realms in the North Atlantic. However, it is noteworthy
commonpolar wanderpath with eratonicNorth Americafor that the presentgeographicdistributionof Devonianbrachioat leastpart of the Devonianand Carboniferousperiods.Our pod provincesin the Atlantic-borderingcontinents[J. G. Johninterpretationof the middle to late Paleozoicpalcomagnetic
data for eratonic
North
America
and for the coastal New
England-Maritime region is shown in Figure 11. Palcomagnetic data (poles D1 and CI 1) from Newfoundlandare not
consideredin this analysisbecauseof possibleadditional tectonic complication [Black, 1964; Robertsonet al., 1968;
Deutschand Rao, 1977].
This interpretation of the data placesthe Devonian palcomagneticpole near the Permianpositionwith respectto eratonic North America but at lower latitudeswith respectto the
Maritime-New England region. Betweenthe Early and Late
Carboniferous,therewas an apparentpolar shift of about 13ø
for the coastal Maritime-New England region;this shift has
beennotedpreviouslyby Roy andRobertson[1968]and others.
However,the pattern of apparentpolar wanderover this same
time interval for eratonic North America, and hence the times
at whichthe two areasbeganto sharea commonpolar path, is
not clear.This is largelybecausethe bestestimateof the North
American Late Carboniferous palcomagneticpole as calculated by Van der Voo and French [1974] is based on data
obtained only from the Maritime-New England region and
becausethere are few reliable Carboniferouspalcomagnetic
data that can be consideredto be representativeof eratonic
North America. These few data, i.e., the Lower Carboniferous
Mauch Chunk pole (CI 5 (Table 2)) and a preliminarypalco-
,,.,j 20øN
NORTH
AMERICA
T';,.'.
IOøN
'"""••
/ -0o
_ IOøS
DEVONIAN
20øS
Fig. 12. Paleogeographicsketchof North America in the Devonian showingthe positionof the New England-Maritime region,along
with parts of the British Isles, with respectto the North American
craton. The paleolatitude framework is basedon the mean Devonian
pole positionfor eacharea as shownin Figure II. The arrow shows
the inferredsenseof motion during the Carboniferouswhichbrought
the Maritime-New England-British Islesarea to the position shown
by the dashed outline (see text).
KENT AND OPDYKE: PALEOMAGNETISM
OF DEVONIAN CATSKILL RED BEDS
4449
sonand,4. J. Boucot, 1973] apparently can also be accounted from southern hemispherepaleolatitudesnorthward to the
for by the Wilson cycle of openingand closingof oceans. equatorial regionsthen occupiedby the now contiguouspart
McKerrow and Ziegler [1972] pursuedWilson's idea further of cratonic North America (Figure 12).
and applied the conceptsof plate tectonicsin interpreting
Morris [1976] recentlycomparedpaleomagneticpole posicertain orogeniczonesas sutureswhere continental collisions tions from North America and western Europe (particularly
closedpreviouslyexistingoceans.In particular, they consid- England), representingthe time interval from the late Preeredthe Acadian orogenyin the Middle Devonianto be due to cambrian to the Devonian. His interpretation of the paleothe collision of part of the Baltic Shield (eastern New- magnetic data indicated that the southern part of England
foundlandto Massachusetts)
with the Canadian Shield,clos- occupieda more southerly position with respectto North
ing the proto-Atlantic.
America in the lower Paleozoic and subsequentlymoved
Our interpretationof middle to late Paleozoicpaleomag- northward during the Devonian. By the end of the Devonian,
neticdata from North Americaprovidessupportfor the idea England and North America were together as part of Euthat the coastalMaritime-New England regionwas separate tamefica in a configurationsimilar to the morphologicalfit of
from cratonicNorth America sometimeduringthe Paleozoic. continentsdescribedby Bullard et al. [1965], a conclusion
However,this interpretationis in apparentdisagreement
with reached previously by Roy [1972] in his analysis of Late
the timingproposedby McKerrowandZiegler [1972]for their Devonian to early Mezozbic paleomagneticdata from eastern
unification:the paleomagneticevidencesuggests
relativemo- North America and westernEurope.
tion between these blocks until about the Late Carboniferous
In M orris's analysisthe paleomagneticpole positionsthat
(Figure 11), whereasMcKerrow andZiegler'stectonicanalysis wereconsideredto be representative
of North Americafor the
impliessuturingin the Devonian.In supportof theirviewthey Late Devonian, and which in fact constrained the inferred
cite evidencefrom freshwaterfishfaunaswhich suggests
that timing of relative motion with respectto England, were obthere was a land connection between the Canadian and Baltic
tained from the Canadian Maritimes and northern New Engshieldsstartingin the Middle Devonian.Moreover, we are not land (i.e., the Perry Formation); North Americanpaleomagawareof any geologicevidencein supportof the existenceof netic data for earlier geologicperiods came from outsidethis
any substantialoceanin New Englandor the CanadianMari- region. In addition to using this same set of Late Devonian
times that closed in the late Paleozoic. On the other hand the
paleomagneticpole positions,Roy [1972] consideredCarbonipresenceof an extensivesystemof northeast-southwest
trend- ferous paleomagneticdata which also were entirely derived
ing faultsin this region,believedto be mostlystrikeslip and from studiesof rocks from the Canadian Maritimes as being
activeprimarily in the Carboniferous[Webb,1969],pointsto a representativeof North America. However, we believethat the
meansof reconcilingthe apparentconflict betweenthe paleo- paleomagneticand geologic evidence is consistentwith the
magneticand tectonicestimatesof the sutureage.We suggest idea that the CanadianMaritime-coastalNew Englandregion
that the relative motion betweenthe Maritime-New England was not firmly attached to North America until the Late
region and cratonic North America was largely along these Carboniferous. We would therefore interpret the apparent
shearzonesduring the Carboniferous,perhapsin responseto close agreement between paleomagneticpoles from Britain
the approachof Africa andits subsequent
collisionwith North and the Canadian Maritimes for the Late Devonian and the
America to form the Appalachiansto the south. Unlike the Lower Carboniferousdemonstratedby Morris [1.976]and Roy
main collisionapparentlyresponsiblefor the Devonian'Aca- [1972]
aseviden
cethatthese
regions
werepossibly
attached
yet
dianorogeny
intheMaritimes
andNewEngland,
which
pro- distinct from cratonic North America. This would imply that
duced regional folding and metamorphism,the subsequent Englandsharedthe sametranslationrelativeto cratonicNorth
shearingin the Carboniferousgenerallycausedfault-bounded America with the coastalNew England-Maritime region durbasinsfilled with primarily restrictedmarine and terrestrial ing the Carboniferous,as sketchedin Figure 12. The apparent
sediment,which havebeenlocally(e.g., NarragansettBasin) discordanceof Silurian-Lower Devonian paleomagneticpoles
metamorphosed[Kay and Colbert, 1965]. We estimatethe betweenBritain and the Baltic area [Bridenet al.. 1973] sugcumulative left lateral relative movement in the Carboniferous
geststhat the Baltic-Russianarea need not have a similar
to be of the order of 1500 km (the equivalent of 15ø of history of motion with respectto North America as is suglatitude), which brought the Maritime-New England region gestedfor Britain.
TABLE A1.
Site
Fsrmation
,
Age
Latitude, øN
Location of Sampling Sites
Longitude, *W
,
Description
,
DPA
DMA
Plattekill
Manorkill
Dm
Dm
74.05
74.40
75.32
West Saugerties,streambedat bridge
Du
42.11
42.38
42.07
DWA
Walton
DWB
NYD
1
Walton
Walton
Du
Du
42.03
41.6
75.07
74.65
NYD
2
Walton
Du
41.82
74.67
NYD
NYD
NYD
3
4
5
Walton
Walton
Walton
Du
Du
Du
41.86
41.84
41.77
75.78
74.75
74.74
outcropalongroute 30, 4.7 mi (7.5 km) north of Harvard
outcropalongroute 17, 0.5 mi (0.8 km) north of exit 104
(Whitelake)
outcropalong route 44, 5.5 mi (8.8 km) north of Liberty,
near Bradley
outcrop along route 17, 0.5 mi (0.8 km) west of Parksville
outcrop along route 17, I mi (1.6 kin) east of Parksville
outcrop along route 17, at exit 101 (Ferndale)
stream
bed,1.5mi(2.4km)westofConesviii
e
drainageditchalongroute97, I mi (1.6km) southof Cannonsville Reservoir
Dm is Middle Devonian, and Du is Upper Devonian.
4450
KENT AND OPDYKE: PALEOMAGNETISMOF DEVONIAN CATSKILL RED BEDS
heatinghaematitein air and water vapour, Nature LondonPhys.Sci.
Acknowledgments. We thank R. A. Schweickertand T. Engelder
239(96), 151-152, 1972.
for critically reading the manuscriptand offeringhelpful comments.
The reviewersalso provided usefulcriticism.The field assistanceof Johnson,J. G., and A. J. Boucot, Devonian brachiopods,in Atlas of
Paleobiogeography,
edited by A. Hallam, pp. 89-96, Elsevier,New
C. A. Kent in collectingmanyof thesamplesis appreciated.
Thiswork
York, 1973.
was supportedby the National ScienceFoundation,grant EAR 7518955,Lamont-DohertyGeologicalObservatorycontributionnumber Kay, M., and E. H. Colbert, Stratigraphyand Life History, 736 pp.,
2710.
John Wiley, New York, 1965.
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