analysis of the magnetic anomalies of buried archaeological...

Research ArticleAnalysis of the Magnetic Anomalies of Buried ArchaeologicalOvens of An Kerouach (Morocco)

Abderrahim Ayad and Saacircd Bakkali

Earth Sciences Department Faculty of Sciences and Techniques Abdelmalek Essaadi University Tangier Morocco

Correspondence should be addressed to Abderrahim Ayad ayadabderrahim0gmailcom

Received 26 May 2018 Revised 13 September 2018 Accepted 26 September 2018 Published 11 October 2018

Academic Editor Angelo De Santis

Copyright copy 2018 Abderrahim Ayad and Saad Bakkali This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Aın Kerouach is one of the most important archaeological sites in the northern part of Morocco The main buried archaeologicalruins in this area were surveyed in 1977 using magnetic prospecting This survey highlights the mean anomalies that are related topotteries ovens built to theMarinid dynasty that governedMorocco from the 13th to the 15th century In order to find themaximumdepth of the sources we computed the enhanced downward continuation filter in order to highlight the magnetization contrastsin high detail depending on the depth downward included in the computation The main goal is providing a reliable mapping toobserve the ovens in depth by shifting the data below the plane of measurementThe results showed an important depth variationof the main ovens given by the original magnetic map and revealed others Indeed the downward continuation process applied toanalyze the magnetic data shows its efficiency to highlight the buried archaeological structures

1 Introduction

Morocco is a country with very ancient origins The territoryoffers a huge cultural heritage called ldquoTourathrdquo of higheducational value that dates back to the ancient era ofmany empires and invaders groups The Moroccan historybegan about 1100 BC by the Phoenicians followed by theCarthaginians (814-146 BC) and the Romans (146 BC-429AD) respectively [1] Over time the Romans fell apart lettingArabs take over with the introduction of Islam to Moroccosince 705Afterwards during this epochMorocco soon brokeup into different kingdoms the first was the Adarissa (788-974) followed by the Almoravids (974-1147) the Almohads(1147-1248) the Marinids (1248-1465) the Wattasids (1465-1555) the Saadians (1554-1659) and later the Alaouites (1664-present day) [2ndash4]

Specific studies on historical Morocco in the pre-RomanRoman and Islamic era were initiated since 1950 andcontinue today with several works [5ndash8] All these studiesrevealed that the Moroccan cultural heritage is spatiallydistributed in different regions Nine famous Moroccanarchaeological sites have been adjudged by UNESCO tobe important historical-cultural resource (Volubilis Historic

City of Meknes Ksar of Ait-Ben-Haddou Mogador Medinaof Fez Medina of Marrakesh Titawin Portuguese City ofMazagan and Historic City of Rabat) (Figure 1) Thesewonderful historical sites show the way early people livedtheir day-to-day lives in pre-Roman Roman and Islamic era

Nowadays the increasing interest in preserving theMoroccan archaeological sites requires the integration ofmultidisciplinary studies In this paper we have essentiallyfocused on an archaeological site called ldquoAın Kerouachrdquosituated at the borders of the Rif belt in the north of MoroccoThis site is at a distance of about 60 km from Fez (Figure 1)It dates back to the Middle Ages especially to the Marinidperiod more than a thousand years ago

According to Hassar-Benslimane [9] the site was discov-ered in 1976 during a drilling groundwater activity by theresidents of Maarif and Kerouach villages These activitiesrevealed the presence of some architectural and decorativestructures and highlighted the first remains of materials usedfor building (Figure 2(b))Most of these structures are similarto those existing in ancient cities such as Fez MarrakeshMeknes Sale and others historical Moroccan cities [10]

Amagnetic surveywas carried out in 1977 at the southeastof the discovered decorative structures (Figure 2(a)) [11] The

HindawiInternational Journal of GeophysicsVolume 2018 Article ID 9741950 7 pageshttpsdoiorg10115520189741950

2 International Journal of Geophysics

35∘00N

25∘00N

30∘00N

35∘00N

25∘00N

30∘00N

15∘00W 10

∘00W 5

∘00W

15∘00W 10

∘00W 5

∘00W

0 400Km

200

Prehistoric sitesPre-Islamic sitesIslamic sites

Figure 1 Main Moroccan archaeological sites The site of Aın Kerouach is highlighted with red rectangle [13]

purpose of this survey was to try to reveal possible archaeo-logical buried objects near the structures already discovered

The idea of doing a magnetic survey was encouraged bythe presence of somemagneticmineral included in the buriedarchaeological objects Hence the archaeological structuressuch as kilns furnaces slag blocks fire-places ceramicsbricks and tiles possess significant magnetic susceptibilitycontrast The intensity of magnetization produced may varydepending on the magnetic properties of the materials wherethese structures were constructed

According to Tatyana [12] buried ovens filled with earthpottery or ashes will show positive magnetic anomalies withan amplitude range from 20 to 50 nT These anomalies aredue to the magnetization of certain ferromagnetic oxidesgrains of iron magnetite and hematite present in the bakedclay of the ovens When the kiln is heated above the Curietemperatures of the grains the latter become demagnetizedand as the kiln cools the grains acquire a magnetic potential

Furthermore other archaeological structures such aswells cisterns or pits filled with ashes fragments of ceramicsand burnt soil may create positive anomalies of about 50-75 nT The structures made of earth typically create magneticanomalies in the range of 1-20 nT The walls of sandstone orlimestone can give negative magnetic anomalies with valuesranging from -2 to -20 nT Streets covered with tiles ofceramic pots or metal slag may give positive anomalies withamplitudes of about 10-100nT Pithoi associated with ancientGreek sites give positive anomalies of a greater intensity 50-100 nT [14 15]

2 Materials and Methods

The magnetic survey was undertaken by means of a G-816 geometric scalar magnetometer (Figure 3) [16 17] Thedata were measured in gamma (rsaquo) unit where 1 rsaquo = 1 nT(nanotesla)

Within our study project it is necessary for the anoma-liesobjects (paper map format) (Figure 4(a)) to be availablein an assigned digital format (Figure 4(b)) [18] This activityis the most important aspect to provide extreme flexibility ofour magnetic anomalies

In this technical brief we describe the digitization processof this nonpublished magnetic anomalies map provided byDr Patrice Cressier [11] Firstly we undertook the scanning ofourmagnetic mapThen the digitization has been performedusing a metric coordinate grid by preserving the originalinformation quality We have digitized (100x67) magneticdata manually and processed them to be useful as a tabularXYZ file

In order to eliminate the error introduced by the processof digitization operation we have geo-referenced the avail-able map using 4 calibration points (0 0) (0 30) (30 45)and (45 0) as indicated on the corners of the resulting map(Figure 4) Afterwards we have evaluated the overall residualerror which is of the order of 5 times 10minus5m Taking into accountthe scale of the digitized map (1 cm997888rarr5m) the real valuerepresented on the map is 0025m which is smaller thanthe dimension of the interpolation grid of 045 times 045m2Therefore when digitizing the intervals of the values ofanomalies and their position will not be affected or distorted

The magnetic map has described positive anomalies ofelongated and nearly semicircular shapes located mainly inthe southwestern part of the area with moremodest negativeanomalies immediately around the main positive signalsAccording toCressier [9] the three mainmagnetic anomaliesof amplitude higher than 20 nT are associated with buriedceramic ovens ldquobakedrdquo located at a few centimeters below theground This assumption coincides with the interpretationgiven by Tatyana in the section above which suggests thatthe rooms containing ovens filled with earth pottery or asheswill be seen in magnetic maps as positive anomalies with anintensity of 20-50 nT

International Journal of Geophysics 3

5∘27

20

W 5∘27

10

W 5∘26

50

W 5∘26

40

W

34∘30

50

N

34∘30

40

N

34∘30

30

N

34∘30

50

N

34∘30

40

N

34∘30

30

N

5∘27

0W

5∘27

20

W 5∘27

10

W 5∘26

50

W 5∘26

40

W5∘27

0W

(a)

(b)

Figure 2 Archaeological site of Aın Kerouach (a) Google Earth view of the archaeological site (b) photographs of some discovereddecorative structures [9]

(a)

G-816

Buried oven

(b)

Figure 3 Materials and method used in the survey (a) G-816 geometrics scalar magnetometer (b) the magnetic prospecting


41

-29-22-15-8-1613202734

0 30252015105

0

45

40

35

30

25

20

15

10

5

nT

(a)

-30-26-22-18-14-10-6-226101418222630343842

0 30252015105

0

45

40

35

30

25

20

15

10

5nT

(b)

Figure 4 Magnetic map of the archaeological site of Aın Kerouach (a) original map (b) gridded map

Although these magnetic anomalies provided clearresults since we could locate three buried ovens the analysisof these anomalies requires the employment of new process-ing tools In this study we chose to use the downward con-tinuation filter in order to determine clearly the topographicposition and the maximum depth of these anomalies Thisapproach of analysis was applied extensively in many studiesand scientific researches [19ndash23]

3 Methodology of Analysis

Interpretation of magnetic data is the process of extractinginformation on the position and extent of buried ruins inthe ground [24ndash26] In the present case the buried ruinswere essentially the potteries ovens The amplitude of ananomaly may be assumed to depend on the mass of the bodywith altered burned material which in turn corresponds torecognizable magnetic contrast from surrounding rocks Ifthe body has the samemagnetic susceptibility as the neighborrock no anomaly will be detected

The magnetic map may be considered the sum of a scalarpotential set assumed to be harmonic everywhere exceptabove the ovens Downward continuation filter will amplifythe effect of the deep structures and enables us to separate theeffect of neighbor sourcesThis technique allows us to find thedepth to the roof of the body without confusing with otherstructures

The desired potential anomalies of the sources can becontinued mathematically downward to any horizontal plane[27] The solution of the observed anomalies may be built upusing the following equation

n2sum

f=minusn2exp[2120587120587i(z0minusz1)120582]

(1)

where z is the targeted depth for Δ 119911 = 1199110 minus 1199111 the downwardcontinuation operators are as follows

n2sum

f=minusn2exp[(21205872120587if120582)z]

(2)

According to (2) the downward continuation filter of themagnetic anomaly increases exponentially with depth Theeffectiveness of this method is important since the anomaliescan be clearly visible and well smoothed [28 29] It would beeasy to discern the buried archaeological ruins of the studyarea

4 Results and Discussion

The magnetic anomalies data over this archaeological sitewere firstly gridded by kriging to an interval of 045m in bothx and y directions Afterwards the downward continuationfilter was applied to the data to highlight the significant signalat different selected plans below the surface The residualheading error is removed by using a moving average filterwhich proved satisfying results

For the best delimitation of our targets the magneticdata anomalies were downward continued vertically by a stepdepth of 02mTheburied ovenswere outlined in depth downto 12m This filter mathematically transforms our magneticdata acquired from the surface to the values that would havebeen measured at the different selected planes

Figure 5 is a plot of the different filtering responses mapsOn inspection of our processed data the contours values ofthese maps are restricted to an interval range between 20 nTand 37 nT This way enables isolating anomalies of interest ofhigher amplitude from the total data in order to delineate theanomaliesobjects highlighted in the original map (Figure 4)Except for these higher amplitude anomalies the rest of


363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(a)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(b)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(c)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(d)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(e)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(f)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(g)

Figure 5 Downward continuation responses of the original magnetic data (contour interval = 2 nT) The original data (a) are downwardcontinued to six different levels (b) 02m (c) 04m (d) 06m (e) 08m (f) 1m (g) 12m


0 30252015105

0 302520151050

45

40

35

30

25

20

15

10

5

0

45

40

35

30

25

20

15

10

5

Figure 6 Response of the magnetic data downward continued to14m

our historic site surface still containing short wavelengthanomalies may be associated with debris

This analysis produced different characteristic anomaliesand confirmed our expectations for anomalies caused by theburied ovens with spatial dimensions of several meters Itgives us sharper images so that as depth increases we canestimate the field of ovens and outline the field for othernew sources of anomalies This filtering process highlightsanomalies edges and provides more accurate determinationof their extents It is clear that the fitted maps establish aninfluence of deeper features of different anomalies The linearfeature gradually appears and becomes more prominent asthe anomalies continue downward

Furthermore we emphasize that at 14m the filteringresponse produces unreliable and erratic results (Figure 6)The anomalies become clumsy and the interpretations turnout to be consequently impossible Consequently this depthlimit is thus assumed to be the basis of the buried ovens

5 Conclusions

In this work we describe the results regarding the integrationof downward continuation filter for reanalyzing the magneticanomalies of the archaeological site of Aın Kerouach region(northern Morocco) This filter appears as a powerful toolto define variation of the buried archaeological ovens indepth with a very clear shape which was revealed on themaps

Data Availability

The data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this work

Acknowledgments

The authors thank Dr Patrice Cressier (University of Lyon)for having provided access to the magnetic data used in thiswork Also they would like to thank Mr Miftah Abdelhalim(University Hassan I) for many helpful suggestions andcomments This research was performed at the EnvironmentOceanology and Natural Resources Laboratory Faculty ofSciences and Techniques of Tangiers Morocco This researchis supported by a doctoral grant [UAE L002005 2016] fromthe National Center for Scientific and Technical Research ofMorocco (CNRST)

References

[1] H Limane and R Rebuffat ldquoLrsquoAfrique du Nord antiqueet medievale VIe colloque international sur lrsquohistoire etlrsquoarcheologie de lrsquoAfrique du Nordrdquo in Proceedings of the 118econgres des societes historiques et scientifiques vol 16 Editionsdu CTHS Pau Paris France 1995

[2] J L Boone andN L Benco ldquoIslamic settlement inNorth Africaand the Iberian PeninsulardquoAnnual Review of Anthropology vol28 pp 51ndash71 1999

[3] E Pappa ldquoReflections on the earliest Phoenician presence innorth-west Africardquo Talanta vol 41 pp 53ndash72 2009

[4] Y Lintz ldquoLe Maroc medieval une histoire meconnuerdquoDossiersdrsquoArcheologie vol 365 pp 8ndash13 2014

[5] E Fentress H Limane and G Palumbo ldquoTheVolubilis projectMorocco excavation conservation andmanagement planningrdquoArchaeology International vol 5 pp 36ndash39 2012

[6] L B Nancy A Ettahiri and M Loyet ldquoWorked bone toolslinking metal artisans and animal processors in medievalIslamic Moroccordquo Cambridge Core vol 76 pp 447ndash457 2002

[7] A Rodrigue ldquoPrehistoire du Marocrdquo Eddif pp 117 2002[8] A Larocca ldquoRock art conservation inMoroccordquo Public Archae-

ology vol 3 no 2 pp 67ndash76 2017[9] J Hassar-Benslimane ldquoAın Karuash un nouveau site

archeologique dans le gharbrdquo Bulletin drsquoArcheologie Marocainevol 80 pp 361ndash376 1979

[10] M Cardenal-Breton ldquoRamassage de surface a Aın karuashmethode resultats et perspectivesrdquoBulletin drsquoArcheologieMaro-caine vol 16 article 339 1985

[11] P Cressier ldquoProspection geophysique sur le site medieval drsquoAınKerouachrdquo Bulletin drsquoArcheologie Marocaine vol 14 pp 247ndash255 1981

[12] N Tatyana and T Smekalova ldquomagnetometric survey in thetemple of athena alea at tegea - a reportrdquo T Ix pp 563-568

[13] R Rebuffat ldquoLa carte archeologique duMarocrdquo Les nouvelles delrsquoarcheologie no 124 pp 16ndash20 2014

[14] A Schmidt ldquoArchaeology magnetic methodsrdquo Encyclopedia ofEarth Sciences Series pp 23ndash31 2007

[15] B W Bevan and T N Smekalova ldquoMagnetic Exploration ofArchaeological Sitesrdquo Good Practice in Archaeological Diagnos-tics pp 133ndash152


[16] S J Maksimovskikh and V A Shapiro ldquoPortable proton pre-cession magnetometer of high accuracy T-MIIrdquo Geomagnetismy Aeronomia vol 16 pp 389ndash391 1976

[17] V Mathe F Leveque and M Druez ldquoWhat interest touse caesium magnetometer instead of fluxgate gradiometerrdquoArcheoSciences vol 33 pp 325ndash327 2009

[18] M A Oliver and R Webster ldquoKriging a method of inter-polation for geographical information systemsrdquo InternationalJournal of Geographical Information Science vol 4 no 3 pp313ndash332 1990

[19] C-H Huang C Hwang Y-S Hsiao Y M Wang and D RRoman ldquoAnalysis of alabama airborne gravity at three altitudesexpected accuracy and spatial resolution from a future tibetanairborne gravity surveyrdquo Terrestrial Atmospheric and OceanicSciences vol 24 no 4 pp 551ndash563 2013

[20] A H Mansi M Capponi and D Sampietro ldquoDownwardcontinuation of airborne gravity data by means of the changeof boundary approachrdquo Pure and Applied Geophysics vol 175no 3 pp 977ndash988 2018

[21] J Sebera M Pitonak E Hamackova and P Novak ldquoCompara-tive study of the spherical downward continuationrdquo Surveys inGeophysics vol 36 no 2 pp 253ndash267 2015

[22] J Huang and M Veronneau ldquoApplications of downward-continuation in gravimetric geoid modeling case studies inWestern Canadardquo Journal of Geodesy vol 79 no 1-3 pp 135ndash145 2005

[23] P Novak and B Heck ldquoDownward continuation and geoiddetermination based on band-limited airborne gravity datardquoJournal of Geodesy vol 76 no 5 pp 269ndash278 2002

[24] P Barral G Bossuet M Joly et al ldquoApplied geophysics inarchaeological prospecting at sites of Authumes (Saone-et-Loire) andMirebeau (Cote-drsquoOr) (Bourgogne Eastern France)rdquoArcheoSciences no 33 (suppl) pp 21ndash25 2009

[25] T Hatakeyama Y Kitahara S Yokoyama et al ldquoMagnetic sur-vey of archaeological kiln sites with OverhausermagnetometerA case study of buried Sue ware kilns in Japanrdquo Journal ofArchaeological Science Reports vol 18 pp 568ndash576 2018

[26] C Gaffney ldquoDetecting trends in the prediction of the buriedpast A review of geophysical techniques in archaeologyrdquoArchaeometry vol 50 no 2 pp 313ndash336 2008

[27] R J Blakely Potential Theory in Gravity and Magnetic Applica-tions Cambridge University Press Cambridge UK 1995

[28] G Ma C Liu D Huang and L Li ldquoA stable iterative down-ward continuation of potential field datardquo Journal of AppliedGeophysics vol 98 pp 205ndash211 2013

[29] H Trompat F Boschetti and P Hornby ldquoImproved downwardcontinuation of potential field datardquo Exploration Geophysicsvol 34 no 4 pp 249ndash256 2003

Hindawiwwwhindawicom Volume 2018

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Volume 2018Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

ScienticaHindawiwwwhindawicom Volume 2018


Geological ResearchJournal of

Analytical ChemistryInternational Journal of


Submit your manuscripts atwwwhindawicom


35∘00N

25∘00N

30∘00N

35∘00N

25∘00N

30∘00N

15∘00W 10

∘00W 5

∘00W

15∘00W 10

∘00W 5

∘00W

0 400Km

200

Prehistoric sitesPre-Islamic sitesIslamic sites

Figure 1 Main Moroccan archaeological sites The site of Aın Kerouach is highlighted with red rectangle [13]

purpose of this survey was to try to reveal possible archaeo-logical buried objects near the structures already discovered

The idea of doing a magnetic survey was encouraged bythe presence of somemagneticmineral included in the buriedarchaeological objects Hence the archaeological structuressuch as kilns furnaces slag blocks fire-places ceramicsbricks and tiles possess significant magnetic susceptibilitycontrast The intensity of magnetization produced may varydepending on the magnetic properties of the materials wherethese structures were constructed

According to Tatyana [12] buried ovens filled with earthpottery or ashes will show positive magnetic anomalies withan amplitude range from 20 to 50 nT These anomalies aredue to the magnetization of certain ferromagnetic oxidesgrains of iron magnetite and hematite present in the bakedclay of the ovens When the kiln is heated above the Curietemperatures of the grains the latter become demagnetizedand as the kiln cools the grains acquire a magnetic potential

Furthermore other archaeological structures such aswells cisterns or pits filled with ashes fragments of ceramicsand burnt soil may create positive anomalies of about 50-75 nT The structures made of earth typically create magneticanomalies in the range of 1-20 nT The walls of sandstone orlimestone can give negative magnetic anomalies with valuesranging from -2 to -20 nT Streets covered with tiles ofceramic pots or metal slag may give positive anomalies withamplitudes of about 10-100nT Pithoi associated with ancientGreek sites give positive anomalies of a greater intensity 50-100 nT [14 15]

2 Materials and Methods

The magnetic survey was undertaken by means of a G-816 geometric scalar magnetometer (Figure 3) [16 17] Thedata were measured in gamma (rsaquo) unit where 1 rsaquo = 1 nT(nanotesla)

Within our study project it is necessary for the anoma-liesobjects (paper map format) (Figure 4(a)) to be availablein an assigned digital format (Figure 4(b)) [18] This activityis the most important aspect to provide extreme flexibility ofour magnetic anomalies

In this technical brief we describe the digitization processof this nonpublished magnetic anomalies map provided byDr Patrice Cressier [11] Firstly we undertook the scanning ofourmagnetic mapThen the digitization has been performedusing a metric coordinate grid by preserving the originalinformation quality We have digitized (100x67) magneticdata manually and processed them to be useful as a tabularXYZ file

In order to eliminate the error introduced by the processof digitization operation we have geo-referenced the avail-able map using 4 calibration points (0 0) (0 30) (30 45)and (45 0) as indicated on the corners of the resulting map(Figure 4) Afterwards we have evaluated the overall residualerror which is of the order of 5 times 10minus5m Taking into accountthe scale of the digitized map (1 cm997888rarr5m) the real valuerepresented on the map is 0025m which is smaller thanthe dimension of the interpolation grid of 045 times 045m2Therefore when digitizing the intervals of the values ofanomalies and their position will not be affected or distorted

The magnetic map has described positive anomalies ofelongated and nearly semicircular shapes located mainly inthe southwestern part of the area with moremodest negativeanomalies immediately around the main positive signalsAccording toCressier [9] the three mainmagnetic anomaliesof amplitude higher than 20 nT are associated with buriedceramic ovens ldquobakedrdquo located at a few centimeters below theground This assumption coincides with the interpretationgiven by Tatyana in the section above which suggests thatthe rooms containing ovens filled with earth pottery or asheswill be seen in magnetic maps as positive anomalies with anintensity of 20-50 nT


5∘27

20

W 5∘27

10

W 5∘26

50

W 5∘26

40

W

34∘30

50

N

34∘30

40

N

34∘30

30

N

34∘30

50

N

34∘30

40

N

34∘30

30

N

5∘27

0W

5∘27

20

W 5∘27

10

W 5∘26

50

W 5∘26

40

W5∘27

0W

(a)

(b)


(a)

G-816

Buried oven

(b)



41

-29-22-15-8-1613202734

0 30252015105

0

45

40

35

30

25

20

15

10

5

nT

(a)

-30-26-22-18-14-10-6-226101418222630343842

0 30252015105

0

45

40

35

30

25

20

15

10

5nT

(b)







n2sum


(1)


n2sum

f=minusn2exp[(21205872120587if120582)z]

(2)







363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(a)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(b)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(c)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(d)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(e)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(f)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(g)



0 30252015105

0 302520151050

45

40

35

30

25

20

15

10

5

0

45

40

35

30

25

20

15

10

5





5 Conclusions


Data Availability




Acknowledgments


References
































Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy
















5∘27

20

W 5∘27

10

W 5∘26

50

W 5∘26

40

W

34∘30

50

N

34∘30

40

N

34∘30

30

N

34∘30

50

N

34∘30

40

N

34∘30

30

N

5∘27

0W

5∘27

20

W 5∘27

10

W 5∘26

50

W 5∘26

40

W5∘27

0W

(a)

(b)


(a)

G-816

Buried oven

(b)



41

-29-22-15-8-1613202734

0 30252015105

0

45

40

35

30

25

20

15

10

5

nT

(a)

-30-26-22-18-14-10-6-226101418222630343842

0 30252015105

0

45

40

35

30

25

20

15

10

5nT

(b)







n2sum


(1)


n2sum

f=minusn2exp[(21205872120587if120582)z]

(2)







363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(a)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(b)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(c)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(d)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(e)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(f)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(g)



0 30252015105

0 302520151050

45

40

35

30

25

20

15

10

5

0

45

40

35

30

25

20

15

10

5





5 Conclusions


Data Availability




Acknowledgments


References
































Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy
















41

-29-22-15-8-1613202734

0 30252015105

0

45

40

35

30

25

20

15

10

5

nT

(a)

-30-26-22-18-14-10-6-226101418222630343842

0 30252015105

0

45

40

35

30

25

20

15

10

5nT

(b)







n2sum


(1)


n2sum

f=minusn2exp[(21205872120587if120582)z]

(2)







363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(a)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(b)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(c)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(d)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(e)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(f)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(g)



0 30252015105

0 302520151050

45

40

35

30

25

20

15

10

5

0

45

40

35

30

25

20

15

10

5





5 Conclusions


Data Availability




Acknowledgments


References
































Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy
















363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(a)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(b)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(c)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(d)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(e)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(f)

363432302826242220

0 302520151050 105

0

45

40

35

30

25

20

15

10

5

m

nT

N

W E

S

(g)



0 30252015105

0 302520151050

45

40

35

30

25

20

15

10

5

0

45

40

35

30

25

20

15

10

5





5 Conclusions


Data Availability




Acknowledgments


References
































Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy
















0 30252015105

0 302520151050

45

40

35

30

25

20

15

10

5

0

45

40

35

30

25

20

15

10

5





5 Conclusions


Data Availability




Acknowledgments


References
































Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy































Journal of










Volume 2018





Geophysics


Journal of




Microbiology





Agronomy















analysis of the magnetic anomalies of buried archaeological...

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