Annals of Library Science and Documentation

1982,29(4},17t'-18'-

PLATE TECTONICS AND SEA-FLOOR SPREADING:A CITATION ANALYSIS STUDY FORIDENTIFYING PERIODICAL LITERATURE

A paper by LePichon on sea-floor spreadingpublished in 1968 in the Journal of GeophysicalResearch was cited 642 times during the years1968 to 1979. 79 journals originating from 19countries throughout the world cited this work.The work was not only cited by the journals ofgeophysics and geology but by several in generalscience, chemistry, physics, botany, zoology etc.Wide scattering and seepage of information wasobserved as the citations were made in a largenumber of journals of various subject areas andspecialities, published from so many countries,This supports the hypothesis of epidemic natureof this work of X LePichon. A list of the citingjournals is presented and a group of core jour-nals is suggested for the documentalists who areto serve the scientists in the research areas ofEarth Tectonic or Geotectonics.

1 INTRODUCTION

Citation analysis is becoming an importantresearch tool for the understanding of science,scientists, scientific contributions and publica-tions. Citation studies and other bibliometrictechniques are being applied for the manage-ment of science, analysing the structure anddirection of science, measuring the utility ofjournals and relationships between journals andfields and measuring the performance of scien-tists. A vast amount of literature is getting publi-shed on such kind of evaluative studies. Theliterature on bibliometrics and citation indexingand analysis is well documented in a recentbibliography [6]. A comprehensive review ofthe whole area is available in a report [8] . Narin

178

DAVENDRA k. GUPTADepartment of Library StudiesUniversity of IbadanIBADAN {Nigeria]

in his report [8] has made a thorough review ofseveral papers in which bibliometric measures,publication and citation counts have been cor-related with other measures of eminence such asawards, listings and academic rank or affiliation.In almost all cases the bibliometric measures forgroups of scientists are correlating reasonablywell from 0.5 to 0.8 with the other measures.

As a communication system, the networkof journals play a paramount role in the ex-change of scientific and technical information.Garfield has said that citation analysis could beused as a tool in evaluating and ranking thejournals [1]. In his Essays [4] Garfield hasreported several studies on journal citations inspecific subject areas. In his Current Comments[2] there -is reference to most cited journals ingeology and geophysics; and also on one of themost cited journal in geophysics [3] .

2 SCOPE OF THE STUDY

In this paper, an attempt is made to present dataabout the periodical literature which cited themost cited article of LePichon on sea-floorspreading published in the most cited journal ingeophysics [3]. The data of citation analysis ofLePichon's works and detailed analysis of thisspecific paper are reported in an earlier study[5]. The scope, definition etc. of sea-floorspreading and plate tectonics are also given inthe same paper. It was found that LePichon'spaper published in 1968 received 593 citationsout of 1513 citations received for all his contri-butions. Moreover, this was not only citedheavily, but was also cited for a considerably

Ann Lib Sci Doc

PLATE TECTONICS AND SEA-FLOOR SPREADING

longer period of time. To illustrate how widelyLePichon's ideas, contained in this paper, havespread it was necessary to analyse the range ofjournal titles in which this work was cited.Therefore, the scope of the previous study wasextended to examine the followings:

the range of the journal titles which havecited this paper to prove the hypothesisthat the greater the number of titles themore widely the ideas are spread;

the countries in which the citing journalsare published, to prove that fur a set ofjournals, the greater the number of coun-tries the more widely the ideas have spread;

the disciplines to which the citing journalsbelong to prove that larger the number ofdisciplines (wide scattering) of the journals,wider the spread of ideas and better theinterrelationship of the disciplines; (greaterinteraction with other fields is the measureof multidisciplinary activity of a specificfield). The main purpose of this investiga- .tion was to build a model of journalcommunication network that should pro-vide more functional definition of disci-pline (Marine geology in this case) andspeciality (sea-floor spreading in this case)that will make it possible to define in detailhow different fields of knowledge interact;

Further, it also aimed to make a rank list of cit-ing journals which may be useful to scientistsand documentalists who are concerned with thisarea of specialization.

3 METHODOLOGY

The data base which was created for a previousstudy to examine the epidemic nature of Le-Pichon's paper [5] was used in this study. Theanalysis is extended upto 1979 in the presentstudy. Citations were counted for the years1968 to 1979 for LePichon's most cited paper[7] and data were collected for the titles ofciting journals, kind of publications citing thepaper, the year of citation etc. The informationregarding the full titles, country of publication

Vol 29 No 4 Dee 1982

etc. was supplemented by consulting the latestedition of Ulrich's International PeriodicalsDirectory (20th edition, 1981).

4 ANALYSIS AND DISCUSSION

The data about the forms of publications citingthis work, year to year for the period 1968-1979are given in Table 1.

4.1 Annotations:

1. During the period, 1968-1979, 642citations were received by this paper.

2" the paper was very heavily citedduring 1970, 1971 and 1q72 receivingalmost 100 citations per year on theaverage.

3. There is a declining trend of citationsover the rest of the years but thenumber of citations even during theyear 1979, after 11 years of its publi-cation, is quite high, being 23.

4. Journal articles have cited it for 561times, ie, 87.4% of all the citations;

5. Review articles are next in number,and still continuing to cite this item.

Other characteristics of citations for thispaper have been already discussed in the earlierpaper[5] .

The data of citing journals for differentperiods are given in Table 2.

l.2 Annotations: Citing journals:

1. In all, 79 journals have cited it for 639times. This number is quite large for aspeciality like "sea-floor spreading"which is a minor aspect of marine geo-logy and tectonics. This clearly indi-cates that the ideas contained in thiswork of LePichon were. very widelycited and that confirms the hypothesismade in this study;

179

GUPTA

Tabl,e 1: Chronological, distribution of citations accordingto the forms of citing publications:

Year ofcitation:

19681969197019711972

1973

197419751976197719781979

4

46

9690806837

31)

39

262321

Total 561Percentageof tota I: 87.4

A R LN TotalD E percentage oftotal

2 6 0.911 61 9.5

16.7

15.7

14.6

35

4

53

7

2 107

2 101

2 9473 11.43

3

7

42 6.5

5.96.44.74.0

38

412

3 30263

2 23642

3.7

35 21 20 3 100.02

5.5 3.3 3. 1 0.5 0.3 100.0

2. Only a few journals, say only five ofthem or 6% of all have cited 343 times(53.6% of all the citations);

ce in first twelve titles have emergedas important journals of this specialityalso. In Garfield's list [2] of most cit-ed journals in geology and geophysics,they were listed at 5th, 3rd and 13thrank respectively while in this caseNature has improved its rank. Al-though these journals are not devotedto geology/geophysics journals, theyare "general science" journals, yetthey are ranked as important journalsin geosciences as well as in this specia-lity.

3. Only 12 journals (15% of all) havegiven upto 75% of all the citations;

4. All other journals, 67 of them carrythe remaining citations in which thecontributions on the topic of sea-floorspreading is scattered.

5. Nature in first five, Science in firsteight, and American Journal of Scien-

180 Ann Lib Sci Doc

PLATE TECTONICS AND SEA-FLOOR SPREADING

Tabl.e 2: RANK LIST OF CITING JOURNALS:

S. Abbreviated title of Period of Citation Total No. cumul at ive percentage cumulat.No. Journals 1965-1969 1970-1974 1975-1979 citations c itat ions of total %

1 2 3 4 5 6 7 8 9I 1 Jou r Geophys Res 13 66 14 93 93 14.5 14.52 2 Geol Soc Amer Bull 7 65 9 81 174 12.7 27.23 ~ Na ture 9 54 3 66 240 10.3 37.54 4 iectonophys ics 3 30 21 54 294 8.5 46.05 5 Earth Planet sci lett. 8 30 11 49 343 7.7 53.76 6 Am Assoc Pet.Geol .Bull. 0 23 15 38 381 5.9 59.67 7 Geophys J Roy Astro Soc. 3 21 12 36 417 5.6 65.28 8 Science 10 12 1 23 440 3.6 68.89 9 Bull Seismol Soc.Amer. 8 4 13 453 2.0 70.8

10 10 Phil T Roy A 0 11 1 12 465 2.0 ]2.811 10 Amer J se t , 0 8 4 12 477 1.9 74.712 12 J. Geology 1 8 2 11 488 1.7 76.413 13 Cr Acad Sci 0 5 4 10 498 1.6 78.014 14 Can J Earth Sci 0 7 2 9 507 1.4 79.415 15 Marine Geology 0 4 4 8 515 1.2 80.616 16 Trans Amer Geophys (EOS) 0 6 7 522 1.1 81.717 17 Nz J Geology 0 3- " 7 529 1.1 82.818 18 Rev Geophys space Phys. 0 3 3 6 535 0.9 83.719 19 Rev (,eog Ph 0 2 1; 6 541 0.9 84.620 20 Deep Sea Research 2 3 0 5 546 0.8 85.421 20 Annals Acad Brasil 0 4 5 551 0.8 86.222 20 Geology 0 0 5 5 556 0.8 87.023 23 Pure App. Geophys 0 3 1 4 560 0.6 87.624 24 J Geomagn Geoelect. 0 3 0 3 563 0.5 88.125 24 Anatarctica J U.S. 0 3 0 3 566 0.5 88.626 24 Annual Rev Earth PI.net 0 0 13 3 569 0.5 89.127 24 Contrib Mln.Petrol 0 1 2 3 572 0.5 89.628 28 Naturwi ssen 1 0 2 574 0.3 89.929 28 J Geophysics 0 1 1 2 576 0.3 90.230 28 Annals de Geophysique 0 1 1 2 578 0.3 90.531 28 Geop.hysics 1 0 2 580 0.3 90.832 28 Ann Ny Acad Sci 1 1 0 2 582 0.3 91.133 28 ScJ.J. 1 1 0 2 584 0.3 91.434 28 Botan Rev 0 2 0 2 586 0.3 91.1735 28 Papers Meteoro I Geophys 0 2 0 2 588 0.3 92.036 28 Geological Magazine 0 2 0 2 590 0.3 92.337 28 Earth Science Review 0 2 0 2 592 0.3 92.638 28 J.Fluid Mechanics 0 2 0 2 594 0.3 92.939 28 Economic Geology 0 2 596 0.3 93.240 28 J Geol Soc India 0 2 598 0.3 93.541 28 Pa Iaeogeog P 0 0 2 2 600 0.3 93.842 28 J Petrology 0 0 2 2 602 0.3 94.1

Table 2 (Contd.)

Vol 29 No 4 Dee 1982 181

SI.No.1;3 1.44 2.45 3.46 447 5.48 6.49 7.50 8.51 9.52 1053 11.54 1255 1356 1457 1558 1659 1760 1861 1962 2063 2164 22f5 2366 2467 2568 2669 2770 2871 2972 3073 3174 3275 3376 3477 3578 3679 37

GUPTA

The following 37 journals have contributed one citation each comprising totalpercentage 5. f} of the total: at the rank of 43:

Name of the JournalScientific AmericanDann)SSR SfRiv ltal GeoGeof is /'Ie t.IBISJ ZoologySearchAnn Geof i5Current sc ienceB Mar ine SciAstro AeronQ Rev lew BioiStud GeophysGeoch Cos AAnnual Rev FluidCopeiaAnnual Rev EntomAct Cicntifica VenezuelaBioscienceSyst Zool.Vie e t MilieuEngineering geologyAmerican ScientistBioI J LinnL1thosOkeaneologiaReport of Progress Phys.Rer.hercheAnnee BioiCC/Phys ChernRev Geol DyPhys_E 'PlanB CSAR 'Belgium8 Astr I CzRev.I.F.Pet.J VoldcanologyJ. Sed. Pet.

The data of citations by the publicationsother than the journal articles and journals inwhich they have been cited are presented mTable 3.

4.3 Annotations

182

1. Out of 642 citations, 562 citations aremade by the journal articles and theremaining 80 by other forms like re-views, letters to editors, notes, dis-cussions and editorials. This also con-firms the hypothesis that the item hasbeen covered by all kinds of publica-tions. Coverage by review publicationsaccounting for 35 citations is of consi-derable importrnce.

2. Out of 79 journals, 13 journals havecited the item only through review

and notes. Out if 13, nine journalshave cited the item only once in aplace other than a journal article.

3. One can easily observe that the firstsix journals listed in Table 2, are listedin Table 3 also; and that the Nature isthe only journal which has cited theitem in its editorials.

The wide scattering of information on sea-floor spreading could be seen from the data andanalysis presented above and they support thehypothesis on the epidemic nature of the ideascontained in the work of LePichon. The data onthe publications from the various countries!regions are presented in Table 4. Index to thepublications is given in Appendix I.

Ann Lib Sci Doc

PLATE TECTONICS AND SEA-FLOOR SPREADING

Table J: Distribution of citations made Ly the publications at herthan the journal articles:

Journal/publ ication:+ 1.

+ 2.+ 3.+ 4.

5.6.7.8.

+ 9.10

11

+ 12

+ 1314

+ 15+16

17+ 18

+ 19.+ 19.

20

21

22232425

+ 262728

Rev. GeophysAnn. Rev. EarthBotan RevEarth Science RevTectonophysics(4)AAPG Bulletin (6)J Geophys Res (1)Amer J. Sci. (11)

IBISCanad J Earth set (14)Antarct icaAstro aeronQ~Rev. B io I.

J Fluid Mech.Ann. Rev. Flu idLi thosPalaegeog PJ VolcanolRep.prog.phys.Ann. Rev. EntomolBooksEarth Sc.Planet lett. (5)

Nature (3)

Nz.J .Geol.Geol S Am B (2)Deep sea Res.Current scienceGeophysicsPhil.T Roy Soc Aother 52 journals

Total:

Review letters Notes Discussion Editorial

632

2

2

2

2

1

1

1

1

1

3

1

2

2

632

2

543'89312

1

931

1

2

1

1

2

1

1

34966

781

51

2

12

182

642

I'

1

3952

131

1

1

35 20 20 3 2

T* •• Total including journal articles;+ published only in one form, i.e., Review, Notes

Note: Within the parentheses is given the rank number of the journals.

Vol 29 No 4 Dee 1982 183

Table 4: ~ of pubUoation ~f tlw ";'tinq journals

C""nl:y of N"",ber of percentage cumulativepubllc.otlon Journals of total percentage

1. iJ.!:.A. 35 ~~.) ~~.32. U.K. 10 12.7 57.03. T~ Nether 1ands 9 n." 68.~

~. Fr.nce 7 8.9 77.3

5. West Ger.nany ) 3. ~ 80.76. Italy 3 3.4 84.0

7. U.S.S;R. 2 2.5 86.5

8. Belgium 1.3 87.8

9· 8razll 1.3 89.210. Canada 1.3 90.511. Czecko,s 'avak I II 1.3 91. 8

12. India 1.~ 93.2

13. Japan 1.3 ~.514. NewZeland 1.3 95.8

15. Norway 1.4 97.216. Swt t zer land 1.4 98.6

17. Venzuel. 1.~ 100.0

Total 79 100.0 100.0

4.4 Annotations

1. In all, 17 countries published the 79journals which have cited LePichon'swork. TIle scatter of the countries ofpublication indicate that the ideascontained in LePichon's paper havein fluenced many.

The nature of the seepage of informationcan be estimated by considering the subjectspread of the citing journals. This is shown inTable 5.

4.5 Annotations

1. The group of journals in general scien-ce is the largest, and many of themoccupy higher ranks. This a groupwhich serves a general population ofresearchers, specially to the peoplewho are working in the areas of multi-disciplinary nature. This group ofjournals is also a faster media ofcommunication of recent develop-ments in a specific field, controversialareas and issues on a specific topic.The large number of citing journals inthis group indicates that idea of sea-floor spreading must have attractedthe attention of scientists in many dis-ciplines.

184

GUPTA

Table s: LiaV-'ibution of tlul citing jourrtale =rding to."bj • .,t

subject .rea nl.lftber of percentage cumulativeJournals of tot.' percentage

General ScIence 18 22.8 22.8Ceophys ; cs :theoret Ica 1, exp l0-

ration. astronortl'f; 15Geoiogy 9Ceo logy + Geop""s! es ~(G.neral)

810SCIEHCE~:Biology

ZooJo'JY

Bot.any

Entomolog'1'

Horine geolOJiYPhys I cs

Fluid mechanics

Pet ro leum 'Geology

Engineering geology

Geochem is t rvPetrology

Sedimentology

Oceanography·

Geomagnet ism.

VolcatJology*

Tectonophys j cs *~eismo Iogy*

Heteorology*

Economic 9eolng~

Pa 1aeogeography

Geography

Mineralogy

Total

19.0 41.811.4 53.25.1 58.3

6.3 64.63.8 68.41.3 69.71.3 7'.0J.8 7~.82.5 77.32.5 79.82.5 82.31.3 83.61.3 8~.91.3 86.H1.3 8i.51.3 88.81.3 90.11.3 91.41.3 92.71.3 9~.01.3 95.3I.l 96.61.3 97.91.3 99.21.3 100.5

iOO.O 100.079

• Conmon "";th (;eophy8i.,. aZao.

2. The seepage of information can beobserved from a large number of jour-nals in the specialities of geology andgeophysics, physics and other relateddisciplines,

3. '.The seepage of information throughthe journals in the subject areas inBiosciences and Chemistry, Geogra-phy etc, affirms the wider scope andinfluence of the ideas contained inLePichon's paper.

4. The analysis of this data establishesthe theory of infectious and epide-mic nature of the idea and also estab-lishes the new theory of global tec-tonics. The subject has become nowa target of research of several speciali-ties" forming an important and Integ-ral part of Ocean Sciences - Tectonics.

Ann Lib Sci Doc

PLATE TECTONICS AND SEA-FLOOR SPREADING

5.1

CONCLUSION

The seepage and scattering of informationthrough several forms of publications andin a large number of journals, journals ofseveral disciplines and specialities, journalsoriginating from 17 countries throughoutthe world, support the hypothesis thatLePichon's paper contained ideas of edi-demic and infectious nature.

2. A core of five most important journals canbe identified out of 79 journals which havecited this work, as carrying and conveyingmost of the information on this speciality.The journals which have larger citingfrequency are likely to contain greateramount of data and information in thatspecific speciality.

3. A documentation or information centreserving the needs of scientists who areworking in the areas of sea-floor spreadingand plate tectonics, should have at leastthe first fifteen journals listed in Table 2,and should also scan journals from otherdisciplines and specialities or make use ofsecondary services to supplement infor-mation needs of their users.

4. The concept of sea-floor spreading andplate tectonics appears' now to have beenaccepted and recognised very widely amongthe scientists.

5. Further analysis of this data to identify themost active workers, their affiliations.jnet-work of scientists and schools of thoughtwithin this speciality would be interesting.

Vo129 No 4 Dee 1982

Another area of investigation suggested isto test the applicability of Bradford's lawon the citation data of this single work ofepidemic nature. The data seems to beadequate enough having 642 citations toanalyse.

REFERENCES

1. Garfield, Eugene. Citation analysis as atool in journal evaluation. Science, 1972,178(4060),471-79.

2. ----------jCurrent Comments: J oumal Cita-tion Studies x. Geology and Geophysics.Current Contents, 30j 5-9j (July 24,1974).

3. ----------jCurrent Comments: Journal Cita-tion Studies. xi. Journal of GeophysicalResearch. Current Contents. 33j 5-8?(August 14, 1974).

----------jEssays of an Information Scientist.Volume 1-2. lnstitute for InformationScience, Philadelphia, Pa.,1977.

Gupta, D.K. Plate Tectonics: A Study ofTransmission of Ideas: Ann Lib Sci Doc,1978,25,86-92.

Hjerppe, Roland. A bibliography of biblio-metrics and citation indexing and analysis.Report TRITA-LIB-2013, RIT, Stock-holm, 1978.

4.

5.

6.

7. LePichon, Xavier. Sea-floor spreading andcontinental drift. J Geophysics Res, 1968,73(12),3661-97.

Narin, F. Evaluative bibliometric: the useof publication and citation analysis in theevaluation of scientific activity. ComputerHorizon project, 1976.

8.

185

GUPTA

Appendix-IIndex to the journals and country ofpublication (item numbers)l. U.S.A. 1,2,7,8,9,11,12,16,18,

22.25.26,27,31,32,33.34,39,43,47,51,52,53,54,55,57,58,59,61,62,65,66,72,77

2. U.K. 3,6,10,20,35,36,38,42,48,69

3. The Netherlands 4,5,15,37,41,64,74,78,79,

4. France 13,19,30,63,70,71,73,5. Italy 45,46,506. West Germany 28,29,687. U.S.S.R. 44,568. Belgium 759. Brazil 21

10. Canada 1411. India 4012. Japan 2413. Newzealand 1714. Norway 6715. Switzerland 2316. Venezuela 6017. Czekoslavakia 76

186

Appendix-II

Index to the subjects covered (itemnumbers)l. General Science 3,8,10,11,13,21,25,

28,32,33,43,44,47,4~~51,60,65,70,75.

2. Geophysics 1,7,16,18,23,24,29,30,31,46,50,53,55,74,76.

3. Geology 2,12,14,17,19,22,36,40,45,67

4. Geology + 5,26,37,73geophysics

5~ Botany 346. Biology 54,61,63,66, 717. Entomology 598. Zoology 48,58,629. Physics 69,72

10. Fluid Mechanics 38,5711. Economic 39

geology12. Engineering 64

geology13. Geochemistry 5614. Marine Geology 15,20,5215. Petroleum 6,77

Geology16. PE'!"Cro1ogy 4217. Palaeogeography 4118. Mineralogy 2719. Sedimentology 7920. Geomagnet ism 242l. Meteorology 3522. Oceanography 6823. Seismology 924. Tectonophysics 425. Volcanology 78

Ann Lib Sci Doc