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D-Index & Metrics

Discipline name D-Index World Ranking Current World Ranking National Ranking Current National Ranking Publications Citations
Earth Science 37 6968 6455 715 662 115 4462

D. A. Spears publications per year

The chart shows the history of publications by D. A. Spears between 1961 and 2025, highlighting the no. of papers published in each year and offering an overview of the publication velocity of this scholar. D. A. Spears published across 65 years, from 1961 to 2025, averaging 2 papers a year. Output peaked at 6 publications in 1981. 4 of the 131 publications appeared in the last two years.

No. of publications
2 4 6
Bar chart. Horizontal axis: year, 1961 to 2025. Vertical axis: number of publications, 0 to 6. Peak 6 publications in 1981. 1961: 2 publications 1962: 0 publications 1963: 0 publications 1964: 2 publications 1965: 1 publication 1966: 2 publications 1967: 1 publication 1968: 1 publication 1969: 2 publications 1970: 3 publications 1971: 2 publications 1972: 2 publications 1973: 2 publications 1974: 2 publications 1975: 3 publications 1976: 3 publications 1977: 0 publications 1978: 1 publication 1979: 3 publications 1980: 1 publication 1981: 6 publications 1982: 3 publications 1983: 2 publications 1984: 3 publications 1985: 2 publications 1986: 3 publications 1987: 2 publications 1988: 1 publication 1989: 5 publications 1990: 0 publications 1991: 3 publications 1992: 2 publications 1993: 5 publications 1994: 4 publications 1995: 4 publications 1996: 1 publication 1997: 3 publications 1998: 2 publications 1999: 6 publications 2000: 3 publications 2001: 3 publications 2002: 1 publication 2003: 1 publication 2004: 4 publications 2005: 1 publication 2006: 3 publications 2007: 4 publications 2008: 0 publications 2009: 1 publication 2010: 0 publications 2011: 0 publications 2012: 1 publication 2013: 2 publications 2014: 0 publications 2015: 2 publications 2016: 2 publications 2017: 1 publication 2018: 0 publications 2019: 2 publications 2020: 0 publications 2021: 2 publications 2022: 3 publications 2023: 1 publication 2024: 3 publications 2025: 1 publication
1961 2025

131 publications in total across all disciplines

View publications per year as a table
D. A. Spears: publications per year, 1961 to 2025
Year Publications
1961 2
1962 0
1963 0
1964 2
1965 1
1966 2
1967 1
1968 1
1969 2
1970 3
1971 2
1972 2
1973 2
1974 2
1975 3
1976 3
1977 0
1978 1
1979 3
1980 1
1981 6
1982 3
1983 2
1984 3
1985 2
1986 3
1987 2
1988 1
1989 5
1990 0
1991 3
1992 2
1993 5
1994 4
1995 4
1996 1
1997 3
1998 2
1999 6
2000 3
2001 3
2002 1
2003 1
2004 4
2005 1
2006 3
2007 4
2008 0
2009 1
2010 0
2011 0
2012 1
2013 2
2014 0
2015 2
2016 2
2017 1
2018 0
2019 2
2020 0
2021 2
2022 3
2023 1
2024 3
2025 1
Total 131
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D. A. Spears publication distribution in Earth Science in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Earth Science in 2026. The highlighted bar marks where D. A. Spears sits on this spectrum.

No. of scientists
100 200 300 400 500
Bar chart with 58 bars. Horizontal axis: publications, 38–47 to 603+. Vertical axis: number of scientists, 0 to 557. Most scientists, 557, have 128–137 publications. The last bar groups every scientist with 603 publications or more. The highlighted bar, 108–117 publications, is where this scientist sits. 38–47 publications: 5 scientists 48–57 publications: 33 scientists 58–67 publications: 94 scientists 68–77 publications: 161 scientists 78–87 publications: 278 scientists 88–97 publications: 376 scientists 98–107 publications: 404 scientists 108–117 publications: 484 scientists 118–127 publications: 540 scientists 128–137 publications: 557 scientists 138–147 publications: 491 scientists 148–157 publications: 495 scientists 158–167 publications: 458 scientists 168–177 publications: 490 scientists 178–187 publications: 414 scientists 188–197 publications: 401 scientists 198–207 publications: 333 scientists 208–217 publications: 292 scientists 218–227 publications: 290 scientists 228–237 publications: 262 scientists 238–247 publications: 243 scientists 248–257 publications: 208 scientists 258–267 publications: 185 scientists 268–277 publications: 147 scientists 278–287 publications: 128 scientists 288–297 publications: 119 scientists 298–307 publications: 120 scientists 308–317 publications: 107 scientists 318–327 publications: 93 scientists 328–337 publications: 87 scientists 338–347 publications: 64 scientists 348–357 publications: 87 scientists 358–367 publications: 60 scientists 368–377 publications: 60 scientists 378–387 publications: 34 scientists 388–397 publications: 50 scientists 398–407 publications: 44 scientists 408–417 publications: 31 scientists 418–427 publications: 39 scientists 428–437 publications: 27 scientists 438–447 publications: 36 scientists 448–457 publications: 27 scientists 458–467 publications: 29 scientists 468–477 publications: 30 scientists 478–487 publications: 19 scientists 488–497 publications: 15 scientists 498–507 publications: 18 scientists 508–517 publications: 19 scientists 518–527 publications: 16 scientists 528–537 publications: 10 scientists 538–547 publications: 11 scientists 548–557 publications: 14 scientists 558–567 publications: 11 scientists 568–577 publications: 7 scientists 578–587 publications: 14 scientists 588–597 publications: 5 scientists 598–602 publications: 4 scientists 603+ publications: 100 scientists
38–47 publications 603+

This scientist: 115 publications — 19th percentile

19% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 603 publications or more.

View publications distribution as a table
Number of Earth Science scientists by publication count, Research.com 2026 ranking edition. Based on 9,176 ranked scientists.
Publications Scientists This scientist
38–47 5
48–57 33
58–67 94
68–77 161
78–87 278
88–97 376
98–107 404
108–117 484 115
118–127 540
128–137 557
138–147 491
148–157 495
158–167 458
168–177 490
178–187 414
188–197 401
198–207 333
208–217 292
218–227 290
228–237 262
238–247 243
248–257 208
258–267 185
268–277 147
278–287 128
288–297 119
298–307 120
308–317 107
318–327 93
328–337 87
338–347 64
348–357 87
358–367 60
368–377 60
378–387 34
388–397 50
398–407 44
408–417 31
418–427 39
428–437 27
438–447 36
448–457 27
458–467 29
468–477 30
478–487 19
488–497 15
498–507 18
508–517 19
518–527 16
528–537 10
538–547 11
548–557 14
558–567 11
568–577 7
578–587 14
588–597 5
598–602 4
603+ 100
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D. A. Spears D-index placement in Earth Science in 2026

The chart shows the D-index (discipline H-index) distribution of Earth Science scientists ranked by Research.com in 2026. The highlighted bar marks where D. A. Spears sits on this spectrum.

No. of scientists
100 200 300
Bar chart with 77 bars. Horizontal axis: D-Index, 30 to 106+. Vertical axis: number of scientists, 0 to 389. Most scientists, 389, have 36 D-Index. The last bar groups every scientist with 106 D-Index or more. The highlighted bar, 37 D-Index, is where this scientist sits. 30 D-Index: 144 scientists 31 D-Index: 215 scientists 32 D-Index: 278 scientists 33 D-Index: 379 scientists 34 D-Index: 366 scientists 35 D-Index: 372 scientists 36 D-Index: 389 scientists 37 D-Index: 366 scientists 38 D-Index: 344 scientists 39 D-Index: 349 scientists 40 D-Index: 296 scientists 41 D-Index: 289 scientists 42 D-Index: 277 scientists 43 D-Index: 279 scientists 44 D-Index: 248 scientists 45 D-Index: 257 scientists 46 D-Index: 212 scientists 47 D-Index: 202 scientists 48 D-Index: 207 scientists 49 D-Index: 204 scientists 50 D-Index: 183 scientists 51 D-Index: 178 scientists 52 D-Index: 182 scientists 53 D-Index: 178 scientists 54 D-Index: 163 scientists 55 D-Index: 117 scientists 56 D-Index: 163 scientists 57 D-Index: 120 scientists 58 D-Index: 113 scientists 59 D-Index: 136 scientists 60 D-Index: 135 scientists 61 D-Index: 96 scientists 62 D-Index: 103 scientists 63 D-Index: 83 scientists 64 D-Index: 103 scientists 65 D-Index: 83 scientists 66 D-Index: 89 scientists 67 D-Index: 92 scientists 68 D-Index: 89 scientists 69 D-Index: 78 scientists 70 D-Index: 75 scientists 71 D-Index: 53 scientists 72 D-Index: 62 scientists 73 D-Index: 54 scientists 74 D-Index: 35 scientists 75 D-Index: 52 scientists 76 D-Index: 50 scientists 77 D-Index: 32 scientists 78 D-Index: 37 scientists 79 D-Index: 20 scientists 80 D-Index: 33 scientists 81 D-Index: 36 scientists 82 D-Index: 34 scientists 83 D-Index: 34 scientists 84 D-Index: 24 scientists 85 D-Index: 19 scientists 86 D-Index: 18 scientists 87 D-Index: 26 scientists 88 D-Index: 30 scientists 89 D-Index: 17 scientists 90 D-Index: 21 scientists 91 D-Index: 19 scientists 92 D-Index: 15 scientists 93 D-Index: 14 scientists 94 D-Index: 20 scientists 95 D-Index: 9 scientists 96 D-Index: 10 scientists 97 D-Index: 15 scientists 98 D-Index: 13 scientists 99 D-Index: 3 scientists 100 D-Index: 13 scientists 101 D-Index: 3 scientists 102 D-Index: 9 scientists 103 D-Index: 4 scientists 104 D-Index: 6 scientists 105 D-Index: 6 scientists 106+ D-Index: 98 scientists
30 D-Index 106+

This scientist: 37 D-Index — 27th percentile

27% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 106 D-Index or more.

View D-Index distribution as a table
Number of Earth Science scientists by D-index, Research.com 2026 ranking edition. Based on 9,176 ranked scientists.
D-Index Scientists This scientist
30 144
31 215
32 278
33 379
34 366
35 372
36 389
37 366 37
38 344
39 349
40 296
41 289
42 277
43 279
44 248
45 257
46 212
47 202
48 207
49 204
50 183
51 178
52 182
53 178
54 163
55 117
56 163
57 120
58 113
59 136
60 135
61 96
62 103
63 83
64 103
65 83
66 89
67 92
68 89
69 78
70 75
71 53
72 62
73 54
74 35
75 52
76 50
77 32
78 37
79 20
80 33
81 36
82 34
83 34
84 24
85 19
86 18
87 26
88 30
89 17
90 21
91 19
92 15
93 14
94 20
95 9
96 10
97 15
98 13
99 3
100 13
101 3
102 9
103 4
104 6
105 6
106+ 98
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Overview

D. A. Spears is affiliated with the University of Sheffield in the United Kingdom and has contributed to the field of Earth and Planetary Sciences, focusing primarily on geochemistry, petrology, and related disciplines.

Their research covers multiple subfields, including geochemistry and petrology, geophysics, mechanical engineering, biomaterials, and anthropology.

The main topics of Spears' work are:

  • Coal and Its By-products
  • Geological and Geochemical Analysis
  • Geochemistry and Elemental Analysis
  • Clay minerals and soil interactions
  • Archaeology and Natural History
  • Advanced materials and composites
  • Extraction and Separation Processes

Spears has authored or coauthored several papers, with notable works including:

  • NEW DIGITAL GEOLOGIC MAP OF VIRGINIA COMPLETED AS A LEVEL 2 GEMS GEODATABASE (2022), published in Abstracts with Programs - Geological Society of America
  • Geology, geochemistry, mineralogy and genesis of the Spetsugli high-germanium coal deposit in the Pavlovsk coalfield, Russian Far East (2021), published in Ore Geology Reviews
  • Modes of occurrence of germanium and tungsten in the Spetsugli germanium ore field, Pavlovka brown coal deposit, Russian Far East (2021), published in Ore Geology Reviews
  • Geochemistry and rare-metal potential of coals of the Sakhalin coal basin, Sakhalin island, Russia (2023), published in International Journal of Coal Geology
  • Mineralogy and geochemistry of rare metal (Zr-Nb-Hf-Ta-REE-Ga) coals of the seam XXX of the Izykh Coalfield, Minusinsk Basin, Russia: Implications for more widespread rare metal mineralization in North Asia (2024), published in International Journal of Coal Geology

Frequent co-authors include:

  • S.I. Arbuzov
  • I. Yu. Chekryzhov
  • Sergey S. Ilenok
  • А. С. Холодов
  • Alexey V. Vergunov

Their research has been published in several scientific venues, among which the most frequent are:

  • International Journal of Coal Geology
  • Abstracts with Programs - Geological Society of America
  • Ore Geology Reviews
  • SSRN Electronic Journal

Best Publications

  • Geochemistry and origin of elements in some UK coals

    D.A Spears;Y Zheng

  • Mineral matter and trace elements in coals of the Gunnedah Basin, New South Wales, Australia

    Colin R Ward;D.A Spears;Carol A Booth;Ian Staton

  • The formation of sedimentary iron minerals

    C. D. Curtis;D. A. Spears

  • The origin of tonsteins, an overview, and links with seatearths, fireclays and fragmental clay rocks

    D.A. Spears

  • A geochemical and mineralogical investigation of some British and other European tonsteins

    D. A. Spears;R. Kanaris‐Sotiriou

  • The breakdown of British Coal Measure rocks

    R.K. Taylor;D.A. Spears

  • Titanium in some Carboniferous sediments from Great Britain

    D.A Spears;R Kanaris-Sotiriou

  • Mineral matter in coals: cleat minerals and their origin in some coals from the English Midlands

    D.A. Spears;S.A. Caswell

  • Towards a classification of shales

    D. A. Spears

  • MAS NMR study of surface-modified calcined kaolin

    Qinfu Liu;D.A. Spears;Qinpu Liu

  • The distribution and origin of trace elements in a UK coal; the importance of pyrite

    D.A Spears;L.I Manzanares-Papayanopoulos;C.A Booth

  • The determination of trace element distributions in coals using sequential chemical leaching—A new approach to an old method

    D.A. Spears

  • Analysis of iron sulphides from UK coal by synchrotron radiation X-ray fluorescence

    Richard N. White;Joseph V. Smith;Joseph V. Smith;D.Alan Spears;Mark L. Rivers;Mark L. Rivers

  • Antimony and arsenic anomalies in the coal seams from the Gokler coalfield, Gediz, Turkey

    A.I Karayigit;D.A Spears;C.A Booth

  • Role of clay minerals in UK coal combustion

    D.A Spears

  • An Upper Carboniferous tonstein of volcanic origin

    D.A. Spears;Clive Maitland Rice

  • Trace elements in combustion residues from a UK power station

    D.A. Spears;M.R. Martinez-Tarrazona

  • Geochemical and mineralogical characteristics of a power station feed-coal, Eggborough, England

    D.A. Spears;M.R. Martinez-Tarazona

  • Nature of tonsteins in the Azeisk deposit of the Irkutsk Coal Basin (Siberia, Russia)

    S.I. Arbuzov;A.M. Mezhibor;D.A. Spears;S.S. Ilenok

  • The geochemistry of environmentally important trace elements in UK coals, with special reference to the Parkgate coal in the Yorkshire–Nottinghamshire Coalfield, UK

    D.A. Spears;S.J. Tewalt

Frequent Co-Authors

Colin R. Ward
Colin R. Ward University of New South Wales
Warren D. Huff
Warren D. Huff University of Cincinnati
A. Martínez-Alonso
A. Martínez-Alonso Spanish National Research Council
Juan M.D. Tascón
Juan M.D. Tascón Spanish National Research Council

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