KIMBERLITl

CONFEREt

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FIFTH INTERNATIONAL KIMBERLITE CONFERENCE

Araxa, June 1991

EXTENDED ABSTRACTS

o CPRM-Special Publication 2/91 Brasilia

Copyright © 1991 by CPRM. All rights reserved.

Additional copies and other volumes associated with the Conference may be purchosed from:

Companhia de Pesquisa de Recursos Minerais - CPRM Centro de Documentagao T6cnica - CEDOT Av. Pasteur, 404 - Urea - 22.290 Rio de Janeiro - RJ - Brazil.

Tel.: (021) 295-0032 R. 389 - Fax.: (021) 542-3647

International Kimberlite Conference, 5. Arax6, 1991.

Extended abstracts. Brasilia, CPRM, 1991.

584p. ilust. (CPRM - Speciai Publication, 2/91).

1. Kimberlito - Congressos. I. Companhia de Pesquisa de Recursos Minerais, il. S6rie. HI. Titulo.

CDD: 552.063 CDU: 552.323.6

Abstracts were submitted by the authors in camera-ready form and, therefore, were not edited. The Organizing Committee of the 5^^ International Kimberlite Conference takes no responsability for author errors or omissions.

FIFTH INTERNATIONAL KIMBERLITE CONFERENCE

ORGANIZING COMMITTEE

CHAIRMEN

H. O. A Meyer Purdue University

O. H. Leonardos University of Brasilia

SECRETARIAT

J. C. Caspar University of Brasilia

L A. Tompkins

University of Western Australia

SPONSORSHIP

The Organizing Committee of the Fifth International Kimberlite Conference generously acknowledges the help and sponsorship of the following organizations:

Academia Brasileira de Ciencias (ABC)

Companhia Brasileira de Metalurgia e Mineragao (CBMM)

Companhia de Pesquisa de Recursos Minerals (CPRM)

Companhia Vale do Rio Doce (CVRD)

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) Departamento Nacional da Produgao Mineral (DNPM)

International Mineralogical Association (IMA)

Mineralogical Society of America (MSA)

National Science Foundation (NSF)

Purdue University RTZ Mineragao Ltda.

Sociedade Brasileira de Geologia (SBG)

SOPEMI - Pesquisa e Exploragao de Min§rios Ltda.

Universidade de Brasilia (UnB)

Author Index

Afanas’ev, V.P . 1

Afanasiev, V.P . 391

Allsopp, H.L . 76

Almeida, F.F.M. de . 3

Ambroise, M . 6

Amshinsky, A.N . 339

Amstrong, R . 17

Andi,Z . 10,154,

. 208, 285, 448

Ashchepkov, I.V . 13

Aspen, P . 241

Bailey, D.K. . 237

Baker, N.R . 14

Barankevich, V.G. . . 495,556

Barasckov, Yu. P . 565

Baxter-Brown, R . 14

Bezborodov, S.M. . . 391, 481

Billington, F.R . 58

Bizzi, L.A. . 17

Blade, J.D . 20

Blaine, J.L . 58

Bodinier, J.L . 281

Bodrov, V. A . 527

Bogatikov, O.A . 484

Bogdanov, G.V . 492,

. 495, 498

Boltenkov, AV . 573

Borch,R.S . 212

Botelho,N.F . 60

Botkunov, A.1 . 391

Botova, M.M . 579

Boyd,S.R . 231

Boyd, F.R . 323, 329

Brandt, S.B . 558

Brey, G.P . 23, 26,

. 29,92,106

Bristow, J.W . 46

Brown, M.A . 76

Brown, L . 329

Browning, P . 405

Bulanova, G.P . 486, 488

Bulatov, V . V .... 29

Bush,M.D . 435

Bushueva, E.B . 490, 530

Caporuscio, F.A . . . 267, 385

Carlson, R.W . 183, 329

Castelo Branco, R.M.G. . . 35

Chappell, B.W . 344

Chaves, M.L.S.C . 40

Chen,Y.D . 42,45,316

Chien-Lu, C . 38

Clark, T.C . 46, 373

Clarke, L.B . 49

Clement, C.R . 361

Colgan, E.A . 76

Condliffe, E . 310

Cooper, G.1 . 279

Coopersmith, H.G . 52

Crozaz, G . 410

Cumming, B.C . 58

Damarupurshad, A. . 163, 383

Daniels, L.R.M . 55, 58

Danni, J.C. M . 60

Dante, C . 32

Davies, G.R . 63, 66,

. 310,326

Dawson, J.B . 69

DeWit,M.J . 17

Deakin, AS . 71

Dehuan, X . 10

Deines, P . 74

Dhamelincourt, P . 448

Dickin, AP . 133, 136

Dheprovskaya, L.V. . 558, 573

Dobbs, P.N . 76

Doroshev, A . 26

Downes, H . 281

Duncan, D.J . 76, 160

Duncan, R . 205

Eckert, J.0 . 410

Edgar, AD . 79

Edwards, D . 82

Eggler,D.H . 85,88

Egorov, K.N . 492,

. 495, 498, 573

Ermolaeva, L.A . 367

,Falk,R.W . 261

Fengxiang, L . 248, 454

Feoktistov, G.D . 501

Fett, A . 92

Field, S.W . 94, 323

Fipke, C.E . 97

Fodor, R.V . 101

Fogel, R . 20

Foley, S.F . 29,

. . 103, 106, 109

Foster, J.G . 112

Frdhlich, G . 245

Frantsesson, E.V . 516

Furlong, K.P . 85

Galimov, E.M . 502

Gandhok, G.R . 101

Garanin, V.K. .

481,484, 490,

.... 505,508,510,525,530

Gaspar, J.C. . .

. 127

Geach, C.L. . .

. 130

Gerneke, D.A .

. 318

Gibson, S.A . .

133, 136, 420

Girnis, A . . . .

. . . 513,564

Gittins, J .

. 193

Gobba, J.M. . .

. 116

Green, D.H. . .

. . .313,417

Green II, H.W.

. 212

Grib, V.P. . . .

. . . 367, 530

Griffin, B.J. . . .

. . . 82,231

Griffin, W.L. . .

... 42, 119,

. 139, 142, 145, 148,

. 310, 316, 332, 463, 475

Griffin, B.W. . .

. 231

Griffin, S.R. . .

. 463

Grossi-Sad, J.H.

. 60

Grubb, M.D. . .

. 151

Guanliang, L.

. 234

Ganther, M. . .

. 122

Guo, L .

. . . 154, 448

Gurney, J J.

119, 125, 142,

. 167, 177,224,225,264

. 298, 318, 320, 322, 336

Haebig, AE. . .

. 376

Haggerty, S.E. .

. 157,

. . . 323, 347

Hall, AE .

202, 376, 380

Hamilton, R. . .

. 112

Harris, J.W. . . .

. . 160,318,

.336, 456,459

Hart,R.J. . . .

. 163

Harte, B .

. . .167,224,

. 313,318,456,459

Hatton, C.J. . .

. . . 370, 383

Hearn, B. CJr. .

. 170

Helmstaedt, H.H.

. .173, 224

Hendry, G.L.

. . . 133, 136

Hochella, M.FJr.

. 432

Hoefer, H. . . .

. 106

Hollis, J.D. . . .

. 398

Hongfu, Z. . . .

. 248

Hops, J.J .

. 177

Horsch, H. . . .

. 383

Hu, S .

. . . .76,466

Huntley, P.M. .

. 261

Hwang, P. ...

. 180

Irving, AJ. . . .

183, 186, 188

Jacob, D .

. 190

Jacques, AL . 202,

. 205,392,475

Jago, B.C . 193

Jagoutz, E . 122, 190

Janse, AJ.A . 196, 199

Jennings, C.M.H . 58

Jianping, Z . 248

Jianzong, Z . 10

Jin,Z-M . 212

Kaminsky, F.V . 214

Kharkiv, AD . 551,

. 567, 579

Keller, J . 217

Kingston, MJ . 219

Kinny,P.D . 45,222

Kirkley, M.B . 224, 225

Kiser S.1 . 516

Knutson, J . 205

Koeber, C . 163

Kogarko,L. ...26,513,564

Kolesnik, Yu.N . 514

Kolod’ko,AA . 516

Komov . 518

Kononova, K.A . 484

Koptil, V.1 . 391

Kornilova, V.P . 521

Kostrovitsky, S.1 . 523

. 525, 527

Kudrjavtseva, G.P. ... 481,

. 484, 490, 505,

. 508,510,530

Kulakova, I.I. .... 533, 547

Kuligin, S . 391

Kvasnitsa, V. N . 569

Lasnier, B.M . 35

Lashchenov, V.A . 543

Laverova, T.N . 490,

. 508, 530

Laz’ko, E.E . 228, 581

Le Bas, M J . 49

Leat, P.T . 133, 420

Lee, J.E . 58

Lee,D.C . 231

Lei, Z . .248

Leonardos, O.H. . . 408, 437

Levin, V.1 . 516

Lihe, G . 10, 208

Lipskaya, V.1 . 495, 556

Lloyd, F.E . 79,237

Logvinova, AM . 240

Long, A . .241

Lorand, J.P . 88

Lorenz, V . 245, 392

Lucas, H . 380

Maggiore, C . 20

Makhin, A. 1 . 579

Makhotkin, I.L . 484

Manning, E.R . 435

Mariano, A.N . 251

Marshall, T.R . 254

Marx,M.R . 435

Maslovskaya, M.N. . . 558, 573

Mathez, E.A. . 20

Matthews, M.B . 167

McCallum, M.E. . . .151, 163, . . . 257,261,273,276,320,443

McCandless, T.E . 264

McCormick, T.C. . . 267, 385 McDonough, W.F. . 270, 344

Memmi, J.M . 273, 276

Mendelssohn, MJ. . . . 279,

. 285, 290

Mendes, M.H . 66

Menshagin, Yu.V . 543

Menzies, M.A. . 186, 241, 281

Meyer, H.O.A. . 17, 88,

. 163,279,

. 285, 290, 408

Mia, Q . 160

Middleton, R.C . 287

Mikhailichenko, O.A . . 484,

. 510,530

Milledge, H J. . 279, 285, 290

Mitchell, T.E . 20

Mitchell, J.G . 136

Mitchell, R.H . 251,

. 292, 295

Moore, R.O. . . 125, 177, 298 Morrison, M.A. . . . 133, 136

Muggeridge, M.T . 301

Nadejdina, E . 535

Navon, 0 . 304, 307

Neal, C.R . 410

Nenashev, N.1 . 541

Nixon, P.H. . . 63, 145, 310,

. 323, 326, 329

Novgorodov, P.G . 537

O’Brien, H.E . 188

O’Reilly, S.Y . 42, 45,

. 139,145,316,332

Odling, N.W.A. . 313

Oleinikov, O.B . 539

Otter, M.L . 261,318,

. 320, 322

Pasteris, J.D . 323

Pavlenko, T.A . 579

Pavlova, L.A . 488

Pearson, N.J . 42,332

Pearson, D.G . 323,

. 326, 329

Plusnin, G.S . 527

Pokhilenko, N.P . 1,

. 329, 339

Ponomarenko, AI. . 391, 581

Posukhova, T.V . 530

Preser, LB . 334

Ramos, Z.N . 383

Ramsey, R.R . 380, 429

Raynor, L.R . 398

Reddicliffe, T . 231

Rex,D.C . 63

Rickard, R.S . 225, 336

Robey, J.V . 460

Robinson, D.N . 440

Robison, H.R . 463

Rock,N.M.S . 82,112,

. 80, 364, 414

Rodionov, AS . 339

Roksandic, Z . 202

Rombouts, L . 342

Rudenko, AP . 533, 547

Rudnick, R.L . 344

Ryabchikov, 1 . 513, 564

Ryan,C.G. ...119,139,142,

. 145, 148, 475

Safronov, A.F . 541

Sautter, V . 347

Schepina, N.A . 481,490,530 Schulze, DJ. . . 148,350,353

Seal,M . 285

Seckerin, AP . 543

Sellschop, J.P.F . 163

Sen,G . 356

Serenko,V.P . 228

Sgarbi, P.B. A . 359

Shalashilina, T . 535

Shcherbakova, Y.P . 541

Shee, S.R. . . 76, 361, 370, 463

Sheppard, S . 364

Sheraton, J . 202

Shirey,S.B . 329

Shpount, B.R . 545

Sial, A.N . 101

Silva, N.B. da . 460

Sinitsyn, AV . 367

Skinner, E.M.W . 46,

Skripnichenko, V.A. . . .527 Skvortsova, V.L. . . . 533, 547

Smelova, G.B . 549

Smirhov, G.1 . 551

Smith, C.B . 17, 46,

. 76, 373, 383

Smith, Chris B. . . .202,376,

. 380, 392

Smith, J.V . 69‘

Smyth, J.R . 267, 385

Sobolev, N.V . 1, 119,

. 142, 190,240,339,391

Sobolev, E.V . 388

Sobolyev, V.K . 553

Solovjeva, L.V. . . .495, 556,

. 558, 560, 562

Solovova, 1 . 513, 564

Souza, J.C.F . 408

Spetsius, Z.V . 391

Spicuzza, M . 353

Spiro, B . 49

Spriggs, A.J . 63

Stachel,T . 392

Steele, I.M . 69

Stern, C.R . 395

Stock, C.F . 370

Suddaby, P . 339

Sun, S-S . 82

Sutherland, F.L . 398

Suvorov, V.D . 541

Svisero, D.P . 3

Svoren, I.M . 565

Swash, P.M . 440

Szab6,C . 401

Tainton, K.M . 405

Tallarico, F.H.B . 408

Tal’nikova, S.B . 565

Taylor, W.R . 82,180,

. 364,414,417

Taylor, L.A . 401,410

Temby,P . 398

Thirlwall,M . 241, 281

Thompson, R.N . 133,

. 136, 420

Thornber, C.R . 423

Tingle, T.N . 212, 432

Tompkins, L.A . . . 426, 429

Towie,N.J . 435

Ukhanov, AV . 567

Ulbrich, M.N.C . 437

Upton, B.G.J . 241

Valenca, J.G . 359

Valle, P . 460

Valley, J.W . 353

Valter, AA. . 569

Varlamov, D.A . 490

Vasiljeva, E.R . 530

Verichev, E.M . 530

Viljoen, K.S . 46,

. 353,373,440

Vishnevsky, A A . 571

Vladimirov, B.M . 498,

. 501,543,560,573

Vladykin, N.V . 576,

. 577, 578

Vos, W.P . 443

Vukadinovic, D . 79

Waldman, M.A . . . 139, 264

Wall, F . 446

Wang, W . 154, 448

Wang, A . 154, 448

Wedepohl,K.H . 451

Weikun, Ye . 454

White, S.H . 71

Wilding, M.C . 318,

Williamson, P.A . 460

Win,T.T . 142,145,475

Winterburn, P.A . 167

Wuyi,W . 10,208

Wyatt, B.A . 463

Xilin, X . 208

Xiling,X . 10

Yefimova, E.S . 391

Zaitsev, AI . 541

Zavjalova, L.L . 562

Zhang, F . 160

Zhang, P . 466

Zhenxin, D . 470, 473

Zhiqiang, X . 234

Zhou, J . 208, 475

Zhu, Y . 160

Zhuravlev, AZ . 581

Zimanowski, B . 245

Zinchuk, N.N . 551

Zuev, V.M . 391

Zweistra, W.L. . 463

CONTENTS

Exogenous Changes of the Indicator Minerals at the Formation of

Mineralogical Halos of Kimberlite Bodies . 1

Structural Setting and Tectonic Control of Kimberlite and Associated Rocks of Brazil . 3

Geology of the NE Angolan Kimberlite Region . 6

The Status and Future of Diamond Exploration in China . 10

Composite Garnet Peridotite Xenolith from Picrite-Basalt, Vitim Plateau (Trans Baikal); Implication

for the Thermobarometry and Reconstructions of the Mantle Sections . 13

Discovery of Diamond Deposits in the Quebrada Grande Catchment, Venezuela . 14

Mesozoic Kimberlites and Related Alkalic Rocks in South-Western Sao Francisco Craton, Brazil: a Case for Local Mantle Reservoirs and their Interaction . 17

Oxygen in Diamond by the Nuclear Microprobe: Analytical Technique and Initial Results . 20

Fictive Conductive Geotherms Beneath the Kaapvaal Craton . . 23

The Join Pyrope-Knorringite: Experimental Constraints for a New Geothermobarometer

for Coexisting Garnet and Spinel . 26

Origin of Low-Ca, High-Cr Garnets by Recrystallization of Low-Pressure Harzburgites . 29

Experimental Evidence for the Exsolution Origin of Cratonic Peridotite . 32

Geology and Geophysics of the Redondao Kimberlite Diatreme, Northeastern Brazil . 35

Inclusions of Carbonatite Calcite from the Oka Complex, Quebec . 38

Palaeogeographic Studies on the Diamond-Bearing Sopa Conglomerate in the

Diamantina Region (Minas Gerais), Brazil . 40

Applications of Olivine-Orthopyroxene-Spinel Oxygen Geobarometers to the

Redox State of the Upper Mantle . 42

Dating the Cratonic Lower Crust by the Ion Microprobe Shrimp:

An U-Th-Pb Isotopic Study on Zircons from Lower Crustal Xenoliths from Kimberlite Pipes . 45

Isotopic and Geochemical Variation in Kimberlites from the South Western Craton Margin,

Prieska Area, South Africa . 46

Rare Earth, Trace Element and Stable Isotope Fractionation of

Carbonatites at Kruidfontein, Transvaal . 49

Geology and Exploration of the Kelsey Lake Diamondiferous Kimberlites, Colorado, USA . 52

A Crystallization Model for Peridotitic Diamond Inclusion Spinels . 55

The Geology of the Ml Kimberlite, Southern Botswana . 58

Bulk and Mineral Chemistry of the Olivine Leucitite from

Juana Vaz, Sacramento, Minas Gerais, Brazil . 60

A Non Cognate Origin for the Gibeon Kimberlite Megacryst Suite . 63

The Petrogenesis of Metasomatised Sub-Oceanic Mantle Beneath Santiago: Cape Verde Islands . 66

Peralkaline Plutonic Magmatic Rocks of the Carbonatite Volcano Oldoinyo Lengai . 69

Shear Zone Control of Alkali Intrusives - Examples from Argyle and West Africa . 71

Model Simulations of Carbon Isotope Variability in the Mantle . 74

The Geology of the Mengyin Kimberlites, Shandong, China . 76

Distribution of Fluorine between Minerals and Glass in Lamproites, Lamprophyres and Kamafugites: Implications for the Role of F in Deep Mantle-Derived Magmas . . . 79

The Aries Diamondiferous Kimberlte Pipe, Central Kimberley Block, Western Australia: Mineralogy,

Petrology and Geochemistry of the Pipe Rock and Indicator Minerals . 82

Destruction of Subcratonic Mantle Keel: the Wyoming Province . 85

Sulfides, Diamonds, Mantle f02, and Recycling . 88

Significance of Aluminium, Calcium, Chromium, Zirconium, Niobium and Iron Concentrations

in Rutile from High Pressure Rocks . 92

Symplectites in Upper Mantle Harzburgites and Garnet Harzburgites . 94

Significance of Chromite, G5 Mg-Almandine Garnet, Zircon and Tourmaline in Heavy Mineral

Detection of Diamond Bearing Lamproite . 97

Vertical Sampling of Mantle beneath Northeastern Brazil as Represented by Ultramafic

Xenoliths and Megacrysis in Tertiary Basalts . 101

Experimental Studies of Olivine Lamproite at Pressures in the Diamond Stability Field . 103

The Stability of Priderite, Lindsleyite-Mathiasite and Yimengite- Hawthorneite under

Lower Continental Lithosphere Conditions: Experiments at 35 to 50 Kbar . 106

The Origin of Kimberlite and Lamproite in Veined Lithospheric Mantle ....... o, ... . . 109

The Minercdogy, Petrology and Geochemistry of Ultramafic Lamprophyres of the

Yilgarn Craton, Western Australia . . . 112

The Geology and Mineralogy of some Kimberlites in the Mwadui Area . 116

Comparative Geochemical Evolution of Cratonic Lithosphere: South Africa and Siberia . . 119

Systematics of Isotopic Disequilibria between Minerals of Low Temperature Garnet Lherzolites . . 122

Geochemical Correlations between Kimberlitic Indicator Minerals and

Diamonds as Applied to Exploration . 125

The Magmatic Evolution of the Jacupiranga Complex, Brazil . 127

Byro Sub-Basin as a Potential Diamond-Bearing Province . 130

Ultrapotassic Magmas along the Flanks of the Oligo-Miocene Rio Grande Rift, USA: Monitors

of the Zone of Lithospheric Mantle Extension and Thinning Beneath a Continental Rift . 133

Geochemieal and Petrographic Evidence for High Mg-Ultrapotassic Magmas in SE Colorado, USA .... 136

Indicator Minerals from Prairie Creek and Twin Knobs Lamproites: Relation to Diamond Grade . 139

Chromite Macrocrysts in Kimberlites and Lamproites: Geochemistry and Origin . 142

Trace Elements in Garnets from Tanzanian Kimberlites: Relation

to Diamond Content and Tectonic Setting . 145

Ilmenite and Silicate Megacrysts from Hamilton Branch: Trace Element Geochemistry

and Fractional Crystallization . 148

Genesis of Diamond Placers on the Guiana Shield, South America . 151

IR Spectroscopic Characters Of Garnets and Spinels -

a Potential Discriminative Tool for Diamond Exploration . 154

Emplacement and Implications of Ultra-Deep Xenoliths

and Diamonds from the Transition Zone . . . . . 157

The Physical Characteristics and Syngenetic Inclusion Geochemistry of Diamonds

from Pipe 50, Liaoning Province, People’s Republic of China . 160

The Trace Element Analysis of Single Diamond Crystal by Neutron Activation Anedysis . 163

Aspects of Melt Composition, Crystallization, Metasomatism and Distribution,

Shown by Mantle Xenoliths from the Matsoku Kimberhte Pipe . 167

Composite Megacrysts and Megacryst Aggregates from the Williams Kimberlites,

Montana, USA: Multiple Products of Mantle Melts . 170

Geotectonic Controls of Diamonds and Kimberlites and their Application to Diamond Exploration . 173

The Individuahty of On and Off-Craton Megacryst Suites in Southern Africa . 177

Petrology, Mineralogy, and Geochemistry of the Metters Bore No. 1 Lamproite Pipe,.

West Kimberley Province, Western Australia . 180

Mantle Xenohths in Potassic Magmas from Montana: Sr, Nd and Os Isotopic Constraints on the

Evolution of the Wyoming Craton Lithosphere . 183

Isotopic Evidence for Variably Enriched Morb Lithospheric Mantle in Xenoliths from

North Queensland, Austraha . 186

Isotopic and Trace Element Remote Sensing of Montana Continental

Lithosphere from Erupted Magmas . 188

A Diamond-graphite Bearing Eclogitic Xenolith from Roberts Victor - Indication for

Petrogenesis from Pb, Nd, and Sr Isotopes . 190

The Role of Fluorine in the Crystallization of Niobium and Phosphorus Ores in Carbonatites. ........ 193

is Clifford’s Rule Still Valid? Affirmative Examples from Around the World . 196

Non-Kimberhtic Diamonds Source Rocks . . . 199

Peridotitic Paragenesis Planar Octahedral Diamonds from the

EUendale Lamproite Pipes, Western Australia . 202

A Review of the Carbonatites of Australia . 205

Spinel - As Indicator for Diamond . 208

Unusual Spinel-Garnet Lherzohte Xenohths from Basalt in Eastern China: Constraints on the

Late-Tertiary Thermal Structure of the Upper Mantle. . . 212

Carbonado and Yakutite: Properties and Possible Genesis . 214

Petrogenetie Carbonatite - Melilitite Relationships in the Kaiserstuhl Complex,

Upper Rhinegraben . 217

Developments in Remote Sensing of Carbonatites; Airborne Imaging Spectrometry at

Mountain Pass, California and Iron Hill, Colorado . 219

High-Resolution Ion-Probe Analyses of Rare Earth Elements in Kimberhtic Zircons . 222

Geochemical Correlations in Roberts Victor Eglogites . 224

Jwaneng Framesites - Inclusions and Carbon Isotopes . 225

Unequilibrated Ultramafic Xenoliths from Udachnaya Kimberlite

Pipe, Western Yakutia . . . 228

Coanjula Diamonds, Northern Territory, Australia . 231

New Type Lamproite of the Dahongshan Area, Hubei Province, China . 234

The Genesis of Perovskite-Bearing Bebedourite and the Problems Posed by

Clinopyroxenite-Carbonatite Complexes. . 237

Crystalline Inclusions in Chromites from Kimberhtes and L2unproites . 240

Geochemical Systematics in Mantle Megacrysts and their Host Basalts from the Archaean

Craton and Post- Archaean Mobile Belts of Scotland . 241

Experiments on Explosive Basic and Ultrabasic, Ultramafic, and Carbonatitic Volcanism . 245

Palaeozoic Lithosphere Mantle Feature Beneath Fuxian, Liaoning Province, China: the

Information from No. 50 Kimberhte Pipe . 248

Mineralogy and Geochemistry of Perovskite-Rich Pyroxenites . 251

The Diamondiferous Gravels of the Southwestern Transvaal, South Africa . 254

Lamproitic(?) Diatremes in the Golden Area of the Rocky Mountain Fold and

Thrust Belt, British Columbia, Canada . 257

Morphological, Resorption and Etch Feature Trends of Diamonds from Kimberhtes

within the Colorado-Wyoming State Line District, USA . 261

Macro and Microdiamonds from Arkansas Lamproites: Morphology,

Inclusions and Isotope Geochemistry . 264

Secondary Phases in Mcmtle Eclogites . 267

Chemical and Isotopic Systematics of Continental Mantle . . . 270

Enhancement of Geophysical Data for Kimberhte Exploration

at Iron Mountain, Wyoming, USA . . . 273

Finite Element Modeling of Resistivity Data from Kimberhtes

in Colorado-Wyoming, USA . 276

Infrared Microspectroscopy of Diamond in Relation to Mantle Processes . 279

Astenosphere-Lithosphere Relationships within Orogenic Massifs . 281

Comprhensive Investigations of Chinese Diamonds . 285

Middle Jequitinhonha Alluvial Diamonds . 287

Infrared and Cathodoluminescence Studies of Inclusion-Bearing Diamonds from Brazil . 290

Accessory Rare Earth. Strontium , Barium and Zirconium Minerals in the Benfontein

and Wesselton Calcite Kimberhtes . 292

What’s in a Name? Suggestions for Revisions to the Terminology of Kimberhtes

and Lamprophyres from a Genetic Viewpoint . 295

G^u•net Megacrysts from Group II Kimberhtes in Southern Africa . 298

Distribution of Lamproite Pathfinders in Surface Soils . 301

Pressure Temperature Volume Path of Micro-Inclusion-Bearing Diamonds . 304

Radial VcU’iation in the Composition of Micro-Inclusions and the Chemical Evolution

of Fluids Trapped in Diamonds . 307

Cr Garnet - Diamond Relationships in Venezuela Kimberhtes . 310

The Composition of Partial Melts in a Volatile Bearing, Reduced Mantle . 313

Geochemical and Geophysical Mantle Domains . 316

Diamond Growth Histories Revealed by Cathodoluminescence and Carbon Isotope Studies. . . 318

A Physical Characterization of the Sloan Diamonds. . . 320

Primary Diamond Subpopulations at Individual Localities . 322

Graphite-Bearing Peridotites from the Kaapvaal Craton their Carbon Isotopic Compositions and Implications for Peridotite Thermobarometry . 323

Diamond Facies Pyroxenites from the Beni Bousera Peridotite Massif and Implications

for the Origin of Eclogjte Xenoliths . . . 326

Rhenium-Osmium Isotope Systematics in Southern African and Siberian Peridotite Xenoliths

and the Evolution of Subcontinental Lithospheric Mantle . 329

The Thermal Evolution of Cratonic Lower Crust/upper Mantle: Examples from

Eastern Australia and Southern Africa . 332

Characterization of Lamproites from Paraguay (South America) . 334

Mineral Inclusions in Diamonds from Jagersfontein Mine . 336

Ilmenite-Bearing Peridotites and Megacrysts from Dalnaya Kimberlite Pipe, Yakutia . 339

Statistical Distributions for Diamonds . 342

Cratonic and Oceanic Lithospheric Mantle beneath Northern Tanzania . 344

Ultra-Deep ( > 300km), Ultramafic Xenoliths: Direct Petrological Evidence for the Transition Zone. . . . 347

Low-Ca Garnet Harzburgite Xenoliths from Southern Africa: Abundance, Composition, and Bearing

on the Structure and Evolution of the Subcratonic Lithosphere . 350

Carbon Isotope Composition of Graphite in Mantle Eclogites. . . .* . 353

On the Scale of Heterogeneities in Clinopyroxenes of Spinel Lherzolite Xenoliths from Oahu, Hawaii: Implications for Non-Modal Advection-Diffusion Controlled Trace Element Enrichment . 356

Petrography and General Chemical Features of Potassic Mafic to Ultramafic Alkaline Volcanic

Rocks of Mata da Corda Formation, Minas Gerais State, Brazil . 359

The Petrology of the Wesselton Kimberlite Sills, Kimberley, Cape Province, South Africa . . 361

Barium-Rich, Olivine-Mica Lamprophyres with Affinities to Lamproites, from the

Mt Bundey Area, Northern Territory, Australia . 364

The Arkhangelsk Diamond-Kimberlite Province - A Recent Discovery in the North of

the East-European Platform . 367

Kimberlitic Olivine . 370

The Petrography, Tectonic Setting and Emplacement Ages of Kimberlites in the South Western

Border Region of the Kaapvaal Craton, Prieska Area, RSA . 373

Patterns of Diamond and Kimberlite Indicator Mineral Dispersal in the

Kimberley Region, Western Australia . 376

Diamond Prospectivity from Indicator Mineralogy: a Western Australian Perspective . 380

Eclogite Xenolith with Exsolved Sanidine from the Proterozoic Kuruman

Kimberlite Province, Northern Cape, RSA . 383

Pyroxene Crystal Chemistry and the Evolution of Eclogites in the Mantle . 385

The Impurity Centers and Some Problems of Diamond Genesis . 388

Eclogite Paregenesis of Diamonds from Udachnaya and Mir Pipes, Yakutia . 391

Volcanology and Geochemistry of the Ellendale Lamproite Field (Western Australia) . 392

Mantle Xenoliths from the Quaternary Pali-aike Volcanic Field of Southernmost South America:

Implications for the Accretion of Phanerozoic Continental Lithosphere . 395

Anomalous Hosts, Unusual Characters and the Role of Hot and Cool Geotherms for

East Austrahan Diamond Sources . 398

Mantle Xenoliths from Alkali Basalts in the Nograd-Gomor Region

of Hungary and Czechoslovakia . 401

The Group-2-KimberUte - Lamproite Connection: Some Constraints from the Barkly-West District,

Northern Cape Province, South Africa . 405

The Mata do Lengo Mica-Rich Kimberlite, Western Minas Gerais . 408

Crustal Signatures in Mantle Eclogites: REE Patterns of Clinopyroxene and

Garnet by Sims and Inaa . 410

Major Element Systematics of Alkaline Volcanic and Lamprophyric Rocks - Toward a Geochemical and Petrogenetic Classification Scheme

for the Potentially Diamondiferous Alkaline Rocks . 414

Mineral Chemistry of Sihcate and Oxide Phases From Fertile Peridotite Equilibrated With A C-O-H Fluid Phase - a Low FO2 Data Set for the Evaluation of

Mineral Barometers, Thermometers and Oxygen Sensors . 417

Overt and Cryptic Strongly Potassic Mafic Liquids in the Neogene Magmatism of the Northernmost Part of the Rio Grande Rift, USA: A Lithospheric

Drip-Feed into a Asthenospheric-source Magmas? . 420

Hot, Cold, Wet, and Dry Hutaymah Ultramafic Inclusions: a Record of Mantle

Magmatism beneath the Arabian Shield and Flanking the Red Sea Rift . 423

Kimberlite Structural Environments and Diamonds in Brazil . 426

The Boa Esperanga and Cana Verde Pipes; C6rrego D’Anta, Minas Gerais, Brazil . 429

Reduced Carbonaceous Matter in Basalts and Mantle Xenoliths . . . 432

The Aries Diamondiferous Kimberlite Pipe Central Kimberley Block, Western Australia . 435

The Ultrabasic Potassic Rocks of Presidente Olegario, Serra da Mata da Corda, Minas Gerais, Brazil. , . . 437

Diamond- and Graphite-Peridotite Xenoliths from the Roberts Victor Mine . 440

Application of Simple Paramagnetic Susceptibility to Rapid Discrimination of Ihnenite

Compositions in Exploration for Kimberlite in the Colorado - Wyoming Province, USA . 443

Comparison of Element Distribution in Rare Earth-Rich Rocks from the Kangankunde

and Knombwa Carbonatite Complexes . 446

Micro-Structural Variations in Mantle Derived Garnets . 448

The Composition of the Primitive Upper Earth’s Mantle . 451

The Chauracteristics and Origins of Ultrabasic Volcanic Rocks and their Xenoliths from

Lbdan Area, Gansu Province, P.R. of China . 454

Evidence for a Deep Origin for Sao Luiz Diamonds . 456

Inclusion Chemistry, C2irbon Isotopes and Nitrogen Distribution in Bultfontein Diamonds . 459

The Moana-Tinguins Milihtite Province, Piaui State, Northeastern Brazil . 460

463

The Petrology of the Cleve Kimberlite, Eyre Peninsula, South Australia.

Metallogenic Model of Kimberlite in North China Craton, China . 466

Micas in Kimberlites from China . 470

Olivines in Shandong Kimberlites . 473

Geochemistry of Indicator Minerals from Chinese Kimberlites and Lamproites . 475

Appendix

The Peculiarities of the Mineral Composition of the Diamond Bearing Eclogites

from the Udachnaja Kimberlite Pipe . 481

Ore Minerals from the Lamproite Ground Mass . 484

Natural Diamonds Growth Conditions According to the Mineral Inclusions Study . 486

The Evolution of Natural Diamond Growth Conditions . 488

Chemico-Genetic Classification of the Most Important Minerals-Satellites of the Diamond . . 490

Mineralogical-Isotopic Dynamics, Physico-Chemical Conditions and Stages of

Serpentinization Process of Kimberlites from Yakutia . 492

Evidence of Magmatism, Matasomatism and Deformation Processes Obtained from the Study

of the Unique Compositionally Complex Nodule from the Udachnaya Kimberlite Pipe (Yakutia) . 495

Geology, Petrology and Mineral Composition of the Udachnaya Kimberlite Ore Complex (Yakutia) . 498

Trend of Si02 in Garnets from Kimberlite Pipes . ' . 501

Isotope Fractionation Related to Kimberlite Magmatism and Diamond Formation . 502

New Technology of the Searching of the Diamond Bearing Kimberlites

Methodological Basis and Fields of Applications . . 505

The Comparative Characteristics of Ilmenite from the Kimberlite Provinces of the USSR . 508

Mineralogy of Oxides from the Ground Mass of Kimberlites of Jakutija and

Northern European Part of the USSR . 510

Petrogenesis of Prairie Creek Lamproites: Constraints from Melt Inclusions

and High-pressure Experiments . 513

Al-Solubility in Orthopyroxene in Equilibrium with Garnet: A Reinterpretation of Existing

Experimental Data and the Petrogenetic Implications in Garnet Peridotite Xenolith . 514

Genetic Types of Kimberlite Pipe Craters of a New Diamond-Bearing Province of the USSR and

some Aspects of their Development . 516

Traditional and New Types of Diamond-Bearing Rocks and Methods

for their Estimation . 518

Composition of Groundmass Minerals from Petrographically Distinct Types of Kimberlites . 521

The Regularities of Variability of Kimberlite Compositions in Multi-Phase Pipes . 523

Chrome Titanate Inclusions of Unusual Composition in Pyropes from Lamprophyres and Kimberlites. . . . 525

Sr, C, O Isotope Composition in Kimberlites of the North-russian Province (USSR) . 527

Geological Structure and Mineralogy of the Kimberlites of the Archangelsk Kimberlite Province . 530

The Formation Kimberlite Diamonds Through Chemical Synthesis in Open Catalytic System . 533

Diamonds in Metamorphic Rocks . 535

Primary Melt Inclusions in Eclogite Diamonds and their Genetic Implication . 537

Native Metals in Kimberlites of Yakytia and their Genesis . 539

Kimberlite-Controlling Zones in the Crust and Uppermost Mantle Of The West Yakutia:

Their Composition And Evolution . 541

Pre-Cambrian Diamond-Bearing Veined Bodies from South-West of the Siberian Platform . 543

Geodinamic Regime of Kimberlite Magmatism Manifistations on the Siberian Platform . 545

The Catalytic Function of Kimberlite Elements in the Formation of Natural Diamonds . 547

Mineral Inclusions in Bort from the Mir Pipe, Yakutia . 549

On the Problem of Vertical 21oning of Kimberhte Bodies, (on the Example of Lesotho) . 551

The Problem of Primary Source of Brazil-Type Diamonds (the Case-History of Discovery of

Diamond Deposits in the Arkhangelsk Region) . 553

Metasomatic Processes in Subcontinental Lithospheric Mantle beneath the Siberian Platform . 556

O, C and Sr Isotopic Composition of Calcites in Garnet Megacrysts and Carbonatizated Granulitic Xenoliths from the Udachnaya Kimberhte Pipe, Yakutia . 558

Cognate Suite of Garnet Clinopyroxenite-Ohvine Websterite- Lherzolite from the

Udachnaya Kimberlite Pipe, Yakutia . . . 560

Layered Structme of the Upper Mantle beneath the Siberian Platform:

Petrological and Geophysical Data . 562

A Study of Microinclusions in Minerals of Spanish Lamproites . 564

Study of Gaseous Phase in Diamonds with Eclogitic and Ultrabasic Inclusions

from Yakutian Kimberhte Pipes . 565

Upper Mantle Composition beneath Yakutian Kimberhte Province . 567

The Genetic Types of Natural Diamonds . 569

Kelyphites on Garnets in Mantle Xenohths and Kimberhtes: Composition, Genesis,

Petrological Imphcation . 571

Basaltic and Mica Kimberhtes of the Siberian Platform and their Time-Space and

Genetic Relationships . 573

Carbonatites of K-Alkahne Complexes of the Aldan, North Pamir and South Mongoha . 576

Chemical Composition and Geochemical Features of Micas from Lamproites of

the Aldan Schield, USSR . 577

Geological Position, Petrology and Geochemistry of Lamproites (Aldan Schield, Siberia) . 578

Inclusions of Plutonic Minerals in Diamonds from Kimberhte Rocks of the

Northern East-European Platform . 579

Ancient Depleted Subcontinental Lithosphere Under Siberian Platform: Nd-Sr Isotopic and

REE Evidence from Garnet Peridotite Xenohths of Mir Pipe (Western Yakutia) . 581

Extended Abstracts 1

EXOGENOUS CHANGES OF THE INDICATOR MINERALS AT THE FORMATION OF

mineralogicaL halos of kimberlite bodies.

Afanas’ev, V.P.; Sobolev, N.V. and Pokhilenko, N.P.

During the mineralogical halos formation the kimberlite minerals are affected by the powerful exogenous factors changing both individual minerals and the composition of mineral associations. The main factors of exogenous changes are mineral transportation during the mineral halos formation and physical-chemical changes in the formed sediments.

The changes during the process of transportation are expressed in two forms - i.e. the hydraulic grading of the transportation of the minerals of different density and proporcional to the value of their hydraulic fall diameter (the velocity of the free fall of the minerals in the aqueous medium, m/sec). The expressions for the fall diameter determination are obtained on the experimental basis: diamond - V = 62,3 . p^’^^ pyrope - V = 61,6 . picroilmenite - V = 69,2 . chromespinel - V = 71,3.p . On their basis the coefficients of the mineral inertness for the plain rivers conditions (Yakultia) are calculated.

Another aspect of the mineral transportation is a decrease in their concentration with the removal from a kimberlite body. The hydraulic gradient and the distribution of the mineral concentration relative to the kimberlite body is expressed by the formulae in the idealized form:

P = Po - BX P = Po e

where X - is the distance up to kimberlite body, B - the coefficient of the mineral inertness, Po - the mineral concentration in kimberlite body elluvium, P - the mineral concentration at a distance X.

The mechanical wearing depends mainly on the landscape dynamic conditions. Under the alluvial conditions on the continent, the kimberlite minerals are weakly rounded, on minerals larger than 2mm, the signs of rounding appear at a distance of some dozens of kilometers. The smaller ones are transported with no rouding to many dozens of kilometers. The minerals assume the medium level of rounding at wearing under the conditions of littoral alluvial plains which could be periodically flooded by the shallow basin waters and the minerals could be rounded under the influence of waves. The minerals are rounded to the maximum extent under the littoral conditions in the process of forth/back moviments under the wave influence, the minerals of the medium and high level of rounding are widely spread in the ancient mineral halos at the different regions of the world. The alluvial conditions are unfavorable for the good hydraulic grading of minerals. The best grading takes place under littoral conditions. Here the formation of the diamond-pyrope association with the similar grain sizes occurs and the mineral concentration grows, therefore, the rich diamond placers could be formed under the given conditions. Besides, according to the calculations and experimental data, the picroilmenite mechanical stability is approximately twice lower than of pyrope. Therefore, whether pyrope ultimetly rounded, than picroilmenite could be destroied completly. Diamonds are also rounded under these