Pilanesberg Alkaline

Taking place on: 29 - 31 August 2014


Bulhoek - dolomite carbonatite sheet in fenitised Bushveld granite  Bulhoek Kop  Pilanesberg - central red syenite 

Tour Leader

Jock Harmer


Day 1 of the excursion will focus on the Bulhoek Kop intrusion - one of three petrologically indentical dolomite carbonatite intrusions distributed over kilometre that are loosely grouped as the Bulhoek Complex.  Bulhoek forms part of the widespread period of alkaline and carbonatitic magmatism that affected the Kaapvaal Craton in the middle Proterozoic (ca 1400Ma). Bulhoek is petrogenetically significant in that well-preserved magmatic features are preserved that leave little doubt that the intrusions formed from successive pulses of magnesian carbonate magma that crystallised dolomite at low crustal pressures.

The remaining two days will be devoted to exploring the geological features of the Pilanesberg Alkaline Complex - one of the few (and the second largest) agpaitic peralkaline nepheline syenitic intrusives know. Both saturated adn undersaturated syenite intrusives are represented and underlie a thin, but aerially extensive, drape of volcanics and volcaniclastics of trachytic composition:
No volcanic equivalents of the undersaturated syenites have been found. Topographically, the Pilanesberg Complex forms a series of annular rings that trace the arcuate ring dyke/cone sheet pattern of the intrusives - the current erosion level is close to the volcanic/sub-volcanic interface.

Much of the Pilanesberg Complex now lies within a game reserve hosting a wide range of indigenous fauna - including the Big Five! Support of the park management has been secured to allow the excursion to visit outcrops of all the major units of the Pilanesberg including the rare, eudialyte-bearing aegirine foyaites also called "lujaurites".

Cost: R8,000 per person

Minimum participants:  10
Maximum participants:  35

 Pilanesberg - eudialyte  Pilanesberg kudu Pilanesberg green foyaite 


Terms and Conditions:

1. Participation will be confirmed on receipt of payment.

2. Preference will be given to registered IMA delegates.

3. Cancellations must be received in writing to This email address is being protected from spambots. You need JavaScript enabled to view it.

4. Any refunds issued will be subject to approval by the organising committee.

5. Cancellations received before 30 May 2014 will receive a full refund less a 10% administration fee.

6. Cancellations received between 31 May and 31 July 2014 will receive a 50% refund.

7. No refunds will be issued after 31 July 2014.

8. In the event that the tour is cancelled by the organisers, a full refund will be issued.

9.  A decision will be made as to whether the tour will go ahead or not by 31 March 2014.

10.  All participants will be required to sign an indemnity form prior to participating in the field trip.

11.  All participants are to take out their own personal insurance cover for general travel insurance, personal liability, medical cover and dangerous activities cover.  A copy of confirmation of insurance must be submitted to the organisers prior to participating in the tour.

12.  The organisers reserve the right to change or cancel the field trip if necessary.