This paper provides an update of Chapter 16 in the Geology of South Africa (2006) and sumniarizes recent advances in understanding the Mesoproterozoic Namaqua-Natal Province (NNP). The NNP forms a major orogenic belt along the southern and southwestern margins of the Kaapvaal Craton, that developed between similar to 1.55 and 0.96 Ga during the assembly of Rodinia, It comprises two main parts: the Namaqua Sector in the west and the Natal Sector in the east, separated by Phanerozoic cover. In South Africa, the Namaqua Sector is a composite of five tectonostratigraphic entities separated by major thrusts and shear zones. The Richtersveld Subprovince in the west contains 1.9 to 1.86 Ga, arc-related volcanic and plutonic rocks partly reworked during the Namaqua orogeny. The Bushmanland Subprovince in the south is dominated by high-grade supracrustal gneisses (1.21 to 1.13 Ga), granitic orthogneisses (similar to 1.21 to 1.12 Ga), abundant late- to post-tectonic granites (similar to 1.10 to 1.04 Ga) and minor mafic intrusions, accompanied by crustal heting, at -1.03 Ga. The Kakamas Domain, also composed of granulite-facies paragneisses (similar to 1.22 Ga), granitic orthognekses (similar to 1.23 to 1.15 Ga), and granites (-1.12 to 1.08 Ga), was thrust south-westward over the Richtersveld and Bushmanland Subprovinces along the Lower Fish River - Onseepkans Thrust Zone, East of the Kakamas Domain, the Areachap Terrane comprises 1.29 to 1.22 Ga island-are volcanic and sedimentary rocks and juvenile granitoids generated after collision with the Kaapvaal-Rehoboth Craton at -1.21 Ga. The easternmost Kaaien Domain represents a foreland thrust complex on the craton margin containing a possible back-arc volcanic sequence in the Wilgenhoutsdrif Group. Deformation in the Namaqua Sector involved several phases. Western Richtersveld Subpovince rocks preserve an older, Paleoproterozoic (-1.89 Ga), greenschist-grade folding event (D1). The Mesoproteroloic Namaqua Orogeny was polyphase, with an initial extended period of isoclinal folding and thrusting under high grade metamorphic conditions, accompanied by a penetrative gneissic foliation (D2 at similar to 1.20 to 1.12 Ga), followed by dome-and-basin type refolding (D3) and regional dextral shearing (D4 at -1.00 to 0.96 Ga). The latter was associated with the emplacement of the Orange River Pegmatite Belt into D2 and Di structures. Two contrasting geodynamic models have been proposed to explain the evolution of the Namaqua Sector. The traditional accretionary model interprets it as a collage of previously unrelated arc terranes successively juxtaposed with the Kaapvaal Craton, later affected by mantle delamination and localised thermal overprinting (metamorphism). The alternative continental back-arc model proposes long-lived (1.2 to 1.0 Ga) crustal extension and heating of a pre-existing crustal block in a continental back-are setting, generating the widespread high-temperature/low-pressure metamorphism and voluminous granite magmatism that typify the Namaqua Sector. The Natal Sector comprises, from north to south, the Tugela, Mzumbe and Margate terranes. Over the past two decades, new geochronological datasets have refined the timing of key events but have not significantly changed the overall model. Juvenile island arcs formed south of the Kaapvaal Craton through southward subduction of the "Tugela Ocean before 1210 Ma. Subsequent northeast directed closure led to obduction of the Tugela oceanic arc terrane onto the craton's southern margin and accretion of the Mzumbe and Margate arcs around 1150 +/- 20 Ma (D1), accompanied by high grade metamorphism, polyphase granite intrusion and minor mafic magmatism. Continued northeast-southwest convergence produced steep ductile sinistral shear belts in the southerly two terranes (D2) but not in the rigid, craton-underlain Tugela Terrane. The 102 phase was accompanied by extensive A-type granitoid magmatism (Oribi Gorge Suite). The Natal Sector is still regarded as an accretionary assemblage of juvenile Mesoproterozoic terranes.

Two small exposures of quartz-porphyritic rocks occur on the farm Zoutpekel 98 in the Marydale Terrane between the Doornberg Fault and Brakbos Shear Zone, apparently overlying Kaapvaal basement granite but lacking clear field relationships due to sand and Dwyka tillite cover. They are lavas and tuffs, metamorphosed in lower amphibolite facies. They contain quartz phenocrysts with a distinctive blue colour, due to metamorphic exsolution of rutile. Microbeam U-Pb zircon dating gives a combined Pb-207/Pb-206 age of 2 722 +/- 3 Ma (seven determinations on four samples), interpreted as the age of extrusion. Three of these samples give the same discordia upper intercept age, but one sample gives discordia intercepts of 2 688 +/- 15 and 1 223 +/- 120 Ma, thought to reflect metamorphic lead loss related to the similar to 1 210 Ma Namaqua terrane assembly collisions. The Zoutpekel exposures are coeval with the 2 720 +/- 2 Ma Makwassie Formation of the Platberg Group, Ventersdorp Supergroup. They also correspond geochemically to the Makwassie Formation and no other unit of the supergroup. A sample from the T'kuip Formation of the nearest Ventersdorp Supergroup inlier on the Kaapvaal Craton (east of the Doornberg Fault), gives an age of 2 716 +/- 8 Ma, also confirming its lithostratigraphic and geochemical correlation with the Makwassie Formation. The Zoutpekel exposures show that not only the Kaapvaal basement granites, but also the supracrustal cover rocks of the Ventersdorp Supergroup, extend southwards across the Doornberg Fault, The Marydale Terrane is thus not an exotic terrane, but probably represents a passive continental margin developed at the beginning of the 1 300 to 1 000 Ma Namaqua-Natal Wilson cycle. The age range of the Ventersdorp Supergroup and the age and stratigraphic correlation of the Marydale Group thrust complex, which straddles the Zoutpekel exposures, will be investigated in two companion papers.

The Koras Group is a bimodal volcanosedimentary group located in post-tectonic grabens in a foreland thrust complex in the Kaaien Terrane of the Mesoproterozoic Namaqua-Natal Province of southern Africa. It contains two sequences of mafic and felsic volcanic rocks with an unconformity between them, only the lower sequence being slightly folded. The Koras Group was long regarded as having formed at the end of the 1 210 to 1 000 Ma Namaqua Orogeny, because it lacks the severe deformation and metamorphism of the underlying rocks, with igneous minerals preserved in many samples. Following years of unsuccessful attempts to precisely date the volcanic rocks, the first two ion probe U-Pb zircon studies both reported ages of-1 172 Ma for the Swartkopsleegte Formation felsic lava in the slightly folded lower sequence (based on relatively few dated zircons) and-1 100 Ma for the Leeuwdraai Formation rhyolite in the undeformed upper sequence. Thus a major 70 m.y. hiatus seemed apparent between the lower and upper sequences despite their similar geochemistry and rift-related setting. This gave rise to models which envisaged the Kaaien Terrane being unaffected by the syn-to late-tectonic deformation, migmatisation and granite intrusions, documented between 1 200 and 1 150 Ma in the adjoining Namaqua-Natal terranes to the west.A high-pressure (10 kbar) metamorphic event, recognised in the Kaaien Terrane basement just south of hardly deformed Koras Group exposures and dated at 1 150 Ma, is inconsistent with such models. A re-investigation and microbeam dating campaign on the Koras Group confirms the 1 101 & PLUSMN; 2 Ma (n = 6) age for felsic volcanic rocks of the upper sequence, but establishes a new reliable age of 1 114 & PLUSMN; 4 Ma for the lower one (n = 2). The 1 170 ages obtained in the earlier two studies were revisited and are now considered to reflect the age of zircon xenocrysts from the source rocks, which dominate the zircon population of some Swartkopsleegte Formation samples.Several criteria to distinguish autocrystic (magmatic) from antecrystic (age-overlappping xenocrystic) data points were investigated. One sample had high Th levels in only the younger zircons, but histograms of sufficiently precise 207Pb/206Pb ages provided the main criterion. Calculations of zircon crystallisation temperature intervals were not useful in predicting the abundance or proportions of magmatic and antecryst zircons. A multi-episode model of magmatic generation and crystallisation events is probably appropriate. In cases when felsic volcanic samples yield few zircons, care must be taken to avoid the problem exposed in this study.The Koras Group sediments have similar detrital zircon U/Pb age distributions to those of the Rehoboth Basement Inlier. This supports the concept that the Kaaien Terrane originated as the southern part of the Rehoboth Province.

The chronostratigraphy of the Bushmanland Ore District and the Namaqua-Natal Province has long been debated, but recent microbeam dating has resolved several issues. An important aspect is the precise age of the sedimentary-exhalative ores and their tectonostratigraphic context. Published constraints on the maximum age of the ores from detrital zircon dating are 1 285 ± 14 Ma (n=4, Gamsberg ore), 1 215 ± 18 Ma (n=6, Wortel Formation) and a tentative 1 118 ± 33 Ma (n=3, Hotson Formation at Black Mountain). The ore is older than the 1 130 ± 35 Ma Koeris Formation metabasalt which unconformably overlies it. Aplite dykes, which intrude the ore of the Black Mountain deposit, provide another potential minimum age constraint on the ore. A sample was dated at 1 175 ± 15 Ma by ion probe U-Pb zircon dating. This shows that the aplite dykes belong to the late-collisional Springputs Suite of granitoids which includes the 1 163 ± 11 Ma Achab and 1 149 ± 15 Ma Hoogoor Gneisses, for which the field relationship with the ores had not been established. The regional M2 metamorphism was recorded in aplite zircon rims at 1 027 ± 9 Ma and at 1 030 ± 6 Ma in monazite and xenotime in the Hotson Formation host rock schists. Detrital zircons, dated by Laser Ablation ICPMS in a host rock schist sample, reflect a dominant Palaeoproterozoic provenance with major age group at 2 003 ± 17 Ma and minor groups at 1 847 and 2 105 Ma. Only 16 analyses were made, which probably accounts for the absence of minor Mesoproterozoic provenance components found in other published datasets. The age of the Black Mountain ore is now constrained between 1 215 ± 18 Ma and 1 175 ± 15 Ma. The tentative 1 118 ± 33 Ma detrital zircon maximum age is shown to be unreliable in view of two younger magmatic rocks with older dates (1 175 and 1 130 Ma). The SEDEX ores thus formed during or just before the ~1 210 Ma assembly of Namaqua terranes and before the ~1 150 Ma syntectonic Springputs Suite granitoid magmatism.

This work investigates Mesoproterozoic volcanic rocks of the Haiber Flats, Barby, Welverdiend and Kairab Formations, and associated intrusive rocks in the Konkiep Terrane. Various correlations have been made in the past and recent dating work yields contrasting ages. U-Pb dating of zircons is applied in combination with Sm-Nd and Lu-Hf isotopes to determine the age, assess correlation and ascertain the much-debated tectonic setting. Ion probe U-Pb zircon dating yields ages of 1218 +/- 5 Ma, 1212 +/- 4 Ma and 1212 +/- 5 Ma (all errors 2 sigma) for three samples of the Haiber Flats Formation and 1219 +/- 13 Ma, 1215 +/- 19 Ma for the Barby Formation. The ages obtained for the Barby Formation agree with the 1217 +/- 2 Ma and 1214 +/- 5 Ma ages reported from previous investigations. Rocks mapped as the supposedly older Kairab rhyolite and felsic tuff gave younger ages of 1220 +/- 4 Ma and 1222 +/- 10 Ma, respectively, which are coeval with the Barby and Haiber Flats Formations. Two Gorab Gabbro samples, previously mapped as Kairab Formation, yield ages of 1341 +/- 8 Ma and 1336 +/- 8 Ma. These older ages are within error of two Welverdiend Formation samples which gave ages of 1344 +/- 6 Ma and 1337 +/- 9 Ma, and the formation was previously dated in the type area at 1327 +/- 10 Ma. These ages confirm the reassignment of rocks originally mapped as tholeiitic Barby Formation into the Welverdiend Formation, north of a newly identified stratigraphic hiatus corresponding to the geophysically defined Wereldend Lineament. Sm-Nd and Lu-Hf isotopic signatures for the Barby, Haiber Flats and coeval Kairab samples indicate that they are co-magmatic and derived from partly depleted mantle contaminated by older crust. T-DM model ages of these samples range from 2.5 to 1.5 Ga with a major 2.2 to 1.8 Ga group. This suggests that the older crustal component was Paleoproterozoic but included some Archean material. The Welverdiend Formation and Gorab Gabbros show similarity in age, Sm-Nd and Lu-Hf characteristics and were probably derived from partially depleted mantle, or from a well-homogenised mixture of depleted mantle and older crust. REE diagrams indicate enrichment in LREE (La-Gd) and a flat HREE pattern (Tb to Lu). On spidergrams, most samples are characterised by negative Nb-Ta anomalies and positive K and Pb anomalies which indicate a subduction-related setting (with positive Sr anomaly) or a reworked crustal origin. The similarity in ages, isotopic signatures and geochemistry confirms the correlation of the Barby and Haiber Flats Formation.

The Ventersdorp Contact Reef (VCR) at the base of the >4.5 km-thick volcanosedimentary Ventersdorp Supergroup unconformably overlies the Witwatersrand Supergroup and is the second youngest mineable reef in the Witwatersrand Goldfields. The volcanic rocks of the Ventersdorp Supergroup are predominantly mafic, affected by low-grade thermal metamorphism and difficult to date. Only the Makwassie Formation in the upper Platberg Group of the main Ventersdorp repository has been reliably dated on four felsic volcanic samples at 2720 +/- 2 Ma. The actual timing of Ventersdorp volcanism and the duration of the three recognised lithostratigraphic groups remains enigmatic, despite much research and heroic attempts to synthesize the available data. In this work detrital zircon grains from VCR conglomerates were U-Pb dated in order to improve the time constraints on the Klipriviersberg Group at the base of the Ventersdorp Supergroup. The six youngest grains in VCR samples were reliably dated at 2799 +/- 9 Ma. The Klipriviersberg Group and the Ventersdorp Supergroup is thus younger than 2808 Ma and the supergroup is older than the 2642 Ma Vryburg Formation at the base of the Transvaal Supergroup. Comparisons of detrital grain dates confirm that the VCR was largely derived from erosion products of the underlying Witwatersrand Supergroup, however the youngest VCR grains are similar to 20 Ma younger and may have been derived directly from magmatic rocks in the provenance or a felsic facet of the synchronous komatiitic Klipriviersberg volcanism. Multi-grain analyses of discordant grains show that recent lead loss is predominant. However about 5% of the data show the effect of complex Mesoproterozoic lead loss, which can yield ages as much as 150 Ma too young in 10% discordant data. This was found in grains with high Th-induced radiation damage, providing a criterion for data rejection. The proposed large igneous provinces dated between 2791 and 2683 Ma, based mainly on dated mafic dykes, which are not in contact with supracrustal Ventersdorp rocks, do fit the established time constraints and might provide a key to Ventersdorp chronostratigraphy. However only the proposed 2754-2709 Ma Platberg volcanic province is based on reliably dated Platberg Group volcanic rocks.

The Verena Granite forms part of the Palaeoproterozoic Lebowa Granite Suite of the Bushveld Complex and was named after the village of Verena in the Mpumalanga Province of South Africa. It occurs over an area of similar to 600 km(2) and is intrusive into the Rooiberg Group, the Rashoop Granophyre Suite and the Klipkloof Granite. It is in turn intruded by the Makhutso Granite, the youngest known granite of the Lebowa Granite Suite. The Verena Granite is characterised by its coarse to very coarse-grained nature, its pinkish to reddish colours and its porphyritic texture defined by the presence of large perthitic K-feldspar phenocrysts within a finer grained groundmass of plagioclase (An(8-15)) and quartz. Geochemically it can be classified as an A-type granite that straddles the boundary between metaluminous and peraluminous compositions. The granite is enriched in REEs relative to chondrite and shows strong fractionation of the LREEs, a distinct negative Eu anomaly and little fractionation of the HREEs. U-Pb dating presented here places the age of the Verena Granite at 2052 +/- 9 Ma, which is the same as that of the published 2054 +/- 2 Ma age of the Nebo Granite. Currently no consensus exists regarding the petrogenesis of the Verena Granite. Doubts have been cast on a genetic link between the Verena Granite and the remainder of the Nebo Granite. A genetic link between the Klipkloof Granite and the Verena Granite appears likely, with the former possibly representing the rapidly chilled roof of the magmas that crystallised to form the latter. Lu-Hf isotope data on zircons are consistent with that from other units of the Lebowa Granite Suite. It also supports the unconventional model involving a common enriched mantle origin for all mafic and felsic units of the Bushveld Complex, with minimal input from older crust.

Metamorphic provinces such as the similar to 1 Ga Grenvillian, similar to 400 Ma Caledonide and Triassic Qinling Provinces often contain rocks with high-pressure assemblages such as eclogites, which formed at mantle depths in subduction zones. These are evidence of the accretion of terranes by subduction of oceans and collision to form large tectonostratigraphic provinces. The Mesoproterozoic Namaqua-Natal Province comprises a number of terranes thought to have been assembled by plate-tectonic processes, but they have generally yielded metamorphic pressures below 5 kbar, corresponding to <20 km, crustal depths, lacking evidence for subduction processes. The Kaaien Terrane in the Namaqua Front contains two large garbenschiefer units with the unusual paragenesis garnet-hornblende-epidote-white mica-plagioclase-ilmenite-quartz. Their protoliths are graywackes influenced by andesitic volcanism during their deposition at similar to 1870 Ma, in a passive margin of the Rehoboth Province or Kaapvaal Craton. Prograde garnet growth dated at 1165 +/- 5 Ma culminated in peak metamorphic conditions of 645 +/- 30 degrees C and 10.4 +/- 0.7 kbar, corresponding to 40 km depth. This is attributed to subduction of these rocks before collision between the overriding arc-related Areachap Terrane, the Kaaien Terrane and the Kaapvaal-Rehoboth cratonic block during the Namaqua orogeny. Exhumation of the garbenschiefer slabs was followed by rapid cooling, as the 1143 +/- 5 Ma argon dates of hornblende and white mica, with closure temperatures similar to 540 degrees C and similar to 440 degrees C respectively, are the same within error. This was probably due to tectonic juxtaposition of the garbenschiefer slab with much cooler rock units. The exhumation was accommodated along the Trooilapspan-Brakbosch Shear Zone due to ongoing transpression. Other components of the Namaqua Front have distinctly different P-T-t paths, exemplified by greenschist metamorphism in the 1300 Ma Wilgenhoutsdrift Group, and medium-pressure metamorphism in the Areachap Terrane. They were juxtaposed by late-tectonic uplift and transpressional movements. The similar to 40 km depth of garbenschiefer peak metamorphism is the deepest yet found in the Namaqua-Natal Province and strengthens the plate tectonic model of accretion by collision of terranes at the end of a Wilson cycle. The high pressure paragenesis of the garbenschiefer was preserved due to its location in the Namaqua Front, whereas most other parts of the Namaqua-Natal Province were overprinted by 1100-1020 Ma thermal events after the collision events.

The volcanosedimentary Guperas Formation contains the youngest volcanic rocks of the Sinclair Supergroup in the Konkiep Terrane of southern Namibia. Precise U-Pb zircon microbeam dating shows that the Guperas Formation as mapped includes felsic volcanic rocks which belong to both the first (1.37 to 1.33 Ga) and the third (1.11 to 1.07 Ga) magmatic cycle of the Sinclair Supergroup. Volcanic rocks of the ‘true’ Guperas Formation are dated by three samples, with a combined age of 1108 ± 10 Ma. The sedimentary rocks mapped as Guperas Formation are also distinguished by two different detrital age spectra into the ~1 100 Ma true Guperas Formation and the Aruab Member of the ~1 217 Ma Barby Formation. Geochronology now resolves the previous stratigraphic separation of the very similar Nubib and Rooiberg (Sonntag) Granites. The two small outcrops of 1 334 ± 5 Ma Rooiberg Granite are now shown to be part of the regional 1 334 ± 8 Ma Nubib Granite batholith. The Konkiep Terrane was affected by faulting and shear zones, but was only gently folded and not involved in regional metamorphism, despite its proximity to the Namaqua-Natal Province to the southwest. This is due to the Konkiep Terrane having a thick and strong continental basement which may have formed as part of the mainly Palaeoproterozoic Rehoboth Province. However no Palaeoproterozoic rocks are exposed in the Konkiep Terrane, which is now interpreted as an unaffiliated terrane. The three cycles of extrusive and plutonic magmatism in the Sinclair Supergroup formed in chronologically distinct periods and different tectonic settings, which requires revision of the stratigraphic nomenclature. The Konkiep Group is replaced by three new groups which are separated by >100 million-year unconformities. The Betta Group, represented by the mainly volcanic Kumbis, Nagatis and Welverdiend formations in the first magmatic cycle, probably formed in a passive continental rift setting due to breakup of the Rehoboth Province between 1 374 and 1 334 Ma. The Vergenoeg Group, represented by the sedimentary Kunjas and volcanic Barby and Haiber Flats formations, formed in a subduction setting at the margin of the Konkiep Terrane. This ~1 217 to 1204 Ma magmatic cycle ended with the accretion of Namaqua-Natal terranes to the Kalahari Craton. The ~1 100 Ma Ganaams Group, represented by the volcanic Guperas Formation and sedimentary Aubures Formation, was the result of interplay between the continental-scale Umkondo mantle heating event and movements between crustal blocks following the Namaqua-Natal collisional orogeny.

The type area of the Copperton Formation is on the farms Vogelstruisbult 104, Somuspan 105 and Dooniespan 108 in Prieska District. Outcrop is poor and the type material is preserved in exploration borehole cores from the Prieska Copper Mines and the Annex Cu-Zn deposits. It is highly deformed and variably metamorphosed. Thus it is a lithodemic unit, but interpreted as a supracrustal sequence and described as a formation including lithologically distinct members. The Copperton Formation comprises a wide range of rock types including metabasic and intermediate gneisses with minor amounts of metapelitic and calc-silicate rocks. Metamorphic parageneses generally reflect amphibolite facies metamorphism, but granulite and retrograde greenschist facies zones also occur. The protoliths are interpreted as an arc-related volcano-sedimentary package and the Smouspan Member metadacite is dated at 1284 ± 9 Ma. Members are distinguished as follows: The Magazine Member is dominated by calc-silicate rocks which are dominant in outcrop but rarely found in borehole cores. The Smouspan Gneiss is a fairly homogeneous hornblende-biotite intermediate gneiss which is up to 400 meters thick in an isoclinal fold structure. It comprises the footwall to the Prieska Copper Mines Member, in which the massive sulphide orebody occurs, enclosed in an alteration assemblage comprising dark gedrite fels and strongly foliated, leucocratic quartz-perthite-sillimanite gneiss. The ore is interpreted as a volcanogenic massive sulphide deposit formed in a Mesoproterozoic island arc system. The Vogelstruisbult Member is the hanging wall unit, comprising mainly laminated amphibolites and metapelites, but also containing a variety of rock types including hornblende gneiss, biotite gneiss, chlorite schist, and calc-silicate gneiss. Away from the Prieska Mines orebody, a similar variety of rock types is found, and not subdivided but classified as Copperton Formation, a mappable unit. The same assemblage of rock types, including massive sulphide mineralization, was intersected in drill holes on the farms Kielder (portion of Doonies Pan 108), Eierdop Pan and Kantienpan to the north. The Copperton Formation is the southernmost unit of the Areachap Group which is exposed between Prieska Copper Mines and Areachap Mine north of Upington, where the Jannelsepan and Bethesda formations occur. The Copperton Formation is partly obscured in many places by Dwyka Group tillite cover which thickens southwards. A sequence of structural and metamorphic events affected the Copperton Formation and Areachap Group during the 1.2 to 1.0 Ga Namaqua-Natal orogeny. These involved collision of the Areachap Terrane with the Kaapvaal-Rehoboth Craton at about 1220 Ma, a thermal and deformational event coeval with the continental-scale Umkondo mantle event at about 1100 Ma, followed by uplift, erosion and the development of right-lateral shear zones of the Doornberg Lineament, with cooling below 300°C by 920 Ma. A Cambrian peneplain developed in the region which was first covered by Nama Group sandstones, then glaciated and covered by Permian Dwyka Group tillites which are presently being eroded to expose the Copperton Formation.

Volcanic and sedimentary rocks of the Sinclair Supergroup occur in the Konkiep Terrane of Southern Namibia. Three volcanic and sedimentary cycles are recognised. In this work we describe and date volcanic rocks of the Barby Formation, a key unit in the Sinclair area. The coeval Spes Bona Syenite and the Tiras Granite Gneiss are also described and dated. The rock types in the Barby Formation are rhyolites, basaltic trachyandesites, trachybasalts and trachydacites as well as volcanoclastic rocks. The rocks are largely undeformed and partly altered by deuteric and contact metamorphic processes but not regionally metamorphosed. Our samples represent both the talc-alkaline and alkaline trends documented in previous work. U-Pb ion probe and laser ablation inductively coupled plasma (LA-ICP) multicollector mass spectrometer Lu-Hf microbeam analyses were made of zircon and baddeleyite grains from four samples. A felsic tuff sample from the base of the Barby Formation has a Pb-207/ Pb-206 zircon age of 1214 +/- 5 Ma (2 sigma). A rhomb porphyry sample from the top of an 8.5 km-thick stratigraphic section gives a Pb-207/Pb-206 baddeleyite age of 1217 +/- 2 Ma. The Spes Bona Syenite which intrudes the top of the Barby Formation has a Pb-207/Pb-206 baddeleyite age of 1217 +/- 3 Ma and an indistinguishable LA-ICP collision cell mass spectrometer Rb-Sr biotite isochron age of 1238 +/- 20 Ma, showing that there was no >350 degrees C regional metamorphic event. Multi-element diagrams for the talc-alkaline samples show a dominant signature of reworked crust which is superimposed on a possible subduction signature. However the alkaline samples contain clear subduction signatures which are not seen in the underlying 1.37 Ga Kumbis rhyolite. The Barby Formation samples and coeval Spes Bona Syenite have Lu-Hf crustal residence ages between 1682 and 1873 Ma, suggesting that both of these units formed from a mixture of juvenile mantle-derived and older crustal material. The Barby Formation is considered to have originated due to a subduction event which took place during the assembly of the Rodinia supercontinent. The duration of the Barby magmatic episode is constrained to a maximum 9 m.y. period between 1219 and 1210 Ma, and during this period the Konkiep Terrane was an active continental margin. The 1204 +/- 9 Ma Tiras Granite Gneiss is slightly younger than the Barby Formation and intruded across the Lord Hills Shear Zone, which is the suture between the hardly metamorphosed Konkiep Terrane and the highly metamorphosed Grunau Terrane of the Namaqua-Natal Province. Its intrusion reflects the end of subduction-related volcanism, due to the collision of Namaqua terranes with the Konkiep Terrane.

AIM:To analyse the elemental composition of dentine in primary teeth from children diagnosed with Dentinogenesis Imperfecta type II (DI) and from normal sound primary teeth using X-ray microanalysis.MATERIALS AND METHODS:X-ray microanalysis of the elements C, O, Na, Mg, P, Cl, K and Ca were performed in the dentine of five normal primary teeth and in seven primary teeth diagnosed DI. The analysis was made in a low magnification in 10 points from the enamel-dentine junction/root surface toward the pulp. The data was also evaluated with an inductive analysis.RESULTS:Lower values for C were found in DI-dentine compared with normal dentine. Na had significantly higher values in DI-dentine while Mg had significantly lower values. The inductive analysis revealed that Na and Mg were the most important elements for discriminating DI-dentine from normal dentine.CONCLUSIONS:Dentine in primary teeth from patients diagnosed with Dentinogenesis Imperfecta type II analysed with XRMA have lower values of C and Mg and higher values of O and Na compared with normal primary dentine.

The Mesoproterozoic rocks of the Kumbis and Nagatis Formations and Helmeringhausen Gabbro in Southern Namibia are now recognised as the oldest rocks in the sedimentary and volcanic Sinclair Supergroup. The stratigraphic subdivision and plate tectonic setting are still debated and reliable ages are sparse. This work investigates the relatively undeformed felsic and mafic lava of the Kumbis Formation, rhyolitic lava of the Nagatis Formation and the intrusive Helmeringhausen Gabbro. Microscopic and field investigation reveals no evidence of regional metamorphism in these units. Ion probe U-Pb zircon dating yields ages of 1374 +/- 7 Ma to 1358 +/- 5 Ma (2 sigma) for the Kumbis Formation, 1363 +/- 11 Ma for the Nagatis Formation and 1372 +/- 12 Ma for the Helmeringhausen Gabbro. These dates are in contrast to the published stratigraphy in which the Helmeringhausen Gabbro was regarded as much older than the Kumbis Formation and both were excluded from the Sinclair Supergroup, whereas the Nagatis Formation was considered to be younger and was included as the oldest unit of the Sinclair Supergroup. Lu-Hf data on zircon indicates different magma sources for the Kumbis and Nagatis Formations, implying that although they are time equivalent, they are not co-magmatic. The geochemical data suggests that the most felsic rocks contain large amounts of older crustal material, from which their apparent subduction signatures were inherited. The more mafic rocks also contain minor crustal components mixed with material derived from depleted mantle. The Helmeringhausen Gabbro is similar to coeval hybrid gabbros at Neuhof Valley 150 Km to the north and they are grouped in the intrusive Helmering Suite. Taking the regional context into account, these oldest rocks of the Sinclair Supergroup probably formed in a rift environment which split the Rehoboth Province apart at the beginning of the Mesoproterozoic Namaqua-Natal Wilson Cycle.

•Three granitoid types identified in SW Kaapvaal Craton basement.•2946–2900 Ma tonalite-trondhjemite Draghoender type are mafic subduction-melts.•2902 ± 11 Ma Skalkseput type reflect Kimberley–Witwatersrand terrane collision.•2719 ±3 Ma Ventersdorp-age Steenkop monzogranite lies athwart the Doornberg Fault.•Kaapvaal basement continues SW of Doornberg Fault beneath Namaqua foreland thrusts.

In this remarkable book, Vera Schwarcz explores the meanings of cultural memory within the two longest surviving civilizations on earth. The author of previous books that the New York Times Book Review called "moving" and Jonathan Spence termed "subtle, elegiac, and elegant," Schwarcz finds a bridge between the vastly different Chinese and Jewish traditions in the fierce commitment to historical memory they share. For both, a chain of remembrance has allowed tradition to endure uninterrupted from ancient times to the present; for both, the transmission of remembrance and the bearing of active witness to the significance of the past are high moral values. From her unique standpoint as China scholar and daughter of survivors of the Holocaust, Schwarcz uncovers resonances between the narratives of Chinese intellectuals recovering from the trauma of the Cultural Revolution and the halting tales of her own parents. Focusing on the transmission of cultural memory in these two cultures, the author examines how metaphor becomes an aid to memory, the role of personal remembrance in public commemorations, and the process of healing historical wounds. Combining poetry and historiography, oral interviews and archival documents, this book brings to life the struggles of Chinese and Jewish survivors who managed to cultivate memory through inimical times and preserve the continuity of their long traditions.

The Mawat ophiolite is part of the Mesozoic Neo-Tethyan ophiolite belt of the Middle East and is located in the Zagros Imbricate Zone of Iraq. It represents fossil fragments of the Neo-Tethyan oceanic lithosphere within the Alpine collisional system between the Arabian and Eurasia Plates. The first U-Pb zircon dating of the Daraban leucogranite from the Mawat ophiolite provides a 207Pb-206Pb age of 96.8 +/- 6.0 Ma. The age is 59.0 +/- 6.0 m. y. older than the previously published age of the Daraban leucogranite obtained by 40Ar-39Ar muscovite dating method. The U-Pb dating of magmatic zircons collected from the Daraban leucogranite, which intrudes into the Mawat ophiolite, reveals that melting of the pelagic sediment beneath the hot Zagros proto-ophiolite in an intra-oceanic arc environment led to anatexis at the subduction front and the generation of granitic melts at 96.8 +/- 6.0 Ma, which were emplaced in the overlaying mantle wedge. This process was a response to the initial formation of the Neo-Tethys ophiolite above a northeast-dipping intra-oceanic subduction zone at 96.8 +/- 6.0 Ma. Published 40Ar-39Ar muscovite dating from the same leucogranite dike yields plateau ages of 37.7 +/- 0.3 Ma, reflecting that the age was reset during the Arabia-Eurasia continental collision. Therefore, the bimodal age populations from the granitic intrusion in the Mawat ophiolite preserve a record of the subduction to the collision cycle of the Zagros Orogenic Belt. The 59.0 +/- 6.0 m. y. age difference from the Daraban leucogranite represents the duration of the subduction-collision cycle of the Zagros Orogenic Belt in the Kurdistan region of Iraq and the time span for the closure of the Neo-Tethys Ocean along the northern margin of the Arabian plate.

The agpaitic Norra Kärr alkaline complex in southern Sweden is rich in heavy rare-earth elements and zirconium. Despite generally containing high concentrations of Zr, agpaitic rocks sensu stricto are devoid of igneous zircon. During the late stages of magmatic activity at Norra Kärr, metasomatic Na- and F-rich fluids transporting Zr complexes caused fenitisation (syn-magmatic alkali metasomatism) of the granitic wall rocks, which formed new metasomatic zircon. Fenite zircon was dated by LA-MC-ICP-MS with the U–Pb method at 1.49±0.01Ga, while the unaltered country rock granite was dated at 1.79±0.01Ga. Zircon in the fenites exhibits εHf+6.58±0.36 at 1.49Ga; significantly above the expected value for Svecofennian crust at that time (ca. −5±2), but identical, within error, of that measured in eudialyte from Norra Kärr. This suggests a common source of Hf for fenite zircon and eudialyte from Norra Kärr, which isotopically strengthens the genetic link between fenite and nepheline syenite. The 1.49Ga age dates not only the fenitisation, but also the relatively small agpaitic intrusion, which caused the fenitisation. This also dates the origin of the rare-earth element and Zr ore within the agpaitic nepheline syenite, which probably formed from an evolved magma derived from the mantle. A few zircon xenocrysts, which survived in the agpaitic nepheline syenite magma, may indicate the presence of an Archaean component in the basement.

The Mesoproterozoic metamorphic formations of the Wilgenhoutsdrif Group underlie a large area around the Orange River east of Upington. The quartzitic Grootdrink Formation occurs at the base of the sequence and contacts with older units are either unconformable or along thrusts. The Zonderhuis Formation is a sequence of low-grade pelitic phyllites and impure quartzites with subordinate lenses of metavolcanic rocks and serpentinite. The Leerkrans Formation is thought to follow conformably and consists of deformed basaltic and quartz-porphyritic lavas and volcanogenic metasediments. The entire group is isoclinally folded and foliated, with greenschist facies metamorphic parageneses, and is altered by carbonate veins and epidotisation. The age of felsic volcanic rocks is reliably established at 1289 or 1293 Ma with 2 sigma errors of 9 Ma. The Wilgenhoutsdrif Group now forms part of the Kaaien Terrane of the Namaqua-Natal Province. It may have formed in a continental back-arc basin at about the same time as the arc-related volcanic rocks of the Areachap Group formed by subduction of an ocean basin to the west, prior to similar to 1.2 Ga Namaqua terrane assembly by collisions with the Kaapvaal-Rehoboth Craton.

The Archaean Ventersdorp Supergroup is the most widespread volcanosedimentary cover sequence on the Kaapvaal Craton. it unconformably overlies the Witwatersrand Supergroup and is unconformably overlain by the Transvaal Supergroup. Due to exploration drilling for Witwatersrand gold, the Ventersdorp Supergroup is the globally most extensively drilled sequence. Early efforts to date its volcanic units have commonly been thwarted by pervasive 2.3 to 2.0 Ga alteration. In situ U-Pb zircon dating promises a panacea, but the effects of lead mobility and high common lead remain potential pitfalls. The ages of the 'type' formations of the. Ventersdorp Supergroup sensu stricto are still not well established and much of the published data is on units only considered to be correlated with the 'type' formations. Quartz porphyry rhyolites of the Makwassie Formation in the Platberg Group are reliably dated by the laser ablation ICPMS U-Pb zircon method on four samples with a combined age of 2720 +/- 2 Ma. This supercedes the first ion probe date of 2709 +/- 4 Ma which is now regarded as a minimum age due to probable ancient lead loss and associated high common lead. The published 2714 +/- 16 Ma age for the stratigraphically lower Klipriviersberg Group was affected by similar problems. The Makwassie Formation is the only formation of the Ventersdorp Supergroup sensu stricto for which an accurate and reliable date has now been established by more than one precise age determination. Two samples considered to be from the Goedgenoeg Formation, which underlies the Makwassie Formation, were investigated. The formation is best dated by a 2746 +/- 9 Ma age on a feldspar porphyry borehole sample from near Wolmaransstad. A sample from a similar rock type also assigned to the Goedgenoeg Formation, which underlies the Makwassie Formation in Wesselton Mine at Kimberley, gave an age of 2781 +/- 5 Ma. A 30 Ma period of Goedgenoeg volcanism is considered to be unlikely. The older sample may rather be a time-correlate of a stratigraphically lower unit such as the 2785 +/- 2 Ma Kanye Formation or the 2769 +/- 2 Ma Derdepoort Outlier.

The Jannelsepan Formation forms part of the 1.30 to 1.24 Ga Areachap Group. It is a pre-tectonic calc-alkaline volcano-sedimentary unit in the 1.2 to 1.0 Ga Namaqua Sector of the Namaqua-Natal Metamorphic Province. The main rock types are amphibolites with subordinate clinopyroxene or biotite. Although some primary volcanic textures have been identified, primary features are generally poorly preserved. Minor interlayered units include felsic metavolcanic rocks, pelitic schists and calc-silicate rocks which may represent primary marls. Field and geochemical evidence suggests that the Jannelsepan Formation represents metamorphosed basaltic to intermediate lavas and associated sedimentary rocks which formed in a subduction-related arc setting.