Alan Woolley

• Natural History Museum, London

Songwe Hill, Malawi, is one of the least studied carbonatites but has now become particularly important as it hosts a relatively large rare earth deposit. The results of new mapping, petrography, geochemistry and geochronology indicate that the 0.8 km diameter Songwe Hill is distinct from the other Chilwa Alkaline Province carbonatites in that it i...

When Dr Campbell Smith published and compiled his first account and catalogue of British jade implements he did not think, he tells us, that many more would be found. For this reason he adopted a numbering system based on counties, as is done for all other stone implements, but with numbers running consecutively through the English, Scottish and Ir...

The central massif of the Lake District around Great Langdale and Scafell Pike was one of the major locations for the production of Neolithic, polished stone axes. In response to the continuing erosion of the axe production sites a field survey was undertaken in 1984 and 1985. 566 distinct working sites were identified, within 35 groups; each site...

A recent database and world distribution map of carbonatites supports previous observations of the spatial and temporal aspects of these rocks, and provides new observations that are important for understanding their petrogenesis. These data reveal that there is an overwhelming concentration of carbonatites in Precambrian cratonic areas, most of wh...

The Quaternary Fort Portal volcanic field occurs at the northern end of the Western Rift in Uganda. The eruptive phases consist of (1) early carbonatite tuff cones followed by (2) a blanket carbonatite tuff (the major unit of the field) and finally (3) a small volume of carbonatite lava. Mantle and crustal xenoliths are found in all eruptive phases...

Data on the diversity and relative abundance of igneous rock types associated with carbonatite have been compiled for 477 occurrences, which represent 90% of the 527 occurrences of carbonatite known to the authors. The carbonatites have been subdivided into magmatic carbonatites (84%) and carbohydrothermal carbonatites (16%) on the basis of their m...

The Borrolan Complex comprises earlier and later rock suites which are separated by an intrusive junction. The earlier suite forms a conformable sheeted complex which has been punched through by a later plug-like body and includes several distinct magma types; while the later suite differentiated gravitationally in place. Field and microscopic evid...

There are 27 known occurrences of carbonatites in China. Brief descriptions are given of all occurrences including geographical coordinates, geological setting, associated rocks, carbonatite forms, ages, mineralogy, mineralisation, and carbon and oxygen isotopic data. About half of the occurrences lie along the margins of orogenic belts and the res...

The Lovozero alkaline massif is the largest of the world's layered peralkaline intrusions (∼650 km²). We describe the evolution of clinopyroxene from the liquidus to the late residual stage throughout the whole vertical section (2.5 km thick) of the Lovozero Complex. Microprobe data (∼990 analyses) of the clinopyroxenes define a relatively continuo...

In a recent paper Peccerillo (2004) quoted chemical, including isotopic, mineralogical and field data which he claimed "..cast serious doubt on the hypothesis that the carbonate-rich pyroclastics from central Italy represent carbonatitic magmas.". He concluded that the carbonate is derived from sedimentary limestone. He also noted that he had enunc...

49 known extrusive carbonatite occurrences are listed with brief details of their tectonic setting, structure, lithologies, associated silicate rocks, chemistry and presence or absence of included mantle materials. Half the occurrences appear to be related to tephra cones, tuff rings, diatremes and maars and the rest occur within strato-volcanoes....

Because the calciocarbonatite lavas at Fort Portal were the first ever described they have received great attention, with the pyroclastic rocks being relatively neglected. Volumetrically the lavas are minute, and the major deposit is a 2 m thick blanket of “flaggy” tuffs, long regarded as carbonatite tuff with crustal debris. Fresh examination show...

Two distinct occurrences of wollastonite- and melilite-bearing rocks from Ricetto and Colle Fabbri, which are located in the central Italy Apennine Range, are referred to as “paralavas” generated by melting and recrystallization of marly sediments “likely due to coal fires” by Melluso et al. (2003). We submit data demonstrating that these conclusio...

A general feature of alkaline and related magmatism is repetition of eruption at the same site over long time intervals. Alkaline activity is widespread across Africa, where there are more than one thousand complexes. Eruption is typically localized by older lithosphere structures. As more igneous age dates have become available, examples of repeti...

The introduction of a fifth amphibole group, the Na-Ca-Mg-Fe-Mn-Li group, defined by 0.50 < (B)(Mg,Fe2+,Mn2+,Li) < 1.50 and 0.50 less than or equal to (B)(Ca,Na) less than or equal to 1.50 apfu (atoms per formula unit), with members whittakerite and ottoliniite, has been required by recent discoveries of (B)(LiNa) amphiboles. This, and other new di...

The Cretaceous Chilwa alkaline province lies at the southern end of the East African rift system. A diverse suite of intrusive and extrusive alkaline igneous rocks is found in the province. The earliest igneous activity (ca 133 Ma) is represented by the extrusion of nephelinites and basanites and the intrusion of nepheline and sodalite syenites.and...

The introduction of a fifth amphibole group, the Na-Ca-Mg-Fe-Mn-Li group, defined by 0.50 < B (Mg,Fe 2+ ,Mn 2+ ,Li) < 1.50 and 0.50 ≤ B (Ca,Na) ≤ 1.50 apfu (atoms per formula unit), with members whittakerite and ottoliniite, has been required by recent discoveries of B (LiNa) amphiboles. This, and other new discoveries, such as sodicpedrizite (whic...

The introduction of a fifth group of amphiboles, the Na-Ca-Mg-Fe-Mn-Li group, defined by 0.50 < (B)(Mg,Fe2+,Mn2+,Li) < 1.50 and 0.50 less than or equal to (B)(Ca,Na) less than or equal to 1.50 atoms per formula unit, with members whittakerite and ottoliniite, has been required by recent discoveries of (B)(Li,Na) amphiboles. These, and other new dis...

The introduction of a fifth group of amphiboles, the Na-Ca-Mg-Fe-Mn-Li group, defined by 0.50 < B (Mg,Fe 2+ ,Mn 2+ ,Li) < 1.50 and 0.50 ≤ B (Ca,Na) ≤ 1.50 atoms per formula unit, with members whittakerite and ottoliniite, has been required by recent discoveries of B (Li,Na) amphiboles. These, and other new discoveries, such as sodicpedrizite (which...

A multidisciplinary approach, based on historically derived information, physical data on tephra deposits and petrochemical analyses of lavas and tephra, has been used in order to obtain the timing of the various eruption phases, the eruptive phenomenology, and the magma supply mechanisms of the 1822 eruption. In 1822 Vesuvius experienced one of th...

L., WHITTAKER, EJW & GUO, YOUZHI ( ): Nomenclature of E. AJ Burke and BE "NAMED AMPHIBOLES BE USED IN AMPHIBOLE NAMES , December 1

Samples from the various volcanic fields in the Uganda portion of the western branch of the East African rift system were analyzed for major and trace elements. The northernmost Fort Portal field consists of extrusive carbonatite tuffs and lavas. All these samples are mixtures of carbonatite, basement rock fragments and peridotite xenoliths. The ce...

New bulk-rock and mineral data on eucite melilitolite from Italy are presented, compared and discussed in terms of their parageneses, petrological significance and petrogenesis. Melilitolite is an intrusive assemblage with more than 10% modal melilite. Leucite-bearing melilitolite (Italite?) is so far only known from Italy, contains about 30vol.% m...

Data on the diversity and relative abundance of igneous rock types associated with carbonatite have been compiled for 377 occurrences, which represents 82% of the ~450 carbonatite occurrences known to the author. Extrusive carbonatite is found at 40 localities and for the purposes of analysis these are treated separately. The extrusive carbonatite...

A new occurrence of a rare kamafugite near L'Aquila, Abruzzo, is described in detail to characterize its paragenesis and to establish possible genetic links with similar alkaline mafic igneous rocks from the Oricola-Camerata Nuova (OC) volcanic field, ˜20 km to the west. Both occurrences belong to the Umbria-Latium-Ultralkaline-District (ULUD), an...

The western branch, in SW Uganda, of the East African rift system is one of the classic localities for potassic alkaline magmatism. From north to south the province consists of carbonatite lavas at Fort Portal, ultrapotassic mafic rocks in the central Katwe-Kikorongo and Bunyaruguru fields and potassic mafic-felsic flows in the Bufumbira field. In...

Ti-bearing phlogopite-biotite is dominant in Ugandan kamafugite-carbonatite effusives and their entrained alkali clinopyroxenite xenoliths. It occurs as xeno/phenocrysts, microphenocrysts and groundmass minerals and also as a major xenolith mineral. Xenocrystic micas in kamafugites and carbonatites are aluminous (> 12 wt% Al2O3), typically contain...

Lovozero, the largest of the world’s layered peralkaline intrusions, includes gigantic deposits of Nb + REE-loparite ore. Loparite, (Na,Ce,Ca)2(Ti,Nb)2O6, became a cumulus phase after crystallisation of about 35% of the ‘Differentiated Complex’, and its compositional evolution has been investigated through a 2.35 km section of the intrusion. The co...

We present petrographic and mineralogical data for 21 mantle xenoliths (12 lherzolites, 8 wehrlites and 1 composite) selected from a suite of more than 70 samples collected from the Monticchio Formation, Mt. Vulture volcano, southern Italy. The xenoliths are rounded, coarse- to porphyroclastic-textured, and very fresh, with the following equilibrat...

A group of carbonate-rich tuffs are described from the Murumuli crater, Katwe-Kikorongo volcanic field, SW Uganda which contain abundant carbonatite pelletal lapilli, together with melilitite lapilli and a range of xenocrysts and lithic fragments including clinopyroxenites considered to be of mantle origin. The carbonatite lapilli consist essential...

Alkali pyroxenite xenoliths from three volcanic fields in Uganda are largely composed of clinopyroxene (cpx) and phlogopite-biotite (together >70% of mode). Inter-field compositional variation in these minerals shown by 749 cpx analyses and 237 mica analyses from 34 xenoliths indicates bulk-chemical lateral variation in the xenolith source. The ubi...

The North Nyasa Alkaline Province of Malawi consists of seven Late Precambrian intrusions emplaced along a north-south trend roughly parallel to that of the current rift valley. The intrusions are predominantly nepheline syenite, but minor pyroxenite is found at IIomba and alkali syenite and granite are associated with nepheline syenite at Mphompha...

The crystal chemistry characteristics of a hydroxyl-fluor apatite from a recently discovered kalsilite-bearing leucitite from Abruzzi, Italy, were investigated by electron microprobe, single crystal X-ray diffraction, IR, Raman and micro-Raman spectroscopy. The apatite has exceptionally high S and relatively high Si, Sr and LREE , whereas the HREE...

The International Mineralogical Association's approved amphibole nomenclature has been revised to simplify it, make it more consistent with divisions generally at 50%, define prefixes and modifiers more precisely, and include new amphibole species discovered and named since 1978, when the previous scheme was approved. The same reference axes form t...

Potassic magmatism occurred on the Aldan Shield during the Paleozoic (288 Ma) and Mesozoic (155-135 Ma). The problems of the origin, composition, and evolution of rocks and their mantle sources were considered using precise majorand trace-element analyses and Sr-Nd isotopic data on a representative collection of rock samples from the Paleozoic pota...

The composition of pyrochlore from the calcite carbonatite and its associated laterite at Bingo, Zaïre was determined and compared with pyrochlore from the nearby and geologically-similar carbonatite at Lueshe. Large compositional variations exist in the Bingo pyrochlore which relate both to primary magmatic zonation and, more commonly, a secondary...

The International Mineralogical Association's approved amphibole nomenclature has been revised to simplify it, make it more consistent with divisions generally at 50%, define prefixes and modifiers more precisely, and include new amphibole species discovered and named since 1978, when the previous scheme was approved. The same reference axes form t...

This paper is based on the study of the alkaline layered southern Sakun Massif in the western Aldan area. The rocks of the massif contain pseudoleucite aggregates (intergrowths of alkali feldspar with kalsilite, nepheline, and leucite). These aggregates dominate in the pseudoleucite syenites and synnyrites of the massif, which also contains biotite...

The paper reviews the published work, and presents new data, on the four occurrences of carbonatite that have been recognised in Italy since 1990. All are Recent in age. Three are extrusive and comprise tuffs and breccias while the fourth is high level and consists of tuffisites. They form diatremes with tuff rings, three of them being intimately a...

The International Mineralogical Association’s approved amphibole nomenclature has been revised in order to simplify it, make it more consistent with divisions generally at 50%, define prefixes and modifiers more precisely, and include new species of amphibole discovered and named since 1978, when the previous scheme was approved. The same reference...

A detailed study of weathered pyrochlore in the laterite above carbonatite at Lueshe, NE Zaire, has been made in order to determine its chemical and textural variations. Pyrochlore in fresh carbonatite at Lueshe is close to an ideal formula of (Ca,Na)2Nb2O6(OH,F) (where a general formula is A2-xB2O6(OH,F)1-y·zH 2O). The first and principal change o...

The nomenclature and classification of lamprophyres, lamproites, kimberlites and the kalsilitic, melilitic and leucitic rocks are inadequately defined. The recommendations of three working groups established by the IUGS Subcommission on the Systematics of Igneous Rocks to resolve aspects of the problem are presented for discussion. New definitions...

The North Nyasa Alkaline Province (NNAP) of central and northern Malawi, eastern central Africa, consists of seven nepheline syenite intrusions which were, to varying degrees, affected by the Mozambique Orogenic event. We have analyzed the constituent clinopyroxene in rocks of five of these intrusions by electron microprobe. Three groups of pyroxen...

The Bingo complex, on which little information has been published heretofore, is located in northeastern Zaire, 30 km west of the western branch of the East African rift. Although outcrop is poor, fresh float has enabled construction of a geological map showing that the intrusion consists of ijolites cut and net-veined by nepheline and sodalite sye...

The Cretaceous Chilwa Alkaline Province of southern Malawi has an exceptional variety of lithologies ranging from carbonatite to granite. The largest plutons consist of syenite and peralkaline granite, with somewhat smaller intrusions consisting of syenite, nepheline syenite and sodalite syenite. Carbonatite and minor nephelinite occur on Chilwa Is...

Many solid inclusions occur in apatite of the Sukulu carbonatite, Uganda, of which the most abundant are carbonate, which can be classified into clear (Mg-calcite) and pitted (calcite) inclusions based on their morphology, texture and chemical composition. Although such solid inclusions are ubiquitous in carbonatite apatite and have been described...

Electron microprobe investigations of carbonates in carbonatites of the Nkombwa, Zambia, and Newania, India, intrusions indicate that they consist of dolomite-ankerite, and magnesite-siderite. Hitherto carbonates of the magnesite-siderite series have been considered to be very rare in carbonatites, but the complete series has been found during this...

This paper describes the reasoning that lies behind the construction of the field boundaries in the Total Alkali-Silica diagram (TAS) for the chemical classification of volcanic rocks. It shows that by utilizing nomenclature in common use by petrologists in combination with a large computer database of geochemical analytical information derived fro...

The mafic mineralogy of the Zomba-Malosa alkaline and peralkaline granite-syenite intrusion of the Chilwa Province, Malawi, has been investigated by electron microprobe. Pyroxenes analysed in 28 rocks form two series. Those from Zomba Mountain define a trend from salite through ferrosalite, hedenbergite, and sodic hedennergite to aegirine-hedenberg...

Carbonatites occur in the Uyaynah area, United Arab Emirates, within a tectonic window of oceanic metasediments beneath the Semail Ophiolite Complex at the northern end of the Oman Mountains. The carbonatites form conformable layers, pods, and lenses, up to 10 m thick, associated with deep-sea sediments that include radiolarian cherts and pillow la...