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Introduction
My general area of expertise is geochemistry but I have eclectic interests which range from forensic geology to archaeology. Recent projects - characterizing the glass (trintite) produced during the first atomic bomb blast, determining the concentration of Br in geologic materials, petrology and geochemistry of the Coastal New England dike swarm, F and Cl in apatite, amphibole, and biotite, sources of obsidian, using tree-ring cores to map environmental change and atmospheric pollutants.
Current institution
Additional affiliations
July 1999 - August 1999
September 1970 - present
January 1982 - December 2014
Position
- Visiting Senior Fellow
Description
- Collaborative research projects with Department of Earth Sciences faculty and staff. Utilize various analytical facilities in the department.
Education
September 1967 - May 1971
September 1965 - June 1967
September 1961 - June 1965
Publications
Publications (128)
Mesozoic anorogenic magmatism in New England and Quebec begins with Triassic dikes emplaced at Cape Ann and other eastern Massachusetts locations and an igneous complex (Agamenticus) in Maine. Emplacement ages cluster around 238 Ma. The Jurassic is represented by large felsic intrusions in New Hampshire and Maine which have ages ranging from 200 to...
Glass fragments (16 green glasses and 2 red glasses) were handpicked from crushed Trinitite. X-ray diffraction studies revealed that these samples were essentially pure glass with the exception of minor amounts (less than 4 wt.%) of quartz (which acts as a diluent) in some samples. The concentrations of 45 elements in the Trinity glasses were deter...
Mesozoic magmatism in New England and Quebec begins with Triassic dikes emplaced at Cape Ann and other eastern Massachusetts locations. The oldest dike is a camptonite (245 Ma amphibole Ar-Ar) and other dikes have ages ranging from 240 to 210 Ma. The Jurassic is represented by large felsic intrusions in New Hampshire and Maine which have ages rangi...
New analytical and field techniques, as well as increased international communication and collaboration, have resulted in significant new geological discoveries within the Appalachian-Caledonian-Variscan orogen. Cross-Atlantic correlations are more tightly constrained and the database that helps us understand the origins of Gondwanan terranes conti...
Significance
This article reports the discovery of a heretofore unknown icosahedral quasicrystal created by the detonation of the first nuclear device at Alamogordo, NM, on 16 July 1945 (the Trinity test). Like all quasicrystals, the new example violates crystallographic symmetry rules that apply to ordinary (periodic) crystals. It was found in a s...
Mesozoic intraplate magmatism in the eastern Massachusetts Avalon terrane is represented by over 100 northeast trending dolerite dikes that intrude the Silurian Cape Ann Plutonic Complex (CAPC) and Neoproterozoic sedimentary, volcanic, and calc-alkaline granitoid rocks. Geochronological data are sparse, but the dikes are inferred to be of Triassic...
Thirty emerald crystals from 13 emerald deposits were analyzed using instrumental neutron activation analysis (INAA). The emerald classification scheme of Giuliani et al. [1] is used as the framework for the rationalization of the chemical data.
Logarithmic x-y plots using Cs, Na, Rb, Ga, Fe, Sc, Co, As and Sb, and a three component Cr-Cs-V plot, e...
Over the past 150 years a chestnut oak growing on a ridge above the Palmerton zinc smelters, Pennsylvania, USA, has recorded environmental changes. Changes in chemistry measured in a tree‐ring core from this chestnut oak signal the start of smelting in the late 1800s, the change in ore feed during the 1920s and 1930s, and the positive impact of pol...
The chemistry of emeralds from 24 deposits in 10 countries was determined by Instrumental Neutron Activation Analysis (INAA). The INAA data were augmented by additional high sensitivity measurements from the literature. The chemical data were grouped on the basis of the type of emerald deposit: Type I directly related to igneous processes, Type IIB...
Pyromorphite-group minerals (PyGM), mainly pyromorphite (Pb5(PO4)3Cl), mimetite (Pb5(AsO4)3Cl) and vanadinite (Pb5(VO4)3Cl), are common phases that form by supergene weathering of galena. Their formation is strongly influenced by processes at the Earth's surface and in the soil overlying a lead deposit and they incorporate high amounts of halogens,...
A scientific paper starts with a research idea, followed by an exploration of this idea, and finally the report of the results of this exploration in the form of a scientific paper. The publication of a scientific paper is perhaps the most important step as it makes these results available to the scientific community. The publication process begins...
Dust samples were collected from playas to the west of the Salt Lake City urban corridor, the major cities in the urban corridor, and from dust deposited on snow in the Wasatch mountains. The concentrations of 45 elements were determined by Instrumental Neutron Activation Analysis. The goal was to identify the sources for the various elements and t...
The Avalon terrane (AT) is a microcontinent that rifted from supercontinent Gondwana in the Ordovician and accreted to Laurentia during the latest Silurian to Devonian Acadian orogeny. Today, the extent of the type AT is well constrained in Canada by U-Pb detrital zircon studies and/or isotope geochemistry of (meta)sedimentary and igneous rocks. In...
Paper discusses using emerald chemistry to identify the source of the emeralds.
The Kaleybar, Razgah and Bozqush (KRB) intrusions were studied to better understand subduction-related Eocene-Oligocene alkaline magmatism in NW Iran. The bulk of intrusions mainly consist of Si-undersaturated rocks including foid-bearing monzonite and syenite (nepheline syenite, pseudoleucite syenite) with some foid-bearing diorite and gabbro. In...
Schwarz and Giuliani (2001) divided emerald deposits into two groups. Group 1 includes deposits related to pegmatites, with or without associated schist, and Group 2 includes deposits related to tectonic structures. Occurrences in Group 2 include schist without pegmatite and black shales. Thirty-one individual emerald crystals, from emerald deposit...
The Franklin and Sterling Hill zinc mines, northern New Jersey, were active for more than 100 years. Three hundred and fifty mineral species were found in these mines and 28 are unique to the area. Ninety of these mineral species are fluorescent, usually due to the presence of Mn in the crystal structure. The mineral deposits occur in the Mesoprote...
It is estimated that during their 90 years of operation the Palmerton, PA, zinc smelters (now an EPA superfund site) emitted 3,740 st Cd, 7,560 st Pb, and 286,000 st Zn. The ore mineral feed to the smelters consisted of sphalerite, galena, willemite, franklinite, and zincite. Twenty-four soil samples were collected from the area surrounding the Pal...
Anorogenic magmatism starts in Northeastern North America at ~250 Ma with the emplacement of alkaline mafic dike swarms in New England and the Maritime Provinces of Canada. Emplacement of largely syenititc and granitic magmas begins at ~200 Ma and continues to ~150 Ma. Most of these magmas are silica-oversaturated, but silica undersaturated magmas...
The March 2017 issue of Geostandards and Geoanalytical Research included a Comment (Wiedenbeck 2017) on our article about halogens in reference glasses (Marks et al. 2017). The comment presented new unquantified SIMS F/Si and Cl/Si data for the glasses investigated in our study (BHVO-2G, BIR-1G, BCR-2G, GSD-1G, GSE-1G, NIST SRM 610 and NIST SRM 612...
Measuring the low bromine abundances in Earth’s materials remains an important challenge in order to constrain the geodynamical cycle of this element. Suitable standard materials are therefore required to establish reliable analytical methods to quantify Br abundances. In this study we characterise 21 Br-doped glasses synthesized from natural volca...
Triassic-Jurassic intraplate magmatism in northeastern US and southeastern Canada is represented by the Coastal New England (CNE) and Eastern North America (ENA)provinces, largely composed of mafic dikes and lava flows, and the Older White Mountain (OWM) province which is predominately felsic plutons. The ENA is associated with the tholeiitic Centr...
A large block of pumice with a thick layer of volcanic glass attached to one side was found on a beach in the Chatham Islands. The geochemical signature of the specimen was most unusual: it proved to be a peralkaline phonolite with a negative europium anomaly. Since there was no obvious eruptive event that might have been the source of the floating...
Halogen contents for the widely distributed reference glasses BHVO-2G, BIR-1G, BCR-2G, GSD-1G, GSE-1G, NIST SRM 610 and NIST SRM 612 were investigated by pyrohydrolysis combined with ion chromatography, total reflection X-ray fluorescence analysis, instrumental neutron activation analysis, the noble gas method, electron probe microanalysis and lase...
In 1898 New Jersey Zinc began smelting (West Plant) ores, at Palmerton, PA, from the Franklin Furnace and Sterling Hill zinc mines. A second smelter (East plant) began operation in 1915. Smelting operations continued at these two plants until 1980. Electrostatic precipitators were installed in 1953. In 1954 the Franklin Furnace mine was closed and...
Fluorine and Cl concentrations in melts have been estimated from whole-rock F and Cl contents, melt inclusions, and halogen containing minerals, notably biotite and apatite. Amphibole and titanite also contain F, and an empirical equation has been developed for F partitioning between amphibole and melt (DFamph/Fmelt = 1.03 + 0.06*mg#) in alkaline f...
The Cretaceous age Monteregian Hills Petrographic Province consists of a group of alkaline silica-undersaturated to silica saturated plutons lying along a roughly east-west trend extending from the Oka carbonatite complex 40 km west of Montreal to Monts Brome and Shefford 80 km east of Montreal. The city of Montreal is built around one of these plu...
Trinitite is the glass formed during the first atomic bomb test near Socorro, New Mexico, on July 16, 1945. The protolith for the glass is arkosic sand. The majority of the glass is bottle green in color, but a red variety is found in the northern quadrant of the test site. Glass beads and dumbbells, similar in morphology to micro-tektites, are als...
The Atomic age began the morning of July 16, 1945, with the detonation of an atomic device (a plutonium bomb) near Socorro, New Mexico, USA. Almost seventy years later, with the advent of international terrorism, this event has led to significant research efforts on the characterization of the products of an atomic detonation with the intent to be...
Cretaceous–Tertiary kimberlite–carbonatite magmatism in mid-continent North America extends along a N40°W linear trend from Louisiana to Alberta, and occurs in at least four different pulses (∼109–85, 67–64, 55–52, and less than 50 Ma). The lack of spatial age progressions of magmatism consistent with motion of North America over a fixed hot spot,...
Granites are found in essentially all tectonic environments, are derived from a wide variety of sources, and evolve along multiple pathways. The classification of granites should be devoid of petrogenetic implications because the same mineralogical and textural outcomes can be achieved via different petrogenetic pathways. Various schemes used to cl...
Instrumental neutron activation analysis (INAA) is a non-destructive analytical technique
that can be applied to a wide range of materials. The method requires no pretreatment of
the sample, various geometries can be used and as many as 40 elements can be determined at
the ppb–ppm level, depending on the characteristics of the specific sample. The...
Archean alkaline complexes (and carbonatites) are rare worldwide. Only a few tens complexes in the Canadian Shield (Superior Province), Greenland, and Australia (Yilgarn craton) are known to date. They are composed of alkali and nepheline syenites, foidolites, carbonatites, peralkaline granites, lamprophyres, and potassic volcanic rocks. The age of...
The Central Atlantic Magmatic Province (CAMP) extends approximately 5000 km north to south on both sides of the Atlantic Ocean. The magmatic activity occurred at the Triassic-Jurassic boundary (~200 Ma). In New England and the Maritime provinces this magmatic event is represented by two major suites of Mesozoic dikes emplaced between 225 and 230 Ma...
The Sakharjok Y–Zr deposit in Kola Peninsula is related to the fissure alkaline intrusion of the same name. The intrusion ~7 km in extent and 4–5 km2 in area of its exposed part is composed of Neoarchean (2.68–2.61 Ma) alkali and nepheline syenites, which cut through the Archean alkali granite and gneissic granodiorite. Mineralization is localized...
A-type granites are emplaced in either within plate anorogenic settings or in the final stages of an orogenic event (sometimes referred to as post-orogenic). The universal commonality is that the tectonic environment has become extensional and the granites do not show any tectonic fabric (although such fabric may be introduced by later tectonic eve...
Zinc mining first began in the Franklin, New Jersey, area in the 1700’s. In the late 1800’s the individual claims were consolidated into a single entity known as the New Jersey Zinc Company. The two mining operations were at Sterling Hill and Franklin Furnace. The major ore minerals were franklinite [(Zn,Mn2+,Fe2+)(Fe3+,Mn3+)2O4], willemite [Zn2SiO...
On 16 July 1945, the first atomic bomb was detonated at the Alamogordo Bombing range in New Mexico, USA. Swept up into the nuclear cloud was the surrounding desert sand, which melted to form a green glassy material called ‘trinitite’. Contained within the glass are melted bits of the first atomic bomb and the support structures and various radionuc...
The Keivy alkali granite complex consists of 2650-2660 Ma aegirine-arfvedsonite granites (six sheet-like massifs of a few hundred meters thickness and a total exposure area of ca. 2500 km2), 2670 Ma aegirine-augite-lepidomelane-ferrohastingsite syenogranites that occur in the margins of some massifs, and 2680 Ma lepidomelane-ferrohastingsite syenit...
The intrusion of granitoids into the Eastern Sierras Pampeanas in the Early Carboniferous took place after a long period of mainly compressional deformation that included the Famatinian (Ordovician) and Achalian (Devonian) orogenies. These granitoids occur as small scattered plutons emplaced in a dominant extensional setting, within older metamorph...
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...
The Arkansas alkaline province (AAP) consists of intrusive bodies ranging in lithology from carbonatite and lamproite through nepheline syenite. Apatite and titanite fission-track ages fall into two groups—101–94 Ma and ∼88 Ma. New 40Ar/39Ar ages and those reported in the literature define a third age group of ∼106 Ma. Apatite and titanite fission-...
Mineral chemistry of micas from the subduction-related mafic and felsic
alkaline rocks of the Kaleybar alkali-gabbro and the Bozqush nepheline syenite was
determined. The micas generally occur as large poikilitic grains with Fe-Ti oxides and
mafic minerals and give the rocks a spotted texture. Micas in the alkali-gabbro
sometimes display a distinct...
The Kaleybar alkaline igneous intrusion contains fine- to coarse-grained, anhedral to euhedral brown garnets. Most of the garnets are zoned. Generally, they occur in foid-bearing leucocratic rocks and the phenocrysts typically have analcime inclusions. According to mineral chemistry, the garnets of Kaleybar are Ti-andradites and melanites. The chem...
Instrumental Neutron Activation Analysis (INAA) is a relatively straightforward technique for determining elemental abundances in a wide range of materials. The method utilizes the interaction between a thermal (or higher energy) neutron and a nucleus to produce a radioactive nuclide that emits characteristic gamma rays. The energy of the emitted g...
Instrumental Neutron Activation Analysis (INAA) is a relatively straightforward technique for determining elemental abundances in a wide range of materials. The method utilizes the interaction between a thermal (or higher energy) neutron and a nucleus to produce a radioactive nuclide that emits characteristic gamma rays. Solid state detectors are u...
Archean alkaline complexes are extremely rare but are of particular interest because the magmas have a mantle origin. Given their high Sr and Nd contents, crustal contamination has only a minor impact on the mantle-derived isotopic signatures. Therefore, they can provide valuable information on the isotopic composition of the subcontinental mantle...
A suite of massif-type anorthosites and peralkaline granites is found in the Archean Keivy terrane of the NE Baltic shield. The 2660-2680 Ma Keivy anorthosite complex consists of several large (up to the 170 km2) lopoliths composed mainly of anorthosite and gabbro-anorthosite and marginal gabbro-norite and titanomagnetite-rich troctolite bodies. Th...
Forensic Geology can be used as a vehicle to introduce students to geological concepts and principles using an inquiry driven approach - i.e., crime solving. We have developed such a course largely based on case studies. The course was designed for non-science majors, but biology, chemistry, and physics majors have taken the course as a technical e...
White Island, Ross Sea, Antarctica is a Plio-Pleistocene basanite to tephriphonolite shield volcano, forming part of the Erebus Province, McMurdo Volcanic Group. Four new 40Ar/39Ar dates extend the age of surface volcanism from a previously determined 0.17 Ma to 5.05 ± 0.31 Ma. A U/Pb age on zircon in an anorthoclasite nodule extends White Island m...
Whole rock boron and other mobile and immobile element concentrations are reported for the alkaline maar volcanic rocks from the Bakony–Balaton Highland Volcanic Field (BBHVF/Hungary) and for three other geographically distinct maar volcanic fields from diverse tectonic settings (Spain/Canary Islands, Tenerife; New Zealand/Waipiata, Otago; and Mexi...
Since the inception of the term A-type by Loiselle and Wones (1979), this class of granitoids has proven to be the most controversial and least understood member of the granitoid alphabet soup. Eby (1990, 1992) suggested that there were a variety of granitoids that fell within the A-type classification and that there were multiple petrogenetic path...
Alkaline rocks comprise a minor amount of the total volume of igneous rocks, but in terms of variety and complexity they have challenged petrologic thinking for decades. Alkaline magmatism is widely distributed both spatially and throughout geologic time. Most alkaline provinces show significant lithological diversity and classic examples of this d...
A chain of volcanoes, some of them still active, extends from the Atlantic Ocean into the highlands of Cameroon. Mount Cameroon, located at the edge of the continent, erupted in 1999 and 2000 and spewed lava part-way down its flanks, cutting off a coastal road. A number of the now extinct (or dormant) volcanic craters on the continental part of the...
The Late Archean (2.6-2.8 Ga) is remarkable for the earliest manifestation of syenite-granodiorite-granite magmatism of alkaline affinity. From the published data this magmatism can be related to either “sanukitoid” (subduction) or “A-type granitoid” (anorogenic) magmatism. Key examples from the Superior, Yilgarn, and Baltic shields were studied to...
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...
The Keivy alkaline province, Kola Peninsula, consists of six peralkaline granite bodies, alkaline syenogranite dikes, and two nepheline syenite intrusions emplaced between the tonalite-trondhjemite-granodiorite basement and the supracrustal Keivy terrane. U-Pb zircon ages for the Keivy alkaline province range from 2613 to 2682 Ma and, for the spati...
In order to understand trace element behaviour during combustion of coals from the Greymouth coalfield, combustion tests were performed on three seam composite samples. The major and trace elements from sub-samples of feed coal, bottom ash, fly ash, and flue gas were analysed by different techniques including inductively coupled plasma mass spectro...
The Beemerville alkaline complex, New Jersey, occurs at the western end of the Cortlandt-Beemerville magmatic belt. The eastern end of the belt is defined by the Cortlandt complex, New York, which largely consists of ultramafic and mafic rocks. Between these two intrusive centers is a linear almost east-west trending zone of lamprophyre and felsic...
The Permian to Late Triassic Rakaia sub-terrane—part of the Torlesse superterrane of the New Zealand Eastern Province—is an accretionary complex that comprises an enormous volume of quartzofeldspathic sandstones and mudstones with subsidiary conglomerates plus minor oceanic assemblages. The field of provenance analysis has undergone a revolution wi...
The field of provenance analysis has undergone a revolution with the development of single-crystal isotope dating techniques using mainly silt to sand sized single minerals. This study focuses on coarser-grained rocks, notably conglomerates, which involve much shorter transport distances and therefore may be used to trace proximal sources. The Torl...
Conference title - Second international maar conference, Copyright - GeoRef, Copyright 2012, American Geosciences Institute. Reference includes data supplied by Hungarian Geological Library, Budapest, Hungary, Date revised - 2009-01-01, Language of summary - English, Pages - 59, ProQuest ID - 50556381, SubjectsTermNotLitGenreText - boron; chemical...
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...
Many geochemists focus on natural systems with less emphasis on the human impact on those systems. Environmental chemists frequently approach their subject with less consideration of the historical record than geoscientists. The field of environmental geochemistry combines these approaches to address questions about the natural environment and anth...
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...
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...
Late Archaean alkaline complexes are known from Canada, Australia and Greenland. They are represented by stocks of syenite and nepheline-bearing rocks and carbonatites, as well as by lamprophyre dikes and shoshonitic volcanic suites (Blichert-Toft et al. 1995, Basu et al. 1994, Libby & de Laeter 1980, Bell & Blenkinsop 1987, Sutcliffe et al. 1990)....
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 Hohonu Dyke Swarm and French Creek Granite represent contemporaneous and cogenetic alkaline magmatism generated during crustal extension in the Western Province of New Zealand. The age of 82 Ma for French Creek Granite coincides with the oldest oceanic crust in the Tasman Sea and suggests emplacement during the separation of New Zealand and Aus...
The Median Tectonic Zone in Eastern Fiordland, SW New Zealand, comprises a tectonically disrupted belt of Mesozoic magmatic arc rocks related to subduction along the palaeo-Pacific margin of Gondwana. New ion microprobe (SHRIMP) U-Pb zircon ages confirm that the bulk of the plutonic rocks in eastern Fiordland range from Mid- Jurassic to Early Creta...
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...
Geochemical studies on the Hohonu Batholith, of the West Coast, South Island, New Zealand, have recognised two distinct but
chemically related suites of mid-Cretaceous granitoids. The suites are characterised by restricted radiogenic isotopic compositions
(Sr(i) = 0.7062 to 0.7085; ɛNd(i) = −4.4 to −6.1), and represent melting of a mafic lithospher...
Ion microprobe U‐Pb zircon ages have been obtained from four samples of Cretaceous granitoid and two samples of volcanogenic sediment from the northwest Nelson‐Westland region of the South Island of New Zealand. Crow Granite, which intrudes lower Paleozoic metasedi‐mentary rocks in the Buller Terrane on the eastern side of the Karamea Batholith, ha...
Wet and dry atmospheric deposition of toxic metals was measured at biweekly intervals for one year, from i5 September i992 to i6 September i993 at two sites on Massachusetts Bay, Nahant, near Boston and Truro, near the tip of Cape Cod. Wet and dry deposition was measured using a conventional wet/dry collector, except that the dry bucket contained a...
The Karamea Batholith in the Buller terrane of the South Island New Zealand forms part of an extensive Middle-Late Devonian belt of magmatic activity along, or close to, the Paleo-Pacific margin of Gondwana. The belt includes the I- and S-type granites of the Lachlan Fold Belt in SE Australia and coeval rocks in Antarctica. The northern half of the...
The Brookville terrane forms a fault-bounded region, underlain mainly by plutonic and high-grade metamorphic rocks, flanked on one side by a typical Avalonian terrane (Caledonia terrane), and separated from a typical Avalonian terrane (Mascarene terrane) on the other side by the Silurian Kingston Dike Complex.
Mafic plutons of the Brookville terra...
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 Early Cretaceous Separation Point batholith of the South Island, New Zealand, represents the final magmatic stage of an extensive arc system located on the SW Pacific margin of Gondwana during the Mesozoic. The batholith consists of Na-rich, alkali-calcic diorite to biotite hornblende monzogranite. The rocks are distinct from calc-alkaline sub...
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...
The lower Silurian Kingston complex of southern New Brunswick consists of metamorphosed sheeted bimodal dykes, exposed over a strike length of more than 100 km and a width of 3 to 8 km. The southwestern portion of the complex is bounded by major mylonite zones and the northeastern portion is bounded by brittle faults.
Mafic dykes consist of actinol...
