Henning Sørensen

The agpaitic rocks; an overview

Abstract It is now generally agreed that the term agpaitic should be restricted to peralkaline nepheline syenites (and phonolites) containing minerals such as eudialyte and rinkite, that is complex silicates of Zr, Ti, the rare earth elements (REE), and F and other volatiles. There are, however, cases of transition into more common types of nepheline syenites containing zircon, titanite, ilmenite, etc. The agpaitic rocks are characterized by extremely high contents of rare elements such as Li, Be, Nb, Ta, REE, Zr, Th, etc. and of volatiles, first of all F and C1. This gives rise to a wealth of mineral species, more than 500 in the Lovozero and Khibina complexes of the Kola peninsula, about 250 in Mont Saint-Hilaire, Quebec, Canada, and about 200 in the type locality, the Ilímaussaq complex, South Greenland. These rocks have very long melting intervals and solidus temperatures as low as 500 to 400°C. They are accompanied by a gas phase rich in methane and other hydrocarbons and most probably also by sodium-rich fluids as indicated by the presence of minerals such as ussingite (NaAlSi3O8·NaOH) and villiaumite (NaF) and of pegmatites and hydrothermal veins rich in sodium and rare and volatile elements. Agpaitic nepheline syenites are considered to have been formed by consolidation of melts oversaturated in alkalis, especially sodium, under conditions preventing the volatiles from escaping. These melts have been derived by extreme fractionation processes in alkali basaltic or nephelinitic magmas. The main stage of crystallization of the melts is characterized by minerals such as nepheline (sometimes also sodalite), alkali feldspars, arfvedsonite, aegirine and eudialyte, but the most highly developed, hyperagpaitic lujavrites of the Ilímaussaq complex have been formed from melts with extreme concentrations of sodium and volatiles resulting in the formation of naujakasite instead of nepheline, ussingite instead of sodalite and alkali feldspars, and steenstrupine instead of eudialyte. During the late stages of crystallization, sodium-rich fluids are the cause of late- and postmagmatic alteration and of the formation of hydrothermal mineralizations. The late stages are characterized by water-soluble sodium-rich minerals of which more than 80 have been found in the Khibina and Lovozero complexes.

AUTOLOGOUS FIBRIN GLUE--PREPARATION AND CLINICAL USE IN THORACIC SURGERY

Autologous fibrin glue was used in 20 patients undergoing lung resection to reduce pulmonary air leaks and improve hemostasis. The fibrinogen in the glue was prepared by ethanol precipitation of plasma separated from 88 ml of the patients blood. The mean volume of fibrinogen concentrate +/- SD was 4.9 +/- 0.5 ml with a fibrinogen concentration of 28 +/- 5 mg/ml. The yield obtained by the separation was 81% +/- 9%. One part of fibrinogen concentrate was converted to solid fibrin by means of 0.3 parts of thrombin solution. The outcome was 6.4 ml of two-component fibrin glue. The preparation was performed in a closed system to ensure sterility, and was completed within 90 min. Pulmonary air leak decreased following sealing of the resection lines with autologous fibrin glue and the hemostasis was effective. No adverse effects were observed, and all cultures from the glue were negative. Autologous fibrin glue has the obvious advantages of safety from transmission of viral diseases and from immunological reactions. In summary, we report a new technique for preparing autologous fibrin glue with a high concentration of fibrinogen making it a safe and effective sealant of pulmonary air leak and hemostatic agent in thoracic surgery.

The Use of Autologous Fibrin Adhesive in Skin Transplantation

A method for preparing concentrated fibrinogen for use in autologous fibrin adhesive is described. The adhesive was used in seven patients with eight chronic leg ulcers. The ulcers were divided into two equal sections, and the adhesive was used to seal split-thickness skin grafts in one section, while no adhesive was used to seal the grafts in the other section of the ulcer. The strength of adhesion was measured 3 1/2 minutes after transplantation of a 1-cm2 test split-thickness skin graft. In the sealed grafts, the breaking strength varied from 12 to 26 gm. In the unsealed transplants, the strength was less than 5 gm. The take of the meshed split-thickness skin grafts was equal in the sealed and the unsealed areas, varying from 90 to 100 percent. Biopsies taken on day 7 showed a splitting between graft and recipient bed in half the unsealed grafts; none of the sealed grafts showed splitting, indicating a more stable graft in the sealed areas. Biopsies taken on day 21 showed no difference between sealed and unsealed grafts.

Spheroidal structures in arfvedsonite lujavrite, Ilı́maussaq alkaline complex, South Greenland—an example of macro-scale liquid immiscibility

Abstract Lujavrites are meso- to melanocratic agpaitic nepheline syenites and are the most highly evolved rocks of the Ilimaussaq complex, South Greenland. Spheroidal bodies measuring up to 20 cm in diameter occur locally in arfvedsonite lujavrite. They consist of a core rich in analcime and arfvedsonite and a rim rich in analcime, aegirine and a low temperature potassium feldspar. The host lujavrite is dominated by albite and arfvedsonite. The igneous lamination of the host continues undisturbed through rim and core of spheroids and the arfvedsonite crystals in host, rim and core have identical chemical compositions. There are sharp contacts between host and rim and rim and core. Host, rim and core contain the same accessory minerals and have almost identical chemical compositions, the main differences are high H 2 O and Na 2 O but low SiO 2 in the core and high Fe 2 O 3 in the rim. The spheroids are proposed to have been formed by separation of immiscible interstitial H 2 O-rich globules of magma from the host lujavrite magma at a late stage in the crystallization of the lujavritic melt.

Net-veined complexes in the Oslo Rift, southeast Norway

Abstract The association of acid and basic rocks in the form known as net-veined complexes has been found at Lake Mykle in the southwestern part of the late Paleozoic Oslo Rift in a complicated contact zone between larger bodies of older larvikite and younger granites. The mafic part of the complex is mainly trachyandesitic in composition, aphanitic to fine-grained with xenocrysts of andesine and augite. It forms pillow-shaped bodies with crenulated boundaries, and in a few cases, dykes that are disrupted into trails of pillows contained in nordmarkitic syenites grading into granites. The major part of the trachyandesite forms larger, more coarse-grained masses brecciated by veins of miarolitic granite with mafic pillows. Mineralogical and geochemical data suggest that the trachyandesite is a hybrid rock formed by mixing of alkali basaltic and nordmarkitic melts in the deep crust. The hybrid melts were injected into melts of nordmarkitic to granitic composition in the shallow crust resulting in the formation of the net-veined complexes. This may have taken place in connection with cauldron collapse into a stratified magma chamber.

Autologous Fibrin Glue—Clinical Use and Sealing of High-Porosity Vascular Prostheses

Autologous fibrin glue was prepared in a new way by means of ethanol. From 42 patients 44 mL of blood with a mean plasma fibrinogen concentration of 3.7 mg/mL was drawn. The product of the preparation was a mean of 2.5 mL of fibrinogen concentrate with a concentration of 28 mg/mL. After addition of 0.3 part of thrombin solution containing calcium chloride and aprotinin, an antifibrinolytic agent, the total volume of two-component fibrin glue was 3.3 mL. The preparation was done in a closed system to ensure sterility and com pleted within ninety minutes. Twenty high-porosity double-velour vascular prostheses were sealed with autologous fibrin glue in the laboratory. The pro stheses were tight for blood up to a pressure higher than 300 mmHg, which was comparable to vascular prostheses impregnated with collagen, but to more than twice the pressure of 130 mmHg, where vascular prostheses preclotted with blood started leaking. Autologous fibrin glue imparts a nice white vascular graft with superior handling characteristics, since it is nonsticky compared with blood-clotted grafts and softer and more pliable than the vascular prostheses impregnated with collagen from the manufacturer. In addition autologous fi brin glue has the obvious advantages of safety from transmission of viral dis eases and from immunologic reactions.