Extrusive carbonatite occur only at two places in the Kaiserstuhl volcanic complex: Henkenberg and Kirchberg. In both cases the carbonatitic lapillistone consists round to tear-shape lapillis. Tace element characterisation of the chemical composition reflects alvicitic affiliation with a trachytoidal structure. The localities provides as world wide standart for extrusive carbonatite products.
The Henkenberg outcrop is nearly vanished, whereas only few field stones can be find. In contrast the Kirchberg outcrop exhibit nice outcrop conditions de to the recent vineyard consolidation.
Tace element characterisation of the chemical composition reflects alvicitic affiliation with a trachytoidal structure. The localities provides as world wide standart for extrusive carbonatite products. The lapilli stone consists mainly on calcite, with minor amounts of apatite and magnetite with accessoric augit, melanite, Nb- perovskite and pyrochlor
The Henkenberg Lapilli stone overlays the Henkenberg tuff breccia, witch contains soevitic xenoliths.

Tephrites and the porhphyric subvolcanic equivalent essexites mark the most abundant rock type in the Kaiserstuhl volcanic complex. The best outcrops conditions are along the western flanks of the Kaiserstuhl, whereas the Humber-Sponeck complex as well as the Büchsenberg are nice localities. Both are leucite- beraing tephrites formed by parasitic volcanos on the flank of the Kaiserstuhl volcanic complex, consisting of alternating lava flows, agglomerates formed by strombolian eruption type activity and sills.
The Sponeck ruin is build on a shallow, neat surface essexite intrusion, whereas a grain size increase with depth can be seen.
The petrographic composition varies in a small range with Ti-augite as characteristic dominating phase (25-35 vol. %). Olivine can be found in a few samples. Plagioclase do not present a liquidus phase and appear only in a few sample as phenocryst generation.
Leucite marks the most frequent feldspathoid, however it is fully replace by analcime. Nepheline tephrites accure rarely and sometimes soldaite, K-feldspar, biotite and amphibole are found. Classification by using the QAPF diagram (Streckeisen diagram) results in phonolitic tephrites. Mg-numbers cumulate between 50 and 55, which illustrates a medium fractionation degree. Age dating have shown that tephrites were erupted during the whole magmatic activity of the Kaiserstuhl complex.

Limberg quarry I expose 2 lava flows (λ1 and λ2), each up to 20 meter in thickness. Theses lava flows are divided a tuff layer t1, a significant marker for the Limberg-Lützelberg complex stratigraphy that contains phonolitic components fragments of olivine-nephelinite and xenolith of lherzolith.
The lower lava flow λ1 shows characteristic pahoehoe structures of low viscosity flow conditions.  The upper limburgite lava flow λ2 in contrast is characterized by Aa-lava type formation. The breccias appearance is cause by abrupt evaporation of water und thereby the huge volume increase during that process.
Partially the tuff layer is injected along vertical structures into the upper lava flow, which is also cause by the rapid evaporation.
Both lava flows are defined as limburgites. This term is introduced by Rosenbusch and defined as volcanic rocks with a vitreous matrix and mafic phenocrysts. Phenycrsyts thereby are olivine, magnetite and Ti-augite.
Geochemically the limburgites are of basanitic composition and display beside the olivine-nephelinites from Lützelberg the most primitive volcanic products.
The vitreous matrix often shows palagonitization , whereas elements leached during that process re-precipitates as secondary minerals, like various zeolites (faujasit, offretite,  phillipsite, ...) and carbonates.
A volcanotectonic cross-section is exposed in the Limberg quarry VII. The Limberg Graben strikes in NW-SE direction. The graben shoulders are formed by red olivine-nephelinite agglomerates and the NE graben fault is easily visible. The red wall marks the fault plane. The large volcanic bomb sizes suggest that the former vent is in near distance. The composition of the agglomerates are equeal to he olivine-nephenlinites suggesting that Lützelberg lavas were erupted on the SE site of the Limberg. The inner graben part is build up the Limburgite lava units λ2 and yellow-brownish limnic sediments of Miocene age (Burdigal), which can be dated with fossils. This sediment are overlain by the Limburgite lava flow unit λ3.

chemcial analysis
1 limburgite λ1 (KELLER 1990)
2 limburgite λ2 (MEIGN & STECHER,1930)
3 average limburgite L(WIMMENAUER 1959)


faujasite found in quarry I