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Cracked Mountain (CM) is a basaltic volcano within the northern extension of the Cascade volcanic arc into southwest, British Columbia, Canada (i.e. Garibaldi Volcanic Belt) and is dated at 401 ± 38 ka (40Ar/39Ar). The edifice covers an area of ~1.5 km2 and has a volume of 0.18 km3. The volcano features steep margins with local relief of ~250 m (1,650 m a.s.l), is dissected by abundant 0.5 to ~20 m wide extensional cracks with depths up to 30 m, and has a highly eroded top. The edifice is dominated by massive to poorly stratified, moderately to pervasively palagonitized lapilli tuffs, comprising vitric fine ash to lapilli. Juvenile pyroclasts have blocky to highly vesiculated shapes consistent with a phreatomagmatic (i.e. explosive) origin. The lapilli tuffs are intruded by and mingled with coherent to disaggregated lobes of peperitic pillowed lavas. Contacts between lapilli tuff and peperitic pillowed lava show soft-sediment deformation and in-situ quench-fragmentation indicating that the tephra was both unconsolidated and water-saturated at the time of intrusion. Local stacks of pillow lava are found on the margins of the edifice. More than fifty, 0.5 to 3 m wide dykes intrude CM stratigraphy and display, either, peperitic pillowed margins or sharp, chilled margins and columnar-jointing. Measurements of paleomagnetic directions (9 sites) were made for all CM lithofacies and record a single-pole direction indicating a single monogenetic eruption. A glaciovolcanic origin is strongly suggested by the abundant subaqueous lithofacies (i.e. palagonitized tephra, pillows, peperites) and the physiographic setting of the edifice which is well above any drainage that could sustain a standing body of water. The elevation of CM and depth of surrounding valleys indicate syn-eruptive confinement by a paleo-ice sheet that was ≥850 m thick. The edifice shape, size, and surround- ing topography suggest a ‘leaky’ paleolake system capable of supporting ~0.36 km3 of water. The glacio

An ephemeral (and proximal) outcrop at the quaternary basaltic Puig de la Garrinada cinder volcano was studied in order to decipher eruptive mechanism variations in the course of a single eruption. Once the volcanostratigraphy was established (and recorded by photographs), a very detailed sampling of underlying lava flows, bombs and a large number of fine-sized lapilli and ash beds was carried out. An ad hoc description card was elaborated for study under stereo microscope in order to identify the different types of materials that form the volcanic cone. Ten material types were recognised: sedimentary accidental clasts, massive lava accidental clasts, bombs, xenoliths, xenocrysts and phenocrysts, oxidised scoria, scoria with oxidised film, fluidal pyroclasts, non-fluidal pyroclasts, and coatings. Subsequent studies under SEM + EDS and basic chemical characterization of the samples (whole rock XRF for major and trace elements) and EMPA were conducted. All these studies make possible the reconstruction of the eruptive history of the La Garrinada volcano, which shows a transition from initial strombolian activity to gradually incorporated phreatomagmatic activity. This permits the calculation of magma eruption rates, magma column oscillations and aquifer interactions with magma column. Since our general conclusions agree well with the discrimination of eruptive episodes obtained from the stereo microscope description card, macroscopic volcanostratigraphy and chemical results, it is proposed that a similar study protocol (quick volcanostratigraphy logging, photographic record, detailed sampling, description following this card) might be useful in the reconstruction of eruptive activity of other cinder cones in the Garrotxa region and elsewhere, and therefore can provide a good and quick methodological tool, especially when rapid field description and sampling is required (ephemeral outcrops, risky sampling during active eruptive episodes, etc.). Moreover, the conducted