phenoclasts

phenoclasts

[′fen·ə‚klasts]
(petrology)
The larger, conspicuous fragments in a sediment or sedimentary rock, such as cobbles in a conglomerate.
References in periodicals archive ?
(2007) reported for the first time from the Prato Solaro Member of the basal Servino the presence of 'ventifacts' (Evans, 1911), interpreted as wind-worn phenoclasts which testify to an arid climate in the depositional area just before the first Triassic transgression (Durand, 1972; Smith and Edwards, 1991; Durand, 2006).
Evidence for this can be seen in pyroclastic deposits associated with the Brunswick volcanic massive sulfide deposits (Lentz et al., 1999), where thick units (10s m) of pyroclastic material with large quartz and feldspar phenoclasts (up 10 cm in length) are preserved.
1A) the conglomeratic basal beds of the Prato Solaro member yielded to the authors of this paper many ventifacts: wind worn phenoclasts (Fig.
By further contrast, on the "lower" Tetagouche River near Vallee Lourdes about 9 km east-northeast downstream of the Little Falls locality, the Vallee Lourdes conglomerate, interpreted to be a debris flow (Rice and van Staal 1992), contains a few large rounded, Mesoproterozoic, unfoliated and foliated granodiorite clasts as much as a metre in diameter and abundant quartz phenoclasts derived from felsic volcanic rocks (van Staal et al.