none 10.2110/palo.2009.p09-010r Society for Sedimentary Geology Society for Sedimentary Geology 860 38792344 46058 2026052723533868600 10.2110 2026-05-28T03:53:58Z 2009-08-20T11:16:33Z 10 PALAIOS 1938-5323 0883-1351 09 2009 09 01 2009 09 01 2009 24 9 Thomas L Adams 1Southern Methodist University, Roy M. Huffington Department of Earth Sciences, Dallas, Texas 75275, USAtladams@smu.edu Abstract Late Triassic marine vertebrates occur in the Hound Island Volcanics exposed on the eastern shore of Hound Island, southeastern Alaska. This fossil assemblage derived from slope deposits within an intra-arc basin of a volcanic island arc complex. It is associated with the allochthonous Alexander Terrane prior to its northern translation from tropical latitudes to its current latitude. Fossils occur within a 13-m-thick succession of interbedded calcareous shale and volcaniclastic-rich bioclastic limestone. The limestone layers are skeletal (vertebrate and invertebrate) packstones to wackestones and are interpreted as episodic thin-bedded turbidite and debris flow deposits that resulted from redeposition of slope sediments. Forty-seven vertebrate fossils were collected that consist of complete and fragmented cranial and postcranial elements belonging to Eosauropterygia, Thalattosauria, and Ichthyosauria, including the genus Shonisaurus. Bones are frequently disassociated and show predepositional abrasion and breakage. Another less common taphonomic mode is observed, characterized by several large associated elements, representing a single individual, found parallel to bedding and draped by shale. Rare Osteichthyes and Chondrichthyes teeth are also present. Bivalve and conodont fossils indicate a middle Norian age for the assemblage. 09 2009 09 01 2009 09 01 2009 603 615 10.2110/palo.2009.p09-010r https://pubs.geoscienceworld.org/palaios/article/24/9/603/146089/Deposition-and-taphonomy-of-the-Hound-Island-Late https://pubs.geoscienceworld.org/sepm/palaios/article-pdf/24/9/603/2844109/i0883-1351-24-9-603.pdf https://pubs.geoscienceworld.org/sepm/palaios/article-pdf/24/9/603/2844109/i0883-1351-24-9-603.pdf http://palaios.geoscienceworld.org/cgi/doi/10.2110/palo.2009.p09-010r Geo-Marine Letters Aksu 4 83 1984 10.1007/BF02277077 Subaqueous debris flow deposits in Baffin Bay PALAIOS Badgley 1 328 1986 10.2307/3514695 Counting individuals in mammalian fossil assemblages from fluvial environments American Journal of Science Berner 268 1 1970 10.2475/ajs.268.1.1 Sedimentary pyrite formation Origin of Sedimentary Rocks Blatt 634 1972 Petrology of Sedimentary Rocks Boggs 707 1992 PALAIOS Brett 10 597 1995 10.2307/3515097 Sequence stratigraphy, biostratigraphy, and taphonomy in shallow marine environments PALAIOS Brett 1 207 1986 10.2307/3514686 Comparative taphonomy; a key to paleoenvironmental interpretation based on fossil preservation United States Geological Survey Professional Paper Brew 525-C 38 1965 Upper Triassic undevitrified volcanic glass from Hound Island, Keku Strait, southeastern Alaska Geological Society of America Bulletin Butler 109 1372 1997 10.1130/0016-7606(1997)109<1372:POPSOT>2.3.CO;2 Paleomagnetism of Paleozoic strata of the Alexander terrane, southeastern Alaska Neues Jahrbuch für Geologie und Palaeontologie, Abhandlungen Callaway 178 37 1989 10.1127/njgpa/178/1989/37 Geographic and stratigraphic distribution of the Triassic Ichthyosauria (Reptilia, Diapsida) Conodont Biofacies and Provincialism Carey 295 1984 10.1130/SPE196-p295 Blackwell Science Ltd. 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