Neoproterozoic-early Cambrian successions in Iberia are reexamined. A gradual transition across the Neoproterozoic-Cambrian boundary is present in Central Iberia, whereas in the Cantabrian region and the Iberian Chains Lower Cambrian arenaceous successions rest with profound angular unconformity on Neoproterozoic turbidites. In Central Iberia, the Neoproterozoic sedimentary succession is referred to the informal Domo Extremeño group, representing mostly basinal facies, and the overlying Rio Huso group consisting of slope deposits and proximal turbidites that grade into shallower marine deposits. The latter is inferred to represent distal slope to outer platform depositional conditions and contains widespread carbonate olistostromic units. The position of the Precambrian-Cambrian boundary is within the Pusa shale of the Rio Huso group and can be correlated at the regional level by the occurrence of trace fossils, acritarchs, and in particular the abundant shelly metazoan Cloudina. The succession also yielded megascopic carbonaceous fossils, such as vendotaenids and Beltanelioides? sp. ind., and Sabellidites. Contrary to former interpretations assuming transport of older platform carbonates from the Ibor region into ‘younger’ olistostromic beds of the Rio Huso group, we interpret sedimentary and fossil evidence to suggest that shallower platform deposits of the informal Ibor group were penecontemporaneously incorporated in the olistostromic lower part of the Rio Huso group. Hence, the olistostromes are not believed to mark a major erosive unconformity. Based on the ichnofossil record and recent U-Pb age determinations, we argue that a proposed disconformity between Lower and Upper ‘Alcudian’ strata is neither regional nor does it mark a significant hiatus. Neoproterozoic-early Cambrian deposition in Central Iberia can be accommodated in a model that implies a generalized stretching of the crust during an extensional event which closely followed the Cadomian phase of the Pan-African Orogeny and which eventually could have included transcurrent components. An extensional phase with transcurrent components during the deposition of the Ibor and lower Rio Huso groups is regarded as a probable cause of widespread ponding resulting in the juxtaposition of platform and basinal successions, eventually leading to anoxic conditions in Pusa shale deposition times. A possible cause for repeated collapse events developing olistostromes and intra-sequential folding could be sought in this tectonic context.

Turbidite-associated black shale of the Semanggol Formation is extensively distributed in the northwestern part of the Western Belt, Peninsular Malaysia. The black shale occurs as a dark grey to black and thick to medium-bedded deposit. It represents the distal part of submarine fan system (outer-fan) overlying interbedded sandstone to shale facies of the mid-fan and conglomeratic pebbly sandstone facies of the inner-fan. Field observations and its widespread occurrence have resulted in the black shale being considered as a potential analog for a source rock in offshore Peninsular Malaysia. The present study includes detailed mineralogical (XRD, SEM, and EDX analysis), inorganic geochemical (major oxides, trace elements TEs, and rare earth elements REEs), and Rock-Eval pyrolysis analyses of the black shale samples, collected from the Gunung Semanggol, Bukit Merah, and Nami areas in northwestern Peninsular Malaysia. The primary focus of this study is to investigate the provenance, paleoredox conditions, paleoclimate, sedimentary rate, paleoproductivity, and upwelling system that would be helpful to understanding the role of these parameters in the enrichment of organic matter (OM) in the black shale. The Rock-Eval analysis shows that the black shale of the Semanggol Formation comprises type-III kerogens, which suggests organic input from a terrestrial source. The black shale also contains mature to postmature organic matter. Based on the mineralogical analysis, the mineral composition of the black shale comprises illite and kaolinite, with abundant traces of quartz and feldspar as well as few traces of titanium and zircon. Inorganic geochemical data designate black shale deposition in a passive margin setting that has experienced moderate to strong weathering, semi-arid to hot arid climate, and moderate sedimentation rate. Ratios of Ni/Co, U/Th, and V/(V+Ni) along with slightly negative to positive Ce* anomalies and U_EF-Mo_EF cross-plot unanimously indicate anoxic/dysoxic water conditions that are suitable for organic matter preservation. Geochemical proxies related to modern upwelling settings (i.e., Cd/Mo, Co vs. Mn) show that the deep marine black shale was strongly influenced by persistent upwelling, a first-order controlling factor for organic matter enrichment in the distal part (outer fan of the submarine fan system) of the Semanggol Basin. However, productivity-controlled upwelling and a high sedimentary rate, as well as high-productivity in oxygen-depleted settings without strong anoxic conditions, has played an essential role in the accumulation of organic matter.

A new ichnospecies, Linichnus bromleyi, is described on bone substrate as the result of a very likely predator/scavenger interaction. L. bromleyi consists of a single groove with a non-serrated edge. This new ichnotaxon is compared with L. serratus which was defined as a single elongate serrate-edged groove. L. bromleyi has been identified over the surface of bones of marine mammals (in particular, cetaceans and pinnipeds) from two Pliocene outcrops of Andalusia, southern Spain. The new ichnospecies can be clearly related with a trophic interaction between sharks and marine mammals (mainly whales, dolphins and seals).

Y. Cai & H. Hua comment: Zhuravlev, Gámez Vintaned & Ivantsov (2009) reported the problematic Ediacaran fossil Gaojiashania annulucosta in Siberia and they considered that this is the first find of Gaojiashania outside China, since Gaojiashania had previously only been reported from the Gaojiashan Member of the middle Dengying Formation in the Ningqiang area, southern Shaanxi Province, South China. However, we believe that the so-called Siberian Gaojiashania was mis-identified, and what was described as Gaojiashania annulucosta by Zhuravlev, Gámez Vintaned & Ivantsov (2009) is more appropriately ascribed to Shaanxilithes ningqiangensis, another problematic Ediacaran fossil that has also been known from the Gaojiashan Member in Shaanxi Province of South China (Chen, Chen & Lao, 1975; Xing et al. 1984), as well as the stratigraphically equivalent Taozichong Formation in Guizhou Province (Hua, Chen & Zhang, 2004) and the Jiucheng Member (Dengying Formation) in Yunnan Province of South China (Zhu & Zhang, 2005), the Zhoujieshan Formation in Qinghai Province (Shen et al. 2007), and the Zhengmuguan Formation in Ningxia Hui Autonomous Region of North China (Shen et al. 2007).