Geochemistry of Neogene sedimentary rocks from the Jiyang basin, North China Block: The roles of grain size and clay minerals

Abstract

Major and trace element compositions of 83 fine-grained sedimentary rocks (including 14 fine-grained sandstones, 24 siltstones and 45 mudstones) from the Zhanhua Sag of Jiyang basin in the North China Block were analyzed to investigate the effects of sedimentary processes (e.g., source provenance, mineral assemblage, grain size and chemical weathering etc.) on the bulk chemical compositions. Compared with the average upper continental crust (UCC), these rocks have higher TiO 2 , Al 2 O 3 , Fe 2 O 3 , Ba, Th, U, Nb, Ta, Zr, Hf, Y and REE, but lower SiO 2 , MnO, MgO, CaO, K 2 O, Na 2 O, P 2 O 5 , Cr, Co, Ni and Sr. From sandstones, siltstones to mudstones, there exist systematic increase in Rb, Cs, V, Cr, Co, Ni, Nb, Ta, Th, U and REE, and decrease in SiO 2 , K 2 O, Na 2 O and Ba. Such variation trends reflect a predominant role of grain size effect on the geochemistry of these sediments. K 2 O, Na 2 O, Ba, Zr and Hf positively correlate with SiO 2 and negatively correlate with Al 2 O 3 , whereas other elements generally show negative correlations with SiO 2 and positive correlations with Al 2 O 3 , suggesting that clay minerals are major hosts for most elements, while quartz and feldspar exert a dilution effect. The accessory heavy minerals exert a minor control on the bulk REE composition of the sediments, e.g., the contribution of heavy minerals (apatite, zircon, sphene, monazite etc.) to the bulk REE concentrations is less than 20%. Our results show that grain size and clay minerals are the two most important factors to control the bulk chemical compositions of the Zhanhua Sag sediments, and probably terrestrial fine-grained sediments in general.

Loess-Palaeosol Sequences in the Kashmir Valley, NW Himalayas: A Review

“…It should be noted that smectite is commonly found in arid to semi-arid climatic regions. Under intense weathering conditions it can alter halloysite and kaolinite (Cai et al, 2008). Its presence in soils represents poorly drained environments and a climate characterized by strong seasonal precipitation (Bellotto et al, 1995).…”

Synrift sandstones and clayey rocks: bulk chemical composition and location on a number of discriminant paleogeodynamic diagrams

“…2). Были проанализированы песчаники и глинистые породы: 1) неогенового бассейна Йиянг (Jiyang), Северный Китай (№ 1) [Cai et al, 2008[Cai et al, , 2011; 2) неопротерозойской серии Юинта Маунтин (Uinta Mountain), США (№ 2) [Condie et al, 2001]; 3) палеопротерозойской формации Серпент (Serpent) надсерии Гурон, Канада (№ 8) [Fedo et al, 1997]; 4) мезопротерозойской уйской серии, Учуро-Майский регион, Россия (№ 36) [Подковыров, 2001;Подковыров и др., 2002;Khudoley et al, 2001;Cullers, Podkovyrov, 2002]; 5) отложений мезо-неопротерозоя юго-восточной части блока Янцзы, Южный Китай (№ 37) [Deru et al, 2007]; 6) неопротерозойской формации Гамбл Брук (Gamble Brook), Авалонский террейн, Канада (№ 38) [Murphy, 2002]; 7) перми и триаса Центральной Индии (№ 39) [Ghosh et al, 2012] [Tao et al, 2014]; 14) неопротерозойской чингасанской серии Енисейского кряжа (№ 63) [Ножкин и др., 2007, 2008; Лиханов, Ревердатто, 2015]; 15) прикамской свиты нижнего рифея Волго-Уральской области (№ 64) [Маслов, 1994б; Маслов, Ишерская, 1998].…”

Elemental and Sr-Nd isotopic compositions of Cenozoic sedimentary rocks from the Dongying Sag of Jiyang depression, North China: Implications for provenance evolution

“…The gypsum also can be found in some samples from the Es4 sedimentary rocks. Cai et al (2008), and data for PAAS is from Taylor and McLennan (1985).…”

“…Therefore, it is necessary to look for new methods in order to deduce the historical evolution of the Jiyang depression. To date, however, few geochemical data of sedimentary rocks from the basin were published to investigate sedimentary provenance and denudation of the surrounding highs/uplifts during Tertiary (Cao et al, 2007;Cai et al, 2007Cai et al, , 2008. Therefore, this study compiles the geochemical compositions of a set of samples from the Dongying Sag (data were analyzed in this study) and Zhanhua Sag (data were from our companion work published by Cai et al (2007Cai et al ( , 2008) with the following aims: (a) to characterize the elemental (major and trace elements) and isotopic (Sr, Nd isotope) compositions for Paleogene sedimentary rocks from the Dongying Sag; (b) to interpret the nature of source rocks for sedimentary rocks from the Dongying Sag; (c) and to deduce the evolution of provenance and denudation of the surrounding highs/uplifts in the Jiyang depression during the Cenozoic.…”