New insights into the provenance of Saudi Arabian Palaeozoic sandstones from heavy mineral analysis and single-grain geochemistry
New insights into the provenance of Saudi Arabian Palaeozoic sandstones from heavy mineral analysis and single-grain geochemistry
复制标题
DOI：
10.1016/j.sedgeo.2015.12.009
复制
发表时间：
2016-03-15
影响因子：
2.8
通讯作者：
Meinhold, Guido
中科院分区：
文献类型：
--
作者：
Bassis, Alexander;Hinderer, Matthias;Meinhold, Guido
沙特阿拉伯古生代硅质碎屑岩覆盖了从寒武纪到二叠纪的地层范围。它们沿着阿拉伯地盾的东部边缘出露，由高度成熟的砂岩组成。重矿物组合反映了矿物学成熟度，以超稳定相锆石、电气石和金红石为主。不太稳定的副矿物是磷灰石、十字石和石榴石。对沙特阿拉伯中部/北方（塔布克地区）和南部（瓦吉德地区）两个研究地区的样品进行的标准重矿物分析表明，物源发生了明显变化。寒武-奥陶纪砂岩是第一旋回沉积物，可能来源于“泛非洲”基底。泥盆纪-二叠纪砂岩显示出新鲜基底物质的显著流入，亚稳定重矿物的增加证明了这一点。金红石和石榴石的单颗粒地球化学分析已被证明是一种强有力的补充技术。金红石品种的研究揭示了两个研究区域之间的主岩岩性的明显差异：塔布克地区主要含有长英质褶皱，而瓦吉德地区有更多的镁铁质输入。在塔布克地区下古生界，金红石中的锆测温法确定了麻粒岩相碎屑，并有可能进一步确定源区。两个研究区石榴子石寄主岩石的分布模式非常相似。它们以角闪岩相的变质沉积物和中长英质火成岩为主。此外，也有来自麻粒岩相变质沉积物的石榴石，这在阿拉伯-努比亚地盾中是罕见的。高品位石榴石的可能源岩可以在也门或更南部的莫桑比克带找到。(C)2015 Elsevier B.V.版权所有。
Saudi Arabian Palaeozoic siliciclastics cover a stratigraphic range from the Cambrian to the Permian. They crop out along the eastern margin of the Arabian Shield and are comprised of highly mature sandstones. Their heavy mineral assemblage reflects their mineralogical maturity and is dominated by the ultra-stable phases zircon, tourmaline and rutile. Less stable accessories are apatite, staurolite and garnet. Standard heavy mineral analysis of samples from two study areas in central/northern (Tabuk area) and southern (Wajid area) Saudi Arabia reveals distinct changes in provenance. Cambrian-Ordovician sandstones are first-cycle sediments, probably sourced from the 'Pan-African' basement The overlying Hirnantian glaciogenic deposits consist of recycled Cambrian-Ordovician material. Devonian-Permian sandstones show a significant influx of fresh basement material, as attested by an increase of meta-stable heavy minerals. Single-grain geochemical analysis of rutile and garnet has proven to be a powerful supplementary technique. Rutile varietal studies reveal distinct differences in host rock lithologies between the two study areas: the Tabuk area contains predominantly felsic ruffles, whereas the Wajid area has more mafic input. Zr-in-rutile thermometry identified granulite-facies detritus in the lower Palaeozoic of the Tabuk area and has the potential to further define source areas. The distribution patterns of garnet host rock lithologies are remarkably similar in both study areas. They are dominated by amphibolite-facies metasediments and intermediate to felsic igneous rocks. Garnets derived from granulite-facies metasediments, which are scarce in the Arabian-Nubian Shield, also occur. Possible source rocks for high-grade garnets can be found in Yemen or farther south in the Mozambique Belt. (C) 2015 Elsevier B.V. All rights reserved.