Sandstone diagenesis of the Lower Cretaceous Sindong Group, Gyeongsang Basin, southeastern Korea: Implications for compositional and paleoenvironmental controls
Sandstone diagenesis of the Lower Cretaceous Sindong Group, Gyeongsang Basin, southeastern Korea: Implications for compositional and paleoenvironmental controls
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韩国东南部庆尚盆地下白垩统新东群砂岩成岩作用：对成分和古环境控制的影响
DOI：
10.1111/j.1440-1738.2007.00608.x
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发表时间：
2007
期刊：
影响因子：
1.5
通讯作者：
D. Lim
中科院分区：
文献类型：
--
作者：
Y. Lee;D. Lim
摘要庆尚盆地是朝鲜半岛东南部早白垩世伸展构造作用形成的一个陆相沉积盆地。 沉积充填始于沿着盆地西缘分布的新东群。它由三个岩石地层单位组成：Nakdong（冲积扇），Hasandong（河流）和Jinju（湖泊）地层，年龄递减。新东群砂岩根据其碎屑组成分为四种岩相（PF）：PF-A由平均为Q73 F12 R15的下Nakdong组组成; PF-B由平均为Q66 F15 R18的上Nakdong组和下Hasandong组组成; PF-C由平均为Q49 F29 R22的Hasandong组中部至Jinju组中部组成; PF-D由平均为Q26 F34 R41的上Jinju组组成。碎屑成分的变化影响了新东群砂岩成岩矿物组合。PF-A和PF-B中伊利石和白云石/铁白云石是重要的成岩矿物，而PF-C和PF-D中方解石和方解石是主要的成岩矿物。大多数成岩矿物可分为早成岩和晚成岩两个形成阶段。早期成岩方解石主要产于PF‐C中，可能受砂岩沉积过程中干旱-半干旱气候条件的控制，PF‐A和PF‐B中未发现早期方解石。晚期方解石在所有的新东群砂岩中均有分布。这些钙离子可能来源于页岩成岩作用和哈萨东和金菊砂岩中早期方解石的溶解作用。伊利石是PF-A和PF-B下部唯一的成岩粘土矿物，推测为深埋过程中高岭石转化的产物，而高岭石的先前存在是根据洛东组沉积过程中潮湿的古气候条件推断的。PF-C和PF-D中的亚氯酸盐被解释为在干旱至半干旱气候条件下蒙脱石粘土转化或碱性孔隙水沉淀的产物。晚成岩矿物的产出在很大程度上取决于早成岩矿物的分布，而早成岩矿物的分布首先受沉积物成分和古气候的控制。
Abstract The Gyeongsang Basin is a non‐marine sedimentary basin formed by extensional tectonism during the Early Cretaceous in the southeastern Korean Peninsula. The sediment fill starts with the Sindong Group distributed along the western margin of the basin. It consists of three lithostratigraphic units: the Nakdong (alluvial fan), Hasandong (fluvial) and Jinju (lacustrine) formations with decreasing age. Sindong Group sandstones are classified into four petrofacies (PF) based on their detrital composition: PF‐A consists of the lower Nakdong Formation with average Q73F12R15; PF‐B the upper Nakdong and lower Hasandong formations with Q66F15R18; PF‐C the middle Hasandong to middle Jinju formations with Q49F29R22; and PF‐D the upper Jinju Formation with Q26F34R41. The variations of detrital composition influenced the diagenetic mineral assemblage in the Sindong Group sandstones. Illite and dolomite/ankerite are important diagenetic minerals in PF‐A and PF‐B, whereas calcite and chlorite are dominant diagenetic minerals in PF‐C and PF‐D. Most of the diagenetic minerals can be divided into early and late diagenetic stages of formation. Early diagenetic calcites occur mostly in PF‐C, probably controlled by arid to semiarid climatic conditions during the sandstone deposition, no early calcite being found in PF‐A and PF‐B. Late‐stage calcites are present in all Sindong Group sandstones. The calcium ions may have been derived from shale diagenesis and dissolution of early stage calcites in the Hasandong and Jinju sandstones. Illite, the only diagenetic clay mineral in PF‐A and lower PF‐B, is inferred to be a product of kaolinite transformation during deep burial, and the former presence of kaolinite is inferred from the humid paleoclimatic conditions during the deposition of the Nakdong Formation. Chlorites in PF‐C and PF‐D are interpreted to be the products of transformation of smectitic clay or of precipitation from alkaline pore water under arid to semiarid climatic conditions. The occurrence of late‐stage diagenetic minerals largely depended on the distribution of early diagenetic minerals, which was controlled initially by the sediment composition and paleoclimate.