Petrological parameters of sands and sandstones from DSDP and ODP holes in arc-related areas

Detrital modes for 524 deep-marine sand and sandstone samples recovered on circum-Pacific, Caribbean, and Mediterranean legs of the Deep Sea Drilling Project and the Ocean Drilling Program form the basis for an actualistic model for arc-related provenance. This model refines the Dickinson and Suczek (1979) and Dickinson and others (1983) models and can be used to interpret the provenance/tectonic history of ancient arc-related sedimentary sequences. Four provenance groups are defined using QFL, QmKP, LmLvLs, and LvfLvmiLvl ternary plots of site means: (1) intraoceanic arc and remnant arc, (2) continental arc, (3) triple junction, and (4) strike-slip-continental arc. Intraoceanic- and remnant-arc sands are poor in quartz (mean QFL%Q < 5) and rich in lithics (QFL%L > 75); they are predominantly composed of plagioclase feldspar and volcanic lithic fragments. Continental-arc sand can be more quartzofeldspathic than the intraoceanic- and remnant-arc sand (mean QFL%Q values as much as 10, mean QFL%F values as much as 65, and mean QmKP%Qm as much as 20) and has more variable lithic populations, with minor metamorphic and sedimentary components. The triple-junction and strike-slip-continental groups compositionally overlap; both are more quartzofeldspathic than the other groups and show highly variable lithic proportions, but the strike-slip-continental group is more quartzose. Modal compositions of the triple junction group roughly correlate with the QFL transitional-arc field of Dickinson and others (1983), whereas the strike-slip-continental group approximately correlates with their dissected-arc field.

本数据集包含深海钻探计划（Deep Sea Drilling Project, DSDP）与大洋钻探计划（Ocean Drilling Program, ODP）环太平洋、加勒比海及地中海航次所采集的524件深海砂及砂岩样品的碎屑模态组成数据，以此为基础构建了弧相关物源的现实主义判别模型。该模型优化了Dickinson与Suczek（1979）以及Dickinson等（1983）提出的经典物源判别框架，可用于解析古弧相关沉积序列的物源与构造演化历史。研究基于站位平均值的QFL、QmKP、LmLvLs及LvfLvmiLvl三角图解，划分出四类物源端元：（1）洋内弧与残余弧；（2）大陆弧；（3）三联点；（4）走滑-大陆弧。洋内弧与残余弧砂体的石英含量极低（QFL图解中Q均值<5%），岩屑含量极高（QFL图解中L均值>75%），主要由斜长石及火山岩岩屑构成。大陆弧砂体的石英-长石组分占比高于洋内弧与残余弧砂体（QFL图解中Q均值最高可达10%，F均值最高可达65%，QmKP图解中Qm均值最高可达20%），其岩屑组分更为多样，含少量变质岩与沉积岩岩屑。三联点与走滑-大陆弧组的组分特征存在重叠，二者的石英-长石占比均高于其余两组，岩屑占比变化范围极大，但走滑-大陆弧组的石英含量更高。三联点组的组分特征大致对应Dickinson等（1983）提出的QFL过渡弧区，而走滑-大陆弧组则近似对应其切割弧区。