Tarom Basin

Research hypothesis This study provides new constraints on the tectono-stratigraphic evolution of the Tarom intermontane basin deposits of unknown age (deposition occurred any time after Eocene) in the framework of collisional deformation and plateau building processes. What the data show Folder 1: Analyzed ChRM (characteristic remanent magnetization) data set for samples come from TV, KA and GH measured sections in the basin. Folder 2: Excel files include ChRM and viscous magnetic components, stratigraphic level, declination, inclinations, latitude of Virtual Geomagnetic Poles/VGP, NRM (natural remnant magnetization), magnetic susceptibility (K), maximum angular deviations (MAD), range of demagnetization processes and discarded components. The high quality ChRM (stable directions, MAD &lt;10°) were selected for paper. Folder 3: Fold and reversal paleomagnetic tests were done to verity the reliability of the ChRM dataset. How the data can be interpreted K is a measure of how much a material will become magnetized in an applied magnetic field. NRM is the magnetization carried by magnetic minerals. NRM is a vector which has: Direction: declination (D) and inclination (I), Intensity (A/m), normal (N) and reverse (R) Polarity. Our data show TV and KA samples sourced from Eocene volcanic along southern margin with K higher than GH samples. Conversely, GH sediments sourced from both basin margin with lower K. NRM carries two magnetic components. The most important component of remanence is acquired when a rock is formed/ ChRM. Any later component is called a viscous (an unwanted magnetic component recorded in rocks). Sufficient description to enable others to understand what the data is, how was gathered, how to use Viscous and ChRM components isolated after demagnetizing the samples (Thermal and AF methods). The viscous components removed below 350°C (thermal) and 15 mT (AF), while ChRM components removed between 530 - 580/640°C and between 20 - 100/120 mT. The dominant ChRM were successfully isolated after removing secondary component. The dominant carriers of the ChRM in samples are magnetite and hematite (Curie temperature 580 and 640/680°C, respectively). ChRM data allowed determining N/R polarities. The rest of samples were rejected because of unstable ChRM or MAD &gt;10°. The paleomagnetic analysis was done using Rema soft software, format of analyzed files is rs3. The selected ChRM allowed determining polarities/VGP latitude and hence to build up a local magnetic polarity stratigraphy to be correlated with the Geomagnetic Polarity Time Scale (GPTS). Based on our new ages (U-Pb zircon dating and magnetostratigraphic correlation), we propose an evolutionary model for the last ~38-36 Ma in the Tarom Basin. To perform the fold test a text file was created for all data set, includes (from left to right); D, I, Dip Dir, and Dip (D/I of analyzed samples, Dip Dir/Dip of bedding. 2) to perform the reversal test 3 text files created including D/I.研究假设 本研究在碰撞变形与高原隆升的构造框架下，针对塔罗姆山间盆地（Tarom intermontane basin）未知年代的沉积地层（沉积时限为始新世之后任一时期），为其构造-地层演化提供新的约束。 数据集内容 文件夹1：包含盆地内TV、KA及GH实测剖面样品的特征剩磁（characteristic remanent magnetization, ChRM）分析数据集。 文件夹2：Excel文件涵盖特征剩磁、黏滞剩磁组分、地层层面、磁偏角、磁倾角、虚拟地磁极（Virtual Geomagnetic Poles/VGP）纬度、天然剩磁（natural remnant magnetization, NRM）、磁化率（magnetic susceptibility, K）、最大角偏差（maximum angular deviations, MAD）、退磁过程范围及废弃组分等数据。本次研究选取了高质量特征剩磁（方向稳定，最大角偏差<10°）用于论文撰写。 文件夹3：开展了褶皱检验与倒转古地磁测试，以验证特征剩磁数据集的可靠性。 数据解读 磁化率（K）可表征物质在外加磁场中的磁化程度。天然剩磁（NRM）为磁性矿物携带的磁化强度，属于矢量，包含三大要素：方向（磁偏角D与磁倾角I）、强度（单位：A/m）以及正极性（N）与反极性（R）。本次研究数据显示，采自盆地南缘始新世火山岩的TV与KA样品，其磁化率高于GH样品；反之，GH样品的沉积物则来自盆地两侧边缘，磁化率更低。天然剩磁包含两类磁性组分：岩石形成时获得的核心剩磁组分即为特征剩磁（ChRM），后续形成的额外组分为黏滞剩磁（岩石中记录的非目标磁性组分）。 数据说明与使用指南 通过热退磁与交变退磁（alternating field, AF）方法对样品进行退磁后，可分离出黏滞剩磁与特征剩磁组分。其中，黏滞剩磁可在350℃（热退磁）与15 mT（交变退磁）条件下被完全移除；特征剩磁组分的热退磁移除区间为530~580/640℃，交变退磁移除区间为20~100/120 mT。移除次生组分后，可成功分离出占主导的特征剩磁。样品中特征剩磁的主要载体为磁铁矿与赤铁矿，其居里温度分别为580℃与640/680℃。特征剩磁数据可用于确定正极性/反极性。其余样品因特征剩磁不稳定或最大角偏差>10°被舍弃。 古地磁分析采用Rema软件完成，分析文件格式为rs3。通过筛选得到的高质量特征剩磁数据，可确定极性与虚拟地磁极纬度，进而建立区域磁极性地层序列，用于与地磁极性年表（Geomagnetic Polarity Time Scale, GPTS）进行对比。结合本次获得的新年代学数据（U-Pb锆石定年与磁地层对比结果），本研究提出了塔罗姆盆地近38~36 Ma的演化模型。为开展褶皱检验，针对全部数据集生成了一个文本文件，按从左至右顺序依次包含：磁偏角D、磁倾角I、地层倾向方向、地层倾角（即样品的D/I值与岩层的倾向方向/倾角）；为开展倒转检验，则生成了3个包含D/I数据的文本文件。