This study investigated the diagnostic accuracy (DA) and clinical utility (CU) of DNA methylation (5 methylcytosine) in occupational Pb-exposure from Pb based industry. Blood Lead levels (BLLs) were measured using the ICP-OES method. The total DNA methylation (5-mC) was quantified using ELISA method. Based on their BLLs, the Pb-exposed workers were categorised into three groups: low (< 10 µg/dL), moderate (10-30 µg/dL), and high exposure (> 30 µg/dL). DNA methylation (5-mC) was significantly lower in moderate and high Pb-exposure groups when compared to the low Pb-exposure group. Workers exposed to high levels of Pb-exposure, the DA variables of 5-mC showed that the sensitivity was 74.7% [95% CI 65.4-84.0], specificity was 69.6% [95% CI 50.8-88.4], positive predictive value (PPV) was 89.9% [95% CI 82.7-97.0], Postive likelihood ratio (LR+) was 2.454 [95% CI 1.3-4.6], and diagnostic odds ratio (DOR) is 6.3 [95% CI 6.5-7.7]. In moderate Pb-exposure, the DA variables of 5-mC revealed that the sensitivity is 64.9% [95% CI 55.2-74.5], the specificity is 69.6% [95% CI 50.8-88.4], the PPV is 89.7% [95% CI 82.5-97.0], the LR+ is 2.132 [95% CI 1.13-4.03], and the DOR is 4.2 [95% CI 3.6-5.7]. The high Pb-exposure group had higher DA metrics when compared to moderate Pb exposure. The clinical utility (CU+) of 5-mC was found to have good utility of 0.671 [95% CI 0.566-0.776] in the high Pb exposure group and fair utility of 0.582 [95% CI 0.470-0.694] in moderate Pb exposure group. In conclusion, DNA methylation (5mC) could be used as a predictive biomarker for high Pb-exposure.
本研究调查了 DNA 甲基化（5 甲基胞嘧啶）在铅工业职业性铅暴露中的诊断准确性（DA）和临床实用性（CU）。采用 ICP-OES 方法测量血液铅含量 (BLL)。DNA 总甲基化（5-mC）采用 ELISA 方法进行量化。根据他们的血铅含量，受铅污染的工人被分为三组：低（30 µg/dL）组、中（30 µg/dL）组和高（30 µg/dL）组。与低铅暴露组相比，中度和高度铅暴露组的 DNA 甲基化（5-mC）明显较低。在暴露于高浓度铅的工人中，5-mC 的 DA 变量显示灵敏度为 74.7% [95% CI 65.4-84.0]，特异性为 69.6% [95% CI 50.8-88.4]，阳性预测值（positive predictive value，阳性预测值）为 0.5%。阳性预测值（PPV）为 89.9% [95% CI 82.7-97.0]，阳性似然比（LR+）为 2.454 [95% CI 1.3-4.6]，诊断几率比（DOR）为 6.3 [95% CI 6.5-7.7]。在中度铅暴露中，5-mC 的 DA 变量显示灵敏度为 64.9% [95% CI 55.2-74.5]，特异性为 69.6% [95% CI 50.8-88.4]，PPV 为 89.7% [95% CI 82.5-97.0]，LR+ 为 2.132 [95% CI 1.13-4.03]，DOR 为 4.2 [95% CI 3.6-5.7]。与中度铅暴露相比，高铅暴露组的 DA 指标更高。在高铅暴露组，5-mC 的临床实用性（CU+）为 0.671 [95% CI 0.566-0.776]，良好；在中度铅暴露组，5-mC 的临床实用性为 0.582 [95% CI 0.470-0.694]，一般。总之，DNA甲基化（5mC）可作为高铅暴露的预测性生物标志物。
{"title":"Assessment of Diagnostic Accuracy and Clinical Utility of DNA Methylation (5-mC) in Detecting Severity of Occupational Lead Exposure.","authors":"Ravibabu Kalahasthi, Vinay Kumar Adepu, Raju Nagaraju","doi":"10.1007/s12291-023-01138-z","DOIUrl":"10.1007/s12291-023-01138-z","url":null,"abstract":"<p><p>This study investigated the diagnostic accuracy (DA) and clinical utility (CU) of DNA methylation (5 methylcytosine) in occupational Pb-exposure from Pb based industry. Blood Lead levels (BLLs) were measured using the ICP-OES method. The total DNA methylation (5-mC) was quantified using ELISA method. Based on their BLLs, the Pb-exposed workers were categorised into three groups: low (< 10 µg/dL), moderate (10-30 µg/dL), and high exposure (> 30 µg/dL). DNA methylation (5-mC) was significantly lower in moderate and high Pb-exposure groups when compared to the low Pb-exposure group. Workers exposed to high levels of Pb-exposure, the DA variables of 5-mC showed that the sensitivity was 74.7% [95% CI 65.4-84.0], specificity was 69.6% [95% CI 50.8-88.4], positive predictive value (PPV) was 89.9% [95% CI 82.7-97.0], Postive likelihood ratio (LR+) was 2.454 [95% CI 1.3-4.6], and diagnostic odds ratio (DOR) is 6.3 [95% CI 6.5-7.7]. In moderate Pb-exposure, the DA variables of 5-mC revealed that the sensitivity is 64.9% [95% CI 55.2-74.5], the specificity is 69.6% [95% CI 50.8-88.4], the PPV is 89.7% [95% CI 82.5-97.0], the LR+ is 2.132 [95% CI 1.13-4.03], and the DOR is 4.2 [95% CI 3.6-5.7]. The high Pb-exposure group had higher DA metrics when compared to moderate Pb exposure. The clinical utility (CU+) of 5-mC was found to have good utility of 0.671 [95% CI 0.566-0.776] in the high Pb exposure group and fair utility of 0.582 [95% CI 0.470-0.694] in moderate Pb exposure group. In conclusion, DNA methylation (5mC) could be used as a predictive biomarker for high Pb-exposure.</p>","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"12 1","pages":"572-578"},"PeriodicalIF":1.5,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11436711/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79273717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tao Deng, Xiumian Hu, David Chew, Qin Wang, Jinhai Yu, Foteini Drakou
How to constrain the onset of continental subduction and prograde metamorphism in an orogen remains a fundamental question. The widespread Triassic ultrahigh-pressure (UHP) metamorphic rocks in the Dabie orogen in central-east China are generally attributed to continental subduction. The earliest Triassic peripheral basins (the Huangshi, Yueshan and Nanjing basins) around the Dabie orogen represent an ideal archive to reconstruct the early evolution of the orogen. Here we present a multidisciplinary provenance study on these Triassic strata, including framework petrography and heavy mineral analyses combined with U-Pb age and trace-element analyses of detrital zircon, rutile and apatite. The abundant metapelitic lithics and muscovite grains, a heavy mineral population dominated by metamorphic apatite, and a significant Permian (270–290 Ma) age peak from U-Pb age spectra of detrital zircon, rutile and apatite imply an Early Permian medium-high grade metamorphic source in the uppermost structural levels of the Dabie orogen. Our provenance data indicate that the onset of northward continental subduction of the South China Block commenced no later than the Early Permian (c. 290 Ma). This event is clearly earlier and distinct from the more widespread Triassic UHP metamorphism of the Dabie orogen, suggesting that continental subduction and mountain-basin interaction were protracted processes (>55 Myr, c. 290–235 Ma). When combined with other geological evidence, our results show that the prolonged continental subduction is not always preceded by subduction of oceanic crust.
{"title":"Sedimentological Evidence for Pre-Early Permian Continental Subduction in the Dabie Orogen, Central-East China","authors":"Tao Deng, Xiumian Hu, David Chew, Qin Wang, Jinhai Yu, Foteini Drakou","doi":"10.1029/2023tc007839","DOIUrl":"https://doi.org/10.1029/2023tc007839","url":null,"abstract":"How to constrain the onset of continental subduction and prograde metamorphism in an orogen remains a fundamental question. The widespread Triassic ultrahigh-pressure (UHP) metamorphic rocks in the Dabie orogen in central-east China are generally attributed to continental subduction. The earliest Triassic peripheral basins (the Huangshi, Yueshan and Nanjing basins) around the Dabie orogen represent an ideal archive to reconstruct the early evolution of the orogen. Here we present a multidisciplinary provenance study on these Triassic strata, including framework petrography and heavy mineral analyses combined with U-Pb age and trace-element analyses of detrital zircon, rutile and apatite. The abundant metapelitic lithics and muscovite grains, a heavy mineral population dominated by metamorphic apatite, and a significant Permian (270–290 Ma) age peak from U-Pb age spectra of detrital zircon, rutile and apatite imply an Early Permian medium-high grade metamorphic source in the uppermost structural levels of the Dabie orogen. Our provenance data indicate that the onset of northward continental subduction of the South China Block commenced no later than the Early Permian (c. 290 Ma). This event is clearly earlier and distinct from the more widespread Triassic UHP metamorphism of the Dabie orogen, suggesting that continental subduction and mountain-basin interaction were protracted processes (>55 Myr, c. 290–235 Ma). When combined with other geological evidence, our results show that the prolonged continental subduction is not always preceded by subduction of oceanic crust.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"21 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139422584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Erbello, C. Colleps, D. Melnick, E. R. Sobel, B. Bookhagen, H. Pingel, G. Zeilinger, P. van der Beek, M. R. Strecker
The Gofa Province and Chew Bahir Basin in the Broadly Rifted Zone (BRZ) between the southern Main Ethiopian Rift (sMER) and the northern Kenya Rift (nKR) record early volcanism and associated faulting in East Africa; however, the spatiotemporal relationships between volcanism and faulting remain poorly constrained. We applied apatite (U-Th)/He (AHe) and zircon (U-Th)/He (ZHe) thermochronometry to Neoproterozoic basement rocks from exhumed footwall blocks of the extensional Gofa Province and Chew Bahir Basin, and analyzed our result in the context of well-dated regional volcanic units in the BRZ to unravel the interplay between tectonic exhumation, faulting and volcanism. Single-grain AHe ages ranging from 1.0 to 136.8 Ma were recorded in 32 samples, and single-grain ZHe ages from three samples range between 142.2 and 335.6 Ma. The youngest AHe ages were obtained from the Chew Bahir Basin and the narrow deformation zone in the Gofa Province. Our thermal modeling results reflect little or no significant regional crustal cooling prior to extensive volcanism, which started at about 45 Ma. Conversely, new and previously published thermal history models suggest that widespread crustal cooling related to regional extension occurred between ∼27 and 20 Ma. Thermal modeling results from subsets of samples indicate that following this initial diffuse extensional deformation, renewed exhumation occurred along a narrow zone within the Gofa Province and the Chew Bahir Basin during the middle to late Miocene (15-6 Ma) and Pliocene (<5 Ma), respectively. The crustal cooling phases follow a regional trend in volcanic episodes. For example, initial cooling between 27 and 20 Ma corresponds with the end of widespread flood-basalt volcanism (45–28 Ma), suggesting that spatially diffuse normal faulting may have initiated shortly after the emplacement of voluminous and areally extensive flood basalts. The Miocene and Pliocene shifts in deformation along the Mali-Dancha and Bala-Kela basins in the Gofa Province and the Chew Bahir Basin, respectively, may indicate strain localization during the late stage of rifting and ongoing tectonic interaction between the sMER and the nKR. Our results support the notion of crustal weakening by massive volcanism as a precursor to widespread extensional faulting, and thus offer further insights into magma-assisted deformation processes in the East African Rift System.
埃塞俄比亚主断裂带（sMER）南部和肯尼亚断裂带（nKR）北部之间宽断裂带（BRZ）上的戈法省（Gofa Province）和楚巴希尔盆地（Chew Bahir Basin）记录了东非早期的火山活动和相关断层活动；然而，火山活动和断层活动之间的时空关系仍然没有得到很好的解释。我们应用磷灰石（U-Th）/He（AHe）和锆石（U-Th）/He（ZHe）热时测定法对来自延伸戈法省（Gofa Province）和楚巴希尔盆地（Chew Bahir Basin）出露的底壁岩块的新元古代基底岩石进行了测定，并结合肯尼亚断裂带（BRZ）中年代明确的区域火山岩单元对测定结果进行了分析，以揭示构造出露、断层和火山活动之间的相互作用。32个样品的单粒AHe年龄介于1.0至136.8Ma之间，3个样品的单粒ZHe年龄介于142.2至335.6Ma之间。最年轻的 AHe 年龄来自 Chew Bahir 盆地和戈法省的狭窄变形带。我们的热建模结果表明，在大约 45 Ma 开始的大范围火山活动之前，区域地壳几乎没有明显的冷却。相反，新的和以前公布的热历史模型表明，与区域延伸有关的大范围地壳冷却发生在 27 至 20 Ma 之间。子集样本的热模型结果表明，在最初的弥漫扩展变形之后，中新世中晚期（15-6 Ma）和上新世（<5 Ma）期间，分别在戈法省和Chew Bahir盆地内的一个狭窄地带发生了新的掘起。地壳冷却阶段与火山活动的区域趋势一致。例如，27 至 20 Ma 之间的初始冷却与大面积洪积玄武岩火山活动（45-28 Ma）的结束相吻合，这表明空间弥散的正断层可能是在大体积、大面积洪积玄武岩喷发后不久开始的。戈法省的马里-丹恰盆地和巴拉-凯拉盆地沿中新世和上新世的变形分别发生了变化，这可能表明在断裂晚期以及sMER和nKR之间持续的构造相互作用中出现了应变局部化。我们的研究结果支持大规模火山活动造成的地壳减弱是大范围伸展断裂的前兆这一观点，从而进一步揭示了东非大裂谷系统中岩浆辅助变形过程。
{"title":"Magma-Assisted Continental Rifting: The Broadly Rifted Zone in SW Ethiopia, East Africa","authors":"A. Erbello, C. Colleps, D. Melnick, E. R. Sobel, B. Bookhagen, H. Pingel, G. Zeilinger, P. van der Beek, M. R. Strecker","doi":"10.1029/2022tc007651","DOIUrl":"https://doi.org/10.1029/2022tc007651","url":null,"abstract":"The Gofa Province and Chew Bahir Basin in the Broadly Rifted Zone (BRZ) between the southern Main Ethiopian Rift (sMER) and the northern Kenya Rift (nKR) record early volcanism and associated faulting in East Africa; however, the spatiotemporal relationships between volcanism and faulting remain poorly constrained. We applied apatite (U-Th)/He (AHe) and zircon (U-Th)/He (ZHe) thermochronometry to Neoproterozoic basement rocks from exhumed footwall blocks of the extensional Gofa Province and Chew Bahir Basin, and analyzed our result in the context of well-dated regional volcanic units in the BRZ to unravel the interplay between tectonic exhumation, faulting and volcanism. Single-grain AHe ages ranging from 1.0 to 136.8 Ma were recorded in 32 samples, and single-grain ZHe ages from three samples range between 142.2 and 335.6 Ma. The youngest AHe ages were obtained from the Chew Bahir Basin and the narrow deformation zone in the Gofa Province. Our thermal modeling results reflect little or no significant regional crustal cooling prior to extensive volcanism, which started at about 45 Ma. Conversely, new and previously published thermal history models suggest that widespread crustal cooling related to regional extension occurred between ∼27 and 20 Ma. Thermal modeling results from subsets of samples indicate that following this initial diffuse extensional deformation, renewed exhumation occurred along a narrow zone within the Gofa Province and the Chew Bahir Basin during the middle to late Miocene (15-6 Ma) and Pliocene (<5 Ma), respectively. The crustal cooling phases follow a regional trend in volcanic episodes. For example, initial cooling between 27 and 20 Ma corresponds with the end of widespread flood-basalt volcanism (45–28 Ma), suggesting that spatially diffuse normal faulting may have initiated shortly after the emplacement of voluminous and areally extensive flood basalts. The Miocene and Pliocene shifts in deformation along the Mali-Dancha and Bala-Kela basins in the Gofa Province and the Chew Bahir Basin, respectively, may indicate strain localization during the late stage of rifting and ongoing tectonic interaction between the sMER and the nKR. Our results support the notion of crustal weakening by massive volcanism as a precursor to widespread extensional faulting, and thus offer further insights into magma-assisted deformation processes in the East African Rift System.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"82 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139396288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. I. Soto, M. D. Tranos, Z. Bega, T. P. Dooley, P. Hernández, M. R. Hudec, P. A. Konstantopoulos, E. Lula, K. Nikolaou, R. Pérez, J. P. Pita, J. A. Titos, C. Tzimeas, A. Herra Sánchez de Movellán
The Ionian Zone (IZ) is one of the key elements of the fold and thrust belt (FTB) of the Albanian and Hellenides orogen and contains large outcrops of Triassic evaporites. The IZ consists of various thrust sheets with a general westward vergence, stacking over the Apulian and Pre-Apulian zones, and repeating a thick carbonate sequence of Upper Triassic to Eocene age. Thrusting becomes younger toward the west with a piggyback sequence, starting during the latest Oligocene Epoch in the Internal Ionian and ending in the Pliocene in the External Ionian. We have studied the IZ in southern Albania and northwestern Greece using field observations and borehole data and by fully interpreting a recently acquired 2D seismic data set. Our objectives are to establish the geometry and nature of the contacts associated with the major Triassic outcrops, to unravel precursor salt diapirs, and to assess their role during the Alpine contraction. Salt structures include gentle salt pillows, isolated salt plugs and diapirs, thrust welds, and salt walls. Combining these observations with experimental modeling results, we show how these structures control the geometry and kinematics of the Alpine thrusts or the location and kinematics of recent strike-slip faults. Salt minibasins have also been identified, demonstrating salt mobility conditioned Mesozoic sedimentation in the Ionian Basin. The use of salt-tectonics principles to evaluate the structural style and evolution of the IZ FTB also opens new directions for interpreting the subsurface structure and evolution of the region.
爱奥尼亚区（IZ）是阿尔巴尼亚和希腊造山带褶皱和推力带（FTB）的关键要素之一，包含大量三叠纪蒸发岩露头。IZ由各种推力片组成，总体向西褶皱，叠加在阿普利亚带和前阿普利亚带之上，重复着上三叠世至始新世时代的厚碳酸盐序列。向西的推移变得更年轻，有一个捎带序列，从内部爱奥尼亚岛的最晚渐新世开始，到外部爱奥尼亚岛的上新世结束。我们利用实地观测和钻孔数据，并通过全面解释最近获得的二维地震数据集，对阿尔巴尼亚南部和希腊西北部的内伊奥尼亚区进行了研究。我们的目标是确定与主要三叠纪露头相关的接触点的几何形状和性质，揭示前盐二叠纪，并评估它们在阿尔卑斯山收缩过程中的作用。盐结构包括平缓的盐枕、孤立的盐塞和斜坡、推力焊缝和盐壁。结合这些观测结果和实验建模结果，我们展示了这些结构是如何控制阿尔卑斯山推力的几何形状和运动学特征或近期走向滑动断层的位置和运动学特征的。我们还发现了盐矿小盆地，证明盐的流动性对爱奥尼亚盆地中生代沉积作用的影响。利用盐构造学原理评估 IZ FTB 的构造样式和演变，也为解释该地区的地下结构和演变开辟了新的方向。
{"title":"Contrasting Styles of Salt-Tectonic Processes in the Ionian Zone (Greece and Albania): Integrating Surface Geology, Subsurface Data, and Experimental Models","authors":"J. I. Soto, M. D. Tranos, Z. Bega, T. P. Dooley, P. Hernández, M. R. Hudec, P. A. Konstantopoulos, E. Lula, K. Nikolaou, R. Pérez, J. P. Pita, J. A. Titos, C. Tzimeas, A. Herra Sánchez de Movellán","doi":"10.1029/2023tc008104","DOIUrl":"https://doi.org/10.1029/2023tc008104","url":null,"abstract":"The Ionian Zone (IZ) is one of the key elements of the fold and thrust belt (FTB) of the Albanian and Hellenides orogen and contains large outcrops of Triassic evaporites. The IZ consists of various thrust sheets with a general westward vergence, stacking over the Apulian and Pre-Apulian zones, and repeating a thick carbonate sequence of Upper Triassic to Eocene age. Thrusting becomes younger toward the west with a piggyback sequence, starting during the latest Oligocene Epoch in the Internal Ionian and ending in the Pliocene in the External Ionian. We have studied the IZ in southern Albania and northwestern Greece using field observations and borehole data and by fully interpreting a recently acquired 2D seismic data set. Our objectives are to establish the geometry and nature of the contacts associated with the major Triassic outcrops, to unravel precursor salt diapirs, and to assess their role during the Alpine contraction. Salt structures include gentle salt pillows, isolated salt plugs and diapirs, thrust welds, and salt walls. Combining these observations with experimental modeling results, we show how these structures control the geometry and kinematics of the Alpine thrusts or the location and kinematics of recent strike-slip faults. Salt minibasins have also been identified, demonstrating salt mobility conditioned Mesozoic sedimentation in the Ionian Basin. The use of salt-tectonics principles to evaluate the structural style and evolution of the IZ FTB also opens new directions for interpreting the subsurface structure and evolution of the region.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"29 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139398699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinnan Li, Ian K. D. Pierce, Kai Sun, Junjie Li, Huili Yang, Zicheng You, Shufeng Liu, Zhuqi Zhang, Chuanyou Li, Wenjun Zheng, Peizhen Zhang
The Tieluzi Fault is the largest structure in the East Qinling Mountains, and is considered to be the easternmost continuation of the Altyn Tagh-Haiyuan-Qinling Fault System (AHQFS) that allows the eastward extrusion of the Tibetan Plateau and South China Block. We studied the fault geometry and kinematics of the Tieluzi Fault using field investigations, detailed interpretations of high-resolution satellite imagery and digital elevation models, and late Quaternary dating methods. Paleoseismic investigations indicate that the most recent earthquake along the Tieluzi Fault occurred before 1,500–1,300 cal. BP. Geological and geomorphological observations show that segments west of Lushi County are more active than those to the east. The spatial variations in tectonic activity along the Tieluzi Fault are interpreted to be related to four possible mechanisms: strike change, discontinuity, intersection, and branch. The late Quaternary left-lateral slip rate is determined to be 0.9 ± 0.1 mm/yr on the Tieluzi Fault. The prominent left-lateral faulting along the Tieluzi Fault suggests that most of the left-lateral displacement along the eastern AHQFS has been accommodated by the Tieluzi Fault, which forms the most frontier of the eastward expansion of the Tibetan Plateau. Furthermore, we suggest that the left-lateral faulting in the East Qinling Mountains is a response to relative eastward motion of the South China block pushed by the Tibetan Plateau with respect to the North China Plain Block. Also, our results indicate that the Tibetan Plateau has undergone a stepwise eastward expansion.
{"title":"Fault Geometry and Late Quaternary Kinematics Along the Tieluzi Fault: Implications for Tectonic Deformation and Eastward Expansion of the Tibetan Plateau, China","authors":"Xinnan Li, Ian K. D. Pierce, Kai Sun, Junjie Li, Huili Yang, Zicheng You, Shufeng Liu, Zhuqi Zhang, Chuanyou Li, Wenjun Zheng, Peizhen Zhang","doi":"10.1029/2023tc008015","DOIUrl":"https://doi.org/10.1029/2023tc008015","url":null,"abstract":"The Tieluzi Fault is the largest structure in the East Qinling Mountains, and is considered to be the easternmost continuation of the Altyn Tagh-Haiyuan-Qinling Fault System (AHQFS) that allows the eastward extrusion of the Tibetan Plateau and South China Block. We studied the fault geometry and kinematics of the Tieluzi Fault using field investigations, detailed interpretations of high-resolution satellite imagery and digital elevation models, and late Quaternary dating methods. Paleoseismic investigations indicate that the most recent earthquake along the Tieluzi Fault occurred before 1,500–1,300 cal. BP. Geological and geomorphological observations show that segments west of Lushi County are more active than those to the east. The spatial variations in tectonic activity along the Tieluzi Fault are interpreted to be related to four possible mechanisms: strike change, discontinuity, intersection, and branch. The late Quaternary left-lateral slip rate is determined to be 0.9 ± 0.1 mm/yr on the Tieluzi Fault. The prominent left-lateral faulting along the Tieluzi Fault suggests that most of the left-lateral displacement along the eastern AHQFS has been accommodated by the Tieluzi Fault, which forms the most frontier of the eastward expansion of the Tibetan Plateau. Furthermore, we suggest that the left-lateral faulting in the East Qinling Mountains is a response to relative eastward motion of the South China block pushed by the Tibetan Plateau with respect to the North China Plain Block. Also, our results indicate that the Tibetan Plateau has undergone a stepwise eastward expansion.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"26 1 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139066160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since the Mesozoic, eastern NE Asia has experienced multiple tectonic events, resulting in a complex structure and forming one of the world's largest Meso-Cenozoic lacustrine basin systems. Presently, basin evolution models require further elucidation regarding the simultaneous generation of diverse rift basins and the potential impact stemming from the closure of the Mudanjiang Ocean, whose oceanic closure demarcated the boundary between the Songliao Basin and the eastern basins, raises questions about its influence on the development of the basin-and-range system. To address these questions, we augment new low-temperature thermochronological data on basement highs separating the eastern NE Asia basins to investigate the shallow-deep coupling process of tectonic evolution since the Mesozoic. The new cooling age pattern shows non-overlapping and spatial differences among major basement highs. Inverse thermal modeling revealed five-stage cooling episodes among the basement highs, but with different onset and cooling rates of each episode, indicating a significant differential uplift mode. A major reburial stage was identified throughout eastern NE Asia during the mid-Cretaceous. Compiling cooling age patterns and inverse thermal modeling, we note the existence of a proto-basin covering an area much larger than the previously contemplated “Pan-Sanjiang” Basin. In general, our study indicates the final closure of the Mudanjiang Ocean occurred at ca. 150–140 Ma. Since the Early Cretaceous, with changes in the subduction direction, two-stage flat slab subduction of the Paleo-Pacific plate and the consequent subduction of the Pacific plate co-dominated the basements' differential uplift and the formation of the eastern NE Asia basin-and-range framework.
{"title":"Differential Uplift Triggered Basin-And-Range System: Evidence From Low-Temperature Thermochronology in Eastern NE Asia","authors":"Jianping Zhou, Sanzhong Li, Yongjiang Liu, Boran Liu, Weimin Li, Guangzeng Wang, Liwei Jiang, Tong Zhou, Zunting Li, Zhiqiang Feng","doi":"10.1029/2023tc007857","DOIUrl":"https://doi.org/10.1029/2023tc007857","url":null,"abstract":"Since the Mesozoic, eastern NE Asia has experienced multiple tectonic events, resulting in a complex structure and forming one of the world's largest Meso-Cenozoic lacustrine basin systems. Presently, basin evolution models require further elucidation regarding the simultaneous generation of diverse rift basins and the potential impact stemming from the closure of the Mudanjiang Ocean, whose oceanic closure demarcated the boundary between the Songliao Basin and the eastern basins, raises questions about its influence on the development of the basin-and-range system. To address these questions, we augment new low-temperature thermochronological data on basement highs separating the eastern NE Asia basins to investigate the shallow-deep coupling process of tectonic evolution since the Mesozoic. The new cooling age pattern shows non-overlapping and spatial differences among major basement highs. Inverse thermal modeling revealed five-stage cooling episodes among the basement highs, but with different onset and cooling rates of each episode, indicating a significant differential uplift mode. A major reburial stage was identified throughout eastern NE Asia during the mid-Cretaceous. Compiling cooling age patterns and inverse thermal modeling, we note the existence of a proto-basin covering an area much larger than the previously contemplated “Pan-Sanjiang” Basin. In general, our study indicates the final closure of the Mudanjiang Ocean occurred at ca. 150–140 Ma. Since the Early Cretaceous, with changes in the subduction direction, two-stage flat slab subduction of the Paleo-Pacific plate and the consequent subduction of the Pacific plate co-dominated the basements' differential uplift and the formation of the eastern NE Asia basin-and-range framework.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"32 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139066217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The presence of pre-existing fabrics at all lithospheric scales has been proven to be of primary importance in controlling the evolution of continental rifts. Indeed, observations from natural examples show that even in conditions of orthogonal rifting, when extension should result in simple fault patterns dominated by normal faults orthogonal to extension vectors, inherited fabrics induce complex arrangements of differently-oriented extension-related structures. This paper explored the influence of inherited fabrics on rift-related structures by using a series of analog models deformed in a centrifuge. The models reproduced a brittle-ductile crustal system and considered the presence of pre-existing discrete fabrics in the brittle crust in conditions of orthogonal narrow rifting. These fabrics were reproduced by cutting the brittle layer at different orientations with respect to the extension direction. Modeling shows pre-existing fabrics have a significant influence on rift-related faults, provided that the angle between inherited fabrics and the rift trend is less than 45°. In these conditions, fabrics cause prominent segmentation of rift-related faults and induce the development of isolated depocenters. Pre-existing fabrics strongly influence the geometry of extension-related structures, resulting in curved fault patterns and en-echelon arrangement of oblique faults. These findings provide insights into the development of continental rift systems in nature: our modeling shows indeed significant similarities (i.e., peculiar fault architecture and geometries) with the faults in different sectors of the East African Rift System (e.g., the Magadi and Bogoria basin, Kenya Rift), testifying that reactivation of inherited fabrics is a paramount process in shaping continental rifts.
{"title":"Influence of Inherited Brittle Fabrics on Continental Rifting: Insights From Centrifuge Experimental Modeling and Application to the East African Rift System","authors":"Yaoyao Zou, Daniele Maestrelli, Giacomo Corti, Chiara Del Ventisette, Liang Wang, Chuanbo Shen","doi":"10.1029/2023tc007947","DOIUrl":"https://doi.org/10.1029/2023tc007947","url":null,"abstract":"The presence of pre-existing fabrics at all lithospheric scales has been proven to be of primary importance in controlling the evolution of continental rifts. Indeed, observations from natural examples show that even in conditions of orthogonal rifting, when extension should result in simple fault patterns dominated by normal faults orthogonal to extension vectors, inherited fabrics induce complex arrangements of differently-oriented extension-related structures. This paper explored the influence of inherited fabrics on rift-related structures by using a series of analog models deformed in a centrifuge. The models reproduced a brittle-ductile crustal system and considered the presence of pre-existing discrete fabrics in the brittle crust in conditions of orthogonal narrow rifting. These fabrics were reproduced by cutting the brittle layer at different orientations with respect to the extension direction. Modeling shows pre-existing fabrics have a significant influence on rift-related faults, provided that the angle between inherited fabrics and the rift trend is less than 45°. In these conditions, fabrics cause prominent segmentation of rift-related faults and induce the development of isolated depocenters. Pre-existing fabrics strongly influence the geometry of extension-related structures, resulting in curved fault patterns and en-echelon arrangement of oblique faults. These findings provide insights into the development of continental rift systems in nature: our modeling shows indeed significant similarities (i.e., peculiar fault architecture and geometries) with the faults in different sectors of the East African Rift System (e.g., the Magadi and Bogoria basin, Kenya Rift), testifying that reactivation of inherited fabrics is a paramount process in shaping continental rifts.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"18 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139066276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. A. Lajo-Yáñez, S. S. Flint, M. Huuse, R. L. Brunt
Two main types of subduction are recognized around the world: accretionary and erosive. The northern Peruvian margin is a well-known example of a margin subjected to subduction erosion, but to date the along-margin variability and temporal changes in subduction process and forearc basin evolution have not been characterized in detail. Interpretation of regional seismic lines and integration of oil-industry wells and seafloor data captures the erosive nature of subduction underneath the forearc with only a minor accretionary component to the north. Episodes of uplift driven by plate coupling were followed by normal faulting/extensional collapse due to plate decoupling. This mechanism explains the dominance of normal faulting across the forearc until the Oligocene with a slight reactivation within the Miocene. The subduction history is complex and includes a reduction in plate convergence rate related to forearc crustal shortening, represented by large-scale structures including the Peru fault (reactivated) and the Illescas fault-propagation anticlines of the Northwest Peru transpressional system. This crustal deformation started in the Miocene. Integration with magnetic anomaly data indicates that activity of the present-day transpressional system driven by tectonic escape of the Nazca Sliver toward the northeast, may explain the seismicity gap in southern Ecuador and northern Peru. An evolutionary model of the northern Peruvian margin shows how subduction zone geodynamics left its erosive fingerprint in the forearc basin configuration.
{"title":"Tectono-Stratigraphic Insights on the Dynamics of a Complex Subduction Zone, Northern Peruvian Forearc","authors":"J. A. Lajo-Yáñez, S. S. Flint, M. Huuse, R. L. Brunt","doi":"10.1029/2023tc007860","DOIUrl":"https://doi.org/10.1029/2023tc007860","url":null,"abstract":"Two main types of subduction are recognized around the world: accretionary and erosive. The northern Peruvian margin is a well-known example of a margin subjected to subduction erosion, but to date the along-margin variability and temporal changes in subduction process and forearc basin evolution have not been characterized in detail. Interpretation of regional seismic lines and integration of oil-industry wells and seafloor data captures the erosive nature of subduction underneath the forearc with only a minor accretionary component to the north. Episodes of uplift driven by plate coupling were followed by normal faulting/extensional collapse due to plate decoupling. This mechanism explains the dominance of normal faulting across the forearc until the Oligocene with a slight reactivation within the Miocene. The subduction history is complex and includes a reduction in plate convergence rate related to forearc crustal shortening, represented by large-scale structures including the Peru fault (reactivated) and the Illescas fault-propagation anticlines of the Northwest Peru transpressional system. This crustal deformation started in the Miocene. Integration with magnetic anomaly data indicates that activity of the present-day transpressional system driven by tectonic escape of the Nazca Sliver toward the northeast, may explain the seismicity gap in southern Ecuador and northern Peru. An evolutionary model of the northern Peruvian margin shows how subduction zone geodynamics left its erosive fingerprint in the forearc basin configuration.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"43 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139066163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P.-O. Bruna, G. Bertotti, R. J. G. Charton, R. Dixon, A. Nasri
Southern Tunisia is known to be less deformed and simpler than its neighboring Atlassic domain to the north. This area is complex and basin evolution in the Southern Chotts-Jeffara (SCJ) basin is debated. In this paper we combined surface and subsurface data with low temperature thermochronology (LTT) to reinvestigate the tectono-sedimentary evolution of the SCJ basin from Permian to Jurassic. We reconstruct the present-day architecture of the SCJ basin along two regional sections. In these sections, we focused mainly on regional thickness variations and on internal reflections interpreted from seismic data. We observe three structural elements: (a) A Paleozoic culmination, oriented E-W, capped by Mid-Upper Triassic deposits; (b) the Tebaga of Medenine (ToM), a culmination also oriented E-W but located ∼50 km north of the Paleozoic culmination; and (c) A Triassic culmination in the eastern part of the area, oriented NW-SE. We note the absence of major normal faults along the sections. The LTT data we present are the first published in this area and allow to reconstruct the timing and magnitude of vertical movements. These data prove: (a) exhumation at ∼230 Ma of the Permian and Lower Triassic units associated with the onset of the ToM removing locally about 900 m of pre-Cretaceous sediments; and (b) the development of the Triassic culmination ∼180 Ma removing 2000 m of pre-Cretaceous sediments in the Jebel Rehach. This study demonstrates that vertical movements in the SCJ basin are controlled by long-wavelength processes developed essentially in shortening regimes.
{"title":"Architecture and Evolution of the Southern Chotts-Jeffara Basin, Tunisia","authors":"P.-O. Bruna, G. Bertotti, R. J. G. Charton, R. Dixon, A. Nasri","doi":"10.1029/2023tc008085","DOIUrl":"https://doi.org/10.1029/2023tc008085","url":null,"abstract":"Southern Tunisia is known to be less deformed and simpler than its neighboring Atlassic domain to the north. This area is complex and basin evolution in the Southern Chotts-Jeffara (SCJ) basin is debated. In this paper we combined surface and subsurface data with low temperature thermochronology (LTT) to reinvestigate the tectono-sedimentary evolution of the SCJ basin from Permian to Jurassic. We reconstruct the present-day architecture of the SCJ basin along two regional sections. In these sections, we focused mainly on regional thickness variations and on internal reflections interpreted from seismic data. We observe three structural elements: (a) A Paleozoic culmination, oriented E-W, capped by Mid-Upper Triassic deposits; (b) the Tebaga of Medenine (ToM), a culmination also oriented E-W but located ∼50 km north of the Paleozoic culmination; and (c) A Triassic culmination in the eastern part of the area, oriented NW-SE. We note the absence of major normal faults along the sections. The LTT data we present are the first published in this area and allow to reconstruct the timing and magnitude of vertical movements. These data prove: (a) exhumation at ∼230 Ma of the Permian and Lower Triassic units associated with the onset of the ToM removing locally about 900 m of pre-Cretaceous sediments; and (b) the development of the Triassic culmination ∼180 Ma removing 2000 m of pre-Cretaceous sediments in the Jebel Rehach. This study demonstrates that vertical movements in the SCJ basin are controlled by long-wavelength processes developed essentially in shortening regimes.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"8 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138682380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kai Cao, Di Zhang, Xiaoming Shen, Junfeng Zhang, Dun Wang, Yadong Xu, Guocan Wang
The ∼400-km-long Litang fault system (LTFS) is a major intracontinental strike-slip fault inside the Chuandian block, eastern Tibet, but its evolution and role in accommodating the India-Asia convergence remain poorly known. Structural analysis shows that the LTFS splits into 5 strands as a left-lateral, right-stepping en-echelon pattern formed under NW-directed compression, subsequently reactivated by transtensive faults under NNE-directed extension. Displaced geological and morphological markers yield a cumulative left-lateral offset of 28.9–42.8 km. Inverse thermal-history modeling of thermochronological data of the faulted rocks reveal accelerated cooling at 38–35 Ma, 16–13 Ma, and 7–5 Ma. The late Eocene rapid cooling is ascribed to the reactivation of the Garze-Litang suture. Rapid cooling events at 16–13 Ma and 7–5 Ma record the onset of transpression and transtension of the LTFS, respectively, yielding a geologic slip rate of 2.6 ± 0.7 mm/yr. Both bifurcated geometry and slow slip rate of the LTFS since 16–13 Ma indicate diffuse deformation inside the Chuandian block, contrasting with strain localized on fast-slip strike-slip faults on the block margins. This implies a significant kinematic transition in the middle Miocene, such that the extrusion of the segmented mega-blocks has been accommodated by both localized and distributed deformation in eastern Tibet. This tectonic transition could be explained by a change in lithospheric rheology from an earlier rigid state to a viscous state underneath the Chuandian block due to thermal weakening of the lower crust. We thus reconcile the end-member geodynamic models of block extrusion and lower crustal flow in late Cenozoic times.
{"title":"Middle Miocene Onset of the Litang Fault System Records Kinematic Change in Eastern Tibet","authors":"Kai Cao, Di Zhang, Xiaoming Shen, Junfeng Zhang, Dun Wang, Yadong Xu, Guocan Wang","doi":"10.1029/2023tc007931","DOIUrl":"https://doi.org/10.1029/2023tc007931","url":null,"abstract":"The ∼400-km-long Litang fault system (LTFS) is a major intracontinental strike-slip fault inside the Chuandian block, eastern Tibet, but its evolution and role in accommodating the India-Asia convergence remain poorly known. Structural analysis shows that the LTFS splits into 5 strands as a left-lateral, right-stepping en-echelon pattern formed under NW-directed compression, subsequently reactivated by transtensive faults under NNE-directed extension. Displaced geological and morphological markers yield a cumulative left-lateral offset of 28.9–42.8 km. Inverse thermal-history modeling of thermochronological data of the faulted rocks reveal accelerated cooling at 38–35 Ma, 16–13 Ma, and 7–5 Ma. The late Eocene rapid cooling is ascribed to the reactivation of the Garze-Litang suture. Rapid cooling events at 16–13 Ma and 7–5 Ma record the onset of transpression and transtension of the LTFS, respectively, yielding a geologic slip rate of 2.6 ± 0.7 mm/yr. Both bifurcated geometry and slow slip rate of the LTFS since 16–13 Ma indicate diffuse deformation inside the Chuandian block, contrasting with strain localized on fast-slip strike-slip faults on the block margins. This implies a significant kinematic transition in the middle Miocene, such that the extrusion of the segmented mega-blocks has been accommodated by both localized and distributed deformation in eastern Tibet. This tectonic transition could be explained by a change in lithospheric rheology from an earlier rigid state to a viscous state underneath the Chuandian block due to thermal weakening of the lower crust. We thus reconcile the end-member geodynamic models of block extrusion and lower crustal flow in late Cenozoic times.","PeriodicalId":22351,"journal":{"name":"Tectonics","volume":"4 1","pages":""},"PeriodicalIF":4.2,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138682150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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