Structural complexities in the Alishan area of the Taiwan fold-and-thrust belt inherited from the margin's shelf-slope transition

This article is subject to a CC Attribution 3.0 License.The Alishan area of Taiwan includes a sector of the fold-and-thrust belt that spans the transition from the platform with full thickness of the Eurasian continental margin in the north to the thinning crust of its slope in the south. This part of the fold-and-thrust belt with the highest elevations includes important along-strike changes in structure, stratigraphy, and seismic velocities. Here we present the results of new geological mapping from which we build geological cross sections both across and along the regional structural trend. Fault contour, stratigraphic cut-off, and branch line maps provide 3-D consistency between the cross sections. Minimum shortening is estimated to be 15 km, with displacement overall to the northwest. A P wave velocity model helps constrain the structure at depth by providing insight into the possible rock units that are present there. P wave velocities of > 5.2 km/s point toward the presence of basement rocks in the shallow subsurface throughout much of the south-eastern part of the area, forming a basement culmination. The changes in strike of thrusts and fold axial traces, the changing elevation of thrusts and stratigraphic contacts, and the growing importance of Middle Miocene sediments that take place from north to south are interpreted to be associated with a roughly northeast striking lateral structure coincident with the northern flank of this basement culmination. These transverse structures appear to be associated with the inversion of Eocene- and Miocene-age extensional faults, deeply rooted in the pre Cenozoic basement that were along what was the shelf-slope transition in the Early Oligocene. Inversion causes uplift of the margin sediments and their higher P wave velocity basement during Pliocene-Pleistocene thrusting.Peer Reviewe

Isolated Fetal Ascites Secondary to Persistent Urogenital Sinus

Objective. To present a case of isolated ascites secondary due to urogenital abnormalities (urogenital sinus) without any other prenatal ultrasound marker. Method. A 36-year-old woman with prenatal isolated ascites delivered a female baby, weighing 2.285 g; ascites was drained at birth and the baby underwent several episodes of urinary retention prior to undergoing X-ray investigations. Results. A voiding cystourethrogram revealed a short urogenital sinus: a vesicostomy was performed. A vaginoscopy revealed double vagina with a large posterior vagina. A posterior sagittal anorectal pull-through with genitoplasty was performed at 2 years old with 1-year follow-up. Conclusions. Though rare, a urogenital abnormality is to be suspected in fetal ascites cases with negative viral tests and no cardiac anomalies. The most common ultrasound marker of such abnormalities (fluid filled cavity) may be missing because of complete drainage of urine through the tubes into peritoneum

Structure of the south-central Taiwan fold-and-thrust belt: Testing the viability of the model

A structural model is developed for the south-central Taiwan fold-and-thrust belt that shows consistency across an array of data types and marks an important step forward in the consideration of geological hazards and risks. Although there is general agreement about the regional scale geology of Taiwan, there are considerable differences in the structural interpretations of its western fold-and-thrust belt. In this paper, we bring together results of our previous studies and add new data and data analyses to develop a consistent 3D structural model for the south-central Taiwan fold-and-thrust belt that can explain key aspects of the seismicity, GPS, and topography data. We interpret the fold-and-thrust belt to be a west-verging, imbricate thrust system developed above a single basal thrust that is breached by ENE-striking faults that are inherited from the continental margin. These breaching faults are associated with ENE-striking transverse zones in the fold-and-thrust belt that are marked by changes in stratigraphy, structural style, strike and dip of the basal thrust, and uplift of the stratigraphic contacts. Along the eastern flank of the fold-and-thrust belt, metamorphic basement rocks are involved in the thrusting. Shortening estimates range from 15 km to >25 km. Much of the seismicity is taking place beneath the basal thrust, in the basement, along the flanks of basement highs and lows where strike-slip and transpressive fault types are common. There are systematic changes in GPS displacement vectors and strain rates across the transverse zones. Topography is higher in areas where basement is involved in the thrusting. The proposed structural model has depth and along-strike consistency, and can explain aspects of the distribution of seismicity, faults types, GPS displacement vectors and strain rates, and topography of the study area, and can therefore be considered a viable model

Towards a genealogy of migrant struggles and rescue. The memory of solidarity at the Alpine border

This article advances a genealogy of migrant struggles and citizens solidarity practices, with a focus on the French-Italian migrant passage. It contends that scholarship has mainly mobilised a spatial approach to migrant struggles, while the temporality of solidarity and the collective memory of struggles have remained under-theorised. Then, the article moves on by focusing on the French-Italian Alpine border and it analyses the longstanding history of migrants’ passages there and, jointly, the mobilisations that took place in that area over the last decades exploring how these sedimented a citizen collective memory of solidarity practices. The final section deals with the history of mountain rescue at the French-Italian Alpine border and shows how migrants were saved by volunteers. The piece concludes by arguing that an insight into the memory of migrant struggles and solidarity practices enables foregrounding the transversal alliances which have been built between migrants and citizens and unsettling binary opposition between the former and the latter

Case Report Isolated Fetal Ascites Secondary to Persistent Urogenital Sinus

Objective. To present a case of isolated ascites secondary due to urogenital abnormalities (urogenital sinus) without any other prenatal ultrasound marker. Method. A 36-year-old woman with prenatal isolated ascites delivered a female baby, weighing 2.285 g; ascites was drained at birth and the baby underwent several episodes of urinary retention prior to undergoing X-ray investigations. Results. A voiding cystourethrogram revealed a short urogenital sinus: a vesicostomy was performed. A vaginoscopy revealed double vagina with a large posterior vagina. A posterior sagittal anorectal pull-through with genitoplasty was performed at 2 years old with 1-year follow-up. Conclusions. Though rare, a urogenital abnormality is to be suspected in fetal ascites cases with negative viral tests and no cardiac anomalies. The most common ultrasound marker of such abnormalities (fluid filled cavity) may be missing because of complete drainage of urine through the tubes into peritoneum