The South Tibet Detachment System(STDS) is a flat normal fault that separates the Upper Himalaya Crystalline Sequence(UHCS) below from the Tethyan Sedimentary Sequence(TSS) above.Timing of deformations related to the ...The South Tibet Detachment System(STDS) is a flat normal fault that separates the Upper Himalaya Crystalline Sequence(UHCS) below from the Tethyan Sedimentary Sequence(TSS) above.Timing of deformations related to the STDS is critical to understand the mechanism and evolution of the Himalaya collision zone.The Nyalam detachment(ND)(～86°E) locates in the middle portion of STDS(81°-89°E).Dating of deformed leucocratic dykes that are most probably syntectonic at different depth beneath the ND,allow us to constrain the timing of deformation.(1) Dyke T11N37 located ～3500 m structurally below the ND emplaced at 27.4± 0.2 Ma;(2) Dyke T11N32 located ～1400 m structurally below the ND emplaced at 22.0±0.3 Ma;(3) T11N25 located within the top to the north STD shear zone,～150 m structurally below the ND,emplaced at 17.1±0.2 Ma.Combining ND footwall cooling history and T11N25 deformation temperature,we indicate a probable onset of top to the north deformation at ～16 Ma at this location.These results show an upward younging of the probable timing of onset of the deformation at different structural distance below the ND.We then propose a new model for deformation migration below the ND with deformation starting by pure shear deformation at depth prior to ～27.5 Ma that migrates upward at a rate of ～ 0.3 mm/a until ～18 Ma when deformation switches to top to the north shearing in the South Tibet Detachment shear zone(STDsz).As deformation on the ND stops at 14-13 Ma this would imply that significant top to the North motion would be limited to less than 5 Ma and would jeopardize the importance of lower channel flow.展开更多
目的探讨Nd：YAG激光玻璃体松解术治疗玻璃体Weiss环的效果。设计回顾性病例系列。研究对象以飞蚊症为主诉的、因玻璃体后脱离引起玻璃体漂浮物（Weiss环）的患者192例。方法选择2004年10月至2013年7月期间在厦门眼科中心接受激光玻璃...目的探讨Nd：YAG激光玻璃体松解术治疗玻璃体Weiss环的效果。设计回顾性病例系列。研究对象以飞蚊症为主诉的、因玻璃体后脱离引起玻璃体漂浮物（Weiss环）的患者192例。方法选择2004年10月至2013年7月期间在厦门眼科中心接受激光玻璃体松解术治疗玻璃体Weiss环患者192例（218眼）,术后随访3～36个月。术前进行视力、眼压、三面镜、裂隙灯照相、眼部B超、部分行眼底全景激光照相、眼底自发荧光检查及荧光素眼底血管造影检查,确定玻璃体Weiss环的位置及大小。Weiss环按直径范围分成：小环〈2 mm（119眼）,中环2～4 mm（80眼）,大环〉4 mm（19眼）。选用ZEISS公司生产的VISULAS YAGII或YAGIII激光,单脉冲模式,能量5～10 m J,将激光瞄准于造成症状的玻璃体漂浮物逐个击散、粉碎、气化。以症状是否完全消失、好转或无效用于评估治疗的效果,并观察是否有其他并发症。主要指标有效率、好转率、并发症。结果单个患者单次治疗总能量从56～2136 m J,平均为（961±354）m J。单次治疗时长4～31分钟,平均（18±5.2）分钟。166眼进行1次治疗,35眼2次治疗,17眼3次治疗。症状完全消失者182眼（83.49%）,其中小环为94.12%,中环77.50%,大环42.11%;好转者32眼（14.68%）,无效者为4眼（1.83%）。未观察到激光直接所致的视力或视野损害、晶状体损伤、眼压升高、视网膜血管损害、色素上皮自发荧光损害等。结论对于玻璃体Weiss环引起的飞蚊症,在严格选择治疗适应证下,Nd：YAG激光玻璃体松解术治疗是一种相对安全、简便、快捷的手段,尤其对较小漂浮物的患者效果更佳。展开更多
基金supported by Synthetic Investigation on the Environment in Polar Region (CHINARE2012-02-02)the SYSTER Program of the French INSU-CNRS
文摘The South Tibet Detachment System(STDS) is a flat normal fault that separates the Upper Himalaya Crystalline Sequence(UHCS) below from the Tethyan Sedimentary Sequence(TSS) above.Timing of deformations related to the STDS is critical to understand the mechanism and evolution of the Himalaya collision zone.The Nyalam detachment(ND)(～86°E) locates in the middle portion of STDS(81°-89°E).Dating of deformed leucocratic dykes that are most probably syntectonic at different depth beneath the ND,allow us to constrain the timing of deformation.(1) Dyke T11N37 located ～3500 m structurally below the ND emplaced at 27.4± 0.2 Ma;(2) Dyke T11N32 located ～1400 m structurally below the ND emplaced at 22.0±0.3 Ma;(3) T11N25 located within the top to the north STD shear zone,～150 m structurally below the ND,emplaced at 17.1±0.2 Ma.Combining ND footwall cooling history and T11N25 deformation temperature,we indicate a probable onset of top to the north deformation at ～16 Ma at this location.These results show an upward younging of the probable timing of onset of the deformation at different structural distance below the ND.We then propose a new model for deformation migration below the ND with deformation starting by pure shear deformation at depth prior to ～27.5 Ma that migrates upward at a rate of ～ 0.3 mm/a until ～18 Ma when deformation switches to top to the north shearing in the South Tibet Detachment shear zone(STDsz).As deformation on the ND stops at 14-13 Ma this would imply that significant top to the North motion would be limited to less than 5 Ma and would jeopardize the importance of lower channel flow.
文摘目的探讨Nd：YAG激光玻璃体松解术治疗玻璃体Weiss环的效果。设计回顾性病例系列。研究对象以飞蚊症为主诉的、因玻璃体后脱离引起玻璃体漂浮物（Weiss环）的患者192例。方法选择2004年10月至2013年7月期间在厦门眼科中心接受激光玻璃体松解术治疗玻璃体Weiss环患者192例（218眼）,术后随访3～36个月。术前进行视力、眼压、三面镜、裂隙灯照相、眼部B超、部分行眼底全景激光照相、眼底自发荧光检查及荧光素眼底血管造影检查,确定玻璃体Weiss环的位置及大小。Weiss环按直径范围分成：小环〈2 mm（119眼）,中环2～4 mm（80眼）,大环〉4 mm（19眼）。选用ZEISS公司生产的VISULAS YAGII或YAGIII激光,单脉冲模式,能量5～10 m J,将激光瞄准于造成症状的玻璃体漂浮物逐个击散、粉碎、气化。以症状是否完全消失、好转或无效用于评估治疗的效果,并观察是否有其他并发症。主要指标有效率、好转率、并发症。结果单个患者单次治疗总能量从56～2136 m J,平均为（961±354）m J。单次治疗时长4～31分钟,平均（18±5.2）分钟。166眼进行1次治疗,35眼2次治疗,17眼3次治疗。症状完全消失者182眼（83.49%）,其中小环为94.12%,中环77.50%,大环42.11%;好转者32眼（14.68%）,无效者为4眼（1.83%）。未观察到激光直接所致的视力或视野损害、晶状体损伤、眼压升高、视网膜血管损害、色素上皮自发荧光损害等。结论对于玻璃体Weiss环引起的飞蚊症,在严格选择治疗适应证下,Nd：YAG激光玻璃体松解术治疗是一种相对安全、简便、快捷的手段,尤其对较小漂浮物的患者效果更佳。
