Combined ductal and vascular injuries are awesome complications of pancreatic injury.We report on a 29-year-old male unrestrained driver who sustained a blunt abdominal injury from the steering wheel in a high velocit...Combined ductal and vascular injuries are awesome complications of pancreatic injury.We report on a 29-year-old male unrestrained driver who sustained a blunt abdominal injury from the steering wheel in a high velocity head-on car collision.He developed a pancreatic fistula,portosplenic venous thrombosis and sinistral portal hypertension as a result of complete duct disruption at the pancreatic neck.We describe a safe surgical strategy of spleen-preserving distal pancreatectomy after failed medical and endoscopic management.展开更多
There is a large ductile shear zone, 2 km wide and more than 350 km long, inthe South Qilian Mountains, western China. It is composed of volcanic, granitic and calcareousmylonites. The microstructures of the ductile s...There is a large ductile shear zone, 2 km wide and more than 350 km long, inthe South Qilian Mountains, western China. It is composed of volcanic, granitic and calcareousmylonites. The microstructures of the ductile shear zone show nearly E-W extending subverticalfoliation, horizontal and oblique stretching lineations, shearing sense from sinistral to obliquesinistral strike-slip from east to west, 'A' type folds and abundant granitic veins. Measuredlattice preferred orientations (LPOs) of the mylonitic and recrystallized quartz of the graniticmylonite in the west segment suggest a strong LPO characterized by the dominant slip systems (1010) formed at high temperature (>650 deg C). K-feldspar of the mylonite shows an ^(39)Ar/^(40)Arhigh-temperature plateau age of 243.3 +- 1.3 Ma, and biotite, 250.5 +- 0.5 Ma, which represent theformation age of the ductile shear zone. The ^(39)Ar/^(40)Ar plateau ages of 169.7 +- 0.3 Ma and160.6 +- 0.1 Ma and the ^(39)Ar/^(40)Ar isochron ages of 166.99 +- 2.37 Ma and 160.6 +- 0.1 Ma ofbiotites in the mylonite represent the subsequent deformation age. These ages indicate that thisductile shear zone is similar to the Altun and South Kunlun sinistral ductile shear zones in itsages of movement, formation, reactivation and duration.展开更多
BACKGROUND Sinistral portal hypertension associated with pancreatic pseudocysts is rare,often caused by extrinsic compression of splenic vein,the follow-up examinations by ultrasonography for early diagnosis are quiet...BACKGROUND Sinistral portal hypertension associated with pancreatic pseudocysts is rare,often caused by extrinsic compression of splenic vein,the follow-up examinations by ultrasonography for early diagnosis are quietly necessary since haematemesis,a life-threatening condition.Few studies have reported the ultrasonography findings of sinistral portal hypertension.CASE SUMMARY A 52-year-old man presented with acute abdominal pain after drinking,steatorrhea,weight loss and accidentally melena in the past 2 mo.He underwent ultrasound-guided fine needle aspiration in other hospital and diagnosed with pancreatic pseudocysts.Ultrasonography imaging,in our department,appeared as cystic heterogeneous hypoechoic area with the size of 4.7 cm×3.8 cm that located posterior to the body and tail of pancreas,adjacent to splenic vein associated with thrombosis resulted from compression.Spleen incrassated to approximately 7.3 cm,but no dilation of main portal vein was presented.Color Doppler Flow Imaging demonstrated the formation of splenic venous collateral,nevertheless no significantly flow signals was observed in splenic vein.Pulsed Doppler revealed that the peak velocity of splenic venous collateral was 18.4 cm/s with continuous waveform.Laparotomy confirmed sinistral portal hypertension associated with pancreatic pseudocysts,subsequently distal pancreatectomy combined with splenectomy and partial gastrectomy was performed.CONCLUSION It’s important clinically to know the ultrasound appearance of sinistral portal hypertension associated with pancreatic pseudocysts for sonographer and physician.展开更多
The Jiangshan-Shaoxing fault zone (JSFZ) was formed by the amalgamation of the Yangtze and Cathaysia blocks in the Neoproterozoic.Since the Paleozoic,the JSFZ has experienced three episodes of tectonic activities:t...The Jiangshan-Shaoxing fault zone (JSFZ) was formed by the amalgamation of the Yangtze and Cathaysia blocks in the Neoproterozoic.Since the Paleozoic,the JSFZ has experienced three episodes of tectonic activities:the Early Paleozoic ductile strike-slip shear,Early Mesozoic thrust,and the Late Mesozoic extension.展开更多
There are 18 gullies displaying sinistral contortions to different degrees along the western terminal segment about 10 km long of the active Daqingshan piedmont fault near the Donghe District, Baotou City. The contort...There are 18 gullies displaying sinistral contortions to different degrees along the western terminal segment about 10 km long of the active Daqingshan piedmont fault near the Donghe District, Baotou City. The contortion amount of gullies ranges from 20 m to 300 m. The contortion and length of the gullies are in direct proportion. The relation between piedmont terraces and gullies indicates that the gullies with upper reaches of about 1 ~ 5 km long and those smaller than one kilometer were formed at the end of Late Pleistocene and Holocene.Meanwhile, sandy gravel layer of alluvial-proluvial sediment on the upthrown wall is directly in contact with yellow clayey sand of the downthrown wall. During the Holocene, the sinistral strike-slip rate along the western terminal segment of the active Daqingshan piedmont fault reached 5 mm/a from age data of dislocated sediments. The evolutional mechanism of the active Daqingshan piedmont fault is also discussed in the paper.展开更多
The structural style, fault activity, strike-slip displacement, and the formation mechanism and hydrocarbon migration and accumulation in the center tectonic zone in the northeast Shaleitian Bulge of Zhangjiakou-Pengl...The structural style, fault activity, strike-slip displacement, and the formation mechanism and hydrocarbon migration and accumulation in the center tectonic zone in the northeast Shaleitian Bulge of Zhangjiakou-Penglai Fault Zone were studied by seismic attribute analysis, structural geometric analysis, fault activity analysis, structure evolution history and simulation of hydrocarbon migration, based on 3-D seismic and drilling data. The main results are as follows:(1) The study area is a superimposed tectonic zone, which experienced early(Paleocene and Eocene) extension and late(Oligocene and Pliocene-Quaternary) strike-slip and pull-apart.(2) The sinistral strike slip of the northeast Shaleitian Bulge of Zhangjiakou-Penglai Fault Zone went through two periods, Oligocene and Pliocene-Quaternary, and the Bohai section was active earlier than the inland section.(3) The sinistral strike slip displacement of Zhangjiakou-Penglai Fault is 4 km since Cenozoic, including 1 km in the Oligocene, and 3 km in the Pliocene-Quaternary.(4) The strike-slip movements have resulted in the increase of fault activity and basin-mountain restructure in the fault zone, also contributed to the formation of the central tectonic belt and the conjugate evolution in north-east structural belt.(5) The conjugate strike slip of the Zhangjiakou-Penglai Fault Zone dominated the migration and accumulation of hydrocarbon in shallow formations by controlling the injection points and segments of hydrocarbon from the deep layers to shallow layers.展开更多
Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic sur...Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic surfaces by using carbon fourteen (14C), cos- mogenic nuclides (10Be+26Al) and thermoluminescence (TL) methods, the Holocene sinistral slip rates on different segments of the Altyn Tagh Fault (ATF) are obtained. The slip rates reach 17.5 ±2 mm/a on the central and western segments west of Aksay Town, 11±3.5 mm/a on the Subei-Shibaocheng segment, 4.8±1.0 mm/a on the Sulehe segment and only 2.2±0.2 mm/a on the Kuantanshan segment, an easternmost segment of the ATF. The sudden change points for loss of sinistral slip rates are located at the Subei, Shibaocheng and Shulehe triple junctions where NW-trending active thrust faults splay from the ATF and propagate southeastward. Slip vector analyses indicate that the loss of the sinistral slip rates from west to east across a triple junction has structurally transformed into local crustal shortening perpendicular to the active thrust faults and strong uplifting of the thrust sheets to form the NW-trending Danghe Nanshan, Daxueshan and Qilianshan Ranges. Therefore, the eastward extrusion of the northern Qing- hai-Tibetan Plateau is limited and this is in accord with “the imbricated thrusting transforma- tion-limited extrusion model”.展开更多
The Ailaoshan-Red River(ASRR) shear zone in SW China represents an important discontinuity believed to have accommodated eastward extrusion of the Tibetan Plateau in response to the collision of the Indian and Euras...The Ailaoshan-Red River(ASRR) shear zone in SW China represents an important discontinuity believed to have accommodated eastward extrusion of the Tibetan Plateau in response to the collision of the Indian and Eurasian plates. The onset timing and duration of the ASRR sinistral strike-slip shearing have been hotly disputed. In this paper we present new zircon LA-ICP-MS U-Pb geochronological data from six syntectonic granitic mylonite and leucosomes samples from the ASRR shear zone. Our data reveal a metamorphic age of ~40 Ma, most likely suggesting the maximum age of the shearing initiation. Rocks showing syn-kinematic signatures yield crystallization ages of 38–22 Ma, with inherited components ranging from 716 to 108 Ma. These results, together with existing geological and geochronological data, indicate that the sinistral shearing along the ASRR zone probably began at 40 Ma, mainly activated at 29–22 Ma and lasted at least to ~22 Ma. Our data suggest a continuous extrusion between the Indochina and South China blocks during ~35–17 Ma. The ASRR sinistral shearing has accommodated large scale eastward displacement of the southeastern Tibetan syntaxis, and is likely responsible for the opening of the South China Sea.展开更多
On September 28, 2018, a Mw7.5 earthquake occurred near Sulawesi, Indonesia as a result of strike-slip faulting at shallow depth within the interior of the Molucca Sea Microplate that forms a part of the broader Sunda...On September 28, 2018, a Mw7.5 earthquake occurred near Sulawesi, Indonesia as a result of strike-slip faulting at shallow depth within the interior of the Molucca Sea Microplate that forms a part of the broader Sunda Plate. Focal mechanism solutions and distribution for the earthquakes indicate rupture occurred on a left-lateral NNW-SSE-to N-S-striking fault. This region has been characterized by complex tectonics in which motions of numerous small microplates are accommodating large-scale convergence between the Australia, Sunda, Pacific and Philippine Sea plates. In this paper, the Coulomb stress calculation verified the WNW-, nearly E-W-trending sinistral strike slip receiver fault in Sulawesi, which is consistent with the giant sinisterly strike-slip fault system across New Guinea, Pacific Tectonic System and the Tethys Tectonic System caused by the oblique convergence. The result has been reconciled within the modern GPS velocity field.展开更多
Sinistral portal hypertension (SPH) is usually caused by pancreatic pathology and is characterized bysplenic vein thrombosis with or without portal vein thrombosis.1 The increased pressure caused by splenic vein occ...Sinistral portal hypertension (SPH) is usually caused by pancreatic pathology and is characterized bysplenic vein thrombosis with or without portal vein thrombosis.1 The increased pressure caused by splenic vein occlusion is transmitted via the short gastric and gastroepiploic veins to the portal system. The reversal of blood flow in the left gastric vein results in gastric varices. In patiems with SPH, especially those with occlusion of both the splenic and portal veins, the main or even the only pathway of splenic venous return to the portal vein is via the gastric varices, and these patiems require special management during gastric surgery.展开更多
BACKGROUND Splenic vein thrombosis is a known complication of pancreatitis.It can lead to increased blood flow through mesenteric collaterals.This segmental hypertension may result in the development of colonic varice...BACKGROUND Splenic vein thrombosis is a known complication of pancreatitis.It can lead to increased blood flow through mesenteric collaterals.This segmental hypertension may result in the development of colonic varices(CV)with a high risk of severe gastrointestinal bleeding.While clear guidelines for treatment are lacking,splenectomy or splenic artery embolization are often used to treat bleeding.Splenic vein stenting has been shown to be a safe option.CASE SUMMARY A 45-year-old female patient was admitted due to recurrent gastrointestinal bleeding.She was anemic with a hemoglobin of 8.0 g/dL.As a source of bleeding,CV were identified.Computed tomography scans revealed thrombotic occlusion of the splenic vein,presumably as a result of a severe acute pancreatitis 8 years prior.In a selective angiography,a dilated mesenterial collateral leading from the spleen to enlarged vessels in the right colonic flexure and draining into the superior mesenteric vein could be confirmed.The hepatic venous pressure gradient was within normal range.In an interdisciplinary board,transhepatic recanalization of the splenic vein via balloon dilatation and consecutive stenting,as well as coiling of the aberrant veins was discussed and successfully performed.Consecutive evaluation revealed complete regression of CV and splenomegaly as well as normalization of the red blood cell count during follow-up.CONCLUSION Recanalization and stenting of splenic vein thrombosis might be considered in patients with gastrointestinal bleeding due to CV.However,a multidisciplinary approach with a thorough workup and discussion of individualized therapeutic strategies is crucial in these difficult to treat patients.展开更多
The existing genetic models of the South China Sea(SCS)include an extrusion model of the Indochina Peninsula,a back-arc extension model,and a subduction and dragging model of the Proto-South China Sea(PSCS).However,no...The existing genetic models of the South China Sea(SCS)include an extrusion model of the Indochina Peninsula,a back-arc extension model,and a subduction and dragging model of the Proto-South China Sea(PSCS).However,none of these models has been universally accepted because they do not fully match a large number of geological phenomena and facts.By examining the regional tectonics and integrating them with measured data for the SCS,in this study,a back-arc spreading-sinistral shear model is proposed.It is suggested that the SCS is a back-arc basin formed by northward subduction of the PSCS and its formation was triggered by left-lateral strike-slip motion due to the northward drift of the Philippine Sea Plate.The left-lateral strike-slip fault on the western margin caused by the Indo-Eurasian collision changed the direction of the Southwest Sub-basin's spreading axis from nearly E–W to NE–SW,and subduction retreat caused the spreading ridge to jump southward.This study summarizes the evolution of the SCS and adjacent regions since the Late Mesozoic.展开更多
The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours incl...The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours including thrusting, sinistral strike slip and normal slip. The strike slip and normal slip mainly occurred in the Cretaceous—Cenozoic and Plio-Quaternary respectively, whereas the thrusting was a deformation event that has played a dominant role since the late Palaeozoic (for a duration of about 305 Ma). The formation of the Altun fault was related to strong inhomogeneous deformation of the massifs on its two sides (in the hinterland of the Altun Mountains contractional deformation predominated and in the Qilian massif thrust propagation was dominant). The fault experienced a dynamic process of successive break-up and connection of its segments and gradual propagation, which was synchronous with the development of an overstep thrust sequence in the Qilian massif and the uplift of the Qinghai-Tibet plateau. With southward propagation of the thrust sequence and continued uplift of the plateau, the NE tip of the Altun fault moved in a NE direction, while the SW tip grew in a SW direction.展开更多
How the Altyn Tagh fault(ATF) extends eastwards is one of the key questions in the study of the growth of the Qinghai–Tibetan Plateau. Detailed fieldwork at the easternmost part of the ATF shows that the ATF extends ...How the Altyn Tagh fault(ATF) extends eastwards is one of the key questions in the study of the growth of the Qinghai–Tibetan Plateau. Detailed fieldwork at the easternmost part of the ATF shows that the ATF extends eastward and bypasses the Kuantan Mountain;it does not stop at the Kuantan Mountain, but connects with the northern Heishan fault in the east. The ATF does not enter the Alxa Block but extends eastward along the southern Alxa Block to the Jintanan Mountain. The Heishan fault is not a thrust fault but a sinistral strike-slip fault with a component of thrusting and is a part of the ATF. Further to the east, the Heishan fault may connect with the Jintananshan fault. A typical strike-slip duplex develops in the easternmost part of the ATF. The cut and deformed Quaternary sediments and displaced present gullies along the easternmost ATF indicate that it is an active fault. The local highest Mountain(i.e., the Kuantan Mountain) in the region forms in a restraining bend of the ATF due to the thrusting and uplifting. The northward growth of the Qinghai–Tibetan Plateau and the active deformation in South Mongolia are realized by sinistral strike-slipping on a series of NE–SW-trending faults and thrusting in restraining bends along the strike-slip faults with the northeastward motion of blocks between these faults.展开更多
Tancbeng-Lujiang fault system is one of the largest strike-slip fault systems in eastern Asia.It extends southward to Beibuwan Bay to the west of Hainan Island and northward through Lujiang of Anhui Province, Tancheng...Tancbeng-Lujiang fault system is one of the largest strike-slip fault systems in eastern Asia.It extends southward to Beibuwan Bay to the west of Hainan Island and northward through Lujiang of Anhui Province, Tancheng of Shandong Province and Luobei of Heilongjiang Province in China to the territory of Russia. Its formation is related to the subduction of Kula-Pacific plate to the Asian continent. It is oriented approximately parallel to the eastern edge of Asia. It is dominated by the sinistral translation from Jurassic to Eocene and then by dextrose strike-slip. It has the following characters: (1)clear linear character; (2)sharp dip angle, usually changing between normal and reverse faults; (3)showing braided structure on the plan and flower structure in section;(4)alternated by uplifts and sags along the fault belt; (5)many stages of the eruptions of alkaline to calc-alkaline basalt magma along the fault belt; and (6) frequent activities of earthquakes along the fault belt. Its control over the oil-gas distribution is shown by the following racts: (1) the formation of many oil-bearing fault depressions; (2) the increase of the basin area it has passed through, thus increasing the basin's subsiding quantity and the oil reservoirs; and (3)the formation of many kinds of oil-gas trap structures.展开更多
A set of ENE\|trending fault which locates in the rigid Tarim massif and flexible Qilian massif in the same dynamic system of the uplift of the Qinghai—Tibetan plateau is referred to as the Altun Fault (ALF). ALF dis...A set of ENE\|trending fault which locates in the rigid Tarim massif and flexible Qilian massif in the same dynamic system of the uplift of the Qinghai—Tibetan plateau is referred to as the Altun Fault (ALF). ALF displays a linear geometry or a geometry of overlapping of linear and arcuate segments and a growth and development process of the breakdown segment\|by\|segment, connection segment\|by\|segment and propagation gradually (northeastward migration of the northeast tip, southwestward growth of the southwest tip). The formation of the Altun fault began in the middle or upper Carboniferous. It was characteristic of the sinistral strike\|slip\|thrust before Eocene, of the thrust\|sinistral strike\|slip during Oligocene—Miocene, and of the normal slip, and thrust\|sinistral strike\|slip simultaneously since Miocene.展开更多
The NE-striking Jiamusi-Yitong fault zone(JYFZ) is the most important branch in the northern segment of the Tancheng-Lujiang fault zone. The precise shearing time of its large-scale sinistral strike-slip has yet to de...The NE-striking Jiamusi-Yitong fault zone(JYFZ) is the most important branch in the northern segment of the Tancheng-Lujiang fault zone. The precise shearing time of its large-scale sinistral strike-slip has yet to determined and must be constrained. Detailed field investigations and comprehensive analyses show that strike-slip faults or ductile shear belts exist as origination structures along the western region of Yitong Graben. The strike of the shear belts trend to the NE-SW with steep mylonitic foliation. The zircon U-Pb dating result for the granite was 264.1±1 Ma in the ductile shear belt of the JYFZ. The microstructural observation(rotated feldspar porphyroclasts, S-C fabrics, and quartz c-axis fabrics, etc.) demonstrated the sinistral shearing of the ductile shear zones. Moreover, the recrystallized quartz types show a transitional stage of the subgrain rotation toward the recrystallization of the grain boundary migration(SR-GBM). Therefore, we suggest that the metamorphic grade of the shear zone in the ductile shear zones should have reached high greenschist facies conditions, and the deformation temperatures should approximately 450-500°C, which is obviously higher than the blocking temperature of muscovite(300-400°C). Hence, the ^40Ar/^39Ar isochron age of muscovite from ductile shear zones should be a cooling age(162.7±1 Ma). We infer that the sinistral strike-slipping event at the JYFZ occurred in the late Jurassic period, and it was further inferred from the ages of the main geological events in this region that the second sinistral strike-slip age of the Tancheng-Lujiang fault zone occurred during the period of tectonic movements in the Circum-Pacific tectonic domain. This discovery also indicates the age of the Tancheng-Lujiang fault zone that stretches to northeastern China. The initiation of the JYFZ in the late Jurassic is related to the speed and direction of oblique subduction of the west Pacific Plate under the Eurasian continent and is responsible for collision during the Jurassic period.展开更多
Data on the origin and morphology of lake depressions caused by volcanism are scarce in Mongolia.Previous studies focused on climate change patterns based on Terkhiin Tsagaan Lake sediment.We present a result of exist...Data on the origin and morphology of lake depressions caused by volcanism are scarce in Mongolia.Previous studies focused on climate change patterns based on Terkhiin Tsagaan Lake sediment.We present a result of existing reconstructions of lake depression development and changes in the hydrology system during the Khorgo volcanic activation and the Holocene environmental change.A depression of the Terkhiin Tsagaan Lake is formed by a lava flow barrier from the Khorgo volcano.However,the Khorgo volcanic eruption and the lake depression that could shape a large lake have arisen instead from a fault.The morphometric analysis and field measurements indicate that the derivation of the Terkhiin Tsagaan Lake depression and Khorgo volcano may have evolved from movement on a sinistral strike-slip fault,which is about 70 km long.The southern mountains and rivers were displaced from northwest to southeast along the Terkh Fault.The offset along Terkh Fault is 4.02-5.28 km in the depression of the Terkhiin Tsagaan Lake.After movement,a wide valley of the Terkh River developed in the present landscape.The active Khorgo Volcano formed along the Khorgo Fault.The Terkhiin Tsagaan Lake is formed by blocked water from the PaleoTerkh River after lava damming from the Khorgo Volcano.The initial paleo-lake area was about 195.7km^(2),which was three times larger than the modern lake.The current water volume of the Terkhiin Tsagaan Lake is 0.351 km^(3) while the volume of the paleo-lake was 2.248 km^(3).Based on this volume indicator the paleo-lake was 6.4 times larger than the current lake.Overflowing water from the lake depression formed the Suman River by a drying canyon through the lava plateau,but the canyon is along the Terkh Fault.Changes in the water volume of Terkhiin Tsagaan Lake and erosion of Suman River canyon are inversely related to each other.We present the morphometric relationships between the lava plateau of Khorgo Volcano and development of Terkhiin Tsagaan Lake depression.展开更多
The Louzidian normal fault occurs as the eastern detachment fault of the Kalaqin metamorphic core complex. Field observations and microstructural analyses reveal that the Louzidian-Dachengzi ductile shear zone develop...The Louzidian normal fault occurs as the eastern detachment fault of the Kalaqin metamorphic core complex. Field observations and microstructural analyses reveal that the Louzidian-Dachengzi ductile shear zone developed in its lower-plate was genetically related to sinistral strike-slips and extensional faulting. Two samples from this ductile shear zone yield 40Ar-39Ar plateau ages of 133 Ma (Bi) and 126 Ma (Kp), which are concordant with their isochron ages. The plateau age of 133 Ma (Bi) records the formation age of the ductile shear zone. The inconsistent relationship between the earlier strike-slip ductile shear zone and the later normal fault makes the Kalaqin Quasi-metamorphic core complex distinctive from Cordil-leran nietamorphic core complex. These ages provide important geochronological data for putting constraints on the formation age and genesis of such ductile shear zones.展开更多
Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results ...Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results document two thermal events during the sinistral shear. The early event (12-10 Ma) corresponds to rapid cooling of the Zheduoshan granitic massif from above 700℃ to below 350℃. The late event (5-3.5 Ma) corresponds to cooling of granites intruded along the eastern side of the fault zone. These dating results provide important thermochronological constraint on the timing of late Cenozoic eastward extrusion of the Chuan-Dian Block in the SE Tibetan margin.展开更多
文摘Combined ductal and vascular injuries are awesome complications of pancreatic injury.We report on a 29-year-old male unrestrained driver who sustained a blunt abdominal injury from the steering wheel in a high velocity head-on car collision.He developed a pancreatic fistula,portosplenic venous thrombosis and sinistral portal hypertension as a result of complete duct disruption at the pancreatic neck.We describe a safe surgical strategy of spleen-preserving distal pancreatectomy after failed medical and endoscopic management.
基金the keyproject of the National Natural Science Foundation of China,“Composition and Orogenic Process of Qilian Mountain”(Project No.4973020)the key project of theformer Ministry of Geology and Mineral Resources+1 种基金The Basic Framework and Lithosphere Shearing of Qilian-Altun Mountains”(1996-2000) the projectof the Key Fundamental Research,Development and Planning(No.G 1998040800).
文摘There is a large ductile shear zone, 2 km wide and more than 350 km long, inthe South Qilian Mountains, western China. It is composed of volcanic, granitic and calcareousmylonites. The microstructures of the ductile shear zone show nearly E-W extending subverticalfoliation, horizontal and oblique stretching lineations, shearing sense from sinistral to obliquesinistral strike-slip from east to west, 'A' type folds and abundant granitic veins. Measuredlattice preferred orientations (LPOs) of the mylonitic and recrystallized quartz of the graniticmylonite in the west segment suggest a strong LPO characterized by the dominant slip systems (1010) formed at high temperature (>650 deg C). K-feldspar of the mylonite shows an ^(39)Ar/^(40)Arhigh-temperature plateau age of 243.3 +- 1.3 Ma, and biotite, 250.5 +- 0.5 Ma, which represent theformation age of the ductile shear zone. The ^(39)Ar/^(40)Ar plateau ages of 169.7 +- 0.3 Ma and160.6 +- 0.1 Ma and the ^(39)Ar/^(40)Ar isochron ages of 166.99 +- 2.37 Ma and 160.6 +- 0.1 Ma ofbiotites in the mylonite represent the subsequent deformation age. These ages indicate that thisductile shear zone is similar to the Altun and South Kunlun sinistral ductile shear zones in itsages of movement, formation, reactivation and duration.
文摘BACKGROUND Sinistral portal hypertension associated with pancreatic pseudocysts is rare,often caused by extrinsic compression of splenic vein,the follow-up examinations by ultrasonography for early diagnosis are quietly necessary since haematemesis,a life-threatening condition.Few studies have reported the ultrasonography findings of sinistral portal hypertension.CASE SUMMARY A 52-year-old man presented with acute abdominal pain after drinking,steatorrhea,weight loss and accidentally melena in the past 2 mo.He underwent ultrasound-guided fine needle aspiration in other hospital and diagnosed with pancreatic pseudocysts.Ultrasonography imaging,in our department,appeared as cystic heterogeneous hypoechoic area with the size of 4.7 cm×3.8 cm that located posterior to the body and tail of pancreas,adjacent to splenic vein associated with thrombosis resulted from compression.Spleen incrassated to approximately 7.3 cm,but no dilation of main portal vein was presented.Color Doppler Flow Imaging demonstrated the formation of splenic venous collateral,nevertheless no significantly flow signals was observed in splenic vein.Pulsed Doppler revealed that the peak velocity of splenic venous collateral was 18.4 cm/s with continuous waveform.Laparotomy confirmed sinistral portal hypertension associated with pancreatic pseudocysts,subsequently distal pancreatectomy combined with splenectomy and partial gastrectomy was performed.CONCLUSION It’s important clinically to know the ultrasound appearance of sinistral portal hypertension associated with pancreatic pseudocysts for sonographer and physician.
基金funded by the National Science and Technology Major Project (2008ZX05005–001)China Geological Survey Project (Grant No.1212011120160)
文摘The Jiangshan-Shaoxing fault zone (JSFZ) was formed by the amalgamation of the Yangtze and Cathaysia blocks in the Neoproterozoic.Since the Paleozoic,the JSFZ has experienced three episodes of tectonic activities:the Early Paleozoic ductile strike-slip shear,Early Mesozoic thrust,and the Late Mesozoic extension.
基金the Joint Seismological Science Foundation.Contribution No.2000A 0005, Institute of Crustal Dynamics, China Seismological Bureau, China.
文摘There are 18 gullies displaying sinistral contortions to different degrees along the western terminal segment about 10 km long of the active Daqingshan piedmont fault near the Donghe District, Baotou City. The contortion amount of gullies ranges from 20 m to 300 m. The contortion and length of the gullies are in direct proportion. The relation between piedmont terraces and gullies indicates that the gullies with upper reaches of about 1 ~ 5 km long and those smaller than one kilometer were formed at the end of Late Pleistocene and Holocene.Meanwhile, sandy gravel layer of alluvial-proluvial sediment on the upthrown wall is directly in contact with yellow clayey sand of the downthrown wall. During the Holocene, the sinistral strike-slip rate along the western terminal segment of the active Daqingshan piedmont fault reached 5 mm/a from age data of dislocated sediments. The evolutional mechanism of the active Daqingshan piedmont fault is also discussed in the paper.
基金Supported by the China National Science and Technology Major Project(2016ZX05024-003)
文摘The structural style, fault activity, strike-slip displacement, and the formation mechanism and hydrocarbon migration and accumulation in the center tectonic zone in the northeast Shaleitian Bulge of Zhangjiakou-Penglai Fault Zone were studied by seismic attribute analysis, structural geometric analysis, fault activity analysis, structure evolution history and simulation of hydrocarbon migration, based on 3-D seismic and drilling data. The main results are as follows:(1) The study area is a superimposed tectonic zone, which experienced early(Paleocene and Eocene) extension and late(Oligocene and Pliocene-Quaternary) strike-slip and pull-apart.(2) The sinistral strike slip of the northeast Shaleitian Bulge of Zhangjiakou-Penglai Fault Zone went through two periods, Oligocene and Pliocene-Quaternary, and the Bohai section was active earlier than the inland section.(3) The sinistral strike slip displacement of Zhangjiakou-Penglai Fault is 4 km since Cenozoic, including 1 km in the Oligocene, and 3 km in the Pliocene-Quaternary.(4) The strike-slip movements have resulted in the increase of fault activity and basin-mountain restructure in the fault zone, also contributed to the formation of the central tectonic belt and the conjugate evolution in north-east structural belt.(5) The conjugate strike slip of the Zhangjiakou-Penglai Fault Zone dominated the migration and accumulation of hydrocarbon in shallow formations by controlling the injection points and segments of hydrocarbon from the deep layers to shallow layers.
基金zupported by the Nati onal Natural Science Foundation ofChina(Gramt No.49972070).
文摘Based on technical processing of high-resolution SPOT images and aerophotos, detailed mapping of offset landforms in combination with field examination and displacement measurement, and dating of offset geomorphic surfaces by using carbon fourteen (14C), cos- mogenic nuclides (10Be+26Al) and thermoluminescence (TL) methods, the Holocene sinistral slip rates on different segments of the Altyn Tagh Fault (ATF) are obtained. The slip rates reach 17.5 ±2 mm/a on the central and western segments west of Aksay Town, 11±3.5 mm/a on the Subei-Shibaocheng segment, 4.8±1.0 mm/a on the Sulehe segment and only 2.2±0.2 mm/a on the Kuantanshan segment, an easternmost segment of the ATF. The sudden change points for loss of sinistral slip rates are located at the Subei, Shibaocheng and Shulehe triple junctions where NW-trending active thrust faults splay from the ATF and propagate southeastward. Slip vector analyses indicate that the loss of the sinistral slip rates from west to east across a triple junction has structurally transformed into local crustal shortening perpendicular to the active thrust faults and strong uplifting of the thrust sheets to form the NW-trending Danghe Nanshan, Daxueshan and Qilianshan Ranges. Therefore, the eastward extrusion of the northern Qing- hai-Tibetan Plateau is limited and this is in accord with “the imbricated thrusting transforma- tion-limited extrusion model”.
基金Supported by the National Basic Research Program of China(No.2014CB440901)the China National Natural Science Foundation(No.41190073)the Fundamental Research Funds for the Central Universities to SYSU
文摘The Ailaoshan-Red River(ASRR) shear zone in SW China represents an important discontinuity believed to have accommodated eastward extrusion of the Tibetan Plateau in response to the collision of the Indian and Eurasian plates. The onset timing and duration of the ASRR sinistral strike-slip shearing have been hotly disputed. In this paper we present new zircon LA-ICP-MS U-Pb geochronological data from six syntectonic granitic mylonite and leucosomes samples from the ASRR shear zone. Our data reveal a metamorphic age of ~40 Ma, most likely suggesting the maximum age of the shearing initiation. Rocks showing syn-kinematic signatures yield crystallization ages of 38–22 Ma, with inherited components ranging from 716 to 108 Ma. These results, together with existing geological and geochronological data, indicate that the sinistral shearing along the ASRR zone probably began at 40 Ma, mainly activated at 29–22 Ma and lasted at least to ~22 Ma. Our data suggest a continuous extrusion between the Indochina and South China blocks during ~35–17 Ma. The ASRR sinistral shearing has accommodated large scale eastward displacement of the southeastern Tibetan syntaxis, and is likely responsible for the opening of the South China Sea.
基金National Programme on Global Change and Air-Sea Interaction, State Oceanic Administration (GASI-GEOGE-01)National Key Research and Development Program of China (2017YFC0601401 and 2016YFC0601002)+1 种基金supported by Aoshan Talents Program Supported by Qingdao National Laboratory for Marine Science and Technology to Prof. Sanzhong Li (2015ASTP-0S10)the Taishan Scholar Program to Prof. Sanzhong Li
文摘On September 28, 2018, a Mw7.5 earthquake occurred near Sulawesi, Indonesia as a result of strike-slip faulting at shallow depth within the interior of the Molucca Sea Microplate that forms a part of the broader Sunda Plate. Focal mechanism solutions and distribution for the earthquakes indicate rupture occurred on a left-lateral NNW-SSE-to N-S-striking fault. This region has been characterized by complex tectonics in which motions of numerous small microplates are accommodating large-scale convergence between the Australia, Sunda, Pacific and Philippine Sea plates. In this paper, the Coulomb stress calculation verified the WNW-, nearly E-W-trending sinistral strike slip receiver fault in Sulawesi, which is consistent with the giant sinisterly strike-slip fault system across New Guinea, Pacific Tectonic System and the Tethys Tectonic System caused by the oblique convergence. The result has been reconciled within the modern GPS velocity field.
文摘Sinistral portal hypertension (SPH) is usually caused by pancreatic pathology and is characterized bysplenic vein thrombosis with or without portal vein thrombosis.1 The increased pressure caused by splenic vein occlusion is transmitted via the short gastric and gastroepiploic veins to the portal system. The reversal of blood flow in the left gastric vein results in gastric varices. In patiems with SPH, especially those with occlusion of both the splenic and portal veins, the main or even the only pathway of splenic venous return to the portal vein is via the gastric varices, and these patiems require special management during gastric surgery.
文摘BACKGROUND Splenic vein thrombosis is a known complication of pancreatitis.It can lead to increased blood flow through mesenteric collaterals.This segmental hypertension may result in the development of colonic varices(CV)with a high risk of severe gastrointestinal bleeding.While clear guidelines for treatment are lacking,splenectomy or splenic artery embolization are often used to treat bleeding.Splenic vein stenting has been shown to be a safe option.CASE SUMMARY A 45-year-old female patient was admitted due to recurrent gastrointestinal bleeding.She was anemic with a hemoglobin of 8.0 g/dL.As a source of bleeding,CV were identified.Computed tomography scans revealed thrombotic occlusion of the splenic vein,presumably as a result of a severe acute pancreatitis 8 years prior.In a selective angiography,a dilated mesenterial collateral leading from the spleen to enlarged vessels in the right colonic flexure and draining into the superior mesenteric vein could be confirmed.The hepatic venous pressure gradient was within normal range.In an interdisciplinary board,transhepatic recanalization of the splenic vein via balloon dilatation and consecutive stenting,as well as coiling of the aberrant veins was discussed and successfully performed.Consecutive evaluation revealed complete regression of CV and splenomegaly as well as normalization of the red blood cell count during follow-up.CONCLUSION Recanalization and stenting of splenic vein thrombosis might be considered in patients with gastrointestinal bleeding due to CV.However,a multidisciplinary approach with a thorough workup and discussion of individualized therapeutic strategies is crucial in these difficult to treat patients.
基金funded by the projects of the China Geological Survey(DD20160138,GZH201300502,DD20190378)the Major Special Project for talent team introduction of the Southern Marine Science and Engineering Guang Dong Laboratory(Guang Zhou)(GML2019ZD0207)。
文摘The existing genetic models of the South China Sea(SCS)include an extrusion model of the Indochina Peninsula,a back-arc extension model,and a subduction and dragging model of the Proto-South China Sea(PSCS).However,none of these models has been universally accepted because they do not fully match a large number of geological phenomena and facts.By examining the regional tectonics and integrating them with measured data for the SCS,in this study,a back-arc spreading-sinistral shear model is proposed.It is suggested that the SCS is a back-arc basin formed by northward subduction of the PSCS and its formation was triggered by left-lateral strike-slip motion due to the northward drift of the Philippine Sea Plate.The left-lateral strike-slip fault on the western margin caused by the Indo-Eurasian collision changed the direction of the Southwest Sub-basin's spreading axis from nearly E–W to NE–SW,and subduction retreat caused the spreading ridge to jump southward.This study summarizes the evolution of the SCS and adjacent regions since the Late Mesozoic.
文摘The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours including thrusting, sinistral strike slip and normal slip. The strike slip and normal slip mainly occurred in the Cretaceous—Cenozoic and Plio-Quaternary respectively, whereas the thrusting was a deformation event that has played a dominant role since the late Palaeozoic (for a duration of about 305 Ma). The formation of the Altun fault was related to strong inhomogeneous deformation of the massifs on its two sides (in the hinterland of the Altun Mountains contractional deformation predominated and in the Qilian massif thrust propagation was dominant). The fault experienced a dynamic process of successive break-up and connection of its segments and gradual propagation, which was synchronous with the development of an overstep thrust sequence in the Qilian massif and the uplift of the Qinghai-Tibet plateau. With southward propagation of the thrust sequence and continued uplift of the plateau, the NE tip of the Altun fault moved in a NE direction, while the SW tip grew in a SW direction.
基金funded by the National Natural Science Foundation of China(Nos.41972224,41572190)the National Key Research and Development Program of China from the Ministry of Science and Technology of China(No.2017YFC0601301)the China Geological Survey(DD20190004)。
文摘How the Altyn Tagh fault(ATF) extends eastwards is one of the key questions in the study of the growth of the Qinghai–Tibetan Plateau. Detailed fieldwork at the easternmost part of the ATF shows that the ATF extends eastward and bypasses the Kuantan Mountain;it does not stop at the Kuantan Mountain, but connects with the northern Heishan fault in the east. The ATF does not enter the Alxa Block but extends eastward along the southern Alxa Block to the Jintanan Mountain. The Heishan fault is not a thrust fault but a sinistral strike-slip fault with a component of thrusting and is a part of the ATF. Further to the east, the Heishan fault may connect with the Jintananshan fault. A typical strike-slip duplex develops in the easternmost part of the ATF. The cut and deformed Quaternary sediments and displaced present gullies along the easternmost ATF indicate that it is an active fault. The local highest Mountain(i.e., the Kuantan Mountain) in the region forms in a restraining bend of the ATF due to the thrusting and uplifting. The northward growth of the Qinghai–Tibetan Plateau and the active deformation in South Mongolia are realized by sinistral strike-slipping on a series of NE–SW-trending faults and thrusting in restraining bends along the strike-slip faults with the northeastward motion of blocks between these faults.
文摘Tancbeng-Lujiang fault system is one of the largest strike-slip fault systems in eastern Asia.It extends southward to Beibuwan Bay to the west of Hainan Island and northward through Lujiang of Anhui Province, Tancheng of Shandong Province and Luobei of Heilongjiang Province in China to the territory of Russia. Its formation is related to the subduction of Kula-Pacific plate to the Asian continent. It is oriented approximately parallel to the eastern edge of Asia. It is dominated by the sinistral translation from Jurassic to Eocene and then by dextrose strike-slip. It has the following characters: (1)clear linear character; (2)sharp dip angle, usually changing between normal and reverse faults; (3)showing braided structure on the plan and flower structure in section;(4)alternated by uplifts and sags along the fault belt; (5)many stages of the eruptions of alkaline to calc-alkaline basalt magma along the fault belt; and (6) frequent activities of earthquakes along the fault belt. Its control over the oil-gas distribution is shown by the following racts: (1) the formation of many oil-bearing fault depressions; (2) the increase of the basin area it has passed through, thus increasing the basin's subsiding quantity and the oil reservoirs; and (3)the formation of many kinds of oil-gas trap structures.
文摘A set of ENE\|trending fault which locates in the rigid Tarim massif and flexible Qilian massif in the same dynamic system of the uplift of the Qinghai—Tibetan plateau is referred to as the Altun Fault (ALF). ALF displays a linear geometry or a geometry of overlapping of linear and arcuate segments and a growth and development process of the breakdown segment\|by\|segment, connection segment\|by\|segment and propagation gradually (northeastward migration of the northeast tip, southwestward growth of the southwest tip). The formation of the Altun fault began in the middle or upper Carboniferous. It was characteristic of the sinistral strike\|slip\|thrust before Eocene, of the thrust\|sinistral strike\|slip during Oligocene—Miocene, and of the normal slip, and thrust\|sinistral strike\|slip simultaneously since Miocene.
基金funded by the National Key R&D Program of China (Grant No. 2017YFC0601300–01)973 Program (Grant 2013CB429802)NSFC (Grant 41102140,41303175)
文摘The NE-striking Jiamusi-Yitong fault zone(JYFZ) is the most important branch in the northern segment of the Tancheng-Lujiang fault zone. The precise shearing time of its large-scale sinistral strike-slip has yet to determined and must be constrained. Detailed field investigations and comprehensive analyses show that strike-slip faults or ductile shear belts exist as origination structures along the western region of Yitong Graben. The strike of the shear belts trend to the NE-SW with steep mylonitic foliation. The zircon U-Pb dating result for the granite was 264.1±1 Ma in the ductile shear belt of the JYFZ. The microstructural observation(rotated feldspar porphyroclasts, S-C fabrics, and quartz c-axis fabrics, etc.) demonstrated the sinistral shearing of the ductile shear zones. Moreover, the recrystallized quartz types show a transitional stage of the subgrain rotation toward the recrystallization of the grain boundary migration(SR-GBM). Therefore, we suggest that the metamorphic grade of the shear zone in the ductile shear zones should have reached high greenschist facies conditions, and the deformation temperatures should approximately 450-500°C, which is obviously higher than the blocking temperature of muscovite(300-400°C). Hence, the ^40Ar/^39Ar isochron age of muscovite from ductile shear zones should be a cooling age(162.7±1 Ma). We infer that the sinistral strike-slipping event at the JYFZ occurred in the late Jurassic period, and it was further inferred from the ages of the main geological events in this region that the second sinistral strike-slip age of the Tancheng-Lujiang fault zone occurred during the period of tectonic movements in the Circum-Pacific tectonic domain. This discovery also indicates the age of the Tancheng-Lujiang fault zone that stretches to northeastern China. The initiation of the JYFZ in the late Jurassic is related to the speed and direction of oblique subduction of the west Pacific Plate under the Eurasian continent and is responsible for collision during the Jurassic period.
基金funded by the National University of Mongolia(P2021-4178)funded by the National Natural Science Foundation of China(nos.41961144020,91755213,41967052)+1 种基金additional funding by 111 Project(BP0719022)MOST Special Fund MSFGPMR02-3 from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(Wuhan),China。
文摘Data on the origin and morphology of lake depressions caused by volcanism are scarce in Mongolia.Previous studies focused on climate change patterns based on Terkhiin Tsagaan Lake sediment.We present a result of existing reconstructions of lake depression development and changes in the hydrology system during the Khorgo volcanic activation and the Holocene environmental change.A depression of the Terkhiin Tsagaan Lake is formed by a lava flow barrier from the Khorgo volcano.However,the Khorgo volcanic eruption and the lake depression that could shape a large lake have arisen instead from a fault.The morphometric analysis and field measurements indicate that the derivation of the Terkhiin Tsagaan Lake depression and Khorgo volcano may have evolved from movement on a sinistral strike-slip fault,which is about 70 km long.The southern mountains and rivers were displaced from northwest to southeast along the Terkh Fault.The offset along Terkh Fault is 4.02-5.28 km in the depression of the Terkhiin Tsagaan Lake.After movement,a wide valley of the Terkh River developed in the present landscape.The active Khorgo Volcano formed along the Khorgo Fault.The Terkhiin Tsagaan Lake is formed by blocked water from the PaleoTerkh River after lava damming from the Khorgo Volcano.The initial paleo-lake area was about 195.7km^(2),which was three times larger than the modern lake.The current water volume of the Terkhiin Tsagaan Lake is 0.351 km^(3) while the volume of the paleo-lake was 2.248 km^(3).Based on this volume indicator the paleo-lake was 6.4 times larger than the current lake.Overflowing water from the lake depression formed the Suman River by a drying canyon through the lava plateau,but the canyon is along the Terkh Fault.Changes in the water volume of Terkhiin Tsagaan Lake and erosion of Suman River canyon are inversely related to each other.We present the morphometric relationships between the lava plateau of Khorgo Volcano and development of Terkhiin Tsagaan Lake depression.
基金This work was supported jointly by the Chinese Academy of Sciences (Grant Nos. KZCX1-07 and KZCX1-Y-03-01-05) the National Key Basic Research Project (Grant No. G1999043302).
文摘The Louzidian normal fault occurs as the eastern detachment fault of the Kalaqin metamorphic core complex. Field observations and microstructural analyses reveal that the Louzidian-Dachengzi ductile shear zone developed in its lower-plate was genetically related to sinistral strike-slips and extensional faulting. Two samples from this ductile shear zone yield 40Ar-39Ar plateau ages of 133 Ma (Bi) and 126 Ma (Kp), which are concordant with their isochron ages. The plateau age of 133 Ma (Bi) records the formation age of the ductile shear zone. The inconsistent relationship between the earlier strike-slip ductile shear zone and the later normal fault makes the Kalaqin Quasi-metamorphic core complex distinctive from Cordil-leran nietamorphic core complex. These ages provide important geochronological data for putting constraints on the formation age and genesis of such ductile shear zones.
文摘Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results document two thermal events during the sinistral shear. The early event (12-10 Ma) corresponds to rapid cooling of the Zheduoshan granitic massif from above 700℃ to below 350℃. The late event (5-3.5 Ma) corresponds to cooling of granites intruded along the eastern side of the fault zone. These dating results provide important thermochronological constraint on the timing of late Cenozoic eastward extrusion of the Chuan-Dian Block in the SE Tibetan margin.