global neoproterozoic petroleum systems the emerging potential in north africa the neoproterozoic eon is relatively poorly known from a petroleum perspective despite the existence of producing proven and potential plays in many parts of the world in tectonic climatic and petroleum systems terms the neoproterozoic to early cambrian period can be divided into three distinct phases a tonian to early cryogenian phase prior to about 750 ma dominated by the formation stabilization and initial break up of the supercontinent of rodinia a mid cryogenian to early ediacaran phase c 750 600ma including the major global scale sturtian and marinoan glaciations and a mid ediacaran to early cambrian c post 600ma phase corresponding with the formation and stabilization of the gondwana supercontinent there is increasing evidence that deposition of many mid to late neoproterozoic to early palaeozoic organic rich units was triggered by strong post glacial sea level rise on a global scale following the snowball earth type glaciations coupled with basin development and rifting on a more local scale fieldwork in north africa including the taoudenni basin in mauritania algeria and mali the anti atlas region of morocco and the cyrenaica kufra and murzuk basins in libya has added to the understanding of reservoir source and seal relationships and confirmed the widespread presence of precambrian stromatolitic carbonate units of potential reservoir facies current research on the chronostratigraphy distribution and quality of source rocks controls on reservoir quality and distribution of seals in the precambrian early cambrian hydrocarbon plays through out south america north africa the middle east and the indian subcontinent is documented in this special publication the geological society of london 2009

a new branch of the philippine fault system as observed from aeromagnetic and seismic data abstract the philippine fault is one of the major strike slip faults of the world extending over 1200 km from the lingayen la union region of northwestern luzon to the davao gulf south of mindanao nevertheless its total slip history of displacement and its exact location have been uncertain and even controversial significant new insight has been provided by aeromagnetic and seismic surveys made as part of a basin evaluation project of the philippines bureau of energy development funded by the world bank this paper outlines evidence from these surveys for a previously unrecognized major branch of the philippine fault system and tentatively discusses its paleogeographic implications we have interpreted aeromagnetic data covering most of the length of the fault and seismic profiles crossing it at various locations the philippine fault is well displayed in the aeromagnetic data surprisingly the data also show a major previously unrecognized branch of the philippine fault here named the sibuyan sea branch this branch is almost entirely offshore or is covered by quaternary or recent volcanic rocks it leaves the known philippine fault northeast of masbate island passes along the northeast edge of the sibuyan sea southwest of the bondoc peninsula passes northeast of marinduque island apparently passes through the taal volcano and then offshore west of the batangas peninsula the sibuyan sea branch is 350 km long and is presently active it is more obvious on seismic and aeromagnetic data than the northern part of the known philippine fault and thus may have accommodated more motion we have made a preliminary evaluation of the total slip on the sibuyan sea branch by attempting to restore long wavelength geophysical and geologic features including forearc basins ophiolite belts volcanic belts and regional bouguer free air and magnetic anomalies which suggests the possibility of 200 300 km of slip since about the early or middle miocene in this reconstruction the central luzon basin and luzon volcanic arc are continuous with the forearc basin and volcanic belt on panay as a continuous arc and forearc extending from northern ilocos to southern panay after collision with the palawan mindoro continental block continued motion along the manila trench north of mindoro has ruptured the central philippines along the sibuyan sea branch of the philippine fault thus the sibuyan sea branch could account for most of the post early to middle miocene relative motion between luzon and the visayas

neotectonics of the southern hengchun peninsula taiwan inputs from high resolution uas digital terrain model updated geological mapping and psinsar techniques abstract what is the neotectonics of the southern hengchun peninsula taiwan which corresponds to the accretionary prism of the manila subduction in such an area structural geology is difficult due to the soft and muddy turbiditic outcropping formations consequently different geological maps had been settled with contrasting lithological boundaries as well as various structural wise incompatible interpretations to resolve these questions we acquired numerous aerial photographs using uas surveys and photogrammetric processing to acquire a new high resolution uas digital terrain model dtm we update the lithological boundaries by taking into consideration both the information of the existing geological maps and a detailed morphostructural interpretation of our high resolution uas dtm this leads us to propose a new structural scheme of the southern hengchun peninsula the major tectonic structures folds and faults that affect the hengchun peninsula are located furthermore 13 sar images were processed through psinsar techniques during the 2007 2011 monitoring time period in order to get the mean line of sight los surface velocities consequently we are able to characterize and quantify the active interseismic tectonic structures active folds and faults during the sar monitoring time period finally we reveal that the southern hengchun peninsula is composed of two west verging active ramp structures duplex situated above the kenting melange the kenting melange is actively uplifting and it acts as the frontal lateral and basement muddy mega fault breccia the active hengchun and kenting faults are situated on the west and east side of the kenting melange of the western ramp as we monitor only four 4 years with the psinsar technique the whole earthquake cycle of both hengchun and kenting faults needs to be better constrained as the still in use nuclear power plant n 3 is located close to the hengchun fault

quaternary transfer faulting in the taiwan foothills evidence from a multisource approach abstract the major structures of the western foothills of taiwan mainly consist of nne ssw trending folds and imbricated west vergent thrust systems the additional occurrence of n140 e striking oblique structures was revealed through a multisource approach involving a digital elevation model dem a study of drainage network anomalies aerial photographs side looking airborne radar slar images and spot p and landsat images these structures are described from north to south based on new field analyses including stratigraphy and tectonics studies they are also compared to seismic data and geodetic reconstruction in order to evaluate their present day activity these n140 e major morphostructures are interpreted as left lateral transfer fault zones either inherited from the eurasian passive margin and or newly formed in the cover in response to the presence of basement highs within the foreland basin peikang and kuanyin highs the sanyi and the chishan transfer fault zones display a high seismic activity the distribution of earthquakes and the related focal mechanisms confirm the left lateral movement along n140 e directions the chiayi chishan and fengshan fault zones act presently as transfer fault zones as indicated by gps data the associated n70 e to n100 e trending faults result from the reactivation of normal faults of the eurasian passive margin as right lateral strike slip faults in the foothills during the plio quaternary collision in taiwan we conclude that multisource and multiscale geomorphic studies combined with tectonic analysis in the field yield a significant contribution to the understanding of the structural and kinematic development of the western foothills at the front of the taiwan collision belt

neogene sediment thickness and miocene basin floor fan systems of the celebes sea abstract in the celebes sea basin the middle miocene turbidites were correlated from odp site 767 throughout the studied area differences in their regional thickness variations and distribution indicate two source areas the middle miocene turbidite fan complexes of the central and southern celebes sea basin are controlled by the paleo tarakan delta system the tectonic events and the basin floor morphology respectively the main source area for the time correlative turbidites along the southern sulu arc is assumed to be mindanao the correlation of the middle miocene to pleistocene sequences exhibit tentative ages for the development of the accretionary wedges along the cotabato trench and along the north sulawesi subduction a post middle miocene to pre pliocene age is inferred for the cotabato wedge and a plio pleistocene age is assumed for the north sulawesi wedge

drainage network analysis and tectonics of mindanao southern philippines abstract mindanao southern philippines is the site of an active arc continent collision which began in the late pliocene the principal tectonic features are faults and blind folds and duplexes which are not easily detectable in this island on which 75 of the surface is covered by pleistocene and holocene sediments and volcanics a detailed study of the drainage pattern and its discontinuities in the agusan davao and the cotabato basins when compared with field data radar data and subsurface structures observed on seismic documents enables a correlation of distant seismic lines and features existing on the basin edges the drainage network analysis based on description and interpretation of drainage anomalies and frequency allows us to distinguish 1 subhomogenous drainage areas which correspond to areas bearing consistent geological characteristics and 2 drainage anomalies the results have been checked in the field and compared with the tectonic features in the mountainous areas the extension of these structures could then be traced confidently further towards the flat lowlands we point out the presence of two distinct anomaly directions that intersect in eastern mindanao 1 numerous nnw anomalies in the intra arc basin of agusan davao and both pacific and central cordilleras appear as young features in the morphology and are due to strike slip faults of the arc continent collision some of the faults have proven to be reactivated middle miocene faults related to the initial rifting of the agusan davao basin 2 n s anomaly directions are transpressive ridges due to the collision except one anomaly which corresponds to the trace of the philippine fault zone and connects with the collisional features in contrast the cotabato basin in western mindanao lies between two terranes of different nature in the cotabato basin area the nw and nnw anomaly directions are also present and similarly correspond to strike slip faults and thrust related folds respectively pull apart basins occur in places where sagging is evidenced an additional set of anomalies trends ene and corresponds to the active extensional field below the quaternary sediments some of the en echelon features corresponding to blind flat and ramps structures were identified these observations provide reference examples for the evolution of basins generated within the compressive and strike slip setting of accreted belts

effect of regional slope on drainage networks drainage networks that develop under conditions of no structural control and homogeneous lithology are generally dendritic depending upon the shape and inclination of the surface on which they form an experimental study was designed to investigate the effect of an increase of slope on the evolution and development of dendritic drainage patterns as slope steepens the pattern changes from dendritic at 1 slope to subdendritic at 2 to subparallel at 3 to parallel at 5 and higher the change from a dendritic type pattern to a parallel type pattern occurs at a low slope between 2 and 3 and primary channel junction angles decrease abruptly from about 60 to 43

double diffusive convection in this paper we present a rather personal view of the important developments in double diffusive convection a subject whose evolution has been the result of a close interaction between theoreticians laboratory experimenters and sea going oceano graphers more recently applications in astrophysics engineering and geology have become apparent in the final section we attempt to draw some general conclusions and suggest that further progress will again depend on a close collaboration between fluid dynamicists and other scientists

a neoproterozoic petroleum system in the dalradian supergroup scottish caledonides neoproterozoic petroleum systems occur in several parts of the world based on organic rich hydrocarbon source rocks deposited during the late neoproterozoic high sea level the dalradian supergroup in argyll scotland shows evidence for coupled source rock and reservoir rock the easdale slate contains organic carbon rich enough to be a good source rock pore spaces of the scarba conglomerate are filled with oil residue pyrite spatially associated with the oil residue may reflect microbial sulphate reduction despite greenschist facies metamorphism the easdale subgroup records a hitherto unrecognized petroleum system which adds to a global picture of late neoproterozoic hydrocarbon generation

origin of thermohaline staircases hypotheses concerning the origin of thermohaline staircases in salt fingering regions are reviewed and assessed one such hypothesis that staircases arise from thermohaline intrusions is developed into a quantitative theory it is shown that growing intrusions evolve toward staircases when the background density ratio lies below a threshold value and nonlinear computations confirm that staircases are viable intrusion equilibria staircase properties such as step heights lateral density ratios and layer slopes lie closest to observed values when salt fingers are assumed not to contribute to shear stress and when turbulent mixing rates are smaller than usual thermocline values

role of strike slip faulting in the evolution of allochthonous terranes in the philippines concepts of allochthonous terrane transport and emplacement are dominated by the assumption that most terranes originate on the subducting plate collide with the upper plate and are emplaced there movement of terranes along the convergent margin is recognized but is generally attributed to postcollision slip in the northern philippines allochthonous terranes originate primarily within the arc system have been translated along it by strike slip faults and were emplaced by cessation of that slip the authors suggest that in the philippines some originally vertical strike slip boundaries may have evolved into shallow dipping sutures marked by fold and thrust systems this mode of terrane evolution may be more common than generally appreciated particularly in orogenic belts developed in response to oblique convergence

geomorphic response of the river basin drainage in seismically active regions of india over the last few decades the indian subcontinent is gradually drifting towards northeast at a rate of 10 mm year which is an indication that the areas are actively deforming such a gradual rate of drift is expected to bring modifications and changes in the topography which can be quantified with the help of geomorphic parameters the current study examines the geomorphological changes in the seismically active areas of different geotectonic provinces of india i e northeast india and bhuj region the geomorphological changes have been estimated with the help of remote sensing and geographical information system modeling by calculating the geomorphic parameters a total of 39 drainage basins were extracted from both the study areas using aster gdem data of 30 m resolution geomorphic indices such as stream order stream length bifurcation ratio form factor asymmetry factor and hypsometric integral were calculated for each drainage basin of the study regions the geomorphic parameters reveal that the study areas are dendritic in character even though having different geological formations both study regions express similar lithological characteristics with no strong control of structural elements both study areas seem to be characterized by relatively high permeability and with relatively gentle slope the extent of the carving of topography reveals that the drainage development and morphologic evolution of both areas have practically reached late mature and old stage of terrain development even though the two study areas represent different seismotectonic provinces it is observed that geomorphologically they are gradually approaching the stage of peneplanation

recent tectonic activity of the gafsa fault through morphometric analysis southern atlas of tunisia abstract this article focuses on the neotectonics of the southern atlas of tunisia based on morphometric analyses five major relevant morphometric parameters were processed and analyzed residual topography hypsometric index drainage anomalies maximum vertical curvature and terrain roughness and compared to the structural and tectonics of the study area these are relevant to describe the topographic changes and therefore suggest possible neotectonic activity the analysis of these morphometric indices reveals that two structures in the study area jebels ben younes and bou ramli are distinguished by a specific morphometric footprint high residual topography high hypsometric integral value of some watersheds hi 0 6 high frequency of drainage anomalies high maximum vertical curvature and high roughness index the correlation of these geomorphic indices with the structural pattern of the study area confirms the neotectonic reactivation dating from the quaternary and the dextral strike slip component of the gafsa fault the major tectonic feature in the southern atlas of tunisia thus the morphometric analysis of the digital elevation model and the drainage network provide a more accurate insight into the morphodynamics of the study area

kinematic constraints on intra arc shear and strain partitioning in the southern andes between 38 s and 42 s latitude 1 on the basis of structural field work fault kinematic analysis and the analysis of digital imagery we describe the northern part of the southern andean intra arc liquine ofqui fault zone lofz as an sc like fault zone system accommodating part of the nazca south american plate convergence obliquity kinematic modeling suggests that the lofz accommodated 124 24 21 km of dextral displacement between 40 s and 42 s and 67 13 11 km between 38 s and 40 s since the pliocene associated vertical axis rotations are 31 4 clockwise and 9 1 counterclockwise along synthetic and antithetic faults respectively mean pliocene to recent shear rates along the lofz decrease northward from 32 6 mm yr to 13 3 mm yr compatible with partitioning of half of the convergence obliquity into the intra arc zone north of 40 s and complete partitioning to the south the displacement gradient along the intra arc zone results in margin parallel shortening of the fore arc

upper plate deformation induced by subduction of a volcanic arc the snellius plateau molucca sea indonesia and mindanao philippines abstract the northern molucca sea shows the incipient subduction of a composite oceanic and arc volcanic block the snellius halmahera block shb multi beam reflectivity seismic and gravity data obtained during the modec marine survey showed that the shb disappears beneath the accretionary wedge and the outer ridge of the sangihe arc to the north in mindanao island ongoing convergence generated shortening of the forearc basin and the backthrusting of the shb meanwhile a classical system of paired subduction philippine trench and strike slip fault philippine fault was installed the transition from lithospheric subduction to crustal overthrusting is located where the philippine trench sensu stricto begins and also coincides with the off shore extension of the philippine fault we observe a reversal of the thrusts from an eastward vergence in the molucca sea to a westward vergence in mindanao island this reversal takes place at the latitude where the forearc area emerges by uplift and the downgoing crust shb deepens resulting in a strong gravity low centered above the accretionary wedge the philippine fault initiated in a place where the crust was sliced off by a transfer zone which marked the northern termination of the molucca sea and drags northward a sliver of the previously accreted shb the northward drifting of this sliver created an extension which however cannot account for the gravity low we propose that the shortening and the uplift of the upper plate were induced by the buoyancy of the subducted unit shb and triggered the thrust reversal

role of strike slip faults in the betic rifian orogeny abstract a new model for the betic rifian orogeny of the western mediterranean spain and north africa is proposed in which four strike slip faults play an important role the faults are not of the same age two faults the left lateral jebha fault to the south in morocco and principally in the mediterranean sea and the right lateral north betic fault southern spain to the north define the boundaries of the alboran block betic and rifian internal zones final movement along these faults was during the burdigalian time two other faults the left lateral nekor fault north africa to the south of the jebha fault and the right lateral crevillente fault somewhat to the north of the north betic fault define a larger alboran block including part of the betic and rifian external zones that was present during the tortonian the following sequence of events is proposed 1 a during the eocene and oligocene the african and european plates converged in a n s sense causing the breakup and overthrusting of the betic rifian and kabyle internal zones and then the movement towards the wsw of the alboran block by slip along the jebha and north betic faults 2 b by the end of burdigalian time movement along the jebha and north betic faults ceased 3 c with continued n s convergence the nekor and crevillente faults which bound a larger alboran block were formed during the mid and late miocene the arc of gibraltar the zone lying between the four major faults seems to be a result of wsw motion of a crustal block being thrust over external zones the model proposed adds to the earlier idea that tectogenesis proceeds from the interior to the exterior of an erogenic belt in the betic rifian orogeny major strike slip fracture zones shifted to the exterior of the orogenic belt as the orogeny progressed in order to relieve the stress caused by locking of the more internal faults

geology and volcanic stratigraphy of the canatuan and malusok volcanogenic massive sulfide deposits southwestern mindanao philippines the canatuan and malusok massive sulfide deposits are located near siocon zamboanga del norte in southwestern mindanao philippines the canatuan malusok area is underlain by the jurassic cretaceous tungauan schists which form much of the zamboanga peninsula the volcanic strata at canatuan and malusok can be traced for 7 km along strike and is host to at least three discrete massive sulfide bodies canatuan malusok and se malusok basal basaltic andesite volcanic rocks are generally chemically uniform and show only moderate alteration the massive sulfide deposits occur in overlying rhyolitic to rhyodacitic volcanic rocks that are altered to a schistose assemblage of quartz sericite chlorite and pyrite the alteration is texturally destructive but graded clastic beds are locally observed despite tropical saprolitic weathering four lithogeochemical subunits of the felsic package are identified stratigraphic interleaving however has made correlation of these units over any significant distance difficult the sulfide lenses are overlain by a few metres of felsic schists which locally contain manganese bearing silicates and oxides that serve as a stratigraphic marker hangingwall andesitic volcaniclastic rocks are discontinuously preserved although where present they consist of regularly bedded mafic volcanic sandstones the lateral continuity of a manganese bearing marker and flanking felsic volcaniclastic intervals indicate that locally the volcanic strata form a homoclinal sequence the canatuan au ag cu zn deposit consists of a gossan overlying a massive sulfide lens the sulfides and gossan are flat lying and hosted within felsic volcanic rocks the gossan is gold silver rich and was formed by a combination of oxidation and volume collapse of the original sulfide lens the sulfide minerals present below the current water table are auriferous massive pyrite with base metal sulfides with some supergene chalcocite the transition from gossan to sulfides is very sharp occurring at the water table massive sulfide deposits at malusok are hosted in the same felsic sequence as canatuan and they have similar base and precious metal contents only limited gossan has been found at malusok the bimodal nature of the volcanic rocks at canatuan together with their low hfse contents near flat ree patterns and tholeiitic affinities suggest that they formed in an intra oceanic arc setting above a depleted mantle source mafic and felsic volcanic rocks of similar composition have been recovered from the tonga kermadec and izu bonin marianas island arc systems in the western pacific mafic rocks at canatuan show no evidence for lile enrichment that characterizes melts derived from metasomatized mantle under more mature arcs suggesting that they are the product of a nascent rather than a mature arc there is no evidence from the ree or other incompatible trace elements that continental crust or evolved arc crust was involved in the generation of the canatuan malusok volcanic rocks although it has been proposed that the zamboanga metamorphic complex comprises microcontinental fragments of eurasian affinity our data do not support an evolved crustal setting for the canatuan malusok volcanic rocks which we suggest were derived from an intra oceanic arc and subsequently accreted to the eastern mindanao terrane

active tectonics seismicity and geomorphology with special reference to normandy france integrated studies based on tectonic seismotectonic and geomorphological analyses indicate that normandy northwest france has been an active area during the quaternary topography and landform discontinuities reflect the dislocation and differential uplift of a late cenozoic platform the tectonic activity is represented by i active faults indicated by linear scarps and seismic activity ii offsetting of pre existing surfaces iii plio pleistocene sedimen tation restricted within narrow subsiding zones and iv morphometric properties of drainage basins that indicate zones of differential uplift the inferred strain pattern involves i a shortening direction that strikes nw se as expected in the european context of alpine compression and ii a ne sw trending extension accommodated by nw se normal faults the geomorphological systems encountered in normandy preferentially record differential vertical displacements copy right 2000 john wiley sons ltd

tectonic analysis of fault slip data sets using data that include the direction and the sense of motion on individual fault surfaces determined by slickenside lineations it is possible to reconstruct reduced stress tensors that correspond to the orientation of stress axes and to the ratio 2 3 1 3 between principal stress values 1 2 3 compression being positive no assumption is made concerning the orientation of fault planes relative to stress axes so that reactived faults are taken into account as well as newly created ones qualitative and quantitative methods for analysis of fault slip data were developed during the last 10 years the practical limitation of the methods and the necessity for critical field observations are emphasized these methods can be applied to focal mechanisms of earthquakes a more complex analysis of heterogeneous data sets involving an iterative separation of different stress systems is also discussed this analysis enables one to distinguish successive faulting events careful qualitative study in the field is in all cases essential

investigation of active faults in morocco using morphometric methods and drainage pattern analysis a survey has been done of recently active faults in morocco in addition to field observations morphometric methods were applied and an analysis was made of the drainage pattern in the morphometric analysis a map of vertical deformation was established from the elevations of summit level surfaces this enables the recognition of neotectonic discontinuities and lithological contrasts the actual discrimination of different rock types can only be achieved by comparison with field observations the analysis of drainage patterns including their perturbations and anomalies can also reveal the presence of features due to neotectonics structural control or lithological variation certain faults can be detected which correspond to structures known from field geology or remote sensing ne sw and nw se oriented sets some new faults are observed which belong to these sets as well as others which define a new n s trending set the present analysis leads to a distinction between ancient faults and currently active faults the results of this study are shown on a map of recently active faults where the respective vertical displacements are also indicated

principles of drainage basin analysis from multisource data application to the structural analysis of the zaire basin abstract classifications which attempt to combine descriptive and genetic aspects of types of drainage basins must take into account the application of new techniques satellite imagery high precision topographic maps and digital terrain models in addition the use of new concepts such as neotectonics and drainage basin history will lead to a reassessment of classification schemes after a review of current classifications we propose a genetic scheme that is based on the development of drainage networks and which includes integration of local and regional scale perturbations state of the art methods of drainage basin analysis are applied to the zaire basin to provide new information on deep structures the influence of basin and block tectonics is revealed in the context of major late proterozoic shear faults which have been rejuvenated up to the present day this is demonstrated from an analysis of the drainage network in the light of geological and geophysical observations

accreted terranes in the northern part of the philippine archipelago the philippine archipelago consists of a complex array of ophiolites continental fragments and island arc elements that can be identified as accreted terranes similar to those increasingly recognized as components of orogenic zones the northern philippines including luzon mindoro and nearby smaller islands can be divided into at least six of these tectonic elements from west to east across central luzon there are the neogene accretionary prism of the west luzon arc the eocene zambales ophiolite the cretaceous angat ophiolite and a late cretaceous early paleogene volcanic arc built on an older metamorphic basement this arc terrane is repeated by offset along the philippine fault to the south the western luzon terranes are juxtaposed against the metamorphic basement block of mindoro which itself is colliding with the north palawan microcontinental fragment the ophiolites appear to have originated in back arc basins rather than in oceanic plateaus and the metamorphic belts have protoliths indicating deformation along active margins perhaps deep within accretionary prisms the philippine terranes are interpreted as fragments that originated within the complex pacific eurasian plate boundary rather than as intra pacific basin units these terranes have been assembling at least since the oligocene by strike slip and convergent displacements strike slip displacement either along transcurrent faults or as a component of convergence played a very important if not dominant role in this assembly most terranes identified in the northern philippine appear to be plate fragments with attached crust and upper mantle their characteristics contrast with those usually interpreted for terranes in the north american cordillera where near orthogonal convergence and shallow dipping terrane sutures are favored

morphotectonic evidence from lateral propagation of an active frontal fold pakuashan anticline foothills of taiwan abstract the pakuashan anticline is uniquely suited for study of the forward and lateral growth of fault related folds the pakuashan ridge development arises from the late quaternary uplift of the most external thrust zone of the western foothills of taiwan from kaoshiung to taichung recent and active westward thrusting occurs at the front of the foothills the pakuashan anticline trending n 150 e in the northern part to n 000 in the southern part has been active throughout the quaternary period this activity is marked by geological structures tectonic geomorphology and seismicity a multisource and multiscale approach to study of the continental collision setting has been undertaken to combine tectonics sedimentology and geomorphology studies of fracture patterns allow identification of two main features of stress orientations a wnw ese compression direction and e w and n s extension directions quantitative geomorphic parameters have been used to define the morphotectonic evolution and to infer tectonic style along the mountain front geomorphic evidence provides significant information on the processes that govern lateral propagation of an active anticline quaternary terraces are uplifted tilted and folded over the pakuashan ridge drainage systems in areas of active compression give information on the thrust zone structures and their development steep drainage and high local relief indicate that the pakuashan anticline forms a well defined zone of high uplift especially in the southern part the two main controls on drainage in that area are rock strength in the hanging wall and propagation of the deformation towards the south

experiments on salt fingers in a hele shaw cell salt fingers are generated when a slowly diffusing solute overlies a more rapidly diffusing solute in a gravitationally stable fluid the phenomenon is important in many areas of science for example it affects the temperature and salinity structure in the upper half of the ocean the production of crystals when liquid alloys solidify and the distribution of properties in magma chambers below the earth s crust the evolution of a salt finger from initial instability to a fully developed feature is difficult to follow in a fluid because of the close packed array of cells that is formed however when the fluid is contained in a hele shaw cell individual fingers occupy the entire gap width thereby enabling the experimenter to monitor and record the evolution much more easily the instability of an array of wide fingers to disturbances that lead to preferred smaller scales is documented in a sequence of photographs and a qualitative physically consistent argument is offered to explain the instability