Rectilinear Pattern Research Articles

Specificity of the horizontal cell‐photoreceptor connections in the zebrafish (Danio rerio) retina

Horizontal cells (HCs) are involved in establishing the center-surround receptive field organization of photoreceptor and bipolar cells. In many species, HCs respond differentially to colors and may play a role in color vision. An earlier study from our laboratory suggested that four types of HCs exist in the zebrafish retina: three cone HCs (H1, H2 and H3) and one rod HC. In this study, we describe their photoreceptor connections. Cones are arranged in a mosaic in which rows of alternating blue (B)- and ultraviolet (UV)-sensitive single cones alternate with rows of red (R)- and green (G)-sensitive double cones; the G cones are adjacent to UV cones and B cones adjacent to R cones. Two small-field (H1 and H2) and two large-field (H3 and rod HC) cells were observed. The cone HC dendritic terminals connected to cones with single boutons, doublets, or rosettes, whereas the rod HCs connected to rods with single boutons. The single boutons/doublets/rosettes of cone HCs were arranged in double rows separated by single rows for H1 cells, in pairs and singles for H2 cells, and in a rectilinear pattern for H3 cells. These connectivity patterns suggest that H1 cells contact R, G, and B cones, H2 cells G, B, and UV cones, and H3 cells B and UV cones. These predictions were confirmed by applying the DiI method to SWS1-GFP retinas whose UV cones express green fluorescent protein. Each rod HC was adjacent to the soma or axon of a DiI-labeled cone HC and connected to 50-200 rods.

Morphological types and connectivity of horizontal cells found in the adult zebrafish (Danio rerio) retina.

We describe here different types of horizontal cells in the zebrafish retina and how they connect to photoreceptors. To label horizontal cells, crystals of DiI were placed onto the tips of pulled glass pipettes and inserted into the inner nuclear layer of fixed whole-mount retinas. The DiI-labeled horizontal cells were imaged by confocal microscopy and analyzed according to dendritic arborization, cell depth, dendritic terminal morphology, and connectivity with photoreceptors. Three types of horizontal cells were unequivocally identified: two cone-connecting (H1/2 and H3) and one rod-related cell. H1/2 cells have dendritic terminals that are arranged in "rosette" clusters and that connect to cone photoreceptors without any apparent specificity. H3 cells are larger and have dendritic terminal doublets arranged in a rectilinear pattern. This pattern corresponds to the mosaic of the single cones in the zebrafish photoreceptor mosaic and indicates that H3 cells connect specifically to either the blue-sensitive (long-single) or ultraviolet-sensitive (short-single) cones. Thus, H3 cells are likely to be chromaticity-type cells that process specific color information, whereas H1/2 cells are probably luminosity-type cells that process luminance information. Rod horizontal cells were identified by their shape and dendritic pattern, and they connect with numerous rod photoreceptors via small spherical terminals.

Service capacity design problems for mobility allowance shuttle transit systems

Transit agencies are currently seeking ways to improve service flexibility in a cost efficient manner. Mobility Allowance Shuttle Transit is a transportation concept that merges the flexibility of Demand Responsive Transit systems with the low cost operability of fixed-route bus systems. In this paper, we study the service capacity design problem for such a system. We analyze the relationship between service cycle time, and the length and width of the service area under a desired service level constraint. The analysis can be used as a guide for designing service area parameters. Given that a shuttle travels in a rectilinear pattern and utilizes a non-backtracking nearest-insertion algorithm, we derive closed-form approximate solutions for the service capacity design problem. We show that setting the length of the service area to half the travel speed of the shuttle multiplied by the cycle time is an effective approximation.

A Review of Coalesced, Collapsed-Paleocave Systems and Associated Suprastratal Deformation

Coalesced, collapsed-paleocave systems and associated suprastratal deformation appear to be prominent diagenetic/structural features in carbonate sections at/near composite unconformities. The basic architecture of the system can be divided into two sections. The lower karsted section, where high-density cave formation took place, is preserved as massive breccias commonly displaying a rectilinear pattern in map view. The overlying suprastratal deformation section is characterized by large, circular to linear sag structures containing faults and fractures. Regional distribution of coalesced, collapsed-cave systems commonly appears as large-scale (hundreds to thousands of square kilometers in area), rectilinear patterns with areas of concentrated, coalesced breccias separated by relatively undisturbed host rock. This pattern may reflect development of the paleocave system along fracture swarms. Collapsed-paleocave systems are large, complex features that show broad-scale organization. The complete paleocave system may need seismic data or large, mountain-scale outcrops to define their architecture and distribution.

Wavelet Based Multi-Bit Fingerprinting Against Geometric Distortions

This paper presents a new image fingerprinting scheme which embeds a multi-bits fingerprinting code and is robust against the geometric attack such as rotation, scaling and translation. We construct a 64 bits fingerprinting code and embed into wavelet subband of 512x512 images repeatedly. In order to restore an image from geometric distortion a noise reduction filter is performed and a rectilinear tiling pattern is used as a template. Results of experimental studies show that our method is robust against geometric distortions and JPEG compression.

With a Grain of Salt: What Halite Has to Offer to Discussions on the Origin of Life

This experimental study investigated how the dynamics of the crystallization of the evaporite mineral halite could affect the accumulation and preservation of organic macromolecules present in the crystallizing solution. Halite was grown under controlled conditions in the presence of polymer nanoparticles that acted as an analog to protocellular material. Optical microscopy, atomic force microscopy, and laser scanning confocal fluorescence microscopy were used to trace the localization of the nanoparticles during and after growth of halite crystals. The present study revealed that the organic nanoparticles were not regularly incorporated within the halite, but were very concentrated on its surfaces. Their distribution was controlled dominantly by the morphologic surface features of the mineral rather than by specific molecular interactions with an atomic plane of the mineral. This means that the distribution of organic molecules was controlled by surfaces like those of halite's evaporitic growth forms. The experiments with halite also demonstrated that a mineral need not continuously incorporate organic molecules during its crystallization to preserve those molecules: After rejection by (non-incorporation into) the crystallizing halite, the organic nanoparticles increased in concentration in the evaporating brine. They ultimately either adsorbed in rectilinear patterns onto the hopper-enhanced surfaces and along discontinuities within the crystals, or they were encapsulated within fluid inclusions. Of additional importance in origin-of-life considerations is the fact that halite in the natural environment rapidly can change its role from that of a protective repository (in the absence of water) to that of a source of organic particles (as soon as water is present) when the mineral dissolves.

Transformation of two‐pyroxene hornblende granulite to garnet granulite involving simultaneous melting and fracturing of the lower crust, Fiordland, New Zealand

AbstractGranulite facies gabbroic and dioritic gneisses in the Pembroke Valley, Milford Sound, New Zealand, are cut by vertical and planar garnet reaction zones in rectilinear patterns. In gabbroic gneiss, narrow dykes of anorthositic leucosome are surrounded by fine‐grained garnet granulite that replaced the host two‐pyroxene hornblende granulite at conditions of 750 °C and 14 kbar. Major and trace element whole‐rock geochemical data indicate that recrystallization was mostly isochemical. The anorthositic veins cut contacts between gabbroic gneiss and dioritic gneiss, but change in morphology at the contacts, from the anorthositic vein surrounded by a garnet granulite reaction zone in the gabbroic gneiss, to zones with a septum of coarse‐grained garnet surrounded by anorthositic leucosome in the dioritic gneiss. The dioritic gneiss also contains isolated garnet grains enclosed by leucosome, and short planar trains of garnet grains linked by leucosome. Partial melting of the dioritic gneiss, mostly controlled by hornblende breakdown at water‐undersaturated conditions, is inferred to have generated the leucosomes. The form of the leucosomes is consistent with melt segregation and transport aided by fracture propagation; limited retrogression suggests considerable melt escape. Dyking and melt escape from the dioritic gneiss are inferred to have propagated fractures into the gabbroic gneiss. The migrating melt scavenged water from the surrounding gabbroic gneiss and induced the limited replacement by garnet granulite.

Sedimentology and vertebrate taphonomy of the Tritylodon Acme Zone: a reworked palaeosol in the Lower Jurassic Elliot Formation, Karoo Supergroup, South Africa

A semi-continuous bed of pedogenic nodule conglomerates in the floodplain deposits of the Lower Jurassic Elliot Formation (upper Karoo Supergroup) of South Africa, is interpreted as a lag deposit that resulted from an extended period of floodplain degradation. The large-scale geometry of the conglomerate bed resembles a sheet-with-holes, only 0.5–1.25 m thick, yet it covers at least 11,000 km 2 of the northwestern part of the Elliot outcrop area. It is commonly underlain by eroded remnants of a calcic palaeosol and grades upwards into a fully-preserved calcic vertisol. The conglomerate contains reworked pedogenic nodules, mudrock pebbles and numerous fossils of the advanced cynodont Tritylodon . Fossils of Tritylodon occur in such abundance that this interval has been dubbed the Tritylodon Acme Zone. This study uses field observations of the sedimentology, palaeopedology and vertebrate taphonomy of the Tritylodon Acme Zone to reconstruct the geomorphological history and the time constraints involved in the formation of this lag conglomerate and associated palaeosols. Paleosols in the loessic siltstones below the Tritylodon -rich conglomerate are characterised by a rectilinear pattern of large sandstone-filled shrinkage cracks which are commonly offset by small slickensided arcuate shear planes. The fissures in the lower palaeosol are heavily calcretized and some contain vertically stacked calcareous nodules. The upper palaeosol is characterised by similar vertical fissures except that they are filled with siltstone and mudstone and are rarely calcretized. The upper palaeosol contains scattered pebble-sized calcareous nodules along with vertical and horizontal rhizocretions and termitaria-like burrowed sandstone pods. Both palaeosols are interpreted as calcic vertisols formed in clay-rich alluvium on seasonally wet floodplains under warm semi-arid climatic conditions. The relatively high abundance of Tritylodon fossils in the nodule-conglomerate is attributed to regional denudation of an estimated 3–5 m of fossil-bearing calcareous soil resulting in reworking of the resistant glaebules and partlymineralised bones into a lag deposit. Most of the bones occur as disarticulated and broken elements in multitaxa, bonebed-type accumulations within shallow depressions scoured into the underlying alluvium. Haematite perimineralization of bone is ubiquitous and its precipitation on the surfaces of brittle-fractured bone surfaces is evidence that many of the bones were mechanically broken by reworking after they had been buried for long enough to become partially calcified. A time-restored stratigraphic column gives an estimated 50,000 yr for the accumulation of the 2.25 m of Tritylodon Acme zone strata. Using figures derived from studies of modern landscapes, it is estimated that the Tritylodon conglomerate itself records a period of floodplain incision in this part of basin during the earliest Jurassic times, which lasted for some 30,000 yr.

Evolution of the San Juan Basin, Colorado, and New Mexico Basin Analysis Case Study: ABSTRACT

During 1985 to 1989, the US Geological Survey conducted a basin analysis study that investigated the sedimentological and structural history of the San Juan basin and vicinity. The San Juan basin is a large asymmetric basin in southwest Colorado and northwest New Mexico near the southeastern edge of the Colorado Plateau. It formed as a result of northeast-directed compression coupled with a slight northeastward shift of the Colorado Plateau during the Late Cretaceous to Oligocene Laramide orogeny. Although the basin assumed its final configuration during the Laramide orogeny, regional stratigraphic and sedimentologic studies show that uplifts active during the Laramide orogeny were also active in the geologic past. Analysis of 1,000 mi of reflection seismic data defines a rectilinear pattern of northwest- and northeast-trending faults that involved the Precambrian basement in basin development. Middle Pennsylvanian to Late Permian, Middle to Late Jurassic, Early Cretaceous, Late Cretaceous-Oligocene, and Miocene were major times of movements on the faults and/or bounding uplifts. Preserved Mesozoic and older sedimentary rocks in the basin accumulated as part of widespread regional depositional systems. Pennsylvanian strata, consisting of a thick sequence of clastic and carbonate rocks, and evaporites deposited in both open and restricted marine environments contain significantmore » oil and gas resources. Mesozoic strata deposited in a variety of widespread continental and marine environments host 50% of the country's uranium reserves. Five marine transgressive-regressive cycles during the Cretaceous resulted in a thick sequence of intertonguing marine and continental rocks containing large resources of coal, oil, and gas.« less

Asymmetries in the sense organs and central nervous system of the squid Histioteuthis

The visual system of Histioteuthis is markedly asymmetrical, in that the eyes and optic lobes are considerably larger on the left side, and the lens of the left eye is often yellower in colour than that of the right eye. At the histological level, the rhabdomes of the retinas of both eyes show the usual rectilinear pattern typical of cephalopods. Unlike other species described, however, the orientation of the pattern is not uniform over the retina. The optic lobes are well developed on both sides, again following the typical squid pattern, although the plexiform and inner granular layers are thicker on the left side. In life it is likely that the animals orient at an oblique angle with the arms downward, and the left eye pointing upwards and the right eye downwards, and the asymmetries of the visual system are probably related to this posture. No corresponding asymmetries in the statocysts or other parts of the central nervous system have, however, been detected

Quantification of colonic lamina propria cells by means of a morphometric point-counting method

The lamina propria of colonic mucosa normally contains eosinophils, lymphocytes, plasma cells, and a few neutrophils. If the number of such cells is judged to be increased, colonic inflammation is said to be present. However, the number of cells present in normal mucosa has not been clearly established. Mild abnormalities are difficult to identify, yet might be associated with colonic dysfunction. We therefore developed a morphometric point-counting method to quantitatively analyze the areas occupied by different structures in the mucosa of the human colon. A computer was used to move a dot in a rectilinear pattern over the × 400 magnified image of biopsy specimens obtained from throughout the colon by colonoscopy. The structure on which the dot landed was identified and tabulated by a pathologist. In preliminary studies, we established counting parameters that would yield the most representative results. Based on statistical analysis, it was decided to count 98 points in each of seven regions of six biopsy specimens, i.e., over 4000 points per subject. Results were expressed as percentages of counts landing on a given item, and represented the area of the biopsy specimen covered by that item. Using this method, we determined the range of normal in healthy volunteers. The sensitivity of this method was tested by studying patients with chronic diarrhea previously diagnosed as having or not having mild to moderate mucosal inflammation. In the patient group, colonic fluid absorption measured by a perfusion technique was directly correlated with epithelial cell counts and inversely correlated with lamina propria cellularity and with the counts of lamina propria neutrophils and plasma cells. We conclude that morphometric analysis of colon biopsy specimens can be used to quantitate histologic features of colonic mucosa and to accurately identify even mild abnormalities, and that it can be a useful clinical research tool.

Fractures in the northern plains, stream patterns, and the midcontinent stress field

Fractures in Late Cretaceous to Late Pleistocene sediments in Saskatchewan, eastern Montana, and western North Dakota form two vertical, orthogonal sets trending northeast–southwest and northwest–southeast. The pattern is consistent, regardless of rock type or age (except for concretionary sandstone). Both sets appear to be extensional in origin and are similar in character to joints in Alberta. Modem stream valleys also trend in the same two dominant directions and may be controlled by the underlying fractures.Elevation variations on the sub-Mannville (Early Cretaceous) unconformity form a rectilinear pattern also parallel to the fracture sets, suggesting that fracturing was initiated at least as early as Late Jurassic. It may have begun earlier, but there are insufficient data at present to extend the time of initiation.We interpret the fractures as the result of vertical uplift together with plate motion: the westward drift of North America. The northeast–southwest-directed maximum principal horizontal stress of the midcontinent stress field is generated by viscous drag effects between the North American plate and the mantle. Vertical uplift, erosion, or both together produce a horizontal tensile state in near-surface materials, and with the addition of a directed horizontal stress through plate motion, vertical tension cracks are generated parallel to that horizontal stress (northeast–southwest). Nearly instantaneous elastic rebound results in the production of second-order joints (northwest–southeast) perpendicular to the first. In this manner, the body of rock is being subjected with time to complex alternation of northeast–southwest and northwest–southeast horizontal stresses, resulting in the continuous and contemporaneous production of two perpendicular extensional joint sets.

Calleva Atrebatum: An Interim Report on the Excavation of the Oppidum, 1980–86

Excavation of the basilica of the Roman town of Silchester (Calleva Atrebatum) has produced evidence for two phases of pre-Roman occupation. The earlier, probably dating to the mid-first century BC, consisted of roundhouses and pits. Around 20 BC a rectilinear steet pattern, with building plots at right angles to the streets and rectangular buildings, was laid out; later a palisaded enclosure was built. Imports included amphorae and fine pottery; Central Gaulish wares suggest an early trade connection to the south. There is some evidence of disuse before the Roman streets were laid out on a different alignment in mid first century AD.

Propagation and bit error ratio measurements for a microcellular system

Propagation measurements are provided for highway and city centre microcells. Measurements along various motorways were taken with base station (BS) antennas at 10 m elevations. Pseudo-random binary sequences (PRBS) were transmitted via non-coherent FSK at 905 MHz. Low radiated power (16 mW into an 18-element Yagi) was used, and the signal level and bit error ratio (BER) were recorded by a mobile station (MS). The microcell length was found to be a function of the received field strength and, therefore, the BER. It was found that the cell lengths varied between 1 to 2 km for a BER of 10−3 or better. Although the PDF of the received signal was Rician the microcell length was determined using the more pessimistic Rayleigh PDF. Two and three microcell clusters were considered. An inverse fourth power law was observed, and the received signal power in the microcell varied linearly with radiated power. For power levels of only 1 μW, error free transmission was found to occur over a cell length of 400 m.Detailed measurements in the Harley Street area in Central London enabled us to study how signals propagate in a nearly rectilinear grid pattern of roads. A theoretical model was established that provided signal levels that were close to those measured. Experiments were performed with the base station at junctions, roundabouts and at major city arteries. The inverse fourth power loss characteristics occurred, and the radiation distribution was found to be relatively insensitive to antenna type as the street pattern was the dominant factor.

Structures associated with extensional tectonics in the Suez rift

Summary The opening of the Suez rift, which was initiated at the beginning of the Miocene (23 Ma), was the result of a regional extensional stress more or less perpendicular to the rift axis. A detailed study of selected areas within the onshore part of the rift (Abu Durba, Gebel Ekma and Wadi Dib) shows that the fault geometries visible in the Precambrian basement and the overlying sedimentary rocks are distinct; brittle deformation in one, ductile deformation in the other. In the basement (metamorphic and granitic rocks), faults display a rectilinear pattern. Two sets of faults are predominant; (i) N140-150E faults, parallel to the Gulf trend, with pure dip-slip displacement, (ii) cross-faults (transfer faults) trending N00 to N30E with strike-slip component. These faults delineate diamond-shaped tilted blocks. In the overlying sedimentary rocks (Cretaceous-Eocene sands, shales and limestones) faults are spoon-shaped. Spoon faults are generally superimposed over concave wedges of the basement blocks but are decoupled from basement fault sets. The decoupling is accommodated by ductile deformation and detachment in the Cretaceous marks.

Tectonic Framework of Powder River Basin, Wyoming and Montana, Interpreted from Landsat Imagery

Linear features in the Powder River basin, Wyoming and Montana, were interpreted from Landsat images and analyzed to define major lineaments. Lineaments identified include several that trend northwest and a prominent set that trends northeast. These lineaments represent broad (5-10 km or 3-6 mi) linear zones where smaller, parallel and subparallel linear features are concentrated at the surface. The smaller linear features are interpreted as possible expressions of joints, fractures, folds, or lithologic boundaries produced by periodic readjustment along basement-block boundaries. The lineaments discussed in this report were visually interpreted from maps of linear features and contour maps showing concentrations of linear features. Lineaments were subsequently compared to mapped structures, outcrop patterns, geophysical data, and isopach maps to assess their geologic significance. Correlations of these lineaments with mapped structures, geophysical gradients, or facies changes strongly support the interpretation that they represent the surface expression of boundaries of crustal blocks that have been periodically reactivated through time. The northeast and northwest patterns provide evidence that a systematic, rectilinear pattern of crustal blocks formed early in the earth's history and has largely controlled subsequent adjustments of the earth's crust. These findings suggest the potential for depositional control of sedimentary units by structural adjustments between basement blocks and, thus, lead to the conclusion that lineaments may be used as guides in petroleum and mineral exploration if favorable source and host rocks are present.

A Golgi and ultrastructural study of a dominant form of Kufs' disease

A cerebral biopsy from a patient with inherited dominant autosomic Kufs' disease was studied with Golgi's method and ultrastructurally. A marked PAS positive, sudanophile, autofluorescent deposit was observed in the cytoplasm and in the proximal region of the axon of neurons from the third layer. Ultrastructurally this is a granular, membrane-bound product, sometimes with with a dense, compact rectilinear pattern in which the typical clear component of adult lipofuscin is scanty. Sections stained with Golgi's method show a prominent, sometimes double, axon hillock swelling without dendritic spines. These facts are compared with additional samples of Alzheimer's disease and Huntington's chorea processed in a similar way.

Cohort analysis of death from malignant neoplasms in Japan.

(1) Cohort analyses were made of the total and partial death rate for malignant neoplasms in both sexes.(2) The cohort phenomenon was shown in the transition of the total death rate induced by malignant neoplasms in both sexes. The age-specific death rate curve forms a line similar to the rectilinear pattern seen in the middle age groups and above.(3) Decreasing cohort phenomena were seen in the uterine and stomach cancer analyses. Both forms of cancer are now on the decrease.(4) Increasing cohort phenomena were demonstrated in the lung and pancreas cancer analyses for both sexes. The rate of increase has nearly reached zero, and the age-specific death rate curves are approximately straight lines.(5) A two-phase cohort phenomenon was observed in the liver cancer analysis for females.(6) The transition of the death rate for leukemia showed cohort phenomena for both sexes. However, a final age-specific death rate curve is being reached, and the nature of this disease has changed.(7) The transition of the death rates for malignant neoplasms according to site can be classified as with and without cohort phenomena. Those that showed cohort phenomena can be classified into four types.a) The simple decreasing cohort phenomenonb) The two-phase cohort phenomenonc) The increasing cohort phenomenon that produces an age-specific death rate curve with a rectilinear pattern.d) The increasing cohort phenomenon in all age groups.(8) Suggestions for health control and related etiology were made in relation to the cohort phenomenon shown in malignant neoplasms.

Cornwallis Fold Belt and the mechanism of basement uplift

Cornwallis Fold Belt is a north-trending anticlinorium more than 650 km (400 mi) long, that extends from the Precambrian Shield to the Sverdrup Basin. It is the folded and faulted sedimentary suprastructure that overlies Precambrian crystalline basement rocks of the Boothia Horst. The horst and fold belt represent lower and intermediate levels of the Boothia Uplift. Evolution of the Cornwallis Fold Belt includes two phases, formation and modification.Formation. The basic structure of the Cornwallis Belt, a relatively simple, steep-sided, north-plunging anticlinorium, was formed in the interval from Proterozoic to Late Devonian time during several discrete phases of deformation that involved a similar stress pattern. These phases can be attributed to pulses of differential vertical uplift of the underlying Boothia Horst. The earliest phases involved periods of gentle arching of the crystalline basement and sedimentary cover in late Proterozoic and early Paleozoic times. The fold belt was formed mainly by the Cornwallis Disturbance (new name) which involved further differential vertical uplift, and comprised several pulses: (1) Early Silurian, mild, affecting only part of the belt; (2) Early Devonian, very strong, affecting the entire belt; (3) late Early Devonian, moderately strong, affecting the entire belt; (4) Late Devonian, moderately strong, affecting the entire belt. Each pulse was a cycle that began with uplift and erosion of the fold belt and shedding of detritus into the adjacent basins, and was followed by broader regional subsidence and the resumption of deposition on the belt. Between pulses of uplift there was regional subsidence, during which the fold belt subsided less than the flanking basins and received less sediments.Differential vertical displacement originated in the crystalline basement, occurring along fault zones that define the Boothia Horst, and are parallel to and controlled by a steep to vertical north-trending foliation. Faults extend into the sedimentary suprastructure comprising the overlying Cornwallis Fold Belt, and change gradually upward from vertical faults to high-angle reverse faults, overturned anticlines, and finally to asymmetric anticlines. Because the fold belt plunges north, this gradational sequence occurs from south to north in the exposed part of the fold belt. Structures formed by early pulses were rejuvenated by later pulses with the same sense of movement.Modification. The basic structure of the Cornwallis Fold Belt was modified by other types of deformation during the interval from Late Devonian to the present. Many of the preexisting faults were reactivated, but with a different sense of movement. During the Late Devonian to Middle Pennsylvanian Ellesmerian Orogeny, southward overriding of upper levels of the sedimentary succession produced folds in the rocks east and west of the Cornwallis Fold Belt which had not been previously deformed and could easily be displaced southward on an underlying décollement surface. The north-trending Cornwallis Fold Belt, however, was an obstacle to southward overriding in which the effects of overriding were reduced. Zones of interference structures developed near the margins, guided by older basement-controlled structures. Left-lateral faults were developed on the western margin and right-lateral movement is probable on the eastern margin.The Cornwallis Fold Belt extends an unknown distance northward beneath the younger rocks of the Sverdrup Basin. These younger rocks were deposited during a long period of northward downwarping that began in mid-Mississippian time. This same downwarping caused an abrupt increase in the northward plunge of the fold belt.During the Cretaceous–Tertiary Eurekan Rifting Episode the Cornwallis Fold Belt was fragmented by block faulting. The horsts form islands, and the grabens form submarine channels, some of which contain thick sections of semiconsolidated Cretaceous–Tertiary sediments. Numerous other normal faults that occur within the fold belt probably formed at this time. Cretaceous–Tertiary faults within the Cornwallis Fold Belt have a rectilinear pattern that was inherited from preexisting structures.

Structural control of batholithic emplacement in Peru: a review

In the Andes, major lineaments controlled sedimentation, vulcanicity, batholithic intrusions and mineralisation throughout the Mesozoic and Cenozoic. These lineaments represent major fault lines in an ancient crystalline basement. The magmas of the Coastal Batholith were emplaced along one such lineament and the emplacement of the individual plutons was closely controlled by transcurrent faults and by smaller scale joint patterns. Such structures were continuously exploited throughout the long emplacement history of the batholith. Exceptionally, plutons were forcefully emplaced along early lineaments and lifted roof blocks along shear zones coincident with pre-existing faults. More generally subsidence of large fracture-bound crustal blocks provided the space for the emplacement of magma in bell-jar and cauldron-subsidence structures while stoping along the regular, closely spaced joints resulted in a rectilinear pattern of contacts at outcrop scale.