Digitized by Kansas State University Libraries

A subsurface and surface structural study was completed in the southwest part of the Elk Basin Anticline, Wyoming. The goals of this study were to better improve preexisting geologic surface maps of the area and to better understand subsurface structural relationships. A normal fault with a splay to the north was recorded through sections 25, 26. and 35 of T58N, RI00W. Using well logs to create across section, this fault was traced in the subsurface. Strike and dip measurements in undisturbed areas of the anticline averaged 332° (azimuth) or N28W (quadrant). In an area of anomalous strike (section 26 of T58N, R1 00W), strike readings averaged 303° (azimuth) or N57W (quadrant). This region has been interpreted as an area rotated counter clockwise due to drag on a subsurface tear fault located at the northern end of the anticline. The current study is significant since it lends support to a little studied Laramide structural feature. / Department of Geology

The hinge region of a major anticlinal fold structure in the SW Scottish Highlands was located in the eastern part of the Isle of Islay. The structure plunges gently NNW, with the hinge line measuring 02/026. The hinge region was located by mapping a 2km2 area comprised of deformed Neoproterozoic metasedimentary and metacarbonate rocks, and plotting the measurements on stereograms. The data collected was also analysed to attempt to asses evidence of refolding, and it is suggested in this thesis that the area displays evidence of at least one subsequent refolding event.

The Wabash Valley Seismic Zone (WVSZ) has produced three moderate sized earthquakes greater than or equal to mb 5.0 in the past 50 years. The majority of Wabash Valley faults originate near the junction of the Rough Creek and Cottage Grove faults and extend northeastward along the Wabash River. These faults extend through the Paleozoic and into the Precambrian and are believe to be associated with the Reelfoot Rift. Two of these moderate sized earthquakes have occurred north of the terminus of the Wabash Valley faults that the WVSZ is commonly associated with. This suggests that other sources of seismicity exist. The La Salle anticline, a Precambrian basement feature, is oriented NW to SE just north of the termination of these faults. The La Salle anticline creates up to a 750 meter uplift in the above Paleozoic strata. This uplift creates faults within the Paleozoic strata and within the La Salle anticline. This study uses seismometers arranged in a phased array near the southern terminus of the La Salle anticline to analyze the seismicity of the region. Analyzing the seismicity of the region over a 6-month period found 834 events. The vast majority were determined to be mine blasts or otherwise human induced. Two small earthquakes (~M 1.0) located near the La Salle anticline. These earthquakes likely occur on faults associated with the anticline. The lack of earthquakes suggested the b-value of the La Salle region could be as low as 0.56. This is lower than the typical value of 1, but consistent with other intraplate regions and previous studies of the WVSZ finding values nearer 0.7.

<p> A syncline-anticline pair in miogeosynclinal sediments of the western margin of the Labrador Trough was mapped. Samples were taken of each rock unit and a structural analysis was performed. The structure determined was compared in an elementary fashion to geophysics completed over the mapping area. </p> <p> The folds in the pair are highly variable along their length changing from an open to tight folding style and with a rolling plunge varying from 3° NW to 12° SE. </p> <p> The beds of the folds show no internal deformation except for drag folding in the shaly units. The rocks were folded by a flexural slip mechanism. </p> <p> The gravity and ground magnetics successfully outlined the structure of the fold, dipping of the beds and in one instance located a fault. Typical gravity values (signatures) for a number of rock units are easily determined.</p> / Thesis / Bachelor of Science (BSc)

The Bear River Range, in north-central Utah, contains a variety of geomorphic elements influenced by the geologic setting and events. Controlling factors of the geologic setting include: (1) a syncline (west) and an anticline with a crestal graben (east) within the part of the mountain range studied, and an adjacent graben valley along the west side of the range; and (2) bedrock of Precambrian and Paleozoic age in the core of the range, predominantly of shallow-marine carbonates and covered in the graben by shaly and conglomeratic rocks of early Cenozoic age, with fanglomerates and lake deposits of later Cenozoic age. Geologic events contributing to geomorphic development include: (1) (?) Bull Lake and Pinedale glaciation; ( 2) various levels of Lake Bonneville; and (3) Hypsithermal climatic conditions. The eighteen canyons along the western front of the Bear River Range in Utah, in sequence from north to south, are: High Creek, Oxkiller Hollow, Cherry Creek, City Creek, Nebo Creek, Smithfield, Birch, Dry (North), Hyde Park, Green, Logan, Dry (South), Providence, Millville, Blacksmith Fork, Hyrum, Paradise Dry, and East. An attempt was made to relate gradient changes along longitudinal canyon profiles to lithologies, attitudes, or other structural controls. The only consistent gradient change is a steepening of the gradient downstream from outcrops of Swan Peak Formation. A pronounced asymmetry in cross-valley profiles probably results from micro-climatic differences that cause north-facing slopes to be steeper than southfacing slopes despite close similarities in structure and lithology across canyons. Several canyons which do not cross the syncline axis have no measurable discharge. Water from these drainages apparently moves along the strike or down the east-dipping rocks of the western limb of the Logan Peak syncline to emerge as springs added to the surface flow in cross-axial canyon streams. Leakage is probably concentrated in the Lodgepole and Great Blue Formations. Minor geomorphic elements within the Bear River Range result from glacial, periglacial, and fluvial processes, and landslides. Periglacial action has produced both nivation and patterned diamicton. Glacial features are present in Logan Canyon and its tributaries, Birch, Providence, and the South Fork of Smithfield canyons. In addition to these previously mapped glacial areas, High Creek Canyon was subjected to glacial modification in the upper reach of South Fork tributary, and Leatham Hollow (Blacksmith Fork Canyon ), in the upper reach of its major southern tributary. Nivation modified the heads of Smithfield, Green, Cottonwood, and Dry (South) canyons by carving cirques floored by rock debris. Evidence for glacial action downstream from these cirques is absent. Patterned diamicton sites are widely distributed within the range. There is no consistent relationship to exposed lithologies or physical setting. The apparent relationship of slope aspect, elevation, and solar radiation suggests an origin by a temperature-dependent process, for near-identical temperatures were calculated for all patterned diamicton sites. Based, in part, on a reconstruction of Pleistocene temperatures, the patterned diamicton sites probably are a form of patterned ground resulting from frost action during glacial episodes. Alluvial fans lie at the mouths of many tributary canyons. Based on degree of soil development and relations to features of known age, a sequence of fan development is recognized. Alluvial fans formed prior to Wisconsinan time and repeatedly thereafter during interglacial and glacial periods. Many of the fans formed after the Pleistocene under the favorable conditions that existed during the Hypsithermal interval. Landslides in the study area are commonly old, inactive features. Only a few sites are recent in age, or currently active. Slopes with a west-component aspect are more prone to movement than other aspects. The most frequently disturbed lithology consists of Tertiary formations which are often conglomeratic. A wide range of slope inclinations have landslides, but the dominant slope is 20 to 24 percent. The main elevation range for landslides is between 6, 000 to 6, 999 feet. Quaternary stream alluvium and Lake Bonneville deposits are found along the eastern margin of Cache Valley and in the lower reaches of most canyons. This material has been deposited since the Provo phase of Lake Bonneville. In several places, lake or stream terraces are mapped.

Adiyaman region is situated within SE Anatolian Fold and Thrust Belt which is a part of Alpine-Himalayan Mountain Belt system. The Belt is evolved as Eurasian plate and Arabian plate amalgamates in SE Anatolia. There are two main contractional deformational periods, Late Cretaceous and Late Miocene, which are followed by a strike slip deformation, during post-Late Miocene characterizing the tectonics of SE Anatolia. Series of folds and thrusts have a trend of almost ENE-WSW direction. The analysis on bedding planes and folds shows around N70E trend. On the other hand, two overthrusts that are closely linked to the folds and a sinistral strike-slip fault with reverse component are differentiated. The overthrust belt with ENE-WSW trend bounds the study area from north with a vergence from north to south and situated on top of folded upper Miocene sequences. Another overthrust and a cross-cutting strike slip fault with reverse component &ndash / Adiyaman Fault- form a &ldquo / pop-up&rdquo / structure (positive flower structure) which is characteristic for in a transpressional regimes manifested in geological cross-sections done from borehole correlations and seismic sections. To conclude, by combining the surface (field data) and subsurface data (seismic and borehole data), the Alidag anticlinal structure that is formed along the Adiyaman Fault are developed after the Late Miocene under transpressional regime.

This study investigates evidence for linkages and fault interactions centred on the Cust Anticline in Northwest Canterbury between Starvation Hill to the southwest and the Ashley and Loburn faults to the northeast. An integrated programme of geologic, geomorphic, paleo-seismic and geophysical analyses was undertaken owing to a lack of surface exposures and difficulty in distinguishing active tectonic features from fluvial and/or aeolian features across the low-relief Canterbury Plains. LiDAR analysis identified surface expression of several previously unrecognised active fault traces across the low-relief aggradation surfaces of the Canterbury Plains. Their presence is consistent with predictions of a fault relay exploiting the structural mesh across the region. This is characterised by interactions of northeast-striking contractional faults and a series of re-activating inherited Late Cretaceous normal faults, the latter now functioning as E–W-striking dextral transpressive faults. LiDAR also allowed for detailed analysis of the surface expression of individual faults and folds across the Cust Anticline contractional restraining bend, which is evolving as a pop-up structure within the newly established dextral shear system that is exploiting the inherited, now re-activated, basement fault zone. Paleo-seismic trenches were located on the crest of the western arm of the Cust Anticline and across a previously unrecognised E–W-striking fault trace, immediately southwest of the steeply plunging Cust Anticline termination. These studies confirmed the location and structural style of north-northeast-striking faults and an E–W-striking fault associated with the development of this structural culmination. A review of available industry seismic reflection lines emphasised the presence of a series of common structural styles having the same underlying structural drivers but with varying degrees of development and expression, both in the seismic profiles and in surface elevations across the study area. Based on LiDAR surface mapping and preliminary re-analysis of industry seismic reflection data, four fault zones are identified across the restraining bend structural culminations, which together form the proposed Oxford–Cust–Ashley Fault System. The 2010–2012 Canterbury Earthquake Sequence showed many similarities to the structural pattern established across the Oxford–Cust–Ashley Fault System, emphasising the importance of identification and characterization of presently hidden fault sources, and the understanding of fault network linkages, in order to improve constraints on earthquake source potential. Improved understanding of potentially-interactive fault sources in Northwest Canterbury, with the potential for combined initial fault rupture and spatial and temporal rupture propagation across this fault system, can be used in probabilistic seismic hazard analysis for the region, which is essential for the suitability and sustainability of future social and economic development.

This thesis contains several distinct studies aimed at better understanding fracturing in compressional fault-cored folds. At outcrops of growth strata in the Oliana anticline in the Spanish Pyrenees, the relationship of two joint sets may reflect changing mechanical properties (i.e. via diagenesis) during the folding process. Using a Schmidt hammer, I assess the rigidity contrast between the individual units and suggest that late-stage, throughgoing joints formed in strata with conditions similar to those of the present day and that early, bed-contained joints formed when the rigidity contrast between beds was significantly greater than the present day contrast. Modeling algorithms that are used for fracture prediction assume plane strain to construct, model and restore fault-cored folds. Using mechanical models that allow heterogeneous transport in three dimensions, I explore the distribution and magnitude of out-of-plane transport in plunging fault-cored anticlines and provide guidelines of where plane strain should and should not be applied. I show that out-of-plane transport is significant in the simplest non-cylindrical folds, and suggest that complex non-cylindrical structures should not be modeled using plane strain. I mapped five bed-orthogonal fracture sets associated with folding and faulting events at Sant Corneli anticline, a non-cylindrical, fault related anticline in the Spanish Pyrenees. Fold axis perpendicular, calcite healed joint sets associated with similarly oriented normal faulting both pre-date, and are cross cut by calcite healed, N-NW striking joints. Later bed strike oblique joint sets are distinguished by the presence of iron oxide mineralization that probably occurred during Paleocene-Oligocene time. This study directly links fold-related fracturing to fold evolution because fracture sets can be dated relative to the structural evolution of the anticline. I use three-dimensional restorations of Sant Corneli anticline in the Spanish Pyrenees to test the fracture prediction capability of a fully three-dimensional finite element geomechanical restoration algorithm. Reconstruction of the three-dimensional architecture of the syn-tectonic strata provides a template for incrementally unfolding the anticline. Strains predicted by the restorations are compared to the fracture sets that formed over the corresponding time intervals, which are consistent with the observed fracture patterns at Sant Corneli anticline.

The Alta-Kvænangen Tectonic Window is part of a regional greenstone belt that formed around 2.3 Ga – 2.0 Ga. The Bergmark anticline in the area has gone through greenschist to amphibolite facies metamorphism and hosts Cu, Co and Au mineralizations in hydrothermal veins, albite felsite and chemical traps. The area was mined during the late 19th century mostly in trenches but it has still got exploration potential. This project will classify carbonate veins that are hosted within two gabbro units, compare orientations between the barren and mineralized veins as well as discuss the origin of the veins.  The study area has been affected by multiple extensional and compressional events during the Svecokarelian orogeny (1.9 – 1.8 Ga) and regional hydrothermal alterations including an influx of Na + Ca ± K ± Fe. Major shear zones were activated and used for transporting fluids which are thought to have controlled the formation of mineralization in second- or even third-order structures. The veins were studied using field work, detailed mapping, optical microscopy as well as scanning electron microscopy (SEM) and structural analysis. Results gave three different types of hydrothermal veins: 1) Fe oxide veins, 2) calcite veins and 3) dolomite-plagioclase-quartz veins. All of them show strong signs of deformation and recrystallization all while the chalcopyrite mineralization is heterogeneously distributed and commonly more or less bornite-altered. The veins pinch and swell over short distances and are sinuous but with a general orientation. Albite haloes are common for the veins but far from all veins have haloes. There are at least two generations of veins as some were found to have offset others. Brecciation, tension gashes and faults are also found in the area apart from veins. From the field measurements, two groups of orientations could be determined: one with a SW-NE direction and the other in NW-SE direction, both with relatively steep dips. Considering all downhole measurements, no conclusive results could be revealed, however, the optical televiewer results showed that the area has gone through a N-S compression giving a fold axis towards the west. In the end the orientations of the larger veins were found to either run parallel to the gabbro units or are connected to the NW-SE directed main brittle faulting in the Fennoscandian Shield. Smaller, surrounding veins having more diverse orientations. There are multiple signs of deformation and recrystallization in the mafic host rock but no fabric development can be seen. Its appearance varies locally depending on which alterations are dominating. It exhibits sodic-calcic, potassic and leucoxene alteration as well as albitization and carbonatization. The grain size varies from fine-grained to medium-grained which is more typical with a dolerite or basalt, even though it has been previously mapped as a gabbro. No pyroxene was found in the host rock and the plagioclase was Na-rich instead of the expected Ca-rich.  The Bergmark anticline has multiple similarities with the Gällivare-Kiruna area in Sweden which include 1) high-temperature, low-pressure metamorphism resulting in regional alterations such as albitization, carbonatization, amphibole and magnetite alteration. 2) The mineralization consists of Cu, Co, Au, Fe and minor P. 3) The mineralization can be found disseminated in albite felsite, in chemical traps and in first to third order structures (e.g., faults or hydrothermal veins) in brittle, deformed rocks. 4) The mineralization is structurally controlled to the vicinity of major fault zones. 5) In both places, greenstone belts are important for the formation of mineralization. 6) Reactivation of brittle structures, similar to those in the Kiruna area during the second phase of subduction during the Svecokarelian orogeny (D2), is likely the cause for the veining in the Bergmark anticline. 7) A younger N-S compression is recorded in the area. Differences between the Bergmark anticline and the Gällivare-Kiruna area include the lack of intrusions in the vicinity to the Bergmark anticline.