North-south Section Research Articles

Exotic plant taxa of Solaklı Watershed (Trabzon/Türkiye)

Solaklı Vadisi (Trabzon) Doğu Karadeniz Bölümü’nde kuzeyden güneye doğru, sahilden 3376 m rakıma kadar yükselen ve toplam alanı 83000 hektar olan geniş bir havzadır. Havza bölge florası (Kolşik sektör) için kuzey-güney yönünde bir kesit özelliğine sahiptir. Yapılan flora ve vejetasyon çalışması sonucu, havzada yayılış gösteren toplam 141 adet vasküler yabancı bitki taksonu belirlenmiştir. Tespit edilen yabancı türlerden 34 adeti istilacı yabancı türdür. Geri kalan türler ise havzada doğallaşma süreçlerini tamamlayarak havza florasının bir parçası haline gelmiştir. Türkiye’de en dikkat çekici istilacı yabancı bitki olarak değerlendirilen 20 bitki taksonunun tümünün havzada yayılmakta olduğu saptanmıştır. Çalışmada ayrıca, havza özelinde istilacı yabancı bitkilerin bitkisel biyoçeşitlilik üzerine etkileri, ekolojik koşullar dikkate alınarak uygulanabilecek mücadele yöntemleri tartışılmıştır. Bu bağlamda ilgi gruplarının neler yapmasının ve nelerden kaçınmalarının uygun olacağı belirtilmiştir.

The tabular Strathbogie batholith in central Victoria

The southern boundary of the high level, discordant, Devonian Strathbogie batholith in central Victoria includes two near-linear sections that strike east–west, and one north–south. Field mapping has delineated the 100 km southern boundary with 2200 waypoints taken where granite and hornfels are within 10 m of one another. There is 790 m of topographic relief along the southern boundary and, where the mapping is overlain on contours, there are intervals that reflect a steep-dipping contact and others that reflect near-horizontal contacts. Of the latter, some reflect the granite roof and others the floor. Complementary evidence from mineralogic and textural data indicates a strong correlation between the interpreted roof of the granite and the abundance of tourmaline, aplite and pegmatite. When combined, the roof and floor intervals indicate a batholith thickness up to 350 m; nowhere along the southern boundary can a thickness of 1 km be demonstrated. Along the southern boundary, at least, the batholith shape is a thin, tabular and extensive composite granite sheet analogous to a pizza rather than a pipe. The roof of the granite is nearly horizontal in both east–west and north–south sections, and the plateaux today are close to the batholith roof. On regional and local scales, granite emplacement was determined by pre-existing anisotropies, such as master joint sets, across which the propagation of magma-filled fractures (granite sheets) was arrested. The emplacement records a fine balance between magma pressure, and the interplay of lower confining (overburden) pressures and pre-existing anisotropies that also facilitated roof uplift. The opportunistic magmas used the slightest variations of those parameters. This interpretation of the Strathbogie batholith matches examples in the Himalaya and Chilean Andes but differs markedly from the portrayal of very large batholiths beneath Cu–Au porphyry systems. KEY POINTS The boundary of the Strathbogie batholith can be mapped in moderately outcropping terrain to an accuracy of 10 m or better. Steep intervals of the boundary are interspersed with near-horizontal intervals that delineate the granite floor and roof along the 100 km of the southern boundary. The batholith, at least near its southern boundary, comprises near-horizontal sheets of <500 m aggregate thickness. The boundary determined by geophysics is adequate for regional studies but has been misleading in three-dimensional interpretations.

Influence of habitat quality and resource density on breeding‐season female monarch butterfly Danaus plexippus movement and space use in north‐central USA agroecosystem landscapes

Abstract The eastern North American monarch butterfly is at risk of quasi‐extinction due, in part, to the loss of breeding habitat in agricultural landscapes of the USA Midwest. Because adult females are not patch residents, egg abundance and distribution across the landscape are a function of their perceptual range, flight directionality and flight step lengths. Conservation actions that account for habitat use in agricultural landscapes can enhance functional connectivity. Field‐captured females (n = 114) were released in a 64‐ha area containing restored prairies, grass‐dominated fields and crop fields in Floyd County, Iowa, USA, and two 1,000 m linear north–south sections of grass‐dominated roadside along secondary roads (~35 ha) with different proximity to prairie habitat in rural Story County, Iowa. Radio‐tagged or untagged monarchs were released in areas with high density, low density and zero density of forage and oviposition resources, as well as on habitat edges between high‐ and zero‐density habitats. Monarchs were observed for 1 hr. Radio‐tagged individuals that flew beyond visual detection were relocated using handheld radiotelemetry. Monarchs moved within and between habitat classes and typically performed upwind search behaviour. Monarchs successfully located resources, with some flying over 500 m to find high‐density areas, providing evidence that the monarch's perceptual distance is &gt;100 m. Regardless of habitat class or field site, most step lengths were &lt;50 m, and turn angles were directional. Large steps (≥50 m) crossing habitat boundaries occurred with approximately half of the monarchs, which may indicate initiation of long‐range searches for suitable habitat, consistent with their vagile behaviour. Establishing habitat patches 50 m apart in agricultural landscapes would facilitate efficient movement. Synthesis and applications. This study provides an extensive dataset of directly observed breeding‐season monarch butterflies to assess the utilization of agricultural landscapes. Documentation of step lengths &gt;50 m in complex, agricultural landscapes would not have been possible without the aid of radiotelemetry. Results provide improved estimates of perceptual range and flight patterns within and between habitat patches that support models that simulate natural population dynamics to enable conservation planning at a landscape scale.

Basement Characteristics of Jakarta Groundwater Basin Based on Satellite Gravimetry Data

Jakarta groundwater basin is one of the most developed basins in Indonesia as Jakarta city is located within the basin, with an elevation ranging from 0 to 1000 m above sea level. The study of the basement characteristics of groundwater basins still needs further study in the Jakarta Groundwater Basin. The objective of this study is to examine the basement characteristics of Jakarta Groundwater Basin by satellite gravimetry. Gravity forward models were constructed using Oasis Montaj and 2-D GM-SYS software for two north-south sections, A and B, and west-east section C-D. Regional anomalies in the study area with a value range of 36.7 to 53.2 mGal, while the residual anomaly values in the study area were in the range of -7.0 - 10.0 mGal. There are four rock formations based on forwarding modeling. Holocene Beach Ridge Deposit formation has a density of 2.0 gr/cc. The thickness of this formation is estimated to be around 10-20 meters. Late Pleistocene Alluvial fan has a density of about 2.2 gr/cc. The depth of this layer ranges from 10-50 meters. Early Pleistocene Formation, has a density of 2.35 gr/cc. The thickness of this formation is at a depth of 50-200 meters in the cross-section. The Tertiary Marine Sediment Formation is a basement of the Jakarta Groundwater Basin. This formation has a rock density of 2.45 gr/cc.

Phytoplankton Phenology in the North Atlantic: Insights From Profiling Float Measurements

Phytoplankton division rate (µ), loss rate (l), and specific accumulation rate (r) were calculated using Chlorophyll-a (Chl) and phytoplankton carbon (Cphyto) derived from bio-optical measurements on 12 Argo profiling floats in a north-south section of the western North Atlantic Ocean (40° N to 60° N). The float results were used to quantify the seasonal phytoplankton phenology and bloom dynamics for the region. Latitudinally varying phytoplankton dynamics were observed. In the north, the CPhyto peak was higher, occurred later, and was accompanied by higher total annual CPhyto accumulation. In contrast, in the south, stronger μ-r decoupling occurred despite smaller seasonal variations in mixed layer depth (suggesting the possibility of other ecological forcing), and was accompanied by an increasing portion of winter to total annual production, consistent with relief of nutrient limitation. The float observations of phytoplankton phenology for the mixed layer were compared to ocean color satellite remote sensing observations and found to be similar. A similar comparison to an eddy-resolving ocean simulation found the model only reproduced some of aspects of the observed phytoplankton phenology, indicating possible biases in the simulated physical forcing, turbulent dynamics, and bio-physical interactions. In addition to seasonal patterns in the mixed layer, the float measurements provided information on the vertical distribution of physical and biogeochemical quantities and therefore are complementary to the remote sensing measurements. Seasonal phenology patterns arise from interactions between “bottom-up” (e.g., resources for growth) and “top-down” (e.g., grazing, mortality) factors that involve both biological and physical drivers. The Argo float data are consistent with the disturbance recovery hypothesis over the full, annual seasonal cycle; for the late winter/early spring transition, the float data are also consistent with other bloom hypotheses (e.g. critical photosynthesis, critical division rate, and meso/sub-mesoscale physics) that highlight the importance of brief, episodic boundary layer shoaling for decoupling of division and grazing rates.

Distribution of Anoxic Conditions in the Photic Layer of Sedimentation Basin during Formation of Organic Matter in the Domanik Sediments of the Northern and Central Areas of the Volga–Urals Petroleum Basin

Abstract—The composition of compounds employed as markers for anoxia in the photic layer of the sedimentation basin is studied in samples from Upper Devonian domanik-type sediments (Sargaevian, Semilukian, and Mendymian horizons, Famennian stage), which are widespread over the Volga–Urals basin. The studies were carried out along the north-south section spanning the northern and central parts of the Volga–Urals areas. The H2S contamination of photic layer was determined over the most part of the studied territory. During the Semilukian time, the boundary of H2S contamination passed through the middle part of the near-slope zone of the Mukhanovo–Erokhov Trough; the contamination reached the highest thickness in the northern part of the region. The intense H2S contamination also occurred in this part in the Pashiiskian and Sargaevian time. The Mukhanovo–Erokhov Trough during Mendymian and Famennian was characterized by a strong change of setting: from a steady strong contamination to its complete absence. It is shown that changes in the content of anoxia markers in samples from the the Kama–Belsk Basin and South Tatar Arch were caused by variations of thickness of the contaminated layer. It is revealed that the processes of complete hydrogenation of initial polyenes prevail over cyclization for the domanik-type sediments over the entire region. It was found that the ratio of the total content of alkyl benzenes in the fraction of aromatic compounds to the total content of products of complete hydrogenation of initial polyenes in OM from the domanik-type sediments of the studied areas does not depend on the OM maturity. Explanation of this fact is proposed.

GEO-ECOLOGICAL STUDY OF CENTRAL PIPELINE CORRIDORS IN GEORGIA

&#x0D; &#x0D; &#x0D; At present, the main pipelines represent the most profitable economic means in terms of transportation, supply and exploitation of energy resources. Since their laying is associated with a change in the natural environment, the ecological study of these corridors is a prerequisite. Geo-ecological study of the main pipelines is divided into three stages. This is the study of the pipeline route, to establish the existing background before the work begins. The second stage is the establishment of environmental impact during the laying of the pipeline. The third step is to monitor the environmental problems encountered during exploitation.The presented article gives a geo-ecological study of the corridors of gas pipelines in the section 1200, 1000 and 700 mm on the Kazbegi-Red Bridge (North-South) section. Carried out works represents the first stage of the study, and we have identified the physical and biological characteristics of the pipeline corridors. It was determined the purity of air, noise, chemical composition of soil, water and vegetation cover, as well as engineering and geological conditions of gas pipeline corridors. The results obtained do not exceed the values of the maximum permissible concentrations adopted in Georgia and in European countries, although Pl, Co, Ni and Cd show increased values directly near the gas pipeline.&#x0D; &#x0D; &#x0D;

The Archaeology of the Ostraca House at Israelite Samaria: Epigraphic Discoveries in Complicated Contexts

The Archaeology of the Ostraca House at Israelite Samaria: Epigraphic Discoveries in Complicated Contexts

Hydrologic and hydrogeologic analyses of an alluvial aquifer underlying Kushabhadra-Bhargavi River basin, Odisha, India

This paper deals with the analysis of groundwater condition in an alluvial aquifer system underlying Kushabhadra-Bhargavi River basin of Odisha, India. The rainfall data and river-stage data of the Kushabhadra River were analyzed for the periods of 1995–2009 and 1991–2010, respectively. Using the available lithologic data, geologic profiles along North-South and East-West sections were prepared and stratigraphy analysis was performed to characterize aquifers and confining layers present in the river basin. The results of stratigraphic analyses indicated that a two-layered aquifer system consisting of an unconfined aquifer and a confined aquifer exists in the study area. The thickness of unconfined aquifer varies from 3.4 to 46.5 m, whereas that of confined aquifer varies from 3.1 to 80.3 m over the basin with an interconnecting confining layer of thickness ranging from 2.1 to 60.0 m. The rainfall-groundwater dynamics and hydraulic connectivity were also investigated for gaining insights into groundwater characteristics. The analysis of groundwater levels indicated that the correlation among the 14 sites is better for most pairs of the sites (r = 0.50 to 0.96) in case of pre-monsoon season’s data and annual data as compared to monsoon and post-monsoon season’s data. This indicates good hydraulic connectivity among the observed sites in the study area. The significant seasonal groundwater fluctuations in the study area indicate appreciable recharge to the aquifer during the monsoon season. The findings obtained and insights gained from this study can be helpful for the water managers and decision makers to understand groundwater dynamics for the efficient planning and management of vital groundwater resources in the region. It is recommended that groundwater monitoring should be continued at more sites to understand long-term spatio-temporal characteristics of groundwater in the study area.

The use of phytoplankton as an indicator of internal hydrodynamics of a large seaside reservoir – case of the Sasyk Reservoir, Ukraine

The Sasyk Reservoir, one of the largest seaside reservoirs on the northwest shore of the Black Sea, the former river delta currently detached from the sea with a narrow bar of sediments, was investigated for spatial distribution of water quality characteristics with the use of bioindication method. A three day preliminary sampling campaign of phytoplankton held in the summer 2013 revealed that the reservoir's dominating species belonged to moderate temperature, freshwater, low acidic and low alkaline indicative groups. They suggest standing to slow-moving hydrodynamics of water masses, that contain a medium amount of oxygen. The indices of ecosystem status, such as index of organic pollution according to Watanabe, modification of Sládeček, water quality classes based on saprobity, trophic state indicator groups, nitrogen metabolism indicator groups, as well as Shannon index coincided, showing medium polluted Class III (saprobity) eutrophic water with prevailing moderate concentrations of organically bounded nitrogen. Environmentally homogeneous water masses were dominated with local anomalies on the locations of inflows of waters of different physicochemical characteristics from rivers and the Danube-Sasyk Canal, saline waters from the sea, and nitrogen enriched groundwater from intensive agricultural area. Two types of ecosystems were identified, the one connected with the main water body and the other with the shallows. The sampling was performed in the condition of no outflow, but the wind direction and the wind driven internal dynamics of the reservoir were the major influencing factors for phytoplankton distribution. A gradient of water pollution in the direction of the north–south section of the receiving water from the Danube-Sasyk Canal was revealed. Although the reservoir ecological processes seems to be effective enough in metabolizing the incoming pollution, the symptoms of progressing deterioration of water quality (small-cell forms of organisms) indicate the need for further monitoring and proper management. The bioindicative method appeared to be in some cases more sensitive in ecosystem and abiotic factors analysis then a standard physicochemical analysis, which creates a ground for further developing of its predictive potential.

Stratigraphic Architecture of a Fluvial-lacustrine Basin-fill Succession at Desolation Canyon, Uinta Basin, Utah: Reference to Walthers’ Law and Implications for the Petroleum Industry

A continuous window into the fluvial-lacustrine basin-fill succession of the Uinta Basin is exposed along a 48-mile (77-kilometer) transect up the modern Green River from Three Fords to Sand Wash in Desolation Canyon, Utah. In ascending order the stratigraphic units are: 1) Flagstaff Limestone, 2) lower Wasatch member of the Wasatch Formation, 3) middle Wasatch member of the Wasatch Formation, 4) upper Wasatch member of the Wasatch Formation, 5) Uteland Butte member of the lower Green River Formation, 6) lower Green River Formation, 7) Renegade Tongue of the lower Green River Formation, 8) middle Green River Formation, and 9) the Mahogany oil shale zone marking the boundary between the middle and upper Green River Formations. This article uses regional field mapping, geologic maps, photographs, and descriptions of the stratigraphic unit including: 1) bounding surfaces, 2) key upward stratigraphic characteristics within the unit, and 3) longitudinal changes along the river transect. This information is used to create a north-south cross section through the basin-fill succession and a detailed geologic map of Desolation Canyon. The cross section documents stratigraphic relationships previously unreported and contrasts with earlier interpretations in two ways: 1) abrupt upward shifts in the stratigraphy documented herein, contrast with the gradual interfingering relationships proposed by Ryder et al., (1976) and Fouch et al., (1994), 2) we document fluvial deposits of the lower and middle Wasatch to be distinct and more widespread than previously recognized. In addition, we document that the Uteland Butte member of the lower Green River Formation was deposited in a lacustrine environment in Desolation Canyon. Two large-scale (member-scale) upward patterns are noted: Waltherian, and non-Waltherian. The upward successions in Waltherian progressions record progradation or retrogradation of a linked fluvial-lacustrine system across the area; whereas the upward successions in non-Waltherian progressions record large-scale changes in the depositional system that are not related to progradation or retrogradation of the ancient lacustrine shoreline. Four Waltherian progressions are noted: 1) the Flagstaff Limestone to lower Wasatch Formation member records the upward transition from lacustrine to fluvial—or shallowing-upward succession; 2) the upper Wasatch to Uteland Butte records the upward transition from fluvial to lacustrine—or a deepening upward succession; 3) the Uteland Butte to Renegade Tongue records the upward transition from lacustrine to fluvial—a shallowing-upward succession; and 4) the Renegade Tongue to Mahogany oil shale interval records the upward transition from fluvial to lacustrine—a deepening upward succession. The two non-Waltherian progressions in the study area are: 1) the lower to middle Wasatch, which records the abrupt shift from low to high net-sand content fluvial system, and 2) the middle to upper Wasatch, which records the abrupt shift from high to intermediate net-sand content fluvial system.

Geodynamic evolution of the Salinas de Añana diapir in the Basque-Cantabrian Basin, Western Pyrenees

The Salinas de Añana diapir is located in the Basque-Cantabrian basin part of the great evaporite basin, along with the Gulf of Mexico and the Central European basin, when the fragmentation of Pangea started. The evolution of these basins can only be achieved by understanding the control of salt in the sedimentary and tectonic evolution of these basins.Sedimentation began with clastic Buntsandstein sediments and minor Muschelkalk limestones. Subsequent Keuper evaporites are the bottom of sedimentary cover constituted by Jurassic limestones and marls, a clastic Lower Cretaceous and an alternant limestone and marl Upper Cretaceous, whose deposition has been conditioned by salt tectonics. The emplacement of salt extends from the Aptian until now, favored by the duplication of the salt thickness associated with the thrust of Sierra Cantabria, so it is an excellent example to study changes in the regime of intrusion along the time. The geodynamic evolution of the Salinas de Añana diapir was determined through the interpretation of 45 reprocessed seismic lines, along with information from three wells. Migration of the salt in this diapir, conditioned by N120E and N30E pre-Alpine basement lineations, was determined using time isopach maps of the various rock layers. Vertical evolution of the diapir was determined through the reconstruction of a north-south section at various geologic times by flattening the respective seismic horizons. A minimum of salt flow into the diapir coincides with a minimum rate of sedimentation during the Turonian. Similarly, maximum flows of salt into the diapir occurred during the Coniacian and Lower Santonian and again from the end of the Lower Miocene to the present, coinciding with maximum rates of sedimentation during these times. In the Tertiary, probably during the Oligocene, the diapir was displaced to the south by the Sierra Cantabria thrust, maintaining the contact between the evaporites of diapir and the same evaporites of the lower block. Since the Oligocene, the salts of the lower block migrated towards and into the diapir, deforming the trace of the overthrust.

Evolution of the NE Qinghai–Tibetan Plateau, constrained by the apatite fission track ages of the mountain ranges around the Xining Basin in NW China

The Laji Shan and Daban Shan which are located along the southern and northern margins of the Xining Basin in the northeastern Qinghai–Tibetan Plateau, experienced important multi-stage exhumations during the Cenozoic. The apatite fission track (AFT) dating of 19 samples along four north–south sections in the Laji Shan and Daban Shan showed that the AFT ages of the Laji Shan from 88Ma to 12Ma and the ages of the Daban Shan are between 60 and 32Ma. All these AFT ages are significantly younger than their host rock formation or sediment deposition ages. Thermal modeling of the AFT data indicated that the Laji Shan had undergone important exhumation events in the Late Cretaceous, ca. 50–30Ma, and 17–8Ma, whereas the only significant thermal event in the Daban Shan occurred at ca. 50–30Ma. The exhumation of the Laji Shan during the Late Cretaceous may result from the Lhasa–Qiangtang collision. During 50–30Ma, the Central Qilian Block rotated clockwise relative to the South Qilian Block, which led to the formation of the Xining Basin. The slow uplift of the Laji Shan and Daban Shan in this period was the isostatic adjustment of the footwalls of normal faults along the two margins of the Xining Basin. The exhumation of the Laji Shan during 17–8Ma resulted from compression due to the clockwise rotation of the South Qilian Block relative to the Central Qilian Block, causing the inversion of the Xining Basin, a marked change in the sedimentary environments and a rapid increase in sedimentation rates.

Evaluation of hydrocarbon generation and migration in the Molasse fold and thrust belt(Central Eastern Alps, Austria) using structural and thermal basin models

The Molasse Basin represents the northern foreland basin of the Alps. After decades of exploration, it is considered to be mature in terms of hydrocarbon exploration. However, geological evolution and hydrocarbon potential of its imbricated southernmost part (Molasse fold and thrust belt) are still poorly understood. In this study, structural and petroleum systems models are integrated to explore the hydrocarbon potential of the Perwang imbricates in the western part of the Austrian Molasse Basin. The structural model shows that total tectonic shortening in the modeled north–south section is at least 32.3 km (20.1 mi) and provides a realistic input for the petroleum systems model. Formation temperatures show present-day heat flows decreasing toward the south from 60 to 41 mW/m2. Maturity data indicate very low paleoheat flows decreasing southward from 43 to 28 mW/m2. The higher present-day heat flow probably indicates an increase in heat flow during the Pliocene and Pleistocene. Apart from oil generated below the imbricated zone and captured in autochthonous Molasse rocks in the foreland area, oil stains in the Perwang imbricates and oil-source rock correlations argue for a second migration system based on hydrocarbon generation inside the imbricates. This assumption is supported by the models presented in this study. However, the model-derived low transformation ratios (20%) indicate a charge risk. In addition, the success for future exploration strongly depends on the existence of migration conduits along the thrust planes during charge and on potential traps retaining their integrity during recent basin uplift.

Cenozoic pure-shear collapse of the southern Menderes Massif, Turkey

Abstract A transition from construction to collapse of the Alpine orogen in Middle to Late Eocene time is recorded in the structural fabrics of gneissic rocks in the southern Menderes Massif, western Turkey. Augen gneiss in the southern Menderes Massif indicates a spatial switch of shear sense along a north–south section through the complex (top-to-north shear in the north and top-to-south in the south). This ‘kinematic hinge’ corresponds to a broad zone of dominant pure shear where crust underwent vertical thinning and approximate north–south extension. During this extension, foliation became corrugated with fold axes parallel to lineation, indicating inflow from neighbouring crust to the east and the west. Published geochronologic work suggests a Middle to Late Eocene age for this dominant fabric. Thermal weakening of felsic Menderes crust beneath Alpine nappes may have triggered this orogenic collapse. Deformation fabrics developed at temperatures of c. 550 °C, and progressive cooling during collapse generated strain localization within a kilometre-thick shear zone at the southern margin of the Menderes Massif. In the southern Menderes, the corrugation of foliation indicates that Middle to Late Eocene flow was constricted into an orogen-perpendicular direction. This behaviour is similar to the collapse and orogen-parallel extension of the European Alps (Lepontine dome, Tauern Window).

Long View (41RB112): Data Recovery of Two Plains Village Period Components in Roberts County, Texas, Volume 1

This archeological data recovery investigation in Roberts County in the northeastern panhandle of Texas was necessitated by the proposed widening of State Highway 70 (CSJ: 0490-04-037) by the Texas Department of Transportation (TxDOT), Amarillo District. This proposed highway rehabilitation program will directly impact a roughly 10 meter (m, 30 ft.) wide north-south section of prehistoric site 41RB112, the Long View site. This site consists of two horizontally distinct Plains Village period occupations shallowly buried along a linear interfluvial ridge between two small tributary creeks to the Canadian River in the midslope of this broad, dissected valley.

Long View (41RB112): Data Recovery of Two Plains Village Period Components in Roberts County, Texas, Volume 2

This archeological data recovery investigation in Roberts County in the northeastern panhandle of Texas was necessitated by the proposed widening of State Highway 70 (CSJ: 0490-04-037) by the Texas Department of Transportation (TxDOT), Amarillo District. This proposed highway rehabilitation program will directly impact a roughly 10 meter (m, 30 ft.) wide north-south section of prehistoric site 41RB112, the Long View site. This site consists of two horizontally distinct Plains Village period occupations shallowly buried along a linear interfluvial ridge between two small tributary creeks to the Canadian River in the midslope of this broad, dissected valley. This site was initially discovered by TxDOT archeologist, Dennis Price in June 2004 during an archeological inventory of the proposed 9.7 kilometer (6 mile) section north of the Canadian River in response to the planned highway rehabilitation program. Based on Mr. Price’s discovery of multiple artifact classes in buried context he recommended this site be assessed for its eligibility for listing on the National Register of Historic Places under criterion d and possible designation as a State Archeological Landmark (SAL) per the requirements of Section 106 of the National Historic Preservation Act (NHPA) and other related legislation. Following the Texas Historical Commissions concurrence with that recommendation, TxDOT through the Environmental (ENV) Affairs Division, contracted to TRC Environmental Corporation (TRC) under an existing Scientific Services Contract No. 57XXSA006 and issued a Work Authorization to TRC of Austin to conduct the site eligibility assessment. During a site visit by TxDOT geoarcheologist James Abbott and TRC archeologist Mike Quigg in February 2005, the site boundaries were expanded to nearly 300 meters (m) along the proposed area of potential effect (APE). Investigative strategies were devised to assess the Long View site. In May 2005, TRC’s archeologists from Austin conducted archeological testing for a NRHP and SAL eligibility assessment investigation at 41RB112. The assessment along the 10-m-wide by 300-m-long APE was accomplished by hand-excavating 28 1-by-1 m units (totaling 16.8 m3), hand-excavating four narrow ca. 30 centimeter (cm) wide trenches (two in each area totaling nearly 32 linear meters), as well as cleaning and inspecting 28 m of existing road cut exposures. These investigations determined that cultural materials clustered at the northern and southern ends (Areas A and C respectively) of the site with nearly 120 m of noncultural bearing deposits (Area B) between the two concentrations. A 4-m-wide mechanically bladed fireguard paralleled the existing fenceline throughout the length

Transverse Tectonics in the Sikkim Himalaya: Evidence from Seismicity and Focal-Mechanism Data

Abstract In the present study, about 356 local earthquakes in the region of the Sikkim Himalaya have been accurately located and analyzed using 2181 P travel times and 2161 S travel times from a network of 11 broadband seismic stations operated by the National Geophysical Research Institute during January 2006 to November 2007. Further refinement of the hypocentral parameters using the hypoDD relocation program resulted in 198 well-constrained locations. Interestingly, this study reveals several characteristic features that distinguish Sikkim from the rest of the Himalaya. The seismicity distribution is found to be confined mostly between the main boundary thrust (MBT) and the main central thrust (MCT) but not quite associated with either. While the entire Himalayan front is generally characterized by shallow-angle thrust faulting, focal mechanisms in this region are predominantly of strike-slip type in conformity with a right-lateral strike-slip mechanism along the northwest-trending Tista and Gangtok lineaments. The P -axis trends of earthquake focal mechanisms are clearly oriented north-northwest, marking a clear transition from the ambient north-northeast trending direction of Indian plate motion with respect to the Eurasian plate all along the Himalayan front. Moderate-sized earthquakes occur down to 70 km depth in this region, compared to an average focal depth of 15–20 km in the rest of the Himalaya. Also, a high average crustal P velocity of 6.66 km/sec and a fairly low b value of 0.83±0.04 are obtained indicating the probability of occurrence of a higher magnitude earthquake in the future. A north–south section in the Sikkim region shows a relatively flat topography, unlike in the rest of the Himalayan mountain chain and suggestive of lower rates of convergence in the recent geologic past. It is proposed that crustal shortening in the Sikkim Himalaya has been substantially accommodated by transverse tectonics rather than underthrusting in recent times.

Dating of shallow faults: New constraints from the AlpTransit tunnel site (Switzerland)

Research Article| June 01, 2010 Dating of shallow faults: New constraints from the AlpTransit tunnel site (Switzerland) Horst Zwingmann; Horst Zwingmann 1CSIRO Earth Science and Resource Engineering, PO Box 1130, Bentley, WA 6102, Australia, and School of Earth and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia Search for other works by this author on: GSW Google Scholar Neil Mancktelow; Neil Mancktelow 2Department of Earth Sciences, ETH-Zurich, CH-8092 Zurich, Switzerland Search for other works by this author on: GSW Google Scholar Marco Antognini; Marco Antognini 3Museo Cantonale di Storia Naturale, Viale C. Cattaneo 4, CH-6900 Lugano, Switzerland Search for other works by this author on: GSW Google Scholar Raffaele Lucchini Raffaele Lucchini 4Geolog.ch SA, Viale Stazione 16a, CH-6501-Bellinzona, Switzerland Search for other works by this author on: GSW Google Scholar Geology (2010) 38 (6): 487–490. https://doi.org/10.1130/G30785.1 Article history received: 16 Oct 2009 rev-recd: 21 Dec 2009 accepted: 30 Dec 2009 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Horst Zwingmann, Neil Mancktelow, Marco Antognini, Raffaele Lucchini; Dating of shallow faults: New constraints from the AlpTransit tunnel site (Switzerland). Geology 2010;; 38 (6): 487–490. doi: https://doi.org/10.1130/G30785.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Methods for dating shallow faults in the Earth's crust are still evolving and their reliability remains controversial. Based on results from well-preserved fault gouge samples from the AlpTransit deep tunnel site in Switzerland, we propose a simplified and readily applicable approach to investigate and date clay-rich gouge zones. We collected 10 samples covering a north-south section of 15 km. All sampled faults are developed in orthogneiss host rock, have a rather consistent approximately northwest-southeast strike, are mainly normal, and are related to northeast-southwest orogen-parallel extension during Alpine exhumation. Fine-grained clay separates from the fault gouges consist of illite 1M/1Md and 2M1 polytypes, smectite and chlorite, with minor amounts of feldspar in some sample fractions. The K-Ar ages for <2 μm illite fractions range between 7.1 and 9.5 Ma (mean 8.5 ± 1.4 [2σ] Ma) and for <0.1 μm range between 3.9 and 7.2 Ma (mean 6.0 ± 2.1 [2σ] Ma); ages consistently decrease with grain size. These ages are close to published apatite fission track ages of ca. 6 Ma from the immediate vicinity, consistent with illite stability in fault gouges generally occurring at temperatures slightly above the partial annealing zone of apatite. The influence on authigenic illite gouge ages of potential contamination by fine-grained cataclastic protolith was evaluated by dating coarse K-feldspar fractions from host-rock clasts in two samples. The K-feldspar ages are significantly older, ca. 13.5 Ma. However, measured illite K-Ar ages are quite constant and do not correlate with amount of K-feldspar impurity, which suggests that fine-grained cataclastic feldspar grains have isotopically reequilibrated, presumably due to fluid-rock interaction within the fault zone. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

SSPX: A program to compute strain from displacement/velocity data

SSPX is a Macintosh, Cocoa/Universal application to compute strain from displacement/velocity data in two and three dimensions. SSPX solves small and large deformation problems, in either the undeformed (Lagrangian) or deformed (Eulerian) configuration. The program offers several options to compute strain: best fit for all or selected data, strain at a point, strain at stations, Delaunay, grid-nearest neighbor, and grid-distance weighted. Except for the strain at stations option in 3D, the program computes the strain on a surface that is either flat (slice) or that follows the topography of the data. In the case of a slice and in 3D, the location and orientation of the slice can be varied to visualize the strain along horizontal or vertical east–west, north–south sections. SSPX plots strain in a 2D view (3D strain is displayed as stereonets). We show the application of the program to GPS data, analogue and DEM mechanical simulations.