Color Mottling Research Articles

Record of palaeoclimate across theCretaceous–Palaeogeneboundary from palaeosols in the west‐central San Juan Basin, New Mexico, USA

AbstractThe mass extinction at the Cretaceous–Palaeogene boundary is widely attributed to sudden and severe climate changes forced by bolide impact and/or flood basalt volcanism. In terrestrial depositional settings, these changes may potentially be recorded by palaeosols. To test the ability of pedogenic features to record both long‐term climate and shorter‐term changes preceding and following the Cretaceous–Palaeogene extinction event, palaeosols in the Upper Cretaceous (Maastrichtian) Naashoibito Member of the Ojo Alamo Formation and the lower Palaeocene (Danian) Nacimiento Formation in the San Juan Basin of north‐western New Mexico, USA, were examined, including data from previous studies. The fine‐grained facies of the Naashoibito Member comprises grey to greenish‐grey and red‐banded mudstones displaying pedogenic features including colour mottling, root traces, cutans, ped fabrics, pedogenic slickensides and calcareous nodules. Aside from a high‐chroma horizon at the formation base, palaeosols in the lower Nacimiento Formation are broadly similar to those observed in the Naashoibito Member. Lateral and vertical variability of the pedogenic features between correlated sections suggest that soil hydrology varied spatially and temporally from very saturated to seasonally well‐drained, with temporal variations controlled by basin sedimentation rates. Abrupt and/or catastrophic climate events precisely at the Cretaceous–Palaeogene boundary are not recorded due to an unconformity at the top of the Naashoibito Member. However, the presence of kaolinite in the clay mineral assemblage of the Nacimiento Formation, particularly near the formation base, but not in the Naashoibito Member, indicates episodic warmth and short (104 years) intervals of more intense weathering conditions during the very early Danian as compared to the late Maastrichtian. Aside from short warm intervals, the overall palaeoclimate during deposition of both formations was warm and consistently subhumid to humid and seasonal, suggesting no substantial long‐term (105–106) climate change took place across the Cretaceous–Palaeogene boundary in the San Juan Basin.

Upper Arm Pain - Lifting

HISTORY: 21 y/o F presents to the ED with progressive left arm pain and weakness. Eight months prior, she was diagnosed with Thoracic Outlet Syndrome (TOS) complicated by left arm thrombus. Additional workup identified antiphospholipid antibody syndrome. Two months prior, she underwent surgical decompression. One month prior, angiography revealed continued evidence of TOS despite surgical treatment. Patient was referred to the ED for evaluation. She otherwise denied chest pain, shortness of breath, cough, recent travel history, fever, and trauma. PHYSICAL EXAMINATION: Vital signs within normal limits. Well appearing and comfortable. Left upper extremity skin with mild blue color mottling. Strength and sensation intact and within normal limits. Normal respiratory effort with normal, equal, and bilateral lung sounds. DIFFERENTIAL DIAGNOSIS: Cervical radiculopathy, Brachial plexopathy, Paget Schroetter Syndrome, Post-operative lymphedema, TOS, Upper Extremity DVT TEST AND RESULTS: APTT: 32.9, PT: 15.0, INR: 1.2 CTA Chest: Stenosis of left subclavian vein with the arm raised and widely patent with the arm down. 2.2 right neck cystic lesion L Upper Extremity US: Positional loss of normal flow in the subclavian and axillary veins with left arm raised. Nonocclusive thrombus cannot be excluded due to basilic vein only visible in arm up position showing it is only partially compressible FINAL WORKING DIAGNOSIS: Upper Extremity DVT and TOS TREATMENT AND OUTCOMES: 1) Patient is currently on Rivaroxaban with a plan for serial US. Several months after the ED visit, she reported bilateral LE paresthesias. RLE US was negative, and neurology recommended neuropathy evaluation with MRI of cervical spine and EMG. 2) TOS is diagnosed clinically, however advanced studies can suggest mechanisms of compression to tailor potential interventions. 3) Anticoagulation coupled with surgical decompression are usually necessary for young athletes with repetitive activity, irrespective of underlying hypercoagulability. 4) Rehab coupled with anticoagulation therapy has a critical role in initial conservative strategies and in post operative recovery. This includes addressing postural mechanics, sports-specific modifications, and targeted cervical and shoulder soft tissue therapies to help guide a return to play strategy.

Evaluation of capsicum hybrids against viral diseases under protected cultivation in Dharwad, Karnataka

Screening of capsicum hybrids were conducted under protected cultivation during kharif 2018 and rabi 2018-19. The results indicated that out of fourteen hybrids screened, none of them were found to be highly resistant, resistant and moderately resistant during both the seasons. During kharif 2018 out of fourteen hybrids screened, six hybrids were found to be moderately susceptible viz., Maxibell, Shristika, SV1865PB, Asha, Arka Gaurav and Arka Basanti for leaf curl disease. For mild mottle disease, hybrids Arka Gaurav and Arka Basanti recorded moderately resistant reaction. However, during rabi 2018-19 eight hybrids viz., Maxibell, Shristika, SV1865PB, Asha, Indra, Arka Gaurav, Arka Basanti and Rithal showed susceptible reaction for leaf curl disease. Whereas, eight hybrids viz., Shristika, SV1865PB, Asha, Indra, Arka Gaurav, Arka Basanti, 35-160-R2 and NSX 8 recorded moderately susceptible for mosaic disease. The symptoms observed during screening included mosaic and mottling, yellow discoloration, vein clearing, leaf deformation and narrowing, stunted plant growth, reduced fruit setting and light green colour mottling symptoms on fruits.

New dinosaur footprints exposed in rocks of the Wessex Formation, Lower Cretaceous, at Sandown, Isle of Wight, southern England

During February 2007, storm waves removed sufficient sand from the foreshore at Sandown beach on the Isle of Wight to expose a number of Lower Cretaceous interbedded fluvial sand sheets and floodplain mudstones from the upper part of the Wessex Formation terrestrial sequence. The sand bodies have been described before, and exhibit a number of water generated ripple marks, as well as bioturbation by burrowing organisms. These sand bodies and a fossiliferous limestone have resulted in the area being designated as a Regionally Important Geological/Geomorphological Site. The mudstones show colour mottling as a result of pedogenic alteration in changing aerobic/anaerobic conditions. From February until the end of May 2007 sufficient exposure of the bedrock on the foreshore occurred to allow identification of a number of dinosaur footprints. Tridactyl and polydactyl prints with a range of sizes were clearly visible with possible ornithopod, theropod, sauropod, and ankylosaur origins. Within the intervening mudstones, preservation of the footprints takes the form of grey–blue infills in red mud, and brown silty infills in red mud (convex hyporeliefs), as well as occasional raised gritty footprint casts. On the sandstone units, the preservation is in the form of raised sandy casts. The greatest variety in terms of size and type are in the mudstone units on the seaward side of the Isle of Wight Zoo (The Granite Fort). These prints are from an area that does not appear to have been previously reported but which requires further investigation. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 758–769.

Alluvial fan and wetland interactions: evidence of seasonal slope wetlands from the Silurian of south central Wales, UK

AbstractDistal environs of the Ludlow‐age Trichrug Formation from south central Wales (UK) detail deposition on the outer fringe of an ephemeral debris flow‐dominated alluvial fan. Debrites and subordinate sheetflood deposits are interbedded with sporadic thin sandstone‐dominated heterolithic units deposited in shallow, ephemeral ponds in the axial valley. The latter slope wetland system fringed the permeable alluvial fan deposits, being maintained by streamflow, precipitation and ground water recharge. A prolonged high water table is indicated by low chroma intervals interpreted as the result of gleying. A variety of redoximorphic indicators, including colour mottling and ferricrete concretions, are evidence of iron mobilization and concentration associated with a seasonally fluctuating water table. The slope wetlands were colonized periodically by Skolithos‐generating organisms, most likely to have been arthropods. The widespread occurrence of redoximorphic indicators and ferricrete contrasts markedly with calcrete Vertisols in penecontemporaneous continental deposits (Lower Old Red Sandstone) of the region. It is likely that the alluvial fan‐toe area was the site of a wetland depression, which maintained a high, though fluctuating, water table. In contrast the alluvial channel reaches of the surrounding drainage network were significantly better drained, with floodplains prone to wetting and drying and Vertisol palaeopedogenesis.

Palaeosols and sequence stratigraphy of the Lower Permian Abo Member, south-central New Mexico, USA

The relationship between palaeosols and sequence stratigraphy is tested in the Lower Permian Abo Member, south-central New Mexico, by comparing interfluve and fluvial-terrace palaeosols with palaeosols that developed within lowstand-fluvial deposits. Interfluve and fluvial-terrace palaeosols consist of primary pedogenic features, including vertical root traces, vertic structures, Stage II and III pedogenic calcite and translocated clay (argillans), which are cross-cut or replaced by low-aluminium goethite, gley colour mottling, sparry calcite veins and ankerite. The polygenetic character of the palaeosols is consistent with initial development for several thousand to tens of thousands of years on well-drained interfluves or fluvial terraces, followed by waterlogging due to invasion by a rising water table that locally may have been brackish. In contrast, lowstand-fluvial sediment that filled incised valleys contains only rooted and vertic palaeosols, whose immaturity resulted from high aggradation rates. Palaeosols similar to those in the Abo Member have been recognized in other ancient strata and, when combined with highresolution correlation, provide evidence for interpretation of sequencestratigraphic surfaces and systems tracts.

Print mottling: Solid–liquid adhesion related to optical appearance

Abstract Print mottling has been widely studied over the years and several reasons for uneven print have been pointed out. Factors affecting mottling are, e.g., heterogeneity of the coating layer, uneven absorption of the ink, ink properties and printing conditions such as machine settings. In this study, the focus was put on the adhesion between the coated base paper and model liquids representing ink components, and its influence on both color and gloss mottling. Furthermore, the aim was to thoroughly characterize the surface structure of the coated papers and to use these features and the optical properties to re-evaluate the physico-chemical meaning of mottling. The surface adhesion energy of the coated papers was determined with static contact angle (CA) measurements, and the topographical analysis was done with atomic force microscopy (AFM). The print quality was inspected using a diffractive optical-element-based glossmeter (DOG) for gloss mottling and an imaging spectrometer for color mottling measurements. By plotting the solid–liquid work of adhesion against color and gloss deviation of prints, it was observed that the samples with lower work of adhesion, between liquid and substrate, produce both color and gloss mottling. The samples appeared to be sensitive only to dispersive model liquids (referring to ink oils). The surface topography had a significant effect on wetting of the studied samples.

Early Permian silt-bed fluvial sedimentation in the Orogrande basin of the Ancestral Rocky Mountains, New Mexico, USA

The Lower Permian (Wolfcampian) Abo Formation of south-central New Mexico was deposited by a silt-dominated fluvial system along the western half of the Orogrande basin a few degrees north of the equator in western Pangaea. Fluvial channel deposits consist primarily of: (1) inclined siltstone stratasets up to 4.5 m thick and 25 m wide interpreted as point bar deposits, and (2) symmetrically infilled siltstone stratasets up to 2.4 m thick and 14 m long that may represent avulsion crevasse channels. Both types of channels are dominated by climbing ripple cross-laminae and plane bed laminae, but trough cross-beds are also present, as are several types of soft-sediment deformation structures and desiccation cracks. Red silty mudstones interpreted as floodplain deposits comprise up to 70% of the formation and are interbedded with thin (<2 m) tabular siltstone beds of crevasse-splay/levee origin, as well as rare lacustrine carbonates (∼0.5 m thick) and structureless siltstones (<1 m thick) interpreted as loessites. Common pedogenic features in floodplain strata and on the tops of some fluvial channel beds include root traces, peds, and calcic nodules/tubules, whereas gypsum, gley colour mottling, and translocated clay and/or iron oxides are rare. Also present is an ichnofauna dominated by opportunistic arthropods that colonized the moist upper surfaces of recently deposited crevasse-splay/levee beds and the uppermost surfaces of fluvial channels following avulsion. The relative abundance of channel and crevasse-splay/levee deposits increases eastward in response to moderate asymmetrical subsidence of the basin, whereas calcic paleosols are more numerous on the more slowly subsiding western margin of the basin. A semi-arid to sub-humid palaeoclimate with seasonal precipitation favoured relatively deep rivers whose point bars were seasonally exposed, the formation of calcic and vertic soils, a sparse ichnofauna and flora, periodic desiccation of small carbonate lakes, and perhaps reworking of loess from the floodplain and/or upstream catchments.

Distinguishing early groundwater alteration effects from pedogenesis in ancient alluvial basins: examples from the Palaeogene of southern Portugal

Colour mottling and horizons of secondary carbonates are common in ancient alluvial sequences and are normally interpreted as pedogenic features. They have been used to assess palaeoclimates, soil drainage conditions and deposition rates. Palaeogene alluvial deposits in the Sado and Lisbon basins of Portugal exhibit prominent colour variations and mottle patterns, as well as carbonate accumulations both at the bases of fining-upwards cyclothems and as thick units (up to 20 m) capping alluvial megasequences. However, these colour and carbonate features are interpreted as the products of shallow, saline, reducing groundwaters, unrelated to pedogenesis. Such non-pedogenic products are easily mistaken for soil-formed ones and criteria for differentiating the two are reviewed to assist interpretations in other alluvial deposits. Key criteria are thickness, gradational tops and bases, absence of soil horizon features, occurrence in coarser alluvium and prevalence of hydromorphic colour and mottling patterns.

Palaeopedogenic features and their palaeoclimatological significance for the nevremont formation (Lower Givetian), the Northern Ardennes, Belgium

The lower member of the Nèvremont Formation is characterized by the frequent occurrence of pedogenic features, which suggest intermittent exposure of the fluvial depositional environment. The evidence for pedogenesis comprises horizons of calcite glaebules and nodular calcrete, haematite segregation, resulting in pronounced colour mottling, and the formation of palaeosolic root-horizons with root tubes, cutanic features, burrows and striotubules. Based upon the presence of these features, it is suggested that the climate was semiarid. The source area of the quartz-rich parent clastic sediment was presumably subjected to intensive chemical weathering, resulting in mature quartzose sediments, with illite and kaolinite as dominant clay minerals.

Transitions in a Fluvial System--Abo Formation, Southeastern Nacimiento Mountains, New Mexico: ABSTRACT

The Abo Formation (Wolfcampian) in the southeastern Nacimiento Mountains, New Mexico, is an alluvial plain red-bed sequence which records the evolution of a fluvial system within the distal reaches of a large clastic wedge. Sediment was derived from the southern Uncompahgre uplift, with a paleoflow to the southwest. The Abo Formation consists of mudstone, feldspathic sandstone, and intraformational conglomerate. Three major lithofacies associations, representing distinct fluvial depositional settings, may be distinguished. The lowermost division (Unit A) (100+ m, or 330+ ft, thick) is mudstone dominant with isolated sandstone bodies showing cutbanks and lateral accretion surfaces. Ridge-and-swale features were noted on an exhumed point bar surface. The sandstones commonly show a progressive upward decrease in the scale of internal bedforms with a lower scour surface containing intraformational conglomerate. Trough cross-bedding is the dominant bedform in the sandstones with common planar-tabular and flat-bedded interbeds. The uppermost sandstones, characteristic of levee and crevasse-splay sands, are ripple cross-bedded with abundant bioturbation and some plant roots. The overbank mudstones contain numerous pedogenic horizons characterized by calcrete nodules (representative of all stages of evolution), vein networks, pseudo-anticlinal structures, slickensides, color mottling, and bioturbation. Vertebrate remains are found in the mudstones. The middle division (Unit B) (approximately 70 m, or 230 ft, thick) is characterized by thick multilateral channel sandstones and thinner mudstones. The sandstones are coarse grained and contain common intraformational conglomerate. Large-scale trough cross-stratification is the dominant bedform. Pedogenic horizons are present but less common than in unit A. The uppermost division (Unit C) (approximately 30 m, or 100 ft, thick) is entirely composed of reddish-orange, very fine-grained sandstone. Flat bedding is the dominant bedform. High aggradation is indicated by abundant dish structures in the sandstones and aggradational ripple cross-bedding. Mudstone is rare and preserved as thin laminae. End_Page 466------------------------------ The fluvial sequence from Unit A to Unit B is thought to represent the transition from a fine-grained to a coarse-grained meander-belt system. The transition to Unit C reflects a change to flash-flood, ephemeral-stream controlled sedimentation. Allocyclic phenomena are suggested as probably cause of these fluvial transitions. End_of_Article - Last_Page 467------------

Experimental Compaction of Lime Sediment: ABSTRACT

More than 30 in-situ cores of modern lime sediments, including environments from tidal flat to shallow marine, have been compressed under loads simulating depths ranging from 280 to 14,000 m of burial. Cores 10 cm in diameter and 30 to 40 cm in length were reduced to between one-quarter to one-third of their original length, resulting in porosity reduction from an initial 70 to 80% to 30 to 45%. Experimental compaction produced sedimentary structures common to many ancient limestones, including (1) wavy organic seams similar to horsetail or microstylolite swarms; (2) reorientation of randomly oriented fossils toward a more horizontal posture; (3) flattening of filled burrows; (4) complete obliteration of birdseye voids; and (5) color mottling in tidal flat sediments produced by collapse and flowage of oxidized sediment surrounding burrows. These studies have shown that, during geologically instantaneous periods of compaction (up to 30 days), the bulk of porosity reduction occurred under conditions simulating less than 300 m of overburden. Although fossils generally are not crushed during compaction, the obliteration of birdseye voids indicates that early cementation or infill by evaporitic minerals was necessary for preservation of ancient birdseye or fenestral structures. Pellets in soft lime mud were obliterated, but slightly hardened pellets in Bahamian muds were preserved during experimental compaction. This observation suggests that well-preserved pellets in ancient limestone indicate predepositional hardening or synsedimentary cementation. Heating of cores to 100°C during compaction has produced hydrocarbon effluents, suggesting that some ancient limestones may have been source rocks. End_of_Article - Last_Page 783------------

Calcrete (caliche) palaeosols in fluvial redbeds of the Aztec siltstone (upper Devonian), Southern Victoria Land, Antarctica

Palaeosols in the Upper Devonian Aztec Siltstone of southern Victoria Land closely resemble pedocal ‘calcareous red earth’ and ‘red earth’ type modern soils and were formed on a low-relief surface under a hot and seasonally wet and dry, semi-arid climate. The Upper Devonian Aztec Siltstone of southern Victoria Land is interpreted as a fluviatile redbed sequence deposited on a broad, low-lying floodplain from high-sinuosity meandering streams which gave rise to characteristic fining-upwards sedimentary cycles. The fine-grained, fine-member portions of the cycles represent vertically accreted overbank sediment laid down on the interchannel floodbasin areas. With the development of relief, these sediments were subaerially exposed for extended periods (4000–10 000 years) during which time they underwent in-situ modification by pedogenic processes. This is evidenced by the common occurrence of carbonate nodules (calcrete), wavy bedding or pseudo-anticlines, colour mottling or gleying, and extensive bioturbation in these unbedded clay-rich sediments. Plant roots and associated plant fossils and spores are also present. The textural character of the fine-grained rocks is closely comparable to that of modern soils including a skel-lattisepic fabric with skew-planes. Mineralogical and detailed chemical analyses, including down-profile element variations, show that there was an in-situ reorganization of ‘soil plasma’ consequent on clay illuviation, translocation and deposition of carbonate, and mobilisation and segregation of iron oxide.

Translocation of Chemical Constituents and Pedogenesis in Early Eocene Willwood Formation in Northwestern Wyoming: ABSTRACT

Chemical data on a 4-ft red mudstone, in association with intense color mottling, high fossil content, and great lateral extent, indicate the development of a soil (paleosol) within the red-banded, fluviatile Eocene Willwood Formation in northwestern Wyoming. Quantitative analyses of free iron, aluminum, and manganese from a vertical section through the mudstone indicates zones of concentration at the 16-30 in. and 35-42 in. intervals from the top. Mudstone textural analysis indicates increased amounts of fine clay (less than 10 ^Phgr) in the 16-30 in. level. Organic carbon content throughout the profile is unusually high compared with similar Willwood mudstones. Carbonate minerals are essentially absent. The distribution of free aluminum through the profile displays a st ong statistical correlation (r = + .748) to fine clay distribution, whereas free iron (r = + .094), free manganese (r = + .160), and organic carbon (r = +.004) show essentially no correlation to fine clay content. Pedogenesis was characterized by organic matter concentration and mobile chemical constituent translocation to lower levels within a parent material of alluvium. Solution and movement resulted primarily from a shallow, fluctuating groundwater table, which produced alternating oxidizing and reducing conditions. Low concentration values and deeper movement of manganese compared with iron may reflect its higher solubility in the reduced state. Mobile ion concentration at the 35-42 in. level probably resulted from minor water table fluctuations directly above an underlying, more permeable sandstone. A significant reduction in the rate of sediment accumulation appears to be the major factor allowing for in-situ development of a soil upon the Willwood alluvial plain. End_of_Article - Last_Page 355------------

Bethany Falls Limestone (Missourian) Sedimentation and Diagenesis, Missouri and Kansas: ABSTRACT

The Bethany Falls Limestone is a 15-30-ft-thick shelf deposit within lower Missourian rocks of the Mid-Continent region. In outcrop the lower Bethany Falls is typically an open-marine, faunally diversified, carbonate wackestone. The upper Bethany Falls consists of a wide variety of shallower water carbonate mudstone, wackestone, and grainstone. Cross-bedded oolitic grainstone and faunally restricted mudstone are perhaps the most distinctive rocks in the upper Bethany Falls. Cross-bed dip azimuths in the oolitic facies provide evidence that deposition resulted from 2 dominant current systems, one basically longshore drift toward the northwest and another essentially onshore tidal flow toward the north-northeast. The sequence of open-marine wackestone succeeded by shallower water limestone resulted from rapid transgression. As progradation built the sea floor into the zone of agitation, oolitic sand developed. These bars restricted circulation in many interbar and back-bar areas which became sites of the faunally restricted carbonate mud. Carbonate deposition ceased when progradation built to normal high tide. Color mottling, ubiquitous in most upper Bethany Falls mudstone and wackestone, is a diagenetic effect related to selective bleaching of the original medium-gray or grayish-tan color. The bleaching apparently follows areas of initially high permeability. The controlling paths are commonly burrows or churned areas, crumbly vugs resulting from bioturbation and other processes, and microfractures formed by slumping and shrinkage. Grain diminution or removal commonly accompanies the bleaching, and many of the bleached areas exhibit microslump and convergence of laminae. End_of_Article - Last_Page 869------------