The Triassic Mercia Mudstone Group of County Antrim, Northern Ireland, is dominated by red beds and evaporites. After only limited study, both marine and continental environments have been proposed previously. Here, we describe these rocks for the first time from core and petrographic observations to interpret depositional environments and conditions, such as water depth, salinity, and aridity. Bedded halite, bedded gypsum, displacive halite, and red siliciclastic mudstone lithologies comprise most (~80%) of the 591.6-m-thick Mercia Mudstone Group in the Gaelectric Carnduff-2 core. Bedded halite consists of chevron and cornet crystals, indicating bottom-growth from shallow surface brines. Bedded-gypsum lithology is composed of halite-replaced pseudomorphs after swallowtail, bottom-growth gypsum crystals. Both bedded halite and bedded gypsum contain dissolution features and are commonly overlain by mud drapes. Bedded-halite and bedded-gypsum lithologies are interpreted to have formed in shallow saline lakes influenced by flooding and evapoconcentration. The displacive-halite lithology is composed of subcubic halite crystals, randomly oriented in mudstone, and represents deposition in a saline mudflat. Some mudstones contain ripple cross-lamination, dewatering structures, mudcracks, and rip-up clasts, suggesting shallow surface water and desiccation. Other mudstones are massive (structureless) and may have been deposited by wind. Both of these mudstone units were likely deposited in dry mudflats. Other red mudstones contain soil slickensides, blocky peds, and circumgranular cracks and are interpreted as paleosols. Our observations indicate that the Triassic Mercia Mudstone Group was formed by shallow perennial saline lakes and associated continental environments in an arid climate. Furthermore, lack of carbonates, lack of fossils, and paucity of organic matter suggest acid saline lakes and groundwaters. The Triassic Mercia Mudstone Group is similar to some other Pangean red beds and evaporites. Therefore, we hypothesize that the supercontinent was an arid barren landscape hosting acid-saline lakes.
The Lower Cambrian Eriboll Formation of northwest Scotland is renowned for the high density, low diversity trace fossils ( Skolithos ichnofacies) found in its upper Pipe Rock Member. Ichnofabric analysis of the member indicates that relatively small examples of Skolithos terminating at the same foreset boundary were formed during a brief colonization window after a single depositional event, that particularly long Skolithos specimens are equilibrichnia, and that palimpsests of Skolithos represent the marginal, slightly deeper water fringes of the Pipe Rock Member depositional environment. Nearest neighbour analysis, however, suggests that such palimpsests were uncommon. A much more diverse trace fossil assemblage is present in the overlying Fucoid Member
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A 54-year-old woman presented with nausea, vomiting and weight loss associated with impaired gastric emptying necessitating institution of parenteral nutrition. Subsequent studies revealed an unusual gastric mucosa! inflammatory nrocess characterized by unique subepithelial collagenous deposits. Collagenous gastritis appears to be a distinct, possibly immune-mediated, chronic disorder, pathologically reminiscent of collagenous sprue and collagenous colitis.Can J Gastroenterol 1989;3(5): [171][172][173][174] Key Words: Collagenous colitis, Collagenous sprue, Gastric histology, Gastritis Gastrite collagenique RESUME: Une patiente de 54 ans presente des nausees, des vomissements et une perte de poids lies a une deterioration de la vidange gastrique necessitant !'institution d'une alimentation parenterale. Des etudes subsequentes revelent un processus inflammatoire inhabituel de la muqueuse gastrique caracterise par des depots sous-cpitheliaux de collagene. La gastrite collagenique semble e tre une affection chronique distincte, peut-etre d 'origine immunitaire, dont la pathologie rappelle celle de la sprue collagenique et de la colite collagenique. I N 1970, WEINSTEIN ET AL ( I ) DESCRIBEDa unique form of sprue -collagenous sprue -characterized clinically by refractory malabsorption and histopathologically by subepithelial collagen deposition in small in testinal biopsies. Simila r histological features in the small intestine were noted in two earlier reports by Schein (2) and Hourihane (3). ln 1976. two reports independently described previously unrecognized histopathological featu res in colorectal biopsies from patients with chronic watery diarrhea ( 4 ,5 ). Thick subepi thelial collagenous de- Medicine (Gastroemerology) posi ts were seen and Lindstrom (5), in one of these reports, proposed the label collagenous colitis because of apparent pathological similarities to collagenous sprue. Since 1976, more than 50 patients with this disorder have been described and reviewed; in at least one patient both the small and large bowel were involved with the same process (7). In the present report, a 54-year-old woman with a distinct form of gastri tis is described. Clinical fea tures suggested a progressive, possibly immune-mediated disorder, while gastri c biopsies were cha racte rized histopathologicall y by trichrome-positive, subepithelial collagenous deposits reminiscent of previously described changes in the small and large intestine of patients with collagenous sprue or collagenous colitis ( 1-7). Departments of CASE PRESENTATIONA 54-year-old woman born in Scotland was initially seen in March 1979 with a three year history of anorexia, intermittent vomiting and weight loss of 14 kg. She d id not use alcohol, salicylates or other medications. Past history included a psychiatric admission in 1972 fo r depression; at that time, nausea and vomiting were apparently present. Examination revealed a weight of 38 kg and generalized muscle wasting. Gastroscopy FREEMAN et al Figure 1) Gastric biopsy showing a dense...
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