The relationship between duodenal ulcer depth and gastric acid output

In the course of 750 routine duodenoscopies. 119 patients with duodenal ulcers who also had gastric acid tests, were assessed. A relationship was found between the depth of duodenal ulcers and the height of the gastric acid output. In both Black and Indian patients, maximal acid output was significantly higher in patients with deep duodenal ulcers compared with flat duodenal ulcers. There were more Blacks with deep ulcers, and more Indians with flat ulcers.S. Afr. Med. J., 48, 1405 (1974)

Preliminary constraints on paleotemperature and landscape evolution in and around Araripe Basin, northeastern Brazil, using apatite fission track analysis

The Araripe Basin, located in the Borborema Province, northeastern Brazil, developed through a sequence of distinct events related to the opening of the South Atlantic. Its geological history is recorded in the preserved stratigraphy, which ranges in age from Paleozoic to Middle Cretaceous. The most conspicuous feature associated with the Araripe Basin is the Araripe Plateau, a large mesa capped by CenomanianAlbian non-marine sandstones (Exu Formation). At the plateau base, gray to black shales ("Batateiras layers") represent deposition in a large lake system covering part of northeastern Brazil during Early Aptian. Previous researchers have used the preserved geological section in the basin to infer the landscape evolution of the Araripe Plateau, and they have suggested that its uplift and exhumation were caused by widespread epeirogenic movements associated with post-break-up events in the Borborema Province. Independent constraints on the timing and magnitude of uplift in the Araripe Plateau area can now be introduced by this preliminary study using apatite fission track analysis. A series of samples along a N-S transect of the Araripe Basin and its neighboring basement provide clear evidence of heating in the past. Results from all samples also show evidence of Late Cenozoic cooling commencing sometime in the last 40 Ma. Maximum paleotemperatures associated with this event are very similar (70° - 90°C) between samples, consistent with little differential movement across the sampled region. Fission track results from the Aptian sandstone sample (Rio da Batateira Formation) indicate an earlier event (pre-40 Ma). However, interpretation of data suggests that any paleo-heating between sediment deposition (112 Ma) and 40 Ma must be associated with paleotemperatures less than ∼100°C, pointing to minor paleoburial during the Late Cretaceous in this area. The timing of these various events are broadly consistent with the timing of events identified in and around the Borborema Plateau using the same method (Morais Neto et al. submitted), which identified two cooling episodes: a Late Cretaceous cooling event commencing sometime between 100-90 Ma and a Late Cenozoic cool ing commencing between 30-0 Ma. This coincidence in the timing of events suggests that these events may be regional in nature and therefore likely to be related to regional exhumation. The uplift of the Araripe Basin can be related to epeirogenic movements associated with (or following) the Late Cretaceous cooling event. Thermal maturity presently observed in the "Batateiras layers" suggests that any source rock in the area ceased its thermal evolution due to such process. Present relief is interpreted as the result of subsequent erosion processes. If we assume a paleogeothermal gradient of 30°C/km (and a surface temperature of 25°C), we estimate an erosion of ∼1.5 km across the Araripe area, associated with the Late Cenozoic cooling event. While important parameters on the timing and magnitude of events in this area have been resolved based on only 6 samples, further work involving additional analysis and U-Th/He thermochronology is suggested