Examples of geologically significant boundaries are the interfingering facies change in sedimentary deposits when discussing a sedimentary basin system, or the leading or boundary thrust of an orogen.
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The Lockatong is often described as lake or litoral sediments. The interfingering nature of the sediments with the surrounding Stockton Formation and Passaic Formation suggests that these litoral environments shifted as climate or as the dynamic terrane of the area developed.Faill, R.T., (2004). The Birdsboro Basin.
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As the collision progressed the Lake District area became part of a foreland basin in which the Windermere Supergroup sediments were deposited, initially interfingering with the volcanics and then overlaying them. The collision reached its end during the Early Devonian, part of the Acadian Orogeny with the final closure of Iapetus and the intrusion of late orogenic granites.
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The Coihaique Group is a group of geological formations in northwestern Patagonia. From top to bottom the formations that make the group are Apeleg, Katterfeld and Toqui. The contact between the formations of the group are diachronous with Katterfeld Formation interfingering with the formations on top and below it. The lower and upper boundaries of the group are unconformities formed by erosion.
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The basal contact of the Cardenas Basalt with the underlying Dox Formation is smooth, planar, parallel to bedding and locally interfingering. In places the sandstones of the Dox Formation have small folds and convolutions that are indicative of soft sediment deformation. In addition, in places, the uppermost of the Dox Formation is mildly baked. A thin lava flow occurs within the uppermost part of the Dox Formation.
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The contact of the Dox Formation with the overlying Cardenas Basalt is smooth, planar, parallel to bedding, and locally interfingering. In places the sandstones of the Dox Formation have small folds and convolutions that are indicative of soft sediment deformation. In addition, in places, the uppermost of the Dox Formation is mildly baked. A thin lava flow occurs within the uppermost part of the Dox Formation.
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The highest temperature of the three textures, grain boundary migration becomes the dominant mechanism at ~500-550°C. Exhibiting much larger recrystallized grain sizes than the other two regimes, in addition to lobate and highly interfingering boundaries, at these temperatures quartz is completely recrystallized. That is, no evidence for original grains can be found. At these high temperatures, grain boundaries are free to sweep across entire grains, resulting in much less localized boundary formation/change.
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Pippin, pp. 216-217, Marine carbonates were being deposited from the Late Pennsylvanian until Early Permian when the western portion of the area was uplifted which resulted in erosion and the deposition of red clays and sands, the future red beds consisting of shales and sandstones.Pippin, p. 217 Marine carbonate deposition followed, resulting in the interfingering of the red beds and carbonates, the basis of the stratigraphic trap and a tilted gas-water contact.
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Thus, the contact between the Cardenas Lavas and the Dox Formation is conformable and interfingering. This indicates that sands were still being deposited when the first lavas erupted and that deposition occurred during the transition from the accumulation of Dox Formation to Cardenas Basalt.Timmons, JM, J. Bloch, K. Fletcher, KE Karlstrom, M Heizler, and LJ Crossey (2012) The Grand Canyon Unkar Group: Mesoproterozoic basin formation in the continental interior during supercontinent assembly. In JM Timmons and KE Karlstrom, eds.
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Thus, the contact between the Cardenas Basalt and the Dox Formation is conformable and interfingering. This indicates that sands were still being deposited when the first lavas erupted and that deposition occurred during the transition from the accumulation of Dox Formation to Cardenas Basalt.Timmons, JM, J. Bloch, K. Fletcher, KE Karlstrom, M Heizler, and LJ Crossey (2012) The Grand Canyon Unkar Group: Mesoproterozoic basin formation in the continental interior during supercontinent assembly. In JM Timmons and KE Karlstrom, eds.
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The formation consists mostly of cyclic marine sandstone and siltstone, but with interfingering tongues of gray limestone (the Getaway, South Valley, and Manzanita Members). These extend from the Goat Seep reef, an earlier and much smaller precursor to the Capitan reef, into what was then deep, anoxic water of the Permian Basin. A lower tongue of the formation extends across the basin margin to grade into the nearby San Andres Formation. Maximum thickness of the Cherry Canyon Formation is .
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The Lower Chamita Tuffaceous Zone has a radiometric age of 7.7 ±0.3 million years.McIntosh and Quade, 1995 The base of the formation contains sediments resembling the underlying Ojo Caliente Member of the Tesuque Formation. This is interpreted as reworking of sediments in a changed sedimentation environment rather than interfingering. Members of the formation include the Cejita and Cuarteles Members west of the modern Rio Grande River and the Pilar Mesa, Vallito, and Hernandez Members on both sides of the Rio Grande.
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Interfingering has been noted at the stratotype (Red Walls) and Hermiin Tsav. There has been no absolute dating of the Nemegt Formation. Historically the Nemegt has been considered late Campanian to Maastrichtian, based on comparisons of fossils present, but no exact dating has been performed. The age for the underlying Baruungoyot Formation (= Svita) has been suggested as Santonian to Campanian, and Shuvalov (2000) found K-Ar dating of basalts that they referred to the mid and upper Baruungoyot to be 75 to 80 million years old.
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To the east, the boundary with the Eastern Carpathians is placed formally in the valley of the river Uzh, but many tectonic divisions consider the Hornád fault system on the line Košice – Prešov the real geological boundary. The northern boundary is the thrust front that separates the nappes from the Carpathian Foredeep. In Bohemia the line Znojmo-Přerov-Karviná approximately forms the western boundary of the Western Carpathians. The southern boundary is not distinct (because of the interfingering boundary between the Carpathians and lowlands of the Pannonian Basin).
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These two formations with their diverse fossils were historically thought to represent sequential time periods with different environments, but in 2009 the Canadian palaeontologist DavidA. Eberth and colleagues found that there was partial overlap across the transition between them. The two formations "interfinger" across a stratigraphic interval that is about 25 m (82 ft) thick, which suggests that the fluvial and aeolian environments coexisted when the area was sedimented. Photos of the interfingering contacts between the formations The environment of the Nemegt Formation has been compared to the Okavango Delta of present-day Botswana.
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In: Drexel, J.F. & Preiss, W.V. (Eds.) The geology of South Australia. Vol.2, The Phanerozoic. pp. 163-171. South Australia Geological Survey, Bulletin 54. These deposits are overlain by Quaternary alluvial fans and piedmont slope deposits, derived from erosion of the uplands, consisting of sands, clays and gravels,Callan, R.A., Sheard, M.J., Benbow, M.C. & Belperio, A.P. (1995): Alluvial fans and piedmont slope deposits. In: Drexel, J.F. & Preiss, W.V. (Eds.) The geology of South Australia. Vol.2, The Phanerozoic. pp. 241-242. South Australia Geological Survey, Bulletin 54. interfingering to the west with transgressive Pleistocene to Holocene marine sands and coastal sediments of the shoreline of Gulf St Vincent.
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Map and diagram showing the relation between the interfingering Baruungoyot and Nemegt Formations Nemegtomaia is known from the Nemegt and Baruungoyot Formations, which date to the upper Campanian–lower Maastrichtian ages of the Late Cretaceous period, about 70million years ago. Though this taxon is known only from the Nemegt locality, unidentified oviraptorid remains from other localities may belong to it. The Nemegt massif has numerous canyons or gorges, up to deep, which have some of the best exposures of these formations. The rock facies of the Nemegt Formation are thought to represent a humid, fluvial (associated with rivers and streams) environment, whereas those of the Baruungoyot Formation are thought to represent an arid or semi-arid environment, with aeolian (affected by wind) beds.
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Farther to the west, a complex island arc assemblage formed above a subduction zone. To the east, in western Colorado, a mountain range similar to today's Himalayas called the Uncompahgre Mountains bordered the Utah lowland. The interfingering of the Kaibab with the White Rim Sandstone, now exposed in Capitol Reef National Park area, to the east suggests that the marine facies of the Kaibab migrated eastward in response to a relative sea-level rise, or transgression (the White Rim is not exposed in the Zion area). The sea moved back and forth across Utah, but by the Middle Permian, the sea had withdrawn and the Kaibab Limestone was exposed to erosion, creating karst topography and channels reaching 30 m (100 ft) in depth.
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