ABSTRACT Fallingwater is a UNESCO World Heritage Site that showcases a unique organic architectural design by Frank Lloyd Wright. Rising from bedrock in Mill Run, Pennsylvania, USA, Fallingwater incorporates large boulders into interior living spaces and is oriented with the geometry of a landscape created by the interplay of mountain and climate. Built to showcase local sandstone, Fallingwater is of the terrain. Building stone was quarried near the house from a 2-m-thick zone of quartzose medium to thin-bedded, fine- to very fine-grained sandstones in the Pennsylvanian upper Pottsville Formation. The building stone has abundant trace fossils and ripple marks, and is interpreted to have been deposited in shoreface environments with some tidal influence, or possibly in tidal flat environments. The house rests on sandstone bedrock of the Homewood sandstone, a Middle Pennsylvanian unit within the upper Pottsville Formation. At Fallingwater, the Homewood sandstone is interpreted to fill an incised valley with coarse, fluvial sandstones common in the lower part of the valley fill and finer-grained fluvial sandstones with possible evidence of marine or brackish influence in the upper fill. The Fallingwater building stone unit overlies the Homewood sandstone, above an interpreted marine flooding surface. Thickening of the Homewood sandstone in synclines suggests that deposition was influenced by Alleghanian deformation. Natural fractures in competent bedrock controlled the orientation of Bear Run at Fallingwater, and the fit of the house within the three-dimensional landscape of the valley, stream, and waterfall. Variation in natural fractures in bedded versus massive sandstone layers appears to have controlled the azimuths of the edges of the waterfalls at Fallingwater. Creation of the Fallingwater sandstone member of the Pottsville Formation is proposed.

Abstract Reactivated Paleozoic faults provided accommodation of rift and synrift basin fill in the Triassic Fundy Basin and Orpheus Graben of the Scotian Margin. Age data (Williams, 1985) suggests that the Minas Subbasin opened as early as the Anisian (242–247.2 ma) while the Orpheus Graben opened as early as the Rhaetian (201.3–208.5 ma). The Minas Fault Zone (MFZ) defines the boundary between the Avalon and Meguma terranes in the Canadian Appalachians and is exposed along mainland Nova Scotia (Murphy et al. , 2011). This series of faults mark the northern flank of the Minas subbasin (Fundy basin) and Orpheus graben (Scotian basin), and were reactivated during Mesozoic regional extension. Faults nearest the highlands accommodated the coarsest material (alluvial) while faults toward the basin center accommodated relatively finer grained fluvial, aeolian, and lacustrine sediments (Wade and MacLean, 1990 ; Leleu et al. , 2009). The Wolfville Formation comprises alluvial facies and generally fines upward into the Blomidon Formation aeolian sediments (Fig. 1), only found along the northern boundary of the basin. Is this facies present due to local deposition within the Minas subbasin in an arid, dry zone or do aeolian sediments persist along all footwalls of eastern North American synrift basins? Figure 1. Schematic transect through the Minas Subbasin showing the structural and stratigraphic elements of this basin during rifting. Alluvial fan facies are found along the northern faulted flank of the basin, with minor occurrence of Aeolian facies. Fluvial facies are found along the entirety of the basin. Lacustrine facies are also found along the entirety of the basin but are dominantly deposited in the central areas of the basin. The Orpheus graben is an oblique trending Mesozoic extensional basin. At outcrop on the western edge of the basin, facies comprise fine to coarse-grained sandstone containing pebble to cobble clasts and having a minor mud and conglomeratic facies. These are interpreted to have been deposited in an alluvial braided channel complex nearest the mouth of the river system (Tanner and Brown, 1999). To the east, more distal facies representing evaporites, playa lake and marginal marine environments are present in cores of the Eurydice Formation and represent initial opening of the Atlantic Ocean. Paleoflow indicators suggest axial rivers once existed between the two basins along the MFZ (Tanner and Brown, 1999 ; Leleu et al. , 2009). Could the “Broad Terrane Hypothesis” of Russell (1879) be applicable? Was there a single connected basin which was separated into two subbasins through uplift and erosion of conjoining strata (alluvial deposits along the axial trend of the MFZ)? During basin inversion (Withjack et al. , 1995 ; Withjack et al ., 2009 ; Withjack et al ., 1998) sediments deposited along the Minas Fault Zone have been uplifted and eroded. This is most likely the reason for the lack of alluvial facies present along the northern edge (footwall) of the Minas Subbasin. Facies associations of surface and subsurface synrift sediments are being characterized to discern sediment distribution patterns and sediment provenance (outcrop, thin section) and subsurface (core, cuttings, thin section).

Abstract The heavy mineral compositions of sandstones in Trinidad and Barbados record the onset of Andean-related erosion and a reduction of craton-derived sediments into NE South America. The changing provenance was deduced by comparing heavy mineral assemblages interpreted from ancient sandstones with associations recognized in modern sands that can be reasonably correlated to existing tectonic domains. The impact of the Andean orogeny across the margin was to introduce a suite of minerals characteristic of low-temperature metamorphism that today is prevalent adjacent to the Caribbean Mountain belt and differs from the zircon-rich assemblage produced within cratonic plains. Twenty-one Paleocene–Late Pliocene sandstone samples from Trinidad revealed systematic changes in mineral diversity and maturity that recorded this provenance transition, and suggests Andean erosion during deposition of the Late Oligocene Nariva Formation. Similar to Palaeogene sandstones of Trinidad, four Eocene Scotland Formation samples from Barbados support craton derivation, but with additional evidence of minor Andean input probably due to the proximity of the Scotland Formation delivery systems to an earlier uplift episode. By the Late Miocene, most of the sediments delivered into Trinidad basins were supplied from the Andean orogeny as suggested by the relative abundance of minerals of this affinity. The heavy mineral records of Trinidad and Barbados are similar to that described across northern South America from both modern and ancient environments that collectively mark the uplift of the Andean mountain belt, with its strong influence on drainage patterns and reservoir provenance along this sector of the continental margin. Supplementary material: Sample location coordinates, sample and outcrop photographs, and summary outcrop sections are available at http://www.geolsoc.org.uk/SUP18728 .

Abstract Coastal exposures of Mesozoic sediments in the Wessex basin and Channel subbasin (southern UK), and the Lusitanian basin (Portugal) provide keys to the petroleum systems being exploited for oil and gas offshore Atlantic Canada. These coastal areas have striking similarities to the Canadian offshore region and provide insight to controls and characteristics of the reservoirs. Outcrops demonstrate a range of depositional environments from terrigenous and non-marine, shallow siliciclastic and carbonate sediments, through to deep marine sediments, and clarify key stratigraphic surfaces representing conformable and non-conformable surfaces. Validation of these analog sections and surfaces can help predict downdip, updip, and lateral potential of the petroleum systems, especially source rock and reservoir.

Abstract Various interpretations have been proposed for depositional environments in the Trinidad-Eastern Venezuela area during the Paleogene, most without supporting sedimentological evidence. We describe lithofacies in the Chaudiere, Pointe-a-Pierre, and San Fernando formations, which suggest that sediment gravity flows were the primary delivery mechanism for the coarse-grained clastics and carbonates that characterize these formations. Outcrop examples of soft sediment deformation, block slides, and floating boulders attest to sediment instability along over-steepened gradients, consistent with a slope environment. Other common facies characteristics include low and high density turbidites and amalgamated channel fills, but there is no evidence for shallow-water reworking of sediments. The reinterpretation of a late Eocene outcrop highlights the need to resolve depositional processes along with biostratigraphy, as estimates of water depths based solely on paleontology may be underestimated. This has implications for Paleogene paleogeographic reconstructions.

Abstract In this work models are developed for the sequence stratigraphic interpretation of estuarine-shoreface-offshore reservoir sands found throughout Europe at the Aptian-Albian boundary. The models so developed are critically appraised through vertical facies analysis, facies distribution and paleogeographic reconstruction combined with correlation of depositional sequences. This process leads to the recognition of depositional sequences for which definitive criteria may vary, depending on paleogeographic and tectonic location. It is only after the effects of paleogeographic position are considered that an accurate account of sea-level history can be deduced in different environments. Arenaceous strata are present throughout southern England at the Aptian-Albian stage boundary (Lower Cretaceous); for example, the Sandrock/Folkestone Formation/Woburn Sands Formations occur both as part of a conformable succession in the Weald and Channel Basins and as an unconformable succession onlapping Jurassic and older strata of the basin margins. The facies and stratigraphy of three type successions are highly variable, suggesting environmental contrasts in Aptian-Albian times across southern England. Comparison of sequence stratigraphic analyses from each succession indicates that the depositional facies developed and preserved at sequence boundaries, as well as the number of sequence boundaries resolved, varies in direct response to the paleoenvironment.