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: Efflorescent salt crusts composed primarily of halite dominate the saline mudflats of Saline Valley and Death Valley, California. These crusts form by the complete evaporation of saline groundwater at the sediment-air interface. Efflorescent crusts also form where halite dust is introduced by wind, then dissolved by rain and reprecipitated as the rainwater is evaporated. Wind-blown silt and clay adhere to thin hydroscopic water films coating crystals in the efflorescent crusts, and coarser sediment is trapped in surface depressions. The sediment is left as a lag deposit when the halite dissolves at the base of the crust in the undersaturated waters below the surface. Efflorescent crust deposits slowly aggrade producing irregular sand and silt lenses in poorly sorted porous mud. The sand and silt lenses have distinctive cuspate contacts, ragged edges, and irregular layering and grain-size distributions. Efflorescent crusts growing on sandy sediment distort the upper surface into polygonal bowl shapes, or deform ripples into hump-shaped lenses. Deposition during flooding over an efflorescent crust commonly produces local areas of solution collapse, which are filled with the sediment as it accumulates. The latter resemble load casts but do not have associated flame structures. Efflorescent crust fabrics similar to those in Saline Valley and Death Valley are documented in the lacustrine Blomidon Formation (Fundy basin, Nova Scotia, Canada) and Bigoudine Formation (Argana basin, Morocco). Efflorescent crusts composed of less soluble minerals, such as gypsum or borates, may leave humpy layers of broken crystals and plates. Powdery efflorescence of minerals, such as thenardite or thermonatrite, generally only disturbs the internal layering of sandy deposits. Puffy ground in dry mudflats, formed by powdery efflorescence growth in mudcracks, produces a distinctive granular fabric.

Abstract The Fundy rift basin, comprising the contiguous Minas, Fundy, and Chignecto structural subbasins (Figure 1), is filled by terrestrial redbed siliciclastics, minor carbonates, and tho leiitic basalts of the Fundy Group, Newark Super group. The Minas subbasinis a shallow transtensional basin formed by left-oblique slip (Olsen and Schlische, 1990) on there activated Minas fault zone, a transform along which the Meguma and Avalon terranes were superimposed during the late Paleozoic. Outcrops of Fundy Group strata occur almost exclusively asseacliffs along the shores of the Bay of Fundy. In the Minas subbasin, a maximum of approximately 1 km of Fundy Group section is exposed along the northern and southern shores of the geographic Minas Basin and the eastern side of the Blomidon Peninsula(Figure 1). The Fundy and Chignec to subbasins are simplehalf-grabens formed when regional extension caused reactivation of Paleozoic thrusts as southeast dipping normal faults with displacement locally exceeding 10 km (With jack et al., 1995).Fundy Group strata are exposed along the Nova Scotia shore of the Bay of Fundy, forming the Fundy subbasin margin. A rider block along the faulted northwestern margin of the Fundy sub basinat Point Lepreau in New Brunswick exposes nearly2.5 km of strata. Over 3.5 km of Mesozoic strata were penetrated in the Chinampas N-37 well (Figure1) drilled offshore in the Fundy subbasin, and interpretation of seismic data suggests that thethickness of the Mesozoic section may exceed 8k min the Fundy subbasin depocenter (Brown and Grantham, 1992; Wade et al., 1996). The Chignectosubbasin is bounded to

Abstract The Triassic Fundy rift basin in Nova Scotia is a large (>70 km wide) half-graben filled with alluvial, lacustrine and aeolian deposits. A major lithospheric lineament, the Cobequid–Chedabucto Fault Zone (CCFZ), which forms the tip of the Newfoundland–Gibraltar Fault Zone, occurs within the Fundy Basin. The timing of early movement on this important fault zone is poorly constrained. We present data from the alluvial and aeolian units that crop out adjacent to the CCFZ in the Minas sub-basin to determine the initiation of fault movement. We use the onset of alluvial fan deposition to infer when the fault became sufficiently active to create the intrabasinal topography and document the influence of fault activity on the intrabasinal drainage. The occurrence and preservation of aeolian deposits immediately adjacent to the CCFZ and concomitant with alluvial fan development suggests a wind shadow effect associated with the fault-generated topography. The onset of alluvial fan deposition associated directly with the fault occurred during Norian times, following an earlier phase of sedimentation in the Fundy Basin, and records a potentially important phase of plate reorganization during early Atlantic rifting.