The Anagance Ridges area is characterized by northeast-southwest ridge and valley topography (Rampton and Paradis 1981) and constitutes about 90% of the study area. Major topographical features parallel northeastward-southwest-ward oriented local faults and bedrock contacts, with relief ranging from 100 to 200 m. In the southeastern corner of the map sheet, the topography becomes increasingly hilly where glacially streamlined ridges rise 120 m to 250 m above the valley floors. In contrast, the northern regions exhibit much less topographic expression, having a gently undulating plateau-like surface interrupted by occasional clusters of rolling hills (Rampton and Paradis 1981; Seaman 1987). In the northeast, the terrain grades to a gently undulating surface and lies below an elevation of 75 m as it encompasses a small part of the Moncton Sub-basin.

Bedrock contacts are not well constrained due to poor exposure throughout most of the Petitcodiac map area. Mapped bedrock units range from Precambrian to Late Carboniferous in age, but Carboniferous marine and terrestrial sedimentary rocks underlie most of the study region (Fig. 2). The larger units consist of Paleozoic sedimentary rocks. The dominant local lithologies include: polymictic conglomerate, sandstone, arkosic sandstone, siltstone, and shale, with rare limestone and gypsum. Munn et al. (1996) reported that the conglomerate units contain rare clasts of extrusive lithologies and lesser amounts of granite, granodiorite and diorite clasts, derived from Caledonia Zone source rocks to the south (van de Poll 1994).

The Central Plateau is located in the southeastern corner of the study area (Fig. 1). Here, the elevation rises from 160 to 325 m along the edge of the plateau. The plateau contains small hills typically 30 to 90 m in relief and slopes gradually toward the southwest.

Igneous units and rare sedimentary strata outcrop in this area and form part of the Caledonia Zone (Fig. 2). The igneous units are mainly rocks of the late Hadrynian Point Wolfe River Pluton, consisting of a variety of folded and faulted felsic and mafic volcanic (rock) units with interbedded sedimentary rocks that are intruded by Cambrian granodiorite, coarse granites, diorite and minor gabbro and rhyolite lithologies (Ruitenberg et al. 1979; Barr and White 1988). These rocks are intensely sheared in some outcrops. A much smaller occurrence of rock with similar lithologies is also found along the western edge of the map area at Jordan Mountain, where Cambrian basement rock outcrops (Fig. 2).

The majority of the mineral exploration in the study area was conducted in the 1970s and 1980s. Presently there are no base metal deposits of economic interest, but there is an active limestone quarry located at Havelock containing sub-economic gypsum deposits (Fig. 2). St. Peter (1992) suggested that cupriferous deposits in the Carboniferous strata may be genetically related to faults in the southeastern section of the Moncton Sub-basin (located in the northeastern corner of the study area).

Eight individual base metal occurrences have been identified in the study area (Fig. 2) that may be useful as "point sources" for glacial dispersal. Several mineralized occurrences are associated with the Jordan Mountain area (Sites 1– 4, Fig. 2). Site 1 (Fig. 2) represents a base metal occurrence associated with a shear zone in a massive rhyolite host rock containing: chalcocite, malachite, silver, and gold (Rose and Johnson 1990; Merlini 1998). The shear zone is 3– 4 m wide and approximately 210 m long. Mineralization is disseminated in the rhyolite host rock and is concentrated along irregular seams. Site 2 (Fig. 2) at Jordan Mountain contains manganite intergrown with pyrolusite, and reduced amounts of hausmannite and psilomelane (Rose and Johnson 1990; Merlini 1998). This near-surface mineralization is found in massive lenses, blebs, and stringers in the cement of a Lower Carboniferous Hillsborough Formation conglomerate unit.

Approximately 4 km northeast of Jordan Mountain, at site 3 (Fig. 2), lenticular quartz veins containing sulphide and gold occur in a 23 m long, 10 m wide zone, cutting dark grey quartzose slate (Rose and Johnson 1990; Merlini 1998). South of Jordan Mountain at site 4 (Fig. 2), disseminated chalcocite and malachite occur in the matrix of a grey conglomerate overlain by red sandstone, red conglomerate, and Windsor Group limestone (Rose and Johnson 1990; Merlini 1998). The mineralized zone here is less than 30 cm thick. A second zone of mineralization, similar to site 4, occurs at site 5 (Fig. 2) in the central part of the study area (Rose and Johnson 1990; Merlini 1998).

Three sites of mineralization occur in close proximity at the southeastern corner of the study area. At site 6 (Fig. 2), primary and secondary minerals occur in a fanglomerate matrix, as coatings on the pebbles and as infillings of fractures and cavities (Rose and Johnson 1990; Merlini 1998). Additional smaller occurrences are found locally. These shallow sub-economic occurrences contain manganese oxides, covellite, chalcopyrite, malachite, azurite, copper, and silver (Rose and Johnson 1990; Merlini 1998). In the Precambrian Coldbrook Group at Site 7 (Fig. 2), felsic tuffs contain lenses of quartz and carbonate, hosting disseminated zinc and copper sulphides along with traces of gold, within schistose zones demonstrating intense drag-folding (Rose and Johnson 1990; Merlini 1998). At Site 8 (Fig. 2), a large tabular body of fault breccia is composed of felsic rock cemented by manganese oxides and containing massive botryoidal psilomelane and braunite, as well as crystals and needles of manganite in vugs with barite. Mineralization extends over an outcrop of approximately 1 m in width by 60 m wide (Rose and Johnson 1990; Merlini 1998).

The absence of datable surficial sediments and the insufficient number of stratigraphic exposures have limited surficial studies in the study area. Brief descriptions of the local soils and surficial geology are found in a soil survey report for southeastern New Brunswick (Aalund and Wicklund 1950). Additional information is found in regional mapping projects of the surficial geology of New Brunswick (Chalmers 1890; Rampton et al. 1984), and in a compilation of all published glacial striae data for New Brunswick (Seaman 1989).

In southeastern New Brunswick, the regional ice-flow direction during the Late Wisconsinan ranged between south-southwest and southeast (Rampton et al. 1984; Munn et al. 1996; Broster et al. 1997). Within the Petitcodiac map area, similar ice-flow directions have been documented (Chalmers 1890; Rampton et al. 1984; Seaman 1987, 1991). However, in the eastern part of the map area, Chalmers (1890) reported striae and grooves indicative of northeastward ice-flow. His observations were refuted by Rampton et al. (1984), but have since gained support from discovery of similar striae orientations at a site immediately east of the Petitcodiac map area (Foisy and Prichonnet 1991).

Mapping by Seaman (1987) revealed that, in the western half of the study area, ice movement was generally southward. Seaman (1987) further suggested that moraine and extensive ice-contact deposits along the sides of the Kennebecasis River valley record the positions of ice margins that were relatively stable for a long time.

In the eastern half of the study area, striae indicate that the dominant ice-flow direction varied between south-southwest and southeast, similar to that reported locally by others (Rampton et al. 1984; Seaman 1989; Munn et al. 1996). Multiple directions were recorded at two sites in the northeastern corner of the study area. Cross-cutting relationships demonstrate directions, from youngest to oldest: (1) 150°– 170°, (2) 095°– 105°, (3) 070°– 090°, (4) 060°– 040° (Fig. 4). These striae sets may record a gradual counter-clockwise shift in ice-flow from the south toward the northeast during expansion of the "Gaspereau Ice Centre", proposed to have been located to the west of our study area (Rampton et al. 1984). However, some eastward readjustment of late-glacial flow should be expected because of flow into the Gulf of St. Lawrence and subsequent drawdown of ice toward that location.

At the southeast corner, striae sites at higher elevations along the edge of the Central Plateau (Fig. 4) record mainly the south-southwest to southeasterly ice movement. Rare north-eastward-southwestward directed striae occur in some valleys, possibly due to early ice-flow around this higher plateau. No evidence of the late phase eastward, northeastward or north-westward ice-flow was found on the plateau, suggesting: (a) that ice did not flow radially off this part of the Central Plateau; and (b) that any northeastward flow affected mainly the northern part of the study area. Streamlined bedrock features found in the western part of the study area indicate that ice flowed both southwestward and northeastward around the Anagance Ridges (Fig. 4). The diversion of ice flow around ridges of < 200 m in elevation indicates an erosive eastward ice-flow event that was likely due to thin ice flowing under topographic control or the result of other influences (e.g. ice growth to the northwest, or ice drainage to the east). However, in the southwestern part of the study area, drumlinoid features and striae imply south-westerly ice movement during the major flow event.

Correlation coefficients (rs) with absolute values greater than 0.599, that is greater than a 35.9% correlation between the data (Silk 1979), are considered indicative of a significant association between the variables, and will be the main values discussed (Table 1). No significant correlations were found between the clast lithology and matrix data. However, a moderate positive relationship (0.589) was found between concentrations of clasts derived from felsic extrusive and intrusive bedrock.

Spatial dispersal of till clasts was examined by measuring the relative abundance (i.e. percentage) of the major indicator lithologies at each sample site. The major lithologies are granitic (igneous and metamorphic), felsic volcanic, felsic tuffs, mafic volcanic, red and grey conglomerates, and sandstones. Of significance, Lower Carboniferous limestone, gypsum, and anhydrite occur in the Havelock syncline (Fig. 2), with multiple smaller units outcropping along faults (McLeod et al. 1994). To facilitate discussion of clast dispersal, the lithologies can be grouped into four main categories: (a) sedimentary rocks that underlie most of the study area; (b) felsic and mafic volcanic rocks that occur in association with (c) granitic rocks of the Central Plateau and parts of the Jordan Mountain anticline; and (d) evaporite bedrock units that are associated with the Havelock syncline (Fig. 2). However, evaporite clasts were not found in the sample collections suggesting that they did not survive any appreciable transport distance.

The complex stratigraphy of the Carboniferous sedimentary rock units in the area has not been established in detail, making it difficult to interpret glacial dispersal of till clasts from sedimentary bedrock sources. Clasts derived from sedimentary rock units are red or grey conglomerates, sandstones, and mudstones/siltstones. Concentrations of clasts with sedimentary rock lithologies are the highest in the till overlying the central area (100%) and decrease south-southeastward of the Carboniferous / Hadrynian boundary (Fig. 5) as the underlying bedrock changes, from mostly sedimentary units in the north to predominantly igneous units in the south.

In contrast to the clasts derived from sedimentary bedrock, granitic clasts, derived from granite and granodiorite, increase in concentration toward the south-southeast, from less than 5% to greater than 50% over a distance of 5 km from the Carboniferous / Hadrynian boundary (Fig. 6). Granitic clasts form south-southeast and south-southwestward oriented dispersal patterns originating from an unidentified source at the northern edge of the study area (Fig. 6). The dispersal patterns suggest possible dispersal of granitic clasts over a distance of 16 km, but the pattern likely represents entrainment from multiple sources of granite/granodiorite clast-rich zones within the underlying conglomerate (Broster et al. 1997). Granitic clast dispersal forms a large (> 90%) "bulls eye" pattern overlying the Jordan Mountain anticline (Fig. 6), although this pattern may continue in a southeastward direction beyond the study area.

Clasts of an immature porphyritic felsic volcanic lithology were observed during fieldwork, in Windsor Group conglomerate outcropping near the base of Jordan Mountain (Fig. 2). Felsic and mafic volcanic clasts have been reported in the Hopewell Conglomerate (van de Poll 1994) and were discovered in Horton Group conglomerate during our investigation of the northern area of Jordan Mountain. The anomalous concentrations of clasts of felsic volcanic origin in the northern part of the area are probably derived from the underlying conglomerate units (Broster et al. 1997). The longest dispersal train occurs at the northern area of the Jordan Mountain rocks (Fig. 7) and extends eastward about 5 km and southeastward over approximately 10 km. Here the concentrations are as high as 70% and felsic rock units underlie some parts of the Jordan Mountain area. However, other "bulls eye" occurrences of felsic volcanic clasts in till overlying the Hopewell Group are probably derived from local conglomerate units. In the southeast corner of the study area (Fig. 7), the concentration of till clasts derived from felsic volcanic rock increases southward across the Carboniferous / Hadrynian boundary (Fig. 7). Clasts of felsic volcanic origin occur rarely in till immediately northwest of this boundary, which does not support the possibility of northward radial ice-flow from the Central Plateau suggested by Foisy and Prichonnet (1991).

Felsic tuffs and mafic volcanic rocks are found south of the Carboniferous / Hadrynian boundary, at Jordan Mountain, and north-northwest of our study area (Fig. 7). These data demonstrate three patterns that were also seen in other clasts and geo-chemical patterns discussed below. For example, south of the Carboniferous / Hadrynian boundary and at Jordan Mountain, many dispersal patterns extend southward for approximately 5 km and eastward for 1– 2 km. In the northwestern corner of the map area, felsic tuff erratics produce a dispersal train 10 km long, elongated southward (Fig. 7) accompanied by a large occurrence of mafic volcanic clasts. There are no mapped felsic tuff or mafic volcanic units in the immediate vicinity of the erratics, but the shape of their dispersal train suggests that a bedrock source is located at the northeastern limits of the study area.

In the granulometric data, sand and clay content demonstrate a strong negative correlation (-0.845) that may be due to closure. "Closure" is one type of false correlation that can occur when examining correlations among grouped variables that sum to a fixed total (Broster 1982). However, it is also possible that this correlation may be partially reflecting the process of comminution of sand to clay-sized fragments or some other glacidynamic process. These observations are also relevant to the strong negative correlation (-0.815) between the sand and silt content (Table 1). However, in both the geochemical and clast lithology data, the magnitude of the closure effect is less significant due to the larger number of variables involved in their fixed total (Broster 1982).

Similar to other locations across southern New Brunswick (Balzer and Broster 1994; Hornibrook et al. 1991; Munn et al. 1996; Stumpf et al. 1997), the texture and composition of till in the study area changes with variation in underlying lithology and topography. This is most noticeable when percent grain-size is contoured and examined relative to a digital topographic model of surface relief. For example, sand-rich areas are coincident with ridges and hilly areas (Fig. 8), and clay content is coincident with topographic lows such as in the northeast of our area (Fig. 9). For the most part, the clay likely represents pre-glacial accumulations contained in low-lying areas that were incorporated during ice advance. Conversely, increased stresses on the stoss side of obstacles, as the glacier climbed over bedrock obstructions, likely facilitated comminution and thrusting within the glacier, resulting in the preferential increase in sand and the coarse fraction of the till, down ice of major topographic obstructions.

Element concentrations in the till were contoured to enable recognition of dispersal patterns of anomalies and allow comparisons between spatial distribution of elements. "Anomalous" concentrations are defined as the upper 95.44^th percentile of element distributions, including values outside two standard deviations from the median. Geochemical covariance is presented in Table 1 for the significant relationships among the 48 elements analyzed, although only a few will be discussed here.

Geochemical dispersal patterns in the till matrix were relatively short (2– 6 km) and irregular, similar to those described by Balzer and Broster (1994), Munn et al. (1996), and Stumpf et al. (1997) for other areas of southern New Brunswick. The lengths of the dispersal trains were observed to be related to topography. Sources located in topographic lows oriented transverse to ice flow, generally display little down-ice glacial dispersion. Conversely, sources on topographic highs or ridges produce longer dispersal trains, previously reported by Hornibrook et al. (1991).

For many elements (e.g. Au, Be, Eu, Ir, Mo, Tb, U), matrix concentrations rarely exceed background levels. A few elements display isolated concentrations ("bulls-eye" patterns), possibly associated with local faults (Allaby 2000), but with no apparent down-ice elongated dispersal fan. For many elements, the highest till concentrations occur near, or down ice of, known mineral occurrences, overlying specific rock types or parallel to local structural trends. For example, seven rare earth elements (Ce, Eu, Lu, Nd, Sm, Tb, and Yb) were examined and the major anomalous till concentrations (Allaby 2000) are associated with the mineralized zone on Jordan Mountain (mineral sites 1 and 2, Fig. 2). However, no dispersal of Ca or Mg was observed from the Windsor Group limestone and evaporites in the Havelock area. The absence of both clasts and matrix components from this unit suggests that these rocks were not eroded appreciably during glaciation.

The lithophile elements (Al, Cr, Na, Sc, Rb, Th), best illustrated by Al (Fig. 10), demonstrate anomalous till concentrations in areas overlying Horton and Windsor group rocks and decline in concentration an east-southeastward direction in till over Cumberland Group bedrock. This pattern of distribution is mirrored by Rb and Th values (Allaby 2000). Aluminum content forms one of the longer dispersal patterns, extending from a point north of the Anagance Ridges, southeastward as a 10 km ribbon-shaped anomaly (Fig. 10).

Sodium distribution forms a broad linear pattern, >10 km wide and extending over 25 km in a northeast-southwest direction (Fig. 11), occurring just west and parallel to the main ridge in the area (Fig. 4). This abrupt change in Na content may be due to the interference of the major down-ice ridge as the glacier flowed eastwardly across it. Additional anomalous concentrations of Na also occur in till overlying rocks of the Caledonia Zone in the southeast corner of the study area. A distribution similar to Na is found for Mg, Sc, Sr, and V, and to a lesser extent for some of the base metals Cr, Pb, and Zn (Allaby 2000).

A total of 10 chalcophile elements (Ag, As, Bi, Cd, Cu, Hg, Pb, Sb, Se, and Zn) were examined for evidence of glacial dispersal. The pattern of Zn (Fig. 12) best demonstrates that these elements generally have short and irregular dispersal trains with elongation toward the east, northeast (similar to Na, Fig. 11), southeast, and southwest. However, the north-easterly and southwesterly elongation of some patterns may be an artefact of the northeast-southwest trend of the local fault system, and not only a product of glacial dispersion. Elevated concentrations of As are associated with base metal occurrences at mineral sites 1 and 2, between faults southeast of mineral site 6 (Fig. 2). High Cu and Hg concentrations were observed in till over the large composite intrusion in the Caledonia Zone and may be associated with the mineral occurrence near mineral site 7 (Fig. 2). High concentrations of Zn (Fig. 12) and Pb, occur similarly in irregularly shaped anomalies coincident with local fault systems and known mineral sites.

Aluminum showed strong correlation with Sc and moderate positive correlations with Fe. The correlation between Al and Fe (0.608) is likely coincidental rather than indicative of secondary weathering, as these elements are not strongly correlative with other mobile elements (Table 1).

Hg and Br display a strong correlation (0.743), which may be attributed to the anomalous concentrations of both elements in the till overlying a large composite intrusion in the Caledonia Zone south of the Carboniferous / Hadrynian boundary (Fig. 2). Anomalous concentrations of Cu (>60 ppm) only occur in this area, forming a small area of dispersal directly over site 7, of about two kilometre wide and extending three kilometres southeastward (not shown).

Significant covariance with granulometric data is demonstrated only with the concentration of Hg; positively with sand content (0.649) and negatively with clay content (-0.604). These correlations suggest that elevated Hg is associated with a mineral whose terminal grade lies predominantly in the sand-sized particle range (e.g. cinnabar), rather than simply an artefact of the geochemical analyses on the fine silt and clay fraction and their strong negative correlations with sand (Table 1). The anomalous Hg concentrations (>100 ppm) were found only in till overlying composite intrusions southward of the Carboniferous / Hadrynian boundary (Fig. 2).

Similarly reported by Munn et al. (1996) for the adjoining map sheet south of the study area, the highest elemental correlations occur amongst the lanthanide elements. Particularly between La and Sm (0.840), La with Ce (0.800), Sm with Ce (0.789), and Sm with Eu (0.719) and lesser correlations between these elements and Nd, Eu, Yb, Y, Lu (see Table 1). Lithophile and rare earth elements have been found to be occasionally elevated slightly in ablation till (Stumpf et al. 1997), but this is not believed to be the cause here. Two areas of commonality identified for most of these elements are indicated by Sm dispersal (Fig.13) and were found to be: (a) the area of mineral sites 1 and 2 (Fig. 2); and (b) sample site H12 (Fig. 3) an area between the intersection of two faults. This latter location also contained anomalous till matrix concentrations for As, Co, Cr, Ni, Zn, and Rb, which may account for some correlation among these elements.

Of the alkali metals, Na correlates strongly with Sr (0.744) and Rb displays a strong correlation with K (0.758) and slightly less (0.635) with Cs. Of the transition metals, Sc exhibits strong correlations with V (0.743) and Fe (0.727). Positive correlations between these elements and Al, Co, Cu, and Ni are likely due to their association with Fe and coincidental anomalous occur-rences rather than solely from reactions with organic matter during diagenesis of sedimentary rocks. However, the latter may be indicated in some units: for example, coincidental point-source anomalies of Cu and Al occur only in the area south of mineral site 7 (sample site T12, Fig. 3). Coincidental point source anomalies for Ni and Co occur at mineral site 6 and over faults (sample sites, Q13, H12, P2, Fig. 3). Anomalous concentrations of Zn also occur at these sites (Fig. 12) but, as Zn is relatively more abundant and likely originates from several sources; Spearman correlations between these elements are weak (Table 1).

The Late Wisconsinan glacial history of the Petitcodiac map area can be divided into three ice-flow phases that account for the observations discussed here. These are informally discussed as: (a) phase 1, early glacial flow; (b) phase 2, glacial maximum; and (c) phase 3, late glacial flow.

Drift prospecting employs the examination of the areal distribution of anomalous clast or matrix components of a till for the delineation of buried mineral sources, expected to be at or near the point of highest concentration. When drawn on a map the dispersal pattern can form a variety of shapes that reflect the size of the source unit and approximate distance of transport. Mathematical techniques can also be used to quantify the transport distance and reduction in glacial load. For example, half-distance length (Gillberg 1967; Bouchard and Salonen 1989) and the empirical exponential decay relationship between distance and load, based on the change in concentration between local and distal components, are discussed by Klassen (2001), and by Stea and Finck (2001). However, entrainment, erosion, mixing and transport (and thus, the dispersal pattern) are affected by several factors, including: (1) grain size fraction and volume of sample investigated; (2) lithology and relative mineral hardness; (3) characteristics of the source unit (e.g. attitude and size of outcrop, both related to the amount of erosion); (4) inheritance, overprinting and dilution of load; (5) glacial dynamics (e.g. basal thermal conditions, velocity and flow direction, centres of ice-growth); (6) erosional and depositional history of the till fraction; (7) local subglacial topography; and (8) the degree of variation of the preceding factors (Dreimanis and Vagners 1971; Shilts 1976; Broster 1986; Hornibrook et al. 1991; Balzer and Broster 1994; Broster and Huntley 1995; Broster et al. 1997; Stumpf et al. 2000; Klassen 2001; Stea and Finck 2001).

The results discussed here indicate that dispersal models are prone to errors when applied to areas of rugged terrain where a glacier has crossed a valley or ridge and at locations containing large deposits of fine-grained sediments. This occurs because the shape and size of a dispersal pattern and the precision of empirical models for estimates of glacial dispersal distance are affected by such conditions. Undulating topography results in change between compressive and transgressive flow and stacking or mixing of englacial debris (Broster 1986). Increased friction and shearing as a glacier flows over a topographic obstruction increases erosion, comminution, mixing, and thus dilution of the glacier load. Extensive englacial mixing of the glacier load would result in tills of compositional uniformity from top to bottom. This may be why researchers often report compositional similarity between ablation and basal tills for many areas of New Brunswick (e.g. Broster and Seaman 1991). In rugged areas where topographic undulations are frequent, till composition would be "immature" (Dreimanis and Vagners 1971), well mixed, and biased toward the lithologies comprising the topographic obstruction.

In the study area, till deposited down ice of topographic obstructions, demonstrate dilution to clast and matrix content with major increases in sand and clast size fractions and minor changes to till geochemical composition. Down ice of valleys the fine fraction of the till matrix is increased relative to the clast fraction, diluting and overprinting till geochemistry (Broster 1986). Thus, as the sediment accumulations at these locations are often second or third derivatives (Shilts1976), geochemistry of a till deposited down ice of valleys or along coasts may be unrelated to local bedrock.