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TUK CONT1NHNTA1. HUALM

'liułiili* 01' clrainage pattwns (o.}*., I laslnlla, 2002, 2iK)4). Si u¹ Ii iniuwations ni*vc*t' fu Iły deviilóped because they could nol lii* u sod or mnintnlned In h,uim*l or paluatrine sol Ki iiiga (o which ihese organika would hnve lo re-ndapt nud competo for ocospnce.

The gTocitest iehnodlversltv in eolian eiwironmonls (1'ie, 16.30 is pred kleci lo bo in wot Interdune eiwironmonls. The dune onvironmenl is conslantly shilting and horsh, and will nol contnln or preserve much bioturbntion. l’reservation polential of traces lossils is tho mosl important factor because in dune eiwironments the wind is constantly reworking these donosi ts and any tracks, trails, or burrows might bc cl in the sediments. Dry interdune environ-ments may be morę stable than the dune; however, tho l;n of water prevents most organisms from living there. Ichnodiversity will be higher in environ-ments ju; laposed to eolian environments that even-me overrun by these erg-scale Systems.

I eolian-fluvial environments contain i li es and abundances that record both yirocesses. Exceptions to these patterns v iron men ts occur when they experience noisture than normal or record a major cl i mai . nge that alters the whole system.

Soils at d Paleosols: Products of Spatial and Temporal Variability on the Landscape

Nearly all of the Continental realm is modified by soils, which are referred to as paleosols when preserved in the geologie record (Retallack,

2001) . Soil formation (Jenny, 1941; Brady and Weil,

2002)    is influenced by the parent materiał, biota, topography, climate, and time (Fig. 16.4). Soils are not primary deposits but are the result of post-dcpositional modifications of the bedrock or sediments in alluvial, palustrine, lacustrine, eolian, glacial, and volcanoclastic environments.

Soils are the result of spatial and temporal variabilily in depositional processes in sedimentary environments (e.g., Bown and Kraus, 1987). Soils develop at different rates with different results based on the magnilude and frequency of depositional event8, di stance from sediment source, parent materiał, position and fluctualion of ground-water profile, and inherent local topography. Soil development is slrongly effecled by the composition of biotic communilies, climatic setting with regard to temperaturę and precipitalion, and time In terms of Hedimenl accumulation ratę and how long

sod I men l Is esposed lo the othor soil-forming factors (Haslotif, 2004),

Tlu» effecl of biota can be observed in soil-proflle duvelopment and uscd to measure the role of nn organism'8 aclivity in Hoil-forming processes (Fig. 16.4). Młcrobes, plants, and animals initiole and promote soil development in freshly deposited sediments, as well as in existing soils, by mounding, mixing, forming voids, backfilling voids, forming and destroying peds; by regułating soil erosion, regulating water, air movement, plant litter, a nim a l litter, nutrient cyding, and biota; and by producing special constituents (Thorpe, 1949; Hole, 1981).

The spatial and temporal variability in the ground-water profile (see Figs. 16.2 and 16.3) will have a major influence on soil development, including organism activity. Soil development is arrested in aquatic settings or is retarded in periaquatic settings (Jenny, 1941; Brady and Weil, 2002). The diversity of soil-forming biota markedly decreases in these types of settings because the greatest diversity of organisms lives in terrestrial settings (Wallwork, 1970; Wilson, 1992). The type, depth, and degree of bioturbation will also change because aquatic organisms become morę dominant.

The type of soil formed will encompass the (1) type of climate; (2) amount of time parent materiał is exposed to the soil-forming factors; (3) frequency and magnitude of depositional events; (4) mineralol-ogy, texture, and depth of the parent materiał; and (5) type and diversity of biota present. Soils are weakly, moderately, or strongly developed, and can be simple, compound, or cumulative in naturę. Soils are classified in soil orders, in inereasing maturity, as Entisols, Inceptisols, Andisols, Gelisols, Histosols, Vertisols, Aridisols, Mollisols, Spodosols, Alfisols, Ultisols, or Oxisols, based on the extent of inter-actions of the five soil-forming factors (Brady and Weil, 2002).

Other Types of Media in the Continental Realm

Other types of media contain traces of organisms besides the sediments found in Continental depositional eiwironments. The tiasues of plants, including leaves, alems (bark and cambium), and roots, also serve as słtes for other organisms to borę into for food, shelter, reproduction, or a combination of behavlors (Ekdale et nl., 1984; Haslolis, 2002, 2004).

Organisms with these behaviors can be considered inhabitants of xylic (plant or wood) grounds.