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272    16. CONTINliNTAI. K IINOI.OOYi RJNDAMIINTAI, PH0OUŚBHH ANI) ( ON I HOI.HON TRACH FOIIII. l)IH II(/m)'||ON

Scdlmenls Ihot iin* found the v.ml mfljorlty ol Ilnu* oht>\'i* ilu¹ Witter labie are relerred In oh lt^arri*h!rliil eiwironmenls .nul Indude olluviol floodplnln .md pl.iy.i, duiit* .md tiry iiilt^,rdimi^,/ piiilillnr.il .md stipr.ilillnr.il, and volcanoclastic snheiwimnmenls (Hasiolis and Uown, 1992; Hnsłotia, 2002), Secltfmenls l hol on* found the v<ist mnjority of linii* helów I lu * wal er-labie level I ho I inlerseiis Ihe land surface are referreil In as acjualie eiwironmenls and inciude slreams, rivers, and overbank lakes and pnnds, and littoral In prnlundal subeiwironments (e.g., I loniolis and Uown, 1992; Hasiotis, 2002). Surface sedlments found Ihe vasl mnjority of U me near In (above or below) or al Ihe walor-tnble level are reforred to as periaqualic eiwironmenls (Ginsberg, R. personal communication, 2004). Th esc includc paluslrine (swamp) and transitional or shoreline subeiwiron-ments (I lasiotis and Bown, 1992; Hasiotis, 2002). Tlius, acjuatic, periaaualic, and Łerrestrial subeiwironments can be further subdivided and defined by the spatial and tein pora I variabi)ity of the groundw&Wtii' profil® (Fig. 16.2).

Continental enyaww-.wtó-f    ci

juxtapofjpd aouatlc, S

menie are gradftwIlPM. goi present withm a łerrestrial, pcrincp _r .v

exiel logelher in a 50 aren m rhr Roim.sou Traci of Ihe Univc*rsily of Kansas FhjIiJ blauon and Ecological Reserve, each will. mit robę-;, olani?;, .mimals, and eoils I hal would leave a uniciue su ile of evidence indicating Ihe amount of waler present for that parlicular climate seliing.

Tcmporal Variability of Waler and lin vi ron in en tal Stabili ty

Terre,slrial, p<!na<|i.mlic, .md acjuatic subeiwiron-menls vary greally in .terial exlcnl over very short periodu of limo (sec Figs. 16,1 16.3). hor exanipie, •ił|ii.iIi«- suhenvironmenls are perenni.il, intennitlent, or ephemer.il in naturę. IVri.u|unlii' i-łubeiwironments are variably mnisi to wet, bul tan betonu* aquatic or terrestrial over short period* of linie for variable lenglhs of limę. When subaerially exposed, periaaualic sellings tan undergo soil forma don (set* Fig. 16.4).

Temporał variabilily of waler in a system is duo lo ilu* amount contributed by di red predpitation, overland flow from runoff, or groundwaler inpul (e.g., Drlscoll, 1986; Ward, 1992; Hasiolis, 2004), and ullimalely conlmlled by climate (Thornlhwaite and

Mather, l^!955), Ihe amonnl of waler input Into tlepoHllIonal sysiern will Influence dlrect wdim# aecumiilalion rales and local groundwaler profili*

■ nul lienee, the environmenl.il słabliby of Ihe l.iiul-se.ipe (I laslolls, 2000, 2002). For exninpl«, Ilu-freł|iiency and niagniliule of flooding event« in alluvi.il deposilional Systems determlnes the rale al wliich sedimenl accumulate. These c*vents ąra controlled by local and regional wealher patlerns willi predpitation inpuls that may cause local or downslrcam flooding il predpitation oecnrs inanare.i over an exlended period of limę. Flooding raises ihe groundwaler lt*vel depending on Ilu* inpul of dircrl predpitation and runoff, as weli as ihe degrec of saluration of the soil prior to the cvent. Subeiwironments prone to fret|uent flooding havt* lower environmenlaI slabilily and higher levels of disturbnnee compared to subeiwironments distal to I >rone areas (Odum, 1971). This variabilily in ;i:ure in an eiwironment can be seasonal, annual, d, and centuria! in scalę, Such variability can .hor i- lo long-term bodies of wator in sellings, and raise and lower lakę lm*ls r al similar scales (Fig. 16.3B),

icntal Environments and their Media

li.ivi.il, lacustrine, and eollan environnu*nb >.3) can be subdivided based on major sedimenlologic.il processes and physicnl characlcris-tics Iliat produce such distincl subenvironmenls as channels, floodplains, shorelines, splays, dunes, and interdunes (Reineck and Singh, 1980). Volcanoclastic environments deliver sedimenl primar-ily by air lali dcposiition, which are Ihen modifled by wind or waler. Faluslrine eiwironmenls can occur in any ol the deposilional eiwironmenls, tlefinwi by the posili on and fludualion of the waler labie. Ali subeiwironments can be furlher subdiyldrd according lo their (1) deposilional energy;

(2)    magniluih* and Ireijuency of flooding experi<^,n(i^,iJ;

(3)    topographic relief; (4) groundwaler profile and d rui nago condilions; (3) sedimenl texlurc; (6) I y jh* and degree of podogonie modification; (7) ciwiron-men lal slabilily va. dislurbance; (H) oxic us. di»nxic W. anoxic condilions; (9) salinily; (10) temperatura; and (II) jonie slrenglh in Ihe waler. Filier siali* divisions based on these charaderistics represenl the spatial and temporal heterogeneity in Continental eiwironmenls that are necessmy to p into |X*rspective when evalualing trace-fossil suitę* or associations.