Annales Societatis Geologorum Poloniae (2015), vol. 85: 473–479. doi: http://dx.doi.org/10.14241/asgp.2015.028
DIS AP PEARED AL MOST WITH OUT A TRACE: TAPHONOMIC
PATH WAYS AND THE REC OG NI TION OF HID DEN
BIOTURBATION EVENTS IN EOCENE STORM DE POS ITS
(PAUJÍ FOR MA TION, LAKE MARACAIBO, VENEZUELA)
Luis A. BUATOIS1, Manuel DELGADO2 & M. Gabriela MÁNGANO1
1
De part ment of Geo log i cal Sci ences, Uni ver sity of Sas katch e wan, Saskatoon, SK S7N 5E2, Can ada; e-mails: luis.buatois@usask.ca, gabriela.mangano@usask.ca
2
División Oriente, Gerencia de Exploración, PDVSA, Edificio PDVSA, Nivel Plaza, Modulo A, Puerto La Cruz, 6023, Ven e zuela; e-mail: delgadomc@pdvsa.com
Buatois, L. A., Delgado, M. & Mángano, M. G., 2015. Dis ap peared al most with out a trace: Taphonomic path ways and the rec og ni tion of hid den bioturbation events in Eocene storm de pos its (Paují For ma tion, Lake Maracaibo, Ven e zuela). Annales Societatis Geologorum Poloniae, 85: 473–479.
Ab stract: Shal low-ma rine de pos its, in cluded in the “Basal Sands” of the Eocene Paují For ma tion of the Mara-caibo Ba sin in west ern Ven e zuela, re cord de po si tion in fore shore to lower off shore set tings. These de pos its are stacked in coars en ing-up ward parasequences that re flect vari able in ten si ties and fre quen cies of storms. Of par ti-c u lar in ter est are sharp-based, amal gam ated, hummoti-cky ti-cross-strat i fied and rip pled, very fine-grained sand stone beds, ob served in the core MOT-X from the Motatán Field. These beds re cord storm de po si tion, un der purely os cil la tory to com bined flows in an off shore-tran si tion set ting. The amal gam ated na ture of the sand stone in ter val in di cates re peated ero sion, due to mul ti ple storm events. The ichnofabrics in these tempestites re sult from a dis tinc tive taphonomic path way, re flect ing the in ter play be tween bioturbation events and storm ero sion and de po si tion. The storm-re lated trace-fos sil suite is rep re sented by Diplocraterion parallelum and lo cal oc cur rences of Palaeophycus tubularis, Bergaueria isp. and Thalassinoides isp., which is con sis tent with the rel a tively high en ergy of for ma tion of these de pos its. Fair-weather de pos its are ab sent from the sand stone in ter val. How ever, high den si ties of Chondrites isp. are pres ent in the infills of Diplocraterion parallelum and, more rarely, Thalassinoides isp. pro vid ing the sole ev i dence of the es tab lish ment of a res i dent fauna dur ing inter-storm in ter vals. De pos its con tain ing the fairweather suites were erosionally re moved dur ing the sub se quent storm. The deeptier em place -ment of Chondrites and the abil ity of its pro ducer to re work other biogenic struc tures fa vour pres er va tion, al low ing rec og ni tion of a “hid den” bioturbation event that oth er wise might have re mained un de tected.
Key words: Trace fos sils, ichnofabric, taphonomic path ways, tempestites, shal low ma rine, Eocene. Manu script re ceived 13 December 2014, ac cepted 1 July 2015
IN TRO DUC TION
The ichnofabric ap proach pro vides a com pre hen siveway of ana lys ing bioturbated de pos its (Bromley and Ekdale, 1986; Bromley, 1990, 1996). A num ber of re lated con cepts are cen tral to this re search programme, in clud ing tier ing struc ture, ichnoguilds, and de gree of bioturbation (Bromley, 1990, 1996; Ekdale et al., 2012). We dem on -strate how the eval u a tion of taphonomic path ways can be a sub stan tial com po nent in ichnofabric anal y sis, as well. This con cep tual tool, orig i nally pro posed for body-fos sil tapho-nomy (Meldahl and Flessa, 1990), was sub se quently impor- ted to and ex panded for ichnology in an at tempt to de ci pher suc ces sions of events, re flect ing the in ter play be tween de-po si tional/ero sional events, bioturbation and preservational pro cesses in spe cific sed i men tary en vi ron ments (Buatois
and Mángano, 2004, 2011). In body-fos sil taphonomy, the con cept of taphonomic path ways re fers to the se quence of in her i tance of taphonomic fea tures by skel e tal re mains. Meldahl and Flessa (1990) noted that shells in dif fer ent en -vi ron ments typ i cally ac quire par tic u lar taphonomic fea tures in a char ac ter is tic or der, as a re sult of the rel a tive in flu ence of var i ous taphonomic pro cesses among dif fer ent deposi-tional en vi ron ments. Sim i larly, ichnofabrics are the prod uct of dif fer ent preservational tra jec to ries (i.e., taphonomic path ways), shaped by the in ter play of bi o log i cal, phys i cal and chem i cal pro cesses that char ac ter ise a di verse range of depositional set tings (Buatois and Mángano, 2011). The na -ture of taphonomic path ways in ichnology has been explo-red in lac us trine (Zhang et al., 1998; Buatois and Mángano,
2004, 2007), flu vial (Buatois and Mángano, 2004, 2007; Buatois et al., 2007) and tidal (Desjardins et al., 2010; Pearson et al., 2013) set tings.
The aim of this pa per is to il lus trate the use of the taphonomic path ways con cept to re veal sub tly pre served bioturbation events in the strati graphic re cord that can be eas ily missed and to show how they can help un ravel storm dy nam ics in the mid dle Eocene shal low-ma rine de pos its of the Paují For ma tion of the Lake Maracaibo area, in west ern Ven e zuela (Fig. 1).
GEO LOG I CAL AND STRATI GRAPHI CAL
SET TING
The tec tonic his tory of the Maracaibo Ba sin has been sub di vided into four phases (Ghosh et al., 1995): (1) Tri as -sic–Ju ras sic graben, (2) Cre ta ceous back-arc to pas sive margin, (3) Paleocene–Eocene fore land, and (4) Oligocene– Plio cene com pres sion and transpression. The strata con sid -ered here were de pos ited dur ing the Eocene as part of the fore land phase.
Dur ing the early to mid dle Eocene, a deltaic to tidal embayment formed, with clastic wedges ad vanc ing to wards the north east, as re corded by the Misoa For ma tion, one of the most pro lific oil-pro duc ing units in Ven e zuela (Van Veen, 1972; González de Juana et al., 1980; Maguregui and Ty ler, 1991; Zambrano, 1995; Higgs, 1996). An in crease in sub si dence, cou pled with a rise in sea level, took place by the mid dle Eocene, re sult ing in transgressive de po si tion of the Paují For ma tion (Fig. 2), which con form ably over lies the Misoa For ma tion (Zambrano, 1995).
The Paují For ma tion, up to 1200 m thick, is dom i nated by mudstone and shale, with mi nor sand stones, en com pass -ing a wide va ri ety of depositional set t-ings, rang -ing from fore shore to slope and in wa ter depths per haps reach ing up to 500 m (González de Juana et al., 1980). In con trast to the more re stricted na ture of the Misoa For ma tion, the Paují For ma tion is char ac ter ised by a more di verse and abun dant bodyfos sil fauna, as well as a higher di ver sity of trace fos -Fig. 1. Lo ca tion map of the Motatán Field in the Maracaibo
Basin.
Fig. 2. Stra tig ra phy of the Maracaibo Ba sin (based on Benitez et al., 1996) with po si tion of 2nd-or der se quence bound aries. Note strati graphi cal po si tion of the Paují For ma tion. Coarser-grained de pos its near the base of the unit are re ferred to as the Basal Sands.
sils (Delgado et al., 2001), in di cat ing de po si tion un der fully ma rine con di tions. Over all, in te gra tion of sedimentological and palaeontological datasets in di cates a deep en ing trend through the de po si tion of the Paují For ma tion (González de Juana et al., 1980).
SEDIMENTOLOGY AND ICHNOLOGY
OF THE STORM DE POS ITS
This study was con ducted in the Motatán Field, where tempestites have been ob served in four cores. Shal lowma -rine de pos its in the Motatán Field rep re sent the so-called “Basal Sands” of the Paují For ma tion, which re cord the on -set of the trans gres sion, sig nal ling the tran si tion from the mar ginal-ma rine Misoa For ma tion to the open-ma rine de-pos its, char ac ter is tic of the Paují For ma tion. The Basal Sands range from the fore shore to the lower off shore. The highdi ver sity ichnofauna pres ent in the Basal Sands in -cludes Asterosoma, Chondrites, Diplocraterion,
Helmin-thopsis, Ophiomorpha, Planolites, Palaeophycus, Rhizoco-rallium, Schaubcylindrichnus, Scolicia, Skolithos, Teichi-chnus, “Terebellina” and Thalassinoides, among other
ichnogen era (Delgado et al., 2001). These de pos its are stac- ked in coars en ing-up ward parasequences, show ing vari able in ten si ties and fre quen cies of storms (MacEachern and Pemberton, 1992). In par tic u lar, this study deals with tem-pestites from core MOT-X.
Of par tic u lar sig nif i cance is a storm sand stone unit en cased in a fairweather mudstone, lo cally dis play ing sand -stone lenses. These fair-weather de pos its are char ac ter ised by an in dis tinct bioturbation mot tling. The in ter ca la tion of storm sand stone and fair-weather mudstone is char ac ter is tic of the off shore tran si tion, which is lo cated im me di ately be -low the fair-weather wave base and well above the storm wave base (Buatois and Mángano, 2011). This unit con sists of five sharpbased, very finegrained sand stone beds show -ing hummocky cross-strat i fi ca tion and rip ples, form -ing a 26-cm-thick bedset that re cords storm de po si tion un der purely os cil la tory to com bined flows (Fig. 3A–C). The amalgamated na ture of the sand stone in ter val in di cates re -peated ero sional events, due to sev eral storms. The storm-re lated trace-fos sil suite is mostly storm-rep storm-re sented by
Diplo-craterion parallelum Torell, which oc curs in two of the
sand stone lay ers, al though small spec i mens are ap par ent in the up per most storm layer, as well. In ad di tion, the sand -stone unit con tains a few spec i mens of Palaeophycus
tubularis Hall and one spec i men of Bergaueria isp. and Thalassinoides isp., the lat ter cross-cut ting Diplocraterion parallelum. The spreite of Diplocraterion parallelum are
made of light sand laminae, al ter nat ing with dark mudstone laminae. The pres ence of this ichnotaxon is con sis tent with the rel a tively high en ergy of for ma tion of these de pos its. In ad di tion, the trun cated tops of these bur rows fur ther sup port strong ero sion, due to re peated storm events. In a strict sense, fair-weather de pos its are not in ter ca lated within the sand stone unit. How ever, high den si ties of Chondrites isp. are pre served in the infills of Diplocraterion parallelum, as well as in the only ob served spec i men of Thalassinoides isp., giv ing rise to patchy, com pos ite ichnofabrics, the sig
-nif i cance of which is ad dressed be low. Chondrites isp. is filled with sand. From a preservational stand point, this oc -cur rence of Chondrites rep re sents an ex am ple of con cealed bed-junc tion pres er va tion (sensu Simpson, 1957), be cause the bur rows ap pear to be iso lated within an in ter val of dif -fer ent li thol ogy.
DIS CUS SION
Al ter nat ing and con trast ing hy dro dy namic en ergy lev els, due to re peated storm events, are ar gu ably the most im -por tant lim it ing fac tor for trace-fos sil dis tri bu tion in wave-dom i nated, shal low-ma rine set tings (e.g., Pem ber ton and Frey, 1984; Vossler and Pem ber ton, 1989; Frey, 1990; Frey and Goldring, 1992; Pem ber ton et al., 1992; MacEachern and Pem ber ton, 1992; Pem ber ton and MacEachern, 1997; Buatois et al., 2002, 2003; Mángano et al., 2005; Carmona
et al., 2008; Savrda et al., 2010; Buatois and Mángano,
2011; Angulo and Buatois, 2012). Storm events typ i cally re sult in ero sion fol lowed by rapid de po si tion, which in turn
HID DEN BIOTURBATION IN TEMPESTITES
475
Fig. 3. Tempestites in core MOT-X, Motatán Field, Mid dle Eocene, Paují For ma tion, Maracaibo Ba sin. Core width is 6 cm. A. Gen eral view of storm sand stone in ter val en cased in fair-weather mudstonedom i nated in ter vals. Ar rows show bound aries of dis -crete storm lay ers. B. Fair-weather Chondrites isp. (Ch) pre served within the infill of storm-re lated Diplocraterion parallelum (Dp) in one of the tempestites. Note as so ci ated Bergaueria isp. (Be) and Palaeophycus tubularis (Pt). C. Close-up of an other tempestite show ing the same as so ci a tion of Chondrites isp. and Diplocrate-rion parallelum. One of the spec i mens of DiplocrateDiplocrate-rion parallelum is crosscut by Thalassinoides isp., which in turn shows re -work ing by the Chondrites pro ducer (ar row). Note the pres ence of tiny spec i mens of Diplocraterion parallelum in the up per most bed.
is fol lowed by a wan ing phase and the re-es tab lish ment of fair-weather sed i men ta tion un der a lower-en ergy re gime. The com bi na tion of strong erosion and rapid de po si tion im poses sig nif i cant stress on shal low-wa ter ben thic com mu ni ties.
Ichnofabrics in wavedom i nated, shal lowma rine set tings are the re sult of a num ber of taphonomic path ways, re -flect ing the com plex in ter play be tween bioturbation events, storm ero sion and de po si tion (Fig. 4). The fre quency and in ten sity of storms dic tate the length of the colo nis ation win -dow, con trol styles of bioturbation, and thus im pact on the
na ture of the re sult ing ichnofabrics. In ad di tion to es cape trace fos sils, which may be pro duced as an im me di ate re sponse to avoid burial dur ing high rates of sed i ment de po si -tion, two con trast ing trace-fos sil suites are pres ent in storm-dom i nated set tings: the storm-re lated suite and the fair-wea- ther suite (Pem ber ton and Frey, 1984; Pem ber ton and Mac-Eachern, 1997). The storm-re lated trace-fos sil suite re cords colo nis ation im me di ately af ter the storm event, and is pro -duced by an op por tu nis tic com mu nity dis play ing r-se lected pop u la tion strat e gies. Infaunal or gan isms bur row down Fig. 4. Taphonomic path ways of storm-af fected shal low-ma rine set tings (based on Buatois and Mángano, 2011). Note lo ca tion of Paují ichnofabrics within this frame work. Diagenetic over prints are not il lus trated for the sake of sim plic ity.
from a colo nis ation sur face, lo cated at the top of the event bed. The fairweather suite, re cord ing the ac tiv ity of the res -i dent ben th-ic com mu n-ity, de vel ops un der more sta ble and rather pre dict able con di tions, re flect ing Kse lected pop u la -tion strat e gies.
Strong in ten sity and fre quency of storms typ i cally re sult in very shortterm, poorly de vel oped ichnofauna (com monly sub ject to sub se quent ero sion) to neg li gi ble colo nis -ation win dows. There fore, the fair-weather suite is in hib ited and in stead amal gam ated storm de pos its oc cur; these tem-pestites con tain only the storm-re lated suite or, un der the most ex treme storm re gime, they are unburrowed (Mac-Eachern and Pem ber ton, 1992; Mángano et al., 2005). In con trast, un der mod er ate in ten sity and fre quency of storms, de pos its show an in ter ca la tion of lam i nated storm beds (sparsely bioturbated or typ i cally unbioturbated), and strongly bioturbated fair-weather de pos its, re sult ing in the so-called “lam-scram” pat tern (Howard, 1978; MacEachern and Pem ber ton, 1992). De pos its formed un der mod er ate in -ten sity and fre quency of storms are typ i cally char ac ter ised by re flect ing lon ger colo nis ation win dows un der lim ited ero sion, re sult ing in the al ter na tion of the storm-re lated suite, if pres ent, and the fair-weather suite. Fi nally, de pos its formed un der low fre quency and in ten sity of storms are char ac ter ised by rel a tively mi nor amounts of tempestites. These de pos its tend to be dom i nated by el e ments of the fair-weather suite, typ i cally dis play ing high ichnodiversity. Storm beds, if pres ent at all, are com monly in tensely oblit -er ated by biogenic re work ing (e.g., Carmona et al., 2008; Angulo and Buatois, 2012).
In the MOT-X tempestites stud ied, the storm-re lated suite is rep re sented by the U-shaped bur row Diplocraterion
parallelum (Fig. 5) and, to a lesser ex tent, by Palaeophycus tubularis, Bergaueria isp. and Thalassinoides isp. No
fair-weather de pos its are pres ent within the sand stone in ter val stud ied in the MOTX core, which may be taken as in dic a -tive of the strong in ten sity and high fre quency of storms. How ever, the pres ence of a patchy, com pos ite ichnofabric of Chondrites isp. within Diplocraterion parallelum and lo cally Thalassinoides isp. bur row fills in the sand stone in ter -val is here re garded as ev i dence of an oth er wise unpreser-ved res i dent fauna. Fair-weather de pos its that con tained the bulk of the fairweather suite were erosionally re moved dur ing the sub se quent storm (Fig. 5). In a sense, this is anal o
gous to the case of tu bu lar tempestites, in which the only re -cord of a storm event is pre served within bur row fills (Te-desco and Wanless, 1991).
Al though there is no di rect ev i dence of the fair-weather com mu nity, it may be pos si ble to fur ther spec u late re gard -ing its na ture. Ex tremely dense con cen tra tions of
Chondrites at the top of tempestiChondrites have been sug gested as in dic a
-tive of the burial of high quan ti ties of or ganic mat ter dur ing storms (Vossler and Pem ber ton, 1988). Al though this may in di cate rapid colo nis ation af ter the storm, the com plex mor phol ogy of Chondrites fa vors K-se lected strat e gies and an af fin ity with cli max pop u la tions (Bromley, 1996). In the case of the MOT-X de pos its, the patchy dis tri bu tion of Chon-
drites in di cates ex ploi ta tion of the or ganic-rich con tent
within pre vi ously pro duced deep-tier Diplocraterion
para-llelum and, to a lesser ex tent, Thalassinoides isp. In fact,
there is gen eral agree ment that Chondrites is a deep-tier ichnotaxon that typ i cally char ac ter ises ma ture com mu ni ties (Bromley, 1996). Its deep-tier em place ment and the abil ity of the Chondrites-maker to re-bur row the fills of other biogenic struc tures fa vour pres er va tion and al low rec og ni tion of a “hid den” bioturbation event, which oth er wise might have re -mained un de tected. Also, its com mon pres ence in ma ture infaunal com mu ni ties fa vours the hy poth e sis of rel a tively long colo nis ation win dows be tween events, in di cat ing that, al though the in ten sity of storms was high, the fre quency of them may have been rel a tively mod er ate. This in ter pre ta tion is also sup ported by the pres ence of a di verse fair-weather trace-fos sil suite in other in ter vals of the “Basal Sands” of the Paují For ma tion in the same oil field (Delgado et al., 2001), as well as by the in tense mot tling in the as so ci ated fair-weather fine-grained de pos its.
Ac cord ing to Savrda (2007), two com monly in de pend ent fac tors are in volved in tracefos sil taphonomy: com -plete ness of the pre served re cord of biogenic ac tiv ity (ichnological fi del ity) and de gree of ichnofossil vis i bil ity. Whereas some ichnofabrics may have high fi del ity, some or all trace fos sils may be dif fi cult to dis cern, there fore show -ing lim ited trace-fos sil vis i bil ity. In con trast, some ichno-fab rics may have low fi del ity (i.e., re flect ing only the work of a small part of the orig i nal tracemaker com mu nity), but some dis crete ichnotaxa may be well ex pressed. More re cently, Savrda (2014) added tem po ral res o lu tion (i.e. the de -gree to which an ichnofabric is a time-av er aged re cord of
HID DEN BIOTURBATION IN TEMPESTITES
477
Fig. 5. Schematical di a gram il lus trat ing the suc ces sion of depositional, ero sional and bioturbation events for the Paují tempestites. To sim plify the di a gram, only one event of ero sion and sub se quent de po si tion are shown. See Fig ure 4 for leg end.
biogenic ac tiv ity) and tem po ral com plete ness (i.e. the per -cent age of the to tal time re corded in an ichnofabric that is ac tu ally rep re sented by the pre served ichnofauna) as rel e -vant pa ram e ters. He noted that tem po ral res o lu tion typ i cally covariates with ichnological fi del ity. Be cause of strong ero sion, stormdom i nated shal lowma rine set tings are par tic u -larly com plex with re gard to these pa ram e ters. Savrda et al. (2010) doc u mented an ex am ple of weakly bioturbated tempestites within oth er wise unbioturbated fairweather de pos -its that ac cu mu lated in the off shore tran si tion. Fair-weather con di tions were in hos pi ta ble for bioturbation, but a com mu nity of allochtonous tracemakers was es tab lished im me di -ately af ter and per haps dur ing storm de po si tion. Savrda (2014) ar gued that this sit u a tion led to an ichnofabric of high fi del ity and high temporal res o lu tion.
Un der nor mal ma rine con di tions fa vour ing bioturbation, ichnofabrics in weakly stormaf fected set tings typ i cally re flect long colo nis ation win dows and some what re -sem ble those from pe lagic set tings. In pe lagic set tings, there is a se lec tive pres er va tion of deep tiers (re sult ing in low ichnological fi del ity and in creased vis i bil ity of the deep tier), and an ex tended res i dence time of sed i ment in the zone of ac tive bioturbation (re sult ing in low tem po ral res o lu tion; Savrda, 2014). Al though these con di tions are not as marked in weakly storm-af fected set tings, still ichnological fi del ity and tem po ral res o lu tion may be re garded as rel a tively low, ow ing to the fact that long colo nis ation win dows and slow sed i men ta tion rates re sult in the ex tended res i dence time of sed i ment in the zone of ac tive bioturbation. In mod er ately stormaf fected set tings, tem po ral res o lu tion may even in -crease due to short-term colo nis ation win dows, but ichnolog i cal fi del ity is ham pered by a bias to wards deeper struc tures that sur vived the ero sional events. Fi nally, these pa -ram e ters are hard to eval u ate in strongly storm-dom i nated set tings, be cause there is lit tle ichnological ev i dence. In the case of very high-en ergy set tings, this may sim ply re veal the lack of colo nis ation win dows, but in less ex treme cases the pos si bil ity of com plete re moval of biogenic struc tures by ero sion can not be dis re garded, in di cat ing zero fi del ity and tem po ral res o lu tion. In the case of the Paují tempestites, the iden ti fi ca tion of Chondrites re work ing Diplocraterion and, to a lesser ex tent, Thalassinoides, may help to eval u ate these pa ram e ters, al though tem po ral res o lu tion and ichnolo- gical fi del ity still may be re garded as low.
Ac knowl edg ments
We would like to thank Rich ard Bromley and Ulla Asgaard for con stant in spi ra tion and sup port. This manu script has been im -proved, thanks to the de tailed and use ful re views by Fran cisco Tognoli and an anon y mous ref eree. We thank Petróleos de Ven e -zuela (PDVSA) for al low ing the pub li ca tion of this study.
REF ER ENCES
Angulo, S. & Buatois, L. A., 2012. Ichnology of an Up per De vo -nian – Lower Mis sis sip pian low-en ergy sea way: the Bakken For ma tion of subsurface Sas katch e wan, Can ada: As sess ing paleoenvironmental con trols and bi otic re sponses.
Palaeogeo-graphy, Palaeoclimatology, Palaeo ec ol ogy, 315–316: 46–60. Benitez, R., Kabbabe, T. & Orribo, J. M., 1996. Estudio Integrado
de los yacimientos presentes en las formaciones Paují y Mi-soa en el Domo Norte del Cam po Motatán, Estado Zulia. Trabajo Es pe cial de Grado, Universidad Cen tral de Ven e -zuela, Un pub lished.
Bromley, R. G., 1990. Trace Fos sils. Bi ol ogy and Taphonomy. Unwin Hyman, Lon don, 280 pp.
Bromley, R. G. 1996. Trace Fos sils. Bi ol ogy, Taphonomy and Ap -pli ca tions. Chap man & Hall, Lon don, 361 pp.
Bromley, R. G. & Ekdale, A. A., 1986. Com pos ite ichnofabrics and tier ing of bur rows. Geo log i cal Mag a zine, 123: 59–65. Buatois, L. A., Bromley, R. G., Mángano, M. G., Bellosi, E. &
Carmona, N. B., 2003. Ichnology of shal low ma rine de pos its in the Mio cene Chenque For ma tion of Patagonia: Com plex ecologic struc ture and niche par ti tion ing in Neo gene eco sys -tems. In: Buatois, L. A. & Mángano, M. G. (eds), Icnología: Hacia una convergencia en tre geología y biología. Publica-ción Es pe cial de la AsociaPublica-ción Paleontológica Ar gen tina, 9: 85–95.
Buatois, L. A. & Mángano, M. G., 2004. An i malsub strate in ter ac -tions in fresh wa ter en vi ron ments: ap pli ca -tions of ichnology in fa cies and se quence strati graphic anal y sis of fluviolac us -trine suc ces sions. In: McIlroy, D. (ed.), The Ap pli ca tion of Ichnology to Palaeoenvironmental and Strati graphic Ana-lysis. Geo log i cal So ci ety Spe cial Pub li ca tion, 228: 311–333. Buatois, L. A. & Mángano, M. G., 2007. In ver te brate ichnology of
con ti nen tal fresh wa ter en vi ron ments. In: Miller, W., III (ed.), Trace Fos sils: Con cepts, Prob lems, Pros pects. Elsevier, Am -ster dam, pp. 285–323.
Buatois, L. A. & Mángano, M. G., 2011. Ichnology: Or gan ismSub strate In ter ac tions in Space and Time. Cam bridge Uni ver -sity Press, Cam bridge, 358 pp.
Buatois, L. A., Mángano, M. G., Alissa, A. & Carr, T. R., 2002. Se quence strati graphic and sedimentologic sig nif i cance of biogenic struc tures from a late Pa leo zoic mar ginal to open-ma rine reservior, Mor row Sand stone, subsurface of south west Kan sas, USA. Sed i men tary Ge ol ogy, 152: 99–132.
Buatois, L. A., Uba, C. E., Mángano, M. G. & Hulka, C., 2007. Deep bioturbation in con ti nen tal en vi ron ments: Ev i dence from Mio cene flu vial de pos its of Bolivia. In: Bromley, R. G., Buatois, L. A., Mángano, M. G., Genise, J. F. & Melchor, R. N. (eds), Sed i ment-Organism In ter ac tions: A Multifaceted Ichnology. So ci ety for Sed i men tary Ge ol ogy, Spe cial Pub li -ca tion, 88: 123–136.
Carmona, N. B., Buatois, L. A., Mángano, M. G. & Bromley, R. G., 2008. Ichnology of the Lower Mio cene Chenque Forma-tion, Patagonia, Ar gen tina: An i mal – sub strate in ter ac tions and the Mod ern Evo lu tion ary Fauna. Ameghiniana, 45: 93–122. Delgado, M., Kabbabe, T., Sampson, E. & Chacartegui, F., 2001.
Ichnofossils as a tool for en vi ron men tal in ter pre ta tion, Pauji and Misoa for ma tions, Barúa and Motatán fields, Zulia and Trujillo states, Ven e zuela. VI In ter na tional Ichnofabric Workshop Ab stracts, Isla Margarita & Puerto La Cruz, p. 27. Desjardins, P. R., Mángano, M. G., Buatois, L. A. & Pratt, B. R., 2010. Skolithos pipe rock and as so ci ated ichnofabrics in the Fort Moun tain For ma tion, Gog Group: Col o ni za tion trends and en vi ron men tal con trols in an Early Cam brian subtidal sand bar com plex. Lethaia, 43: 507–528.
Ekdale, A., Bromley, R. G. & Knaust, D., 2012. The ichnofabric con cept: In: Knaust, D. & Bromley, R. G. (eds), Trace Fos sils as In di ca tors of Sed i men tary En vi ron ments. De vel op ments in Sedimentology, 64: 139–155. Elsevier, Am ster dam.
Frey, R. W., 1990. Trace fos sils and hummocky crossstrat i fi ca -tion, Up per Cre ta ceous of Utah. Palaios, 5: 203–218.
Frey, R. W. & Goldring, R., 1992. Ma rine event beds and recolonization sur faces as re vealed by trace fos sil anal y sis. Geo -log i cal Mag a zine, 129: 325–335.
Ghosh, S., Pestman, P., Melendez, P., Bartok, P., Lorente, M., Duran, I., Pittelli, R., Rull, V., Mompart, L., White, C., Domi- nguez, C., Oropeza, C. & Travaglio, F. 1995. Síntesis Geo-lógica, Marco Secuencial y Perspectivas Exploratorias del Eoceno de la Cuenca de Maracaibo. Maraven S. A., Ca ra cas, EPC-13494.
Gon za lez de Juana, C., Iturralde, J. M. & Picard, X., 1980. Geo-logía de Ven e zuela y de sus Cuencas Petrolíferas, Tercera Edición. Ed. Foninves, Ca ra cas, 1031 pp.
Higgs, R., 1996. A new fa cies model for the Misoa For ma tion (Eocene), Ven e zuela’s main oil res er voir. Jour nal of Pe tro -leum Ge ol ogy, 19: 249–269.
Howard, J. D., 1978. Sedimentology and trace fos sils. In: Basan, P. B. (ed.), Trace Fos sil Con cepts. So ci ety for Sed i men tary Ge ol ogy Short Course Notes, 5: 11–42.
MacEachern, J. A. & Pem ber ton, S. G., 1992. Ichnological as pects of Cre ta ceous shoreface suc ces sions and shoreface vari abil ity in the West ern In te rior Sea way of North Amer ica. In: Pem -ber ton, S. G. (ed.), Ap pli ca tions of Ichnology to Petroleum Ex plo ra tion: A Core Workshop. So ci ety for Sed i men tary Ge -ol ogy Core Work shop, 17: 57–84.
Maguregui, J. & Ty ler, N., 1991. Evo lu tion of Mid dle Eocene tide-dom i nated deltaic sand stones, Lagunillas field, Mara-caibo ba sin, west ern Ven e zuela. In: Miall, A. D. & Ty ler, N. (eds), The Three-Di men sional Fa cies Ar chi tec ture of Terrigenous Clastic Sed i ments and its Im pli ca tions for Hy dro car bon Dis cov ery and Re cov ery. So ci ety for Sed i men tary Ge ol -ogy, Con cepts in Sedimentology and Pa le on tol -ogy, 3: 233– 244.
Mángano, M. G., Buatois, L. A. & Muniz Guinea, F., 2005. Ichnology of the Alfarcito Mem ber (Santa Rosita For ma tion) of north west ern Ar gen tina: an i mal-sub strate in ter ac tions in a lower Pa leo zoic wave-dom i nated shal low sea. Ameghiniana, 42: 641–668.
Meldahl, K. H. & Flessa, K. W., 1990. Taphonomic path ways and com par a tive biofacies and taphofacies in a Re cent intertidal/ shal low shelf en vi ron ment. Lethaia, 23: 43–60.
Pearson, N. J., Mángano, M. G., Buatois, L. A., Casadío, S. & Ro -dri guez Rais ing, M., 2013. En vi ron men tal vari abil ity of Macaronichnus ichnofabrics in Eocene tidalembayment de pos -its of south ern Patagonia, Ar gen tina. Lethaia, 46: 341–354. Pem ber ton, S. G. & Frey, R. W., 1984. Ichnology of stormin flu
-enced shal low ma rine se quence: Cardium For ma tion (Up per
Cre ta ceous) at Seebe, Al berta. In: Stott, D. F. & Glass, D. J. (eds), The Me so zoic of Middle North Amer ica. Ca na dian So -ci ety of Pe tro leum Ge ol o gists Mem oir, 9: 281–304.
Pem ber ton, S. G. & MacEachern J. A., 1997. The ichnological sig -na ture of storm de pos its: The use of trace fos sils in event stratigraphy. In: Brett, C. E. & Baird, G. C. (eds), Paleontological Events. Strati graphic, Eco log i cal and Evo lu tion ary Im -pli ca tions. Co lum bia Uni ver sity Press, New York, pp. 73–109. Savrda, C. E., 2007. Taphonomy of trace fos sils. In: Miller, W. III (ed.), Trace Fos sils: Con cepts, Prob lems, Pros pects. Else-vier, Am ster dam, pp. 92–109.
Savrda, C. E., 2014. Lim ited ichnologic fi del ity and tem po ral res -o lu ti-on in pe lagic sed i ments: Pale-oenvir-onmental and pale-o- paleo-ecologic im pli ca tions. Palaios, 29: 210–217.
Savrda, C. E., Counts, J. W., Bigham, E. & Mar tin, S., 2010. Ichnology of si li ceous fa cies in the Eocene Tallahatta For ma -tion (east ern United States Gulf Coastal Plain): im pli ca -tions for depositional con di tions, storm pro cesses, and diagenesis. Palaios, 25: 642–655.
Simpson, S., 1957. On the trace fos sil Chondrites. Quar terly Jour -nal Geo log i cal So ci ety of Lon don, 112: 475–479.
Tedesco, L. P. & Wanless, H. R., 1991. Gen er a tion of sed i men tary fab rics and fa cies by re pet i tive ex ca va tion and storm in fill ing of bur row net works, Ho lo cene of South Florida and Caicos Plat form, B.W.I. Palaios, 6: 326–343.
Van Veen, F. R., 1972. Ambientes sedimentarios de las formacio-nes Mirador y Misoa del Eoceno in fe rior y medio en la Cu-enca del Lago de Maracaibo. Ven e zuela Ministerio de Minas e Hidrocarburos, IV Congreso Geológico Venezolano, Ca ra cas, 1969, Memoria, Boletín de Geología, Publicación Es pe -cial, 5: 1073–1104.
Vossler, S. M. & Pem ber ton, S. G., 1988. Su per abun dant Chon-drites: a re sponse to storm bur ied or ganic ma te rial? Lethaia, 21: 94.
Vossler, S. M. & Pem ber ton, S. G., 1989. Ichnology and plaeo-ecol ogy of off shore de pos its in the Cardium For ma tion (Turo- nian, Al berta, Can ada). Palaeo ge ogra phy, Palaeoclimato-logy, Palaeo ec ol ogy, 74: 217–239.
Zambrano, E., 1995. Síntesis geológica, marco secuencial y pers-pectivas exploratorias del Eoceno de la Cuenca de Mara-caibo. Maraven, In ter nal Re port.
Zhang, G., Buatois, L. A., Mángano, M. G. & Aceñolaza, F. G., 1998. Sed i men tary fa cies and en vi ron men tal ichnology of a Perm ian playalake com plex in west ern Ar gen tina. Palaeo ge -ogra phy, Palaeoclimatology, Palaeo ec ol ogy, 138: 221–243.
