Le Castella Research Articles

The Petilia-Sosti Shear Zone (Calabrian Arc, southern Italy): An onshore-offshore regional active structure

The integrated interpretation of different types of data, consisting of a detailed Digital Terrain Model, field structural and morphotectonic observations, high resolution seismic data, seismological and Synthetic Aperture Radar interferometry information (vertical and horizontal movements), associated with a review of the available literature, has allowed to analyze the shallow expression of the regional-scale Petilia-Sosti Shear Zone (PSSZ). It is one of the major NW-trending tectonic lineaments affecting the Calabrian Arc and is characterized by a present-day tectonic and gravity-driven deformation. This study investigated the portion of the PSSZ between the offshore Crotone Peninsula, located along the Ionian sea of Calabria, and the central part of the Sila Massif.A complex tectonic history is documented since middle Miocene onward for the PSSZ. It consists of an alternation of sinistral and dextral transpressional and transtensional tectonic phases correlated with the geodynamic events occurred during the SE migration of the Calabrian Arc.The shallow expression of the investigated part of the PSSZ consists of a roughly 14 km wide, ca. 80 km long NW-trending tectonic zone including synthetic NW- to NNW-trending faults and N-NE antithetic minor structures. The main identified NW-trending faults, which show a development between 30 and 50 km, are the Sila and Lakes faults in the Sila Massif, and the Marcedusa-Steccato, Fosso Umbro and Tacina faults located in the SW part of the Crotone Basin and in its offshore area. Currently, the fault segments of the Sila Massif exhibit a prevailing normal kinematics with a left-lateral component, whereas a more complex geological framework occurs in the south-western part of the onshore-offshore Crotone Basin. The latter is dominated by gravity-driven movements, associated with the SE migration of the Crotone Megalandslide and with the regional uplift of Calabria, whereas normal kinematics with a small left-lateral component of movement, locally replaced by reverse/transpressional tectonics, was observed along the southern coast in the late Pleistocene deposits of the Le Castella marine terrace.The seismological data highlight that some strong earthquakes occurred in 1638, 1744 and 1832, with magnitude Mw between 5.7 and 6.8, might be associated with the Lakes, Fosso Umbro and Tacina faults respectively. In this frame, the PSSZ is proposed as a new potential NW-oriented active composite seismogenic source for the central-northern Calabria.

Chronology of the marine terraces of the Crotone Peninsula (Calabria, southern Italy) by means of infrared-stimulated luminescence (IRSL)

The Crotone Peninsula (southern Italy) preserves a well developed flight of marine terraces generated by the interplay of uplift of the Calabrian arc and late Quaternary eustatic oscillations. Good chronologic control on the formation of these raised geomorphic features would help constrain regional tectonic and stratigraphic models. However, precise age assignment and correlation of the individual terraces is hampered by lack of material suitable for radiometric dating.With the goal of improving the resolution of the chronology of the terraces, nine samples were collected from four stratigraphically distinct terraced units and dated with the infrared-stimulated luminescence (IRSL) technique applied on feldspar grains. The obtained ages are consistent with the stratigraphic arrangement of the terraces, with samples from higher terraces older or overlapping in age with those from lower terraces. Three samples from the highest (Cutro) terrace indicated a minimum age ≥ MIS (Marine Isotope Stage) 7. Two samples from the second of the four examined terraces, which is generally correlated with MIS 5.3, gave ages that correlate instead with MIS 5.5 and 5.1, revealing more internal complexity and tectonic disruption than previously inferred from this terrace. Luminescence dating was applied for the first time to the deposits of the Capo Colonna terrace, with results indicating a MIS 5.1 age. Finally, one sample from the lowermost (Le Castella) terrace confirmed the preservation of raised marine deposits from MIS 3, a relatively uncommon finding for the Mediterranean region.These results highlight how IRSL dating can contribute to the development and refinement of a chronostratigraphic context for a flight of marine terraces and, ultimately, to a clearer understanding of the combined tectonic and eustatic controls affecting the morphodynamic evolution of a marine coastal sector. More specifically, they confirm the persistence of relatively high average uplift rates (on the order of 1 mm/yr) over the last two glacial cycles in the Crotone Peninsula and the important role of a local component of tectonic and deformative displacement superimposed on the regional uplift.

Storm-related sedimentation influenced by coastal configuration in the stratigraphic record of a tectonically active shelf (Upper Pleistocene Le Castella terrace, Italy)

Analysis of patterns of coastal circulation and sediment dispersal is an essential step for the study of controlling factors influencing the long-term dynamics of coastal systems. Modern settings offer the possibility to monitor relevant parameters over relatively short time spans. However, geological examples complement this perspective by providing a time-averaged record where longer trends and stratigraphically significant processes can be evaluated. This study investigates the shallow marine deposits of Le Castella terrace (Upper Pleistocene, southern Italy) to document how patterns of circulation influenced by coastline configuration can affect the preserved millennial-scale depositional record of a progradational shoreline system. The regressive portion of the Le Castella terrace deposits, developed during a relative sea-level highstand and falling stage, consists of a progradational wedge mainly composed of redistributed skeletal particles of a coeval shallow water carbonate factory. Preservation of the morphology of the paleocoastline and abundant current-related sedimentary structures allow reconstruction of the predominant sediment dispersal dynamics responsible for the formation of this sedimentary wedge. Facies and paleocurrent analysis indicate offshore and alongshore sediment transport modes, consistent with coastal circulation driven by storms normally incident to the shoreline and a sharp change in coastline orientation. This coastal inflection influenced circulation patterns causing flow separation and eddy formation in the lee of the curved coastline. Syndepositional tectonic deformation also affected the architecture of the preserved deposits, controlling the nucleation and development of a clinostratified body and determining localized lateral stratigraphic variability. This study illustrates how transient but recurrent circulation patterns associated with changes in coastal orientation and related to high-energy storm events can leave a predominant signature in the stratigraphic record of microtidal shallow-marine successions.

Morpho-structural heterogeneity of shallow-water coralligenous in a Pleistocene marine terrace (Le Castella, Italy)

Coralligenous is the most volumetrically significant type of autochthonous carbonate build-up in the Mediterranean, but its range of morphological variability at the macroscale, and potential link with environmental factors have not been fully documented. Well-preserved examples of coralligenous are exposed in shallow marine carbonate deposits from the Upper Pleistocene Le Castella marine terrace (Southern Italy). The coralligenous build-ups occur in the lower part of an unconformity-bounded, transgressive-regressive sequence. They show high structural and morphological heterogeneity in terms of framework type and build-up size, over a distance of several hundred meters. In northern exposures, coralligenous forms banks up to 4m high, with a dense, coralline-dominated framework, laterally adjacent to paleo-channels devoid of build-ups and filled by coeval infra-circalittoral biogenic packstone. To the south, build-ups are smaller (up to 1.8m high), with an open algal framework and local predominance of the coral Cladocora caespitosa as primary framework builder. At both locations, the most important framework-building coralline species is Mesophyllum philippii; Titanoderma pustulatum also occurs. Analysis of sedimentary structures, paleo-topographic indicators, faunal composition of associated mollusk assemblages, and predominance of M. philippii suggest the algal builds-ups grew within a shallow-water, possibly infralittoral setting, competing for space with other biocoenoses. Suitable substrate availability in the form of conglomerate blocks or shell accumulations was the primary factor controlling the inception and spatial distribution of coralligenous. Differences in hydrodynamism and water turbidity determined variability in size and internal composition between the northern and southern locations. To the south, abundant supply of fine suspended sediment resulted in smaller build-ups with more open framework, the growth of which was terminated abruptly by sediment burial. Eventually, relative sea level fall during regression prevented further growth of the coralligenous even in the northern area. This study contributes to a better understanding of the relationship between coralligenous morphology and environmental factors, highlighting the role of suitable substrate availability, turbidity, and sediment burial in influencing spatial and temporal variability of coralligenous assemblages.

BICHORDITES MONASTIRIENSIS ICHNOFABRIC FROM THE PLEISTOCENE SHALLOW-MARINE SANDSTONES AT LE CASTELLA (CROTONE), IONIAN CALABRIA, SOUTHERN ITALY

The analysis of Bichordites ichnofabric has been performed in laminated calcarenites of Upper Pleistocene marine terraces of the Crotone Peninsula, Ionian Calabria, outcropping in the coast nearby the village of Le Castella (southern Italy). These calcarenitic deposits show an intense and pervasive bioturbation, preserved mainly as endichnia s.s., exposed endichnia (false epichnia with hyp- and epireliefs) and crossichnia, dominated by Bichordites monastiriensis . Other forms (more rare) are Cardioichnus isp., Ophiomorpha nodosa, Planolites beverleyensis and ? Macaronichnus -like trace fossils. This shallow-water ichnofabric, that is recurrent in many sandy shallow water marine terraces of Pleistocene, exhibits hundreds of Bichordites monastiriensis (meniscate burrows) that are studied in cross sections and plane views. A detailed taphonomic study shows many differences in the central core of Bichordites monastiriensis that varies in shape, length and dimension, from the outer meniscate envelopment, following the burrowing action of spatangoid echinids in sandy substrate. The rhythmical arrangement in shape and density of Bichordites in foreshore sandy bars with megaripples, with a regressive trend in the stratigraphic section, likely reflects variations and the strength of current along coast.

Anatomy of a late Pleistocene clinoformal sedimentary body (Le Castella, Calabria, southern Italy): A case of prograding spit system?

The Le Castella marine terrace is the smallest and youngest terrace of the Crotone area (southern Italy), and formed after a rapid marine ingression due to a glacio-eustatic rise outpacing the regional uplift of the area. The most prominent feature of the terrace deposits is a seaward-accreting clinoform about 10 m thick, inferred to be formed during forced regressive conditions. This prograding body is mostly composed of bioclastic material, and shows an internal complexity consisting of alternating oblique and sigmoid elementary units inferred to be produced mainly by changes of accommodation development. Foreset avalancing was due to sediment accumulation by gravity-flow processes, while topsets were characterized by the migration of medium- to large-scale dunes showing a unimodal palaeocurrent pattern, oblique with respect to the dip direction of the large-scale clinoform foresets. The Le Castella clinoform starts to develop from a topographic step on the basement due to tectonics, which also controlled the palaeoshoreline trend. The recognized stratigraphic and facies architectures, the palaeocurrent pattern, and the inferred palaeogeographic setting during deposition, all suggest that the Le Castella clinoform is an example of spit system attached to the mainland and accreted due to longshore transport. The present example contributes to establish criteria allowing the recognition of ancient spit systems, which still are poorly known and rarely documented in the pre-Quaternary geological record.

Corrected age of the Pliocene/Pleistocene boundary

Calcareous plankton datum-events are referred to the Pliocene/Pleistocene boundary at Le Castella, the stratotype Calabrian at Santa Maria di Catanzaro, and to deep-sea sediments in six piston cores. The boundary is correlated by multiple overlapping criteria to a level equivalent to, or slightly younger than, the top of the Olduvai Event, giving a revised estimate of about 1.6 Myr for the age of the boundary. The Pliocene I Pleistocene boundary is thus coeval with the earliest of four major climatic deteriorations in the Pleistocene, reconciling palaeoclimatic concepts with the chrono-stratigtaphical definition of the epoch.

Calcareous Nannofossil Datum Levels Associated with Pliocene-Pleistocene Boundary: ABSTRACT

The extinction horizon of Discoaster brouweri, or datum, commonly is applied by calcareous nannofossil workers as a criterion for placement of the base of the Pleistocene in deep-sea cores. Investigators also have said that at Le Castella, Italy, gephyrocapsids having a distinct central-bar area (Gephyrocapsa caribbeanica) appear first at a horizon several meters below the extinction horizon of D. brouweri. Deep-sea cores taken on the Nicaragua Rise in the Caribbean also support this relation. Analyses of piston cores from the southern ocean, however, show that the life ranges of D. brouweri and G. caribbeanica are not concurrent at high latitudes, and here the Coccolithus doroncoides zone was erected to span the interval between the datum levels of these species. This in erval zone subsequently has been observed in southern California, the equatorial Pacific (defined there as the Emeliania annula subzone), and in deep-sea cores from the northern Atlantic and northeast Pacific Oceans, and in the Tyrrhenian basin west of Naples, Italy. The magnitude of this interval at high latitudes seemingly is greater because of an earlier last occurrence of D. brouweri in boreal regions about 2.5 m. y. ago (Deep Sea Drilling Project core 173 offshore northern California, where the interval is 75 m). Therefore, it is suggested, that the first appearance of G. caribbeanica provides a better approximation of the base of the Pleistocene than does the last occurrence of D. brouweri. End_of_Article - Last_Page 1840------------

Pliocene and Pleistocene magnetic stratigraphy in Le Castella area, Southern Italy—A preliminary report

A preliminary study was made of the magnetic stratigraphy of the Pliocene and Lower Pleistocene marine sediments in Le Castella area, Calabria, Southern Italy. Microbiostratigraphic evidence of the measured sediments provides a basis for tentative correlation with the standard magnetic chronology. The Gilsa Event in the Matuyama Reversed Polarity Epoch is estimated to be a little older than the lower limit of the Calabrian in Le Castella area.

Planktonic Foraminiferal Biostratigraphy and Paleomagnetics of Late Pliocene and Early Pleistocene Strata at Le Castella, Italy: ABSTRACT

ABSTRACT Late Pliocene to early Pleistocene stratal segments were measured and sampled along the coast at Le Castella, Italy, to determine their planktonic foraminiferal biostratigraphy and geomagnetic polarity reversal patterns. The percentage distribution of warm- and cold- water planktonic species in the samples defines a warm late Pliocene (Plaisancian) Globorotalia inflata Zone, a cool Calabrian Stage (earliest Pleistocene), a warm Emilian Stage, and a cool Sicilian Stage. Occurrence of Sphaeroidinella dehiscens in Late Pliocene suggests the highest maximum temperature, and dominant left-coiling Globigerina pachyderma in the Sicilian the lowest. The paleomagnetic reversal pattern is partly obscured by covered and weathered intervals between the Late Pliocene and Calabrian, and within the upper Emilian and Sicilian. The exposed Late Pliocene and Calabrian strata show strong normal measured polarities, which suggest that the Late Pliocene falls in the Gauss Epoch and that the exposed Calabrian falls either in the upper Gauss Epoch or Olduvai event. Recommendations are made for the Committee on Mediterranean Neogene Stratigraphy to continuously core the section so as to precisely determine and define the litho-and biostratigraphic base of the Calabrian, and to record the complete paleomagnetic history in the type area of the Calabrian, earliest Pleistocene. Plio-Pleistocene stages of the Mediterranean and Gulf of Mexico are correlated using planktonic foraminifers and climatic implications. The Nebraskan, Aftonian, and Kansan stages correlate with the Calabrian, Emilian, and Sicilian stages, respectively. Paleomagnetic correlations are not entirely clear at this time, except that Late Pliocene strata of both regions seemingly fall within the Gauss Epoch.

The Pliocene-Pleistocene Boundary, Italy and California

Research Article| October 01, 1970 The Pliocene-Pleistocene Boundary, Italy and California ORVILLE L BANDY; ORVILLE L BANDY Department of Geological Sciences, University of Southern California, Los Angeles, California 90007 Search for other works by this author on: GSW Google Scholar JAMES A WILCOXON JAMES A WILCOXON Department of Geological Sciences, University of Southern California, Los Angeles, California 90007 Search for other works by this author on: GSW Google Scholar Author and Article Information ORVILLE L BANDY Department of Geological Sciences, University of Southern California, Los Angeles, California 90007 JAMES A WILCOXON Department of Geological Sciences, University of Southern California, Los Angeles, California 90007 Publisher: Geological Society of America Received: 11 Feb 1970 Revision Received: 12 May 1970 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1970, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1970) 81 (10): 2939–2948. https://doi.org/10.1130/0016-7606(1970)81[2939:TPBIAC]2.0.CO;2 Article history Received: 11 Feb 1970 Revision Received: 12 May 1970 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ORVILLE L BANDY, JAMES A WILCOXON; The Pliocene-Pleistocene Boundary, Italy and California. GSA Bulletin 1970;; 81 (10): 2939–2948. doi: https://doi.org/10.1130/0016-7606(1970)81[2939:TPBIAC]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Pliocene-Pleistocene boundary, defined by the first evolutionary appearance of Globorotalia (Truncorotalia) truncatulinoides (d'Orbigny) from its immediate ancestor Globorotalia {Truncorotalia) tosaensis Takayanagi and Saito, is at or near the base of the Calabrian in Italy and within the Wheelerian Stage of Balcom Canyon, California. This level is thought to be correlative with the base of the Gilsa magnetic event, about 1.79 m.y. ago. The boundary separates also the Discoaster brouweri Tan Sin Hok zone below from the Gephyrocapsa caribbeanica Boudreaux and Hay zone above. A younger Gephyrocapsa oceanica Kamptner zone is defined in the upper part of the Calabrian in both the Santa Maria di Catanzaro and Le Castella sections of Italy; the two sections are of the same age.Referring to paleoclimatic cycles near the Pliocene-Pleistocene boundary, a cooler interval is recorded in the late Pliocene of Italy (Astian) by Lona (1962) and in the late Pliocene of California. The Pliocene-Pleistocene boundary is assigned near the base of a slightly warmer cycle, and it is associated with a transgressive phase with rising sea levels in the Calabrian, a glacioeustatic relationship. A higher stand of sea level in the Calabrian resulted in improved circulation between the Mediterranean and the Atlantic, resulting in the introduction of exotic benthic Atlantic species into the Mediterranean.A long preglacial Pleistocene (Calabrian) of Selli (1967a) is followed by the major glacial Pleistocene; the glacial Pleistocene is thought to coincide mostly with the Brunhes normal magnetic epoch (Bandy and Casey, 1969a, 1969b). A major cooling in southern California and Italy is defined by the influx of a dominantly sinistrally coiled population of the polar form, Globorotalia (Turborotalia) pachvderma (Ehrenberg). This event has been defined at or near the base of the Lomita Marl in southern California, a formation dated radiometrically as being about 3 m.y. old (Obradovich, 1965, 1968); this age is now thought to be slightly more than three times too great (Bandy, 1969a). This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Lower Limit of the Pleistocene in le Castella Area and the Boso Peninsula

Since Emiliani et al. (1961) analysed the paleotemperature of the Pliocene and Pleistocene in le Castella area, southern Italy, the proposed type locality of the boundary between the Pliocene and Pleistocene, more-detailed works had begun on the stratigraphic problems of the Upper Pliocene and Lower Pleistocene in various-areas of the world. Among the recent knowledge, the combined microbiostratigraphy and magnetic chronology is the most useful criteria for the Pliocene and Pleistocene correlation. The authors undertook a tentative correlation of the Upper Pliocene and Lower Pleistocene between le Castella area and the Boso Peninsula (Fig. 2) based on their previous studies of the magnetic stratigraphy made on both areas (Nakagawa, Niitsuma, and Hayasaka, 1969; Nakagawa, Niitsuma, and Elmi, 1970). The base of the Calabrian in le Castella area could be placed at a horizon younger than the Olduvai Event in the Matuyama Reversed Polarity Epoch in the magnetic stratigraphy in the sense of Hays et al. (1969). Designation of the type locality of the Pliocene-Pleistocene boundary and the microbiostratigraphic evidence of the horizon around the boundary were previously reviewed briefly.

Pleistocene Discoasters from Stratotype of Calabrian Stage (Santa Maria di Catanzaro) and Section at Le Castella, Italy: ABSTRACT

Strata exposed near the town of Santa Maria di Catanzaro in southern Italy is the accepted stratotype for the Calabrian Stage (earliest Pleistocene). Although a Pliocene-Pleistocene boundary has been discussed as End_Page 2044------------------------------ occurring in the section at nearby Le Castella, the results of the present study indicate that none of the earliest Calabrian is exposed at that locality. Most of the Quaternary section exposed at Le Castella is younger than the youngest sediment exposed at Santa Maria di Catanzaro. At Santa Maria di Catanzaro, the range of Discoaster brouweri Tan Sin Hok was found to be concurrent with the planktonic foraminiferal species Globorotalia truncatulinoides (d'Orbigny). Most of the section represents cooler water deposition. At Le Castella, most of the exposed Quaternary sediments represent warmer water deposition (Emilian = late warm Calabrian), with cooler water deposition represented near the top (Sicilian). At Le Castella, the range of Discoaster brouweri Tan Sin Hok was found to be concurrent with Gephyrocapsa caribbeanica Boudreaux and Hay. The Calabrian at Santa Maria di Catanzaro, with the presence of both Discoaster brouweri and Globorotalia truncatulinoides in section deposited in cooler water, correlates very well with the American marine Nebraskan. The Emilian at Le Castella, with the occurrence of both Discoaster brouweri and Gephyrocapsa in section deposited in warmer water, is equivalent to the American marine Aftonian. End_of_Article - Last_Page 2045------------

Biostratigraphy and Paleotemperatures of a Section Cored on the Nicaragua Rise, Caribbean Sea

The drilling vesselSubmarex of Global Marine was used to drill and core sediments to a depth of 56.4 m on the Nicaragua Rise, between Walton Bank and Jamaica, in 610 m of water. Seismic reflection profiles revealed thick accumulations of layered sediments with some fossil reefs. The sediments consist of undisturbed layers rich in planktonic microfossils alternating with turbidite layers. Absence of older coccoliths indicates that the redeposited material was not appreciably older than the time of redeposition, and oxygen isotopic analysis of benthonic elements shows that this material was derived from a depth not much shallower. The lower portion of the cored section correlates with the Manchioneal Formation of Jamaica. Taxonornic analysis of the calcareous nannoplankton indicates that the level at 2354 cm correlates with the midportions of the eastern equatorial Pacific cores 58 and 62; with the “Nebraskan-Aftonian” boundary of the Gulf Coast; and with the appearance of Hyalinea baltica at Le Castella, southern Italy. This level, therefore, represents the Plio-Pleistocene boundary as officially designated, and an age of about 700,000 years is estimated for the bou ndary. Oxygen isotopic analysis shows important oscillations, with a full glacial-interglacial amplitude, occurring both above and below the Plio-Pleistocene boundary.

Paleotemperature Analysis of the Plio-Pleistocene Section at Le Castella, Calabria, Southern Italy

Research Article| May 01, 1961 Paleotemperature Analysis of the Plio-Pleistocene Section at Le Castella, Calabria, Southern Italy C EMILIANI; C EMILIANI University of Miami, Coral Gables, Fla Search for other works by this author on: GSW Google Scholar T MAYEDA; T MAYEDA University of Chicago, Chicago, Ill Search for other works by this author on: GSW Google Scholar R SELLI R SELLI University of Bologna, Bologna, Italy Search for other works by this author on: GSW Google Scholar Author and Article Information C EMILIANI University of Miami, Coral Gables, Fla T MAYEDA University of Chicago, Chicago, Ill R SELLI University of Bologna, Bologna, Italy Publisher: Geological Society of America Received: 07 Jul 1959 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1961, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1961) 72 (5): 679–688. https://doi.org/10.1130/0016-7606(1961)72[679:PAOTPS]2.0.CO;2 Article history Received: 07 Jul 1959 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation C EMILIANI, T MAYEDA, R SELLI; Paleotemperature Analysis of the Plio-Pleistocene Section at Le Castella, Calabria, Southern Italy. GSA Bulletin 1961;; 72 (5): 679–688. doi: https://doi.org/10.1130/0016-7606(1961)72[679:PAOTPS]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Plio-Pleistocene boundary has been located at the place where certain northern species of marine invertebrates first appear in the continuous Plio-Pleistocene sections of Italy. The section at Le Castella, near Crotone, southern Italy, consists of clays with diatomaceous layers and a few thin sand layers. The Plio-Pleistocene boundary there is clearly marked by the appearance of Anomalina baltica and other northern species of Foraminifera. Calabnan (lower Pleistocene) sediments 210m thick overlie the boundary, and upper Pliocene sediments 1405 m thick underlie it. The fossil fauna of the Plio-Pleistocene section consists essentially of abundant pelagic and benthonic Foraminifera, and diatoms. The benthonic microfauna indicates a depositional depth of about 500 m. There is no evidence of turbidity currents and submarine slumping.A section 167.80 m thick, including the paleontologically defined Plio-Pleistocene boundary, was logged and sampled at close stratigraphic intervals. Oxygen isotopic analyses of different species of pelagic and benthonic Foraminifera and of shell fragments of benthonic mollusks at successively higher stratigraphic positions in the section have revealed numerous temperature oscillations. Surface temperatures, probably representing summer averages, as indicated by Globigerinoides rubra and G. sacculifera, ranged from 21°C. to more than 30°C. in the late Pliocene, from 16°C. to more than 30°C. in the late Pliocene-early Pleistocene, and from 12° C. to 28° C. in the late Pleistocene. Temperatures at some depth and/or at a season other than the summer, as indicated by Globigerina bulloides and G. inflata, ranged from 20°C. to 28°C. in the late Pliocene, from 11°C. to 22°C. in the late Pliocene-early Pleistocene, and from 9°C. to 18°C. in the late Pleistocene. Temperatures given by benthonic Foraminifera ranged from 14°C. to 20°C. in the late Pliocene and from 11°C. to 22°C. in the late Pliocene-early Pleistocene (no data available for the late Pleistocene). Temperatures above 30°C. may be due, in part, to isotopic effects of the sea water. The above figures clearly indicate a major shift of the temperature ranges toward lower values from the late Pliocene to the late Pleistocene.No major temperature change seems to have occurred across the paleontologically defined Plio-Pleistocene boundary. Since the secular temperature minima of the late Pliocene are somewhat lower than present average summer temperature, an areal extension of the ice somewhat greater than that at present is suggested. Such extension probably increased at the times corresponding to the even lower temperature minima of the early Pleistocene. Major continental glaciations, however, may not have started until later, because none of the temperature minima in the section at Le Castella appear to have reached values as low as those obtaining during the glacial ages in the eastern Mediterranean.The temperature changes in the section at Le Castella are paralleled by important changes in the microfauna. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.