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F. Pepe et al. / Geomorphology 303 (2018) 191–209 197

Fig. 3. a, b and c) Thicknesses of the bedding planes measured in sections of carbonate rocks outcropping in the coastal areas of Punta Faraglione and surroundings, and d) Punta Fanfalo.

4.1.2. Punta Fanfalo and poorly spherical reworked carbonate fragments and rare bivalve
The surveyed area corresponds to the ~1 km-long, SW-facing coast shells (fossiliferous polygenic-conglomerates). The S1 sample is partial-
of Punta Fanfalo (Fig. 1A). The rock coast shows zones characterized ly grain-supported (grainstone-packestone) with interstitial material
by regular topography, with inclinations varying from 4° up to 15° composed of arenitic to silty reddish carbonate-matrix. The matrix con-
(transect d in Fig. 1B), or steep low cliff of ~2 m above sea level. The in- sists of mainly arenitic carbonate fragments with the same lithology of
clination of the submerged platform is in the range from 1.7° up to 2.5° clasts. The sample is part of a graded bed in which alternating coarse
(transects e and f in Fig. 1B). In this locality, 33 boulders and 21 sockets to fine levels with interposition of fossiliferous levels occurs. Alignment
were selected and analyzed. Although isolated boulders are present the of the clasts parallel to the stratification is also observed.
majority of them form small groups located at ~5 m and ~20 m far from Rock samples taken towards the southwest (e.g. S8 in Fig. 8)are
the shoreline with internal seaward imbricate boulders (Fig. 7a). Bio- composed by particle-carbonate-rock with arenitic-size grains mainly
genic encrustations of vermetids were also observed on the surfaces of consisting of reworked poorly-sorted carbonate fragments derived
some of them. from pre-existing rocks (up to ruditic-size), bivalve shells, gasteropods,
The majority of boulders are characterized by a rectangular shape echinidis and rare vermetids fragment (biolastic coarse-calcarenite).
(42% tabular and 55% bladed), and only 3% are rod shaped (Fig. 4a). The grains are altered and wrapped by a thin, reddish, silty carbonate
The average and biggest size of boulders are, respectively, ~2.25 × layer that represents the matrix rich in iron oxides (biomicrite). Align-
~1.42 × ~0.46 m and ~3.70 × 1.70 × 0.50 m (corresponding to ~8.4 t, ment of the grains (lithoclasts and the bioclasts) parallel to the stratifi-
Table A1). cation is also detected. Clastic material is partially grain-supported
The histogram of boulders' thicknesses exhibits three frequency (grainstone-packstone).
peaks, at 25–30 cm, 35–40 cm and 45–50 cm (Fig. 5). The minimum Samples taken from boulders accumulated above the younger
and maximum class values of the C-axis measured in this locality are, re- foreset beds (e.g. S3 in Fig. 8) are characterized by particle-carbonate-
spectively, 15–20 cm and 95–100 cm. rock with arenitic-size grains mainly consisting of fragments of bivalve
The A-axis for most of blocks is approximately oriented perpendicu- shells, gastropods, echinoids, spherical accretionary coated particles
lar to the coastline (from N40 to N80), although there are boulders char- and small rounded lithoclasts (biolastic fine-calcarenite). The S3 sample
acterized by an average trend of N90 and N100 (Table A1 and Fig. 6b). A shows a grain-supported fabric (grainstone) with low percentage of in-
few blocks with their A-axis oriented from N110 to N120 are also terstitial material composed of predominantly silty carbonate-matrix
observed. (biomicrite) and sporadic intergranular sparry calcitic cement. Large bi-
The rupture surface due to the boulder detachment is arranged in valve fragments are present into the coarse calcarenite.
different levels (Fig. 6 b), and displays either smoothed sides or sharped Rock samples taken from boulders accumulated in the Punta Fanfalo
edges. Fig. 7c shows an example of the latter case in which the recent coastal area (e.g. S9 in in Fig. 8) are characterized by particle-carbonate-
detachment of a boulder has determined the formation of a socket char- rock with arenitic-size grains mainly consisting of fragments of bivalve
acterized by sharp and fresh rock surfaces with a clearer color difference shells, gastropods, echinoids, spherical accretionary coated particles
to the surrounding rocks. The majority of sockets exhibit bladed (57%) and small rounded lithoclasts (biolastic fine-calcarenite). Samples dis-
and tabular (38%) shapes (Fig. 4b). On average, sockets have dimensions play a grain-supported fabric (grainstone) with low percentage of inter-
of 1.90 × 0.80 × 0.55 m while the biggest is 3.50 × 1.90 × 0.80 m stitial material composed of predominantly silty carbonate-matrix
(Table A2). (biomicrite). Large bivalve fragments are recognized with random dis-
tribution in the sample.
Table 1 contains the results of bulk density testing for seven rock
3
4.2. Lithofacies, bulk density and mass estimation of boulder samples. The densities vary between 2.37 ± 0,08 g/cm and 1.87 ±
3
0,08 g/cm . The highest value was estimate for the fossiliferous
Rock samples taken from boulders accumulated above the oldest polygenic-conglomerates (Sample ID_1 in Table 1) while the lowest
foreset beds (e.g. S1 in Fig. 8) are characterized by ruditic-size, clastic- value was estimate for the bioclastic coarse-calcarenites (sample ID_8
carbonate-rock consisting of polygenic, poorly-sorted, well-rounded in Table 1). Table A1 contains the bulk density estimation of all boulders