UTRECHT MICROPALEONTOLOGICAL BUllETINS

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Figs. 12 and 13. Chondrites-burrows in the topmost clayey interval of the Trubi at Capo Rossello (exposure 3).
whether its assumed intermediate stratigraphic position was substantiated by the planktonic markers (samples 42-45, some 30 m stratigraphically above 107). The benthonic fauna was studied for comparison with the overlying an'd underlying assemblages. This middle part of the Trubi is well-bedded. Minor lithological differences between the consecutive beds are shown by selective weathering, but in fresh outcrops these differences are hardly detectable. Horizontal partings may contain thin clay seams which show discontinuous lamination and mottled structures. Small, bifurcating burrows as described from section 3 were found in this middle part as well. Section Punta Piccola The uppermost part of the Trubi, exposed in the Punta Piccola section, is very similar to the lowermost few meters at Capo Rossello: thick bedded, highly indurated and thoroughly burrowed (samples PP 1-7, some 60 m stratigraphically above 107). Burrowing is visible by brown and blue coloured stains with diameters of 1 to 2 cm. The burrows seem to diminish in diameter in an upward direction because the brown coloured spots are smaller with diameters of 0.5 to 1 cm; they may be surrounded by concentric rings of 1 to 3 cm diameter. Discussion of the lithology In general, Trubi sediments consist for some 75% of carbonate of mainly planktonic origin, for some 25% of silica and clay minerals. Low sedimentation rates and favourable conditions for bottom life may explain the vague bedding, intense burrowing and compact character of the lowermost 6 to 7 m of the limestones. Burrowing activity evidently destroyed any stratification that might have been present. Sedimentation rates may have increased occasionally to account for the few more clayey intercalations. The distinct bedding higher in the section is caused by marly intercalations possibly indicating periodical supply of fines. The dark coloured clay seams within the marly intercalations indicate homogenization to have been less at times; the decreased burrowing must be due either to increased sedimentation rates or to less favourable bottom conditions. The observed 25 gradual changes from marl to indurated limestone may either be explained by decreasing supply of terrigenous fines or by an increasing activity of burrowers enhanced by either a decreasing rate of deposition or by improving bottom conditions. A varying rate of deposition caused by a fluctuating supply of terrigenous fines seems to be the most plausible mechanism for the rhythmic type of sedimentation. Indications for a turbiditic type of
Page 1 and 2: UTRECHT MICROPALEONTOLOGICAL BUllET
Page 3 and 4: QUANTITATIVE FORAMINIFERAL ANALYSIS
Page 5 and 6: The foraminifera. . . . . . . . . .
Page 7 and 8: Benthonic and planktonic foraminife
Page 9 and 10: and considerable lowering of the er
Page 11 and 12: topmost Messinian evaporites, chara
Page 13 and 14: literature together with Pachysphae
Page 16 and 17: Data and conclusions from the earli
Page 18 and 19: 2 3 Ammonia beccarii Bolivina dente
Page 20 and 21: LITHOLOGY The new exposure to be de
Page 22 and 23: may interfinger. Evidently biogenic
Page 24: CONCLUSIONS The mediocre preservati
Page 27 and 28: 107 107G B.C 107A 106 1394 64 1393
Page 29 and 30: Fig. 9 Laterally displaced loadcast
Page 31 and 32: Orbulina, which in turn seem to dep
Page 33: 0 10 20cm. L--L--J ~II\\ :::0 if.-
Page 37 and 38: cate that larger burrowing organism
Page 39 and 40: The foraminiferal faunas from the T
Page 41 and 42: 42 43 44 45 sa~ 3 4 4 Astrononion i
Page 43 and 44: the accumulation of silica-rich sed
Page 45 and 46: 1 1 i z 1 1 11 3 1 i ~ . 2 •• 7
Page 47 and 48: ently favoured clayey substrates bu
Page 49 and 50: The next higher part of the section
Page 51 and 52: Cibicides pseudoungerianus appears
Page 53 and 54: In the next higher interval the alt
Page 55 and 56: high. It remains equally possible t
Page 57 and 58: I 106 55 52 j 8 Ij I " ~ ~ ! I ll11
Page 59 and 60: 107A 107B 107C 107D 107E 107F 107G
Page 61 and 62: of the faunas remains practically t
Page 63 and 64: 5 -- 4 3 2 7 - - - - - - - - - - -
Page 65 and 66: ;.Monica Say(32) Todos Santos 8ay (
Page 67 and 68: 1000 m, the latter corresponding to
Page 69 and 70: In this respect it is interesting t
Page 71 and 72: for this interval at the three loca
Page 73 and 74: near-absence and bloom. The level o
Page 75 and 76: Fig. 30 Punta Piccola section, show
Page 77 and 78: Chlorite/montmorillonite and albite
Page 79: most of them are of the order of 15
Page 83 and 84: The change in colour from cream to
Page 85 and 86:
The foraminiferal faunas from the M
Page 87 and 88:
, " ~ " , , . ~ . ~
Page 89 and 90:
posite- reactions with higher a-val
Page 91 and 92:
------ Cibicides lobatu(us -- Hanza
Page 93 and 94:
Bulimina inflata, Hopkinsina bononi
Page 95 and 96:
Parker, 1954). In the Andaman Sea t
Page 97 and 98:
athymetric distribution is shown in
Page 99 and 100:
in the manganese-rich interbeds (B
Page 101 and 102:
50 1~N 47 46 45 43 4 M 42 L 41 4 39
Page 103 and 104:
Emiliani (1974) analyzed core mater
Page 105 and 106:
20323, was deposited at the transit
Page 107 and 108:
it is realized that the latter two
Page 109 and 110:
FREQUENCY D ISTR I BUTION OF SOME S
Page 111 and 112:
BENTHONIC FORAMINIFERAL ASSOCIATION
Page 113 and 114:
IK < .o~
Page 115 and 116:
ed by the increase of epiphytes and
Page 117 and 118:
G. puncticulata, recorded from Aren
Page 119 and 120:
our sample 93 suddenly shows a B/P
Page 121 and 122:
loss may be due to the folding. The
Page 123 and 124:
shallowing tendency. This quiet sed
Page 125 and 126:
One of the major aims of this inves
Page 127 and 128:
anean evidently had a nutrient supp
Page 129 and 130:
A taxonomical treatment of all figu
Page 131 and 132:
Remarks: Globigerina pseudobesa (Sa
Page 133 and 134:
Remarks: Colalongo and Sartoni (196
Page 135 and 136:
30. Earland, A. (1934). Foraminifer
Page 137 and 138:
Anderson, G. ]. (1963). Distributio
Page 139 and 140:
Hsii, K. J., Cita, M. B. and Ryan,
Page 141 and 142:
Wright, R. (1977). Neogene paleobat
Page 144:
Figs. 1a-b Figs. 2a-b Figs.3a-b Fig
Page 148:
Figs. 1a-c Figs. 2a-c Figs. 3a-c Fi
Page 152:
Fig. 1 Fig. 2 Figs.3a-b Fig. 4 Fig.
Page 156:
Morphological gradation from Globor
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UTRECHT MICROPALEONTOLOGICAL BUllETINS

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