Plio-Quaternary Volcanism in Italy: Petrology, Geochemistry, Geodynamics

370 Pages·2005·8.57 MB·English

by  Angelo Peccerillo

Angelo Peccerillo
Plio-Quaternary Volcanism in Italy
Petrology, Geochemistry, Geodynamics
Angelo Peccerillo

Plio-Quaternary Volcanism
in Italy

Petrology, Geochemistry, Geodynamics

With 145 Figures and a CD-ROM
PROF. ANGELO PECCERILLO
DEPARTMENT OF EARTH SCIENCES
PIAZZA UNIVERSITÀ 1
06100 PERUGIA

ITALY

E-MAIL: [email protected]

ISBN 10 3-540-25885-x Springer Berlin Heidelberg New York
ISBN 13 978-3-540-25885-8 Springer Berlin Heidelberg New York

Library of Congress Control Number: 2005928988

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Preface
Italian Plio-Quaternary magmatism exhibits a very wide petrological, geo-
chemical and radiogenic-isotope variability, which makes magma genesis
and geodynamic significance difficult issues. A large number of papers
have been published on these rocks trying to explain the petrogenesis and
evolution of single volcanoes or magmatic provinces. However, papers
presenting a comprehensive review of the data and hypotheses on the
magmatism of the region as a whole are few, if any. Synthesis of data at
the local scale has definitely increased our degree of understanding of vol-
canism at that scale, but it has not resolved ambiguous issues such as the
relationship among various magmatic provinces, the significance of re-
gional compositional variations, and the geodynamic setting for this com-
plex magmatism. The objective of this book is to fill this gap by providing
an overview of the most prominent petrological and geochemical data and
discussing currently held ideas on the petrogenesis and geodynamic sig-
nificance of Italian Plio-Quaternary volcanic rocks. In summarising the in-
tense debate on Italian magmatism, I have tried to report on, as objectively
as possible, all the most significant ideas. The different weight given to the
discussion of various points of view depends only marginally on the au-
thor’s choice but is mostly an effect of the very different amounts of fac-
tual constraints which have been brought to supporting various hypotheses.
The book is subdivided into ten chapters. The first one provides an in-
troduction to the main petrological and geochemical characteristics and
gives the rationale for subdivision of the Italian Plio-Quaternary magma-
tism into several distinct magmatic provinces. The last chapter is a sum-
mary of the petrological, volcanological and structural characteristics of
the volcanic provinces and of the most popular hypotheses that have been
proposed to explain the relationship between geodynamics and volcanism.
The other chapters are devoted to the volcanology, petrology and geo-
chemistry of single magmatic provinces into which Recent Italian magma-
tism has been subdivided. The number of these provinces is slightly higher
than recognised by most authors. However, the present subdivision is
based on the bulk of compositional data, included a large number of trace
VI Preface
elements and radiogenic isotopes, which have provided the tools for setting
new boundaries that were not obvious during early studies.
The data discussed in the text have been generally taken from the most
recent literature; old analyses have not been considered in order to avoid
analytical bias. In most diagrams, especially those showing major elements
and the most commonly determined trace elements, a limited number of
representative data have been plotted. Such a choice has been dictated by
the need to avoid excessive crowding, which would have made diagrams
difficult to read. In goes without saying that, in the choice of data points,
care has been taken to select representative compositions, in order to pre-
serve all necessary information. A few representative data for the single
magmatic provinces have been reported in the tables attached to the end of
each chapter. More data can be found in the CD attached to this book and
at the Author’s web-site (http://www.unipg.it/~pecceang).
For classification and nomenclature of volcanic rocks, the IUGS
scheme of Le Maitre (1989) has been consistently adopted through the
book. For rocks related to volcanic arcs, the classification scheme of Pec-
cerillo and Taylor (1976) has been used. These classification schemes, to-
gether with a few notes on the petrogenesis of potassium-rich rocks, have
been explained in the Appendix. Rocks names not reported in these
schemes and eventually used through the book have been defined in foot-
notes. Explanations and comments reported in the Appendix, in footnotes
and, sometimes, through the text are trivial for petrologists and geochem-
ists, but may be useful for other potential readers who are not familiar with
petrological-geochemical issues and jargon.
The bibliography on Italian volcanism and geodynamics is enormous
and would deserve a book by itself. Therefore, the attached reference list is
far from being comprehensive of the large quantity of the published papers
and many important contributions, especially in the field of mineralogy,
geophysics and geodynamics, have been omitted because of space con-
straints. Again, a more complete list of papers is reported in the attached
CD and at the Author’s web-site.
The various chapters of the book have been reviewed by several col-
leagues who made important suggestions, corrections and modifications
which definitively improved the style of writing and quality of science. It
is obvious, however, that the scientific responsibility for the contents of
this book leans entirely on the author. I wish to express my gratitude to
Russell Harmon, Gillian Foulger, Massimiliano Barchi, Michele Lustrino,
Lucia Civetta, Sonia Esperança, Robert Ayuso, Elisabeth Widom, Carlo
Doglioni, Giampiero Poli, Leonsevero Passeri, Alba Santo, Diego Perugini
and Pamela Kempton for their help. Pamela Kempton, NERC, UK, also
Preface VII
co-authored Chapter 10. Very special thanks are due to Carmelita Donati
who constructed the data files used in this book. My gratitude goes also to
Christine Hardwick for correction of an early version of the text and for
competent editing, and to Nicoletta Prosperini and Danilo Chiocchini for
invaluable help with figure drawing and text formatting. Michele Lustrino,
Giampiero Poli, Maria Luce Frezzotti and Gianfilippo De Astis generously
allowed use of their data files and unpublished data on Sardinia, Capraia,
Ernici and Mount Vulture. Luigi Carmignani furnished the DEM bases for
volcanoes location maps. Giuseppe Vilardo and Giovanni Orsi provided
DEM bases used for geological maps of active volcanoes. Giovanni Mace-
donio supplied the DEM base for Etna. The kindness of these colleagues is
gratefully acknowledged. Altair Pirro and Giulio Castagnini assisted dur-
ing drawing of geological maps and handling of DEM bases.
This effort is dedicated to my wife, my daughter and to the memory of
my parents.
Table of Contents
1. Plio-Quaternary Magmatism in Italy: Introductory Overview...1
1.1. Introduction...............................................................................1
1.2. Geochronology and Petrology...................................................1
1.3. Regional Distribution of Magma Types....................................5
1.4. Regional Variation of Trace Element and Sr-Nd-Pb-O
Isotopic Compositions...............................................................6
1.5. Magmatic Provinces in Italy....................................................10
1.6. Petrogenesis and Geodynamics: a Preliminary Perspective....15
1.7. Conclusions.............................................................................16
2. The Tuscany Province....................................................................17
2.1. Introduction.............................................................................17
2.2. Regional Geology....................................................................17
2.3. Compositional Characteristics of Tuscany Magmatism..........20
2.4. Silicic Magmatism...................................................................24
2.4.1. Effusive Rocks.................................................................24
2.4.2. Intrusive Rocks.................................................................28
2.5. Mafic Magmatism....................................................................31
2.6. Petrogenesis.............................................................................38
2.6.1. Silicic Magmatism............................................................38
2.6.2. Mafic Magmatism............................................................39
2.6.3. Summary of Petrogenetic History....................................42
2.7. Geodynamic Implications........................................................43
2.8. Conclusions.............................................................................46
3. The Intra-Apennine Province........................................................51
3.1. Introduction.............................................................................51
3.2. Regional Geology....................................................................51
3.3. Compositional Characteristics of Intra-Apennine
Magmatism..............................................................................53
3.3.1. San Venanzo.....................................................................54
3.3.2. Cupaello............................................................................56
X Table of Contents
3.3.3. Polino...............................................................................57
3.3.4. Intra-Apennine Pyroclastic Deposits................................58
3.3.5. Colle Fabbri......................................................................60
3.4. Petrogenesis.............................................................................60
3.4.1. Kamafugitic Rocks...........................................................61
3.4.2. Carbonate-rich Rocks.......................................................63
3.5. Geodynamic Implications........................................................65
3.6. Conclusions.............................................................................66
4. The Roman Province......................................................................69
4.1. Introduction.............................................................................69
4.2. Regional Geology....................................................................71
4.3. Vulsini District........................................................................72
4.3.1. Volcanology and Stratigraphy..........................................73
4.3.2. Petrography and Mineral Chemistry................................74
4.3.3. Petrology and Geochemistry............................................77
4.4. Vico Volcano...........................................................................80
4.4.1. Volcanology and Stratigraphy..........................................81
4.4.2. Petrography and Mineral Chemistry................................82
4.4.3. Petrology and Geochemistry............................................83
4.5. Sabatini District.......................................................................86
4.5.1. Volcanology and Stratigraphy..........................................87
4.5.2. Petrography and Mineral Chemistry................................88
4.5.3. Petrology and Geochemistry............................................89
4.6. Colli Albani (Alban Hills).......................................................91
4.6.1. Volcanology and Stratigraphy..........................................91
4.6.2. Petrography and Mineral Chemistry................................93
4.6.3. Petrology and Geochemistry............................................94
4.7. Petrogenesis.............................................................................97
4.7.1. Fractional Crystallisation and Magma Mixing.................97
4.7.2. Magma Contamination by Crustal Rocks.........................98
4.7.3. Genesis of Mafic Magmas................................................99
4.8 Age of Mantle Contamination and Geodynamic
Implications..........................................................................102
4.9 Conclusions...........................................................................105
5. The Ernici-Roccamonfina Province............................................109
5.1. Introduction...........................................................................109
5.2. Regional Geology..................................................................109
5.3. Monti Ernici...........................................................................111
5.3.1. Volcanology andStratigraphy........................................111
Table of Contents XI
5.3.2. Petrography and Mineral Chemistry..............................112
5.3.3. Petrology and Geochemistry..........................................113
5.4. Roccamonfina........................................................................118
5.4.1. Volcanology and Stratigraphy........................................118
5.4.2. Petrography and Mineral Chemistry..............................120
5.4.3. Petrology and Geochemistry..........................................121
5.5. Petrogenesis...........................................................................122
5.6. Nature of Mantle Metasomatism and Geodynamic
Implications...........................................................................124
5.7. Conclusions...........................................................................126
6. The Campania Province, Pontine Islands, Mount Vulture.......129
6.1. Introduction...........................................................................129
6.2. Regional Geology..................................................................130
6.3. Campania Province................................................................133
6.3.1. Somma-Vesuvio.............................................................133
6.3.2. Campi Flegrei (Phlegraean Fields).................................141
6.3.3. Ischia..............................................................................146
6.3.4. Procida and Vivara.........................................................149
6.4. Buried Volcanism beneath the Campanian Plain...................152
6.5. Pontine Islands.......................................................................152
6.5.1. Ponza, Palmarola and Zannone......................................153
6.5.2. Ventotene and Santo Stefano..........................................155
6.6. Mount Vulture.......................................................................157
6.6.1. Volcanology and Stratigraphy........................................157
6.6.2. Petrography and Mineral Chemistry..............................158
6.6.3. Petrology and geochemistry...........................................160
6.7. Petrogenesis of Campania, Pontine and Vulture magmas.....162
6.8. Geodynamic Setting...............................................................165
6.9. Conclusions...........................................................................167
7. The Aeolian arc.............................................................................173
7.1. Introduction...........................................................................173
7.2. Regional Geology..................................................................173
7.3. Alicudi...................................................................................177
7.3.1. Volcanology and Stratigraphy........................................177
7.3.2. Petrography and Mineral Chemistry..............................177
7.3.3. Petrology and Geochemistry..........................................178
7.4. Filicudi...................................................................................181
7.4.1. Volcanology and Stratigraphy........................................181
7.4.2. Petrography and Mineral Chemistry..............................181