Isotopic evidence for open system processes within the Campanian Ignimbrite (Campi Flegrei-Italy) magma chamber

被引:51
作者
Arienzo, I. [1 ]
Civetta, L. [1 ,3 ]
Heumann, A. [2 ]
Woerner, G. [2 ]
Orsi, G. [1 ]
机构
[1] Ist Nazl Geofis & Vulcanol, Sez Napoli Osservatorio Vesuviano, I-80124 Naples, Italy
[2] Univ Gottingen, Abt Geochem, GZG, Gottingen, Germany
[3] Univ Naples Federico 2, Dipartimento Sci Fisiche, I-80126 Naples, Italy
关键词
Campanian Ignimbrite; Radiogenic isotopes; Mixing process; LAACHER SEE TEPHRA; PHLEGRAEAN FIELDS; PHLEGREAN FIELDS; DEPOSITIONAL PROCESSES; WEST-GERMANY; CALDERA; EVOLUTION; ERUPTION; CONSTRAINTS; SR;
D O I
10.1007/s00445-008-0223-0
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
New Sr and Nd isotope data for whole rocks, glasses and minerals are combined to reconstruct the nature and origin of mixing end-members of the 200 km(3) trachytic to phonolitic Campanian Ignimbrite (Campi Flegrei, Italy) magmatic system. The least-evolved magmatic end-member shows equilibrium between host glass and the majority of the phenocrysts and is less radiogenic in Sr and Nd than the most-evolved magma. On the contrary, only the Fe-rich pyroxene from the most-evolved erupted magma is in equilibrium with the matrix glass, while all other minerals are in isotopic disequilibrium. These magmas mixed prior to and during the Campanian Ignimbrite eruption and minerals were freely exchanged between the magma batches. Combining the results of the geochemical investigations on magma end-members with geophysical and geological data, we develop the following scenario. In stage 1, a parental, less differentiated magma rose into the middle crust, and evolved through combined crustal assimilation and crystal fractionation. In stage 2, the differentiated magma rose to shallower depth, fed the pre-Campanian Ignimbrite activity and evolved by further open-system processes into the most-evolved and most-radiogenic Campanian Ignimbrite end-member magma. In stage 3, new trachytic magma, isotopically distinct from the pre-Campanian Ignimbrite magmas, rose from ca. 6 km to shallower depth, recharged the most-evolved pre-Campanian Ignimbrite magma chamber, and formed the large and stratified Campanian Ignimbrite magmatic system. During the course of the Campanian Ignimbrite eruption, the two layers were tapped separately and/or simultaneously, and gave rise to the range of chemical and isotopic values displayed by the Campanian Ignimbrite pumices, glasses and minerals.
引用
收藏
页码:285 / 300
页数:16
相关论文
共 68 条
[1]  
*AGIP, 1987, ESPL GEOT
[2]  
[Anonymous], 2003, AM GEOPHYS UNION, DOI DOI 10.1029/139GM20
[3]  
Barberi F., 1978, B VOLCANOL, V41, P10, DOI [10.1007/BF02597680, DOI 10.1007/BF02597680]
[4]   PETROGENESIS AND TECTONIC SETTING OF THE ROMAN VOLCANIC PROVINCE, ITALY [J].
BECCALUVA, L ;
DIGIROLAMO, P ;
SERRI, G .
LITHOS, 1991, 26 (3-4) :191-221
[5]  
Bohrson WA, 2006, DEV VOLCANO, V9, P249
[6]  
CIVETTA L, 1991, EUR J MINERAL, V3, P415
[7]   Geochemical zoning, mingling, eruptive dynamics and depositional processes - The Campanian Ignimbrite, Campi Flegrei caldera, Italy [J].
Civetta, L ;
Orsi, G ;
Pappalardo, L ;
Fisher, RV ;
Heiken, G ;
Ort, M .
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, 1997, 75 (3-4) :183-219
[8]   The present state of the magmatic system of the Campi Flegrei caldera based on a reconstruction of its behavior in the past 12 ka [J].
D'Antonio, M ;
Civetta, L ;
Orsi, G ;
Pappalardo, L ;
Piochi, M ;
Carandente, A ;
de Vita, S ;
Di Vito, MA ;
Isaia, R .
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, 1999, 91 (2-4) :247-268
[9]  
D'Antonio M., 1996, EARTH PROCESSES READ, V95, P253
[10]  
D'Antonio M, 2007, GEOL SOC AM SPEC PAP, V418, P203, DOI 10.1130/2007.2418(10)