Dictionary of Geotourism

2020 Edition
| Editors: Anze Chen, Young Ng, Erkuang Zhang, Mingzhong Tian

Pyroclastics; Tephra

Reference work entry
DOI: https://doi.org/10.1007/978-981-13-2538-0_1971
Pyroclastic is the collective term for all clastic materials that are produced during volcanic eruptions. Pyroclastics are the main component of volcaniclastic rocks. Different types of pyroclastics include agglomerates, breccia, detritus, pumice, scoria, fiamme, plastic vitric fragments, glass fragments, crystal fragments, volcanic balls, hot volcanic balls and volcanic dust. Their characteristics are described below (Table 1).
Table 1

Types of volcaniclastic rocks

Type

Fragment form

Name of deposit

Appearance

Internal structure

Size

Rock

Fragments of consolidated rock

Hard rock

Hard

No definite shape

Indefinite structure

>50 mm

Agglomerate

50–2 mm

Breccia

<2 mm

Lithic fragment

Porous structure

Indefinite

Pumice, scoria

Fragments in molten state

Unconsolidated to semi- consolidated magma

Plastic

Definite shape

Definite structure

>2 mm

Magma fragment

<2 mm

Plastic vitric fragment

Semi-plastic to hard

Definite shape

Definite structure

Generally small

Vitric fragment

Crystalline mineral...

This is a preview of subscription content, log in to check access.

Copyright information

© Springer Nature Singapore Pte Ltd. 2020