Lithostratigraphic analysis and geochemistry of a vitric spatterbearing ignimbrite: the Quaternary Adeje Formation, Cañadas
volcano, Tenerife.
P. Dávila Harris et al. Bulletin of Volcanology 2013
Electronic Supplementary Material 1 (ESM-1)
Table captions
Table 1 Lithofacies association for the Adeje Formation in southwest Tenerife, following the
scheme of Brown & Branney (2004) for other pyroclastic units across southern Tenerife (e.g.
Porís Formation).
Table 2 Description of selected juvenile types within the Adeje Formation illustrating the
wide variety of textures and crystal contents present within single clasts.
Figure captions
Figure 1 Stratigraphic contacts between the Adeje and San Juan Formations. A) Incipiently
welded lapilli-tuff (from the San Juan Formation) on an erosion surface over the Adeje
ignimbrite, at El Puertito by the coast. B) Detail of contact in A, rucksack is 0.3 m. C)
Irregular erosive contact between the Adeje and the San Juan ignimbrites, south of Adeje
town. Note palaeosol at the top of the Adeje ignimbrite. Hammer is 30 cm long.
Figure 2 A) At the base, the Adeje Formation showing massive agglomeratic lapilli-tuff
overlain by lava and on top the San Juan Formation sitting unconformably, Punta Negra. See
person for scale. B) The San Juan Formation unconformably overlying the Adeje Formation
at Playa de Diego Hernandez, probably representing an irregular coastal platform that has
been buried. C) Sketch of picture B.
Figure 1
Figure 2
Table 1
Lithofacies
Name (code)
Description
Interpretation
Pumice lapilli (pL);
massive pumice lapilli
(mpL); stratified or bedded
pumice lapilli (spL, bpL);
difusse-stratified or
diffuse-bedded pumice
lapilli (dspL, dbpL); lithicrich pumice lapilli (lpL)
Litohology: Clast-supported pumice lapilli (massive), well to moderately sorted. Pumice clasts are
angular to sub-angular, smaller than 6.0 to 8.0 cm in diameter, commonly green to grey and pale-grey,
and yellow when altered. It includes lithic lapilli in lower proportions (<20 %). Lithic clasts are
generally smaller, platy and slightly altered, they comprise accidental volcanic lithologies.
Sub-facies: stratified or bedded pumice lapilli (spL, bpL), like mpL but with grading patters due to
grainsize variations showing stratification (thin layering) and bedding (thick, cm sized beds). Diffusestratifed/bedded pumice lapilli (dspL, dbpL), when grading is not obvious but subtle. Lithic-rich
pumice lapilli (lmpL), when proportion of lithic clasts is larger than ~25% to up to ~40% at some
levels of the deposit, it commonly results on grading patterns.
Structure: It presents vertical grading, layers can variously grade upwards from massive to diffusestratified and massive again, for example.
Geometry/occurrence: It is laterally extended; sheet like, mantles topography, lateral thickness
changes are gradual. Boundaries usually parallel, with sharp lower contacts and more diffuse upper
contacts, at places upper contact eroded by overlying lapilli-tuff.
Interpretation: Pumice fallout deposit on the
basis of sorting, framework supported fabric,
topography mantling and little lateral variations
and laterally extended. Stratification and/or
bedding can be the result of changes in lithic
proportions or general grainsize variations,
reflecting fluctuations on dispersal and
deposition, consequence of wind, mass-flux,
source location and paleotopography.
Massive lapilli-tuff (mLT)
Lithology: massive lapilli-tuff (mLT) comprises fine to coarse-ash matrix of variable colours mainly
pale-cream, supporting variable proportions of pumice and lithic lapilli. Pumice lapilli are rounded to
sub-rounded, not exceeding 30% of lithofacies; the average diameter is 2-3 cm: usually weathered and
grey to yellowish. Lithic lapilli occupies 3-5% of the total; they consist of angular to sub-angular
clasts, with average sizes 1-2 cm in diameter, lithologies are variable, including fresh and altered
basalt, phonolite, scoria and spare intermediate syenite clasts.
Sub-facies: lithic-rich massive lapilli-tuff (lmLT); as mLT with an increase in lithic lapilli content of
20 to 25%; massive lapilli-tuff with accretionary lapilli (mLTacc); as mLT and contains matrix
supported, multi-rimmed accretionary lapilli and broken pieces of ash-aggregates (pellets).
Structure: massive; non-graded; presents localized, diffuse and discontinuous stratification; when
lithic-rich often exhibits inverse grading, denoted with (i) or normal grading (n).
Geometry/occurrence: massive lapilli-tuff usually forms thick lenticular, u-shaped and valley-fill
deposits with maximum thicknesses in the range of 20 meters; passes laterally and gradually into
massive tuff (mT) and bedded tuff (bT): grades vertically into dsLT, dbLT, mlBr, mAgT
Interpretation: massive lapilli-tuff records rapid
aggradation from sustained, granular fluid-based
density currents, where the lowermost part of the
current and uppermost part of the deposit were
poorly packed, with abundant ash and clasts.
Absence of structures suggests that tractional
processes and turbulence were suppressed by
high clast concentrations (Kokelaar et al., 2007;
Branney and Kokelaar, 2002).
Diffuse-stratified lapillituff (dsLT)
Lithology: diffuse-stratified lapilli-tuff (dsLT) as mLT.
Structure: thin, discontinuous, diffuse centimetre-thick, sub-parallel strata; in sets 0.1 to 3 m thick;
defined by the alternation of ash-rich layers and lapilli-rich thin layers; presents low-angle truncations;
convergence and bifurcation of laminae; scours and lateral impersistence.
Sub-facies: lithic-rich, diffuse-stratified lapilli-tuff (ldsLT); marked by a higher proportion of lithiclapilli over fines and pumice-lapilli.
Geometry/occurrence: present in topography-filling facies and close to valley margins and
palaeoridges; grades laterally into stratified lapilli-tuff (sLT) and vertically into massive lapilli-tuff
(mLT).
Interpretation:
diffuse-stratified
lapilli-tuff
represents relatively fast progressive aggradation
from a high-concentration fluid escape to
granular flow-dominated boundary-zone of a
pyroclastic density current. The fluctuation and
grading patterns of the impersistent stratification
suggests unsteady deposition from a sustained
current. (Branney and Kokelaar, 2002; Brown
and Branney, 2004)
Diffuse-bedded lapilli-tuff
(dbLT)
Lithology: diffuse-bedded lapilli-tuff (dbLT) as mLT; lithic-rich bedded lapilli-tuff (lbLT) as lmLT
with bedding defined by sub-horizontal concentrations of lithic-lapilli; varied lithologies as mLT.
Structure: it comprises centimetre to decimetres thick bed sets; internally massive; sub-parallel; with
undulating lower and upper boundaries; imbrication common (f); low-angle scours common at basal
Interpretation: diffuse-bedded lapilli-tuff records
similar conditions of emplacement that mLT:
rapid aggradation. The slightly marked bedding
does not correspond to tractional stratification,
Lithofacies
Name (code)
Description
Interpretation
boundary; occasional sharp upper boundary.
Geometry/occurrence: sub-horizontal continuity mainly in packages of more than one or two beds;
common in laterally persistent sheets; pinch-out upslope or laterally into valley margins; grades
horizontally into dsLT and pLT; passes vertically into mLT, mLTacc; mT.
instead,
it
probably
records
localized
unsteadiness in a nearly constant supply of
ash/lapilli in a pyroclastic current. When lithicrich (ldbLT), an inferred increase in lithic-lapilli
supply is invoked, either from source, near to
vent or entrained from substrate. The variation in
bedding thicknesses records current nonuniformity, while low-angle strata and lateral
truncations reflect current unsteadiness (Branney
and Kokelaar, 2002; Brown and Branney, 2004;
Kokelaar et al., 2007).
Pumice-rich lapilli-tuff
(pLT)
Lithology: pumice-rich lapilli-tuff (pLT) is supported in a fine-tuff matrix; it comprises sub-rounded
to sub-angular inflated pumice lapilli; coarse-pumice clasts (10-30 cm on diameter) form pumice
lenses (plens) usually at the top of ignimbrite sheets; normally lithic-poor and with occasional thin
strata of ash-tuff with accretionary lapilli.
Sub-facies: pumice-rich bedded lapilli-tuff (pbLT); as pLT, with centimetre-thick layers of pumicelapilli forming laterally discontinuous bedding; beds are internally massive with diffuse lower and
upper boundaries except when defined by thin ash layers.
Structure: generally massive: plensLT, forms cm- to m-long lenticular structures (pumice lens);
usually in low angle; concave or convex upwards; internally non-graded and moderately sorted;
crudely inverse-graded towards the top when forming beds; occasionally forming pods, pLT(pod),
associated with branch moulds.
Geometry/occurrence: plensLT usually appears at the top and valley margins of mLT and dbLT;
pbLT usually in sheets and laterally discontinuous; pLT(pod), occurs in close contact with substrate,
typically associated with shrub and branch moulds (Brown et al., 2004).
Interpretation: pumice-rich massive lapilli-tuff
as mLT and with high concentration of juvenile
pumice from source (pumice-rich currents);
plensLT –lenses or framework-supported
pumice-lapilli records accumulation of pumice
clasts at the lateral margin of the current (pumice
levees), where conditions of the flow-boundary
(concentration and shear rates) favour deposition;
accumulation of pumice at the top levels of
ignimbrite sheets reflects deposition in waning
stages of the current (Branney and Kokelaar,
2002; Brown and Branney, 2004); pbLT – like
pmLT with unsteady current conditions and
fluctuation in pumice supply.
Cross-stratified tuff and
lapilli-tuff (xsT/xsLT)
Lithology: cross-stratified tuff (xsT) comprises poorly-sorted, fine-grained pumice and lithic lapilli in
ash-tuff matrix; cross-stratified lapilli-tuff is poorly-sorted, ash-matrix supported pumice- and lithiclapilli in higher proportions that xsT. Pumice-lapilli are rounded to sub-rounded in xsT and xsLT
whilst lithic lapilli are angular to sub-angular in xsT and xsLT.
Structure: forms low-angle cross-stratification with dips along 5 to 15˚ up-current and down-current;
stratification is defined by lithic-lapilli, pumice-lapilli or thin layers of fines; thickness of cross-strata
ranges from 5 to 20 cm thick; internally massive or diffusely-stratified; lateral and down-stream
truncations common.
Geometry/occurrence: laterally discontinuous, sub-parallel sets that can extent for 10 to 20 meters
across; thickness of sets can be from 0.1 to 1.5 m thick; dunes and antidune bedforms with
wavelengths from 2 to 15 meters; sharp lower contact with mLT and dbLT; gradational upper contact
with mLT and dbLT; scoured upper contact occasionally; passes laterally and vertically into mLT,
dbLT and ldbLT.
Interpretation: records deposition from tractiondominated flow-boundaries (Branney and
Kokelaar, 2002). However, many variations may
exist regarding type of structures, continuity and
context; stratified and cross-stratified tuff and
lapilli-tuff generally reflects unsteadiness in
pyroclastic density current. The intergradational
character of xsT/xsLT with mLT and dbLT
indicates that the parent currents had
intermediate boundary zones between tractional
and granular-flow dominated flow-boundaries
(Branney and Kokelaar, 2002).
Eutaxitic massive lapillituff (emLT)
Lithology: green to dark brown eutaxitic massive lapilli-tuff (emLT) is matrix-supported in highly- to
incipiently-welded groundmass formed by shards, pyroclasts and small lithic and crystal particles; it
contains high proportion (≤ 20%) of deformed, elongated juvenile pumice (fiamme) and flattened
shards; sizes of fiamme range from a few millimetres to 10 cm across; length-to-thickness ratios of
fiamme increases with increasing welding intensity and decreases progressively; oblate pyroclasts of
Interpretation: eutaxitic massive lapilli-tuff
occurs mostly above the massive lithic-breccia
facies (mlBr) and thus, is more likely to record
hotter material later in the eruption rather than
the effect of loading. Some of the fiamme could
Lithofacies
Name (code)
Description
Interpretation
obsidian are common in partly- and incipiently-welded lapilli tuff, grading into fiamme when welding
becomes intense. Accidental lithic-clasts can vary in volume across welding horizons, lithic-rich
eutaxitic lapilli-tuff (lemLT) usually contains ≥ 10% of lithic lapilli; from mm up to 20 cm in size.
Structure: its fabric is usually elongated in the direction of flow; high-grade kinematic indicators exist
at the margins of lithic lapilli or phenocrysts of different sizes; in microscopic scale, vitroclastic
texture show rotational features around complete and dislocated phenocrysts.
Geometry/occurrence: emLT is exposed in the study area as a 0.5 to 1.5 m thick, longitudinal layer of
eutaxitic tuff; sheet-like horizons of different welding intensities are exposed in the unit; it exhibit
truncations and common changes laterally and vertically; the lower and upper contacts are gradational
from and to non-welded massive lapilli-tuff; sharp boundaries are rare except when associated with
horizons of lithic-breccia (lemLT); it passes gradually, upwards and laterally into mLT.
probably have been originally poorly-vesiculated
hot clasts rather than pumice (as has been
inferred for the Arico Formation in southeast
Tenerife; Bryan et al., 1998; Brown et al., 2003).
Massive tuff (mT), diffusestratified-tuff (dsT) and
cross-stratified tuff (xsT)
Lithology: fine-grained ash matrix supporting 5 to 10% of fine lapilli; negligible amount of coarsegrained clasts are present in this lithofacies; fines-rich ash is the dominant component and it can be
formed by microscopic-scale glass-shards, broken crystals, devitrified glass and highly-fragmented
accidental lithic accessory.
Structure: internally massive; maximum thickness recorded 2 m; common lateral changes in
thickness; sharp and gradational boundaries; grades into diffuse-stratified tuff (dsT).
Geometry/occurrence: presents lenticular shapes in valley-fill; mantles topography but thins
drastically over palaeoridges, from 1 to 300 cm; condensed sequences; grades laterally into mT, mLT,
mLTacc, mTacc; passes vertically into dsT and mTpel draping topography.
Interpretation: broadly similar emplacement
processes as mLT and dsLT with the absence of
abundant lapilli.
Massive lithic-breccia
(mlBr)
Lithology: consists of matrix- to clast-supported, lithic lapilli and blocks (pebble to boulder size) in
poorly-sorted lapilli-tuff; maximum clast size recorded ~0.5 m; average clast size 10 to 30 cm in
diameter; lithic blocks are usually sub-rounded but can be angular and rounded; usually present
exfoliation rims; pumice-lapilli is sparse and in similar proportion as mLT in interclast sections;
lithologies are very variable and comprise in descending abundance: basalt; phonolite; basanite;
scoria; fine-grained syenite; obsidian; porphyritic glassy blocks and occasionally welded tuffs.
Structure: internally massive; can present crude to diffuse bedding (dblBr) or well-developed bedding
(blBr). Boulders commonly aligned with long-axis parallel to flow direction; usually normal graded;
lower contact can present load structures; upper contact transitional and gradational into mLT or
ldbLT.
Geometry/occurrence: highly variable; sub-horizontal sheet-like; irregular; localized, pods (loaded),
connected to main breccia body or isolated; thickness varies from 0.3 m to 3 m thick; grades laterally
into ldbLT and lmLT; passes vertically into normal-graded lithic breccia.
Interpretation: massive co-ignimbrite lithic
breccias (mlBr) are deposited similarly to other
lithofacies (e.g. mLT) but more energetically;
mlBr derive from granular flow- and/or fluid
escape-dominated flow boundaries of pyroclastic
density currents. Stratified or bedded breccias in
ignimbrite (blBr) are commonly imbricated and it
is inferred they deposit at traction dominated
flow-boundary zones with rolling and saltation of
big lithic clasts. Lithic breccias may originate
from erosion or collapse of the eruptive
conduits/vent, avalanches into the pyroclastic
density current, or substrate erosion from waxing
gravity currents (Branney and Kokelaar, 2002).
Massive tuff with
accretionary lapilli
(mTacc)
Lithology: mTacc – matrix supported in fine ash-tuff; pumice and lithic lapilli subordinated (≤2%);
poorly sorted; contains variable proportions of ash aggregates (accretionary lapilli) in the range of 2 to
8%; they can be complete circular to oblate shape or debris from brittle broken bits, multi-rimmed or
single rimmed.
Structure: internally massive; crudely stratified and bedded with sharp to diffuse boundaries;
longitudinal variations common; normal grading common.
Geometry/occurrence: 3 to 100 cm thick; geometry influenced by topography as mLT; lenticular,
sheet-like, thinning in valley-margins and thickening towards valley-axis; grade upwards into mTpel
and mLT and laterally into mT, mLT and dsLT.
Interpretation: accretionary lapilli in massivetuff (mTacc) is formed by the fallout of ashpellets from a plume, dropping into rapid,
ground-hugging pyroclastic density currents;
accreting successive concentric laminations then
dried out to be deposited in low aspect ratio
ignimbrites (Brown et al., 2010).
Lithofacies
(see sketch above)
Name (code)
Description
Interpretation
Massive ash-pellet tuff
(mTpel)
Lithology: poorly-sorted, fine-grained tuff; pumice and lithic lapilli subordinated (<2%) and
occasionally at base or top of lithofacies.
Structure: internally massive; framework-supported with localized and sparse interstitial ash-matrix;
formed mainly by clast-supported pellets (mTpel); lower contact usually gradational, top contact sharp
and gradational.
Geometry/occurrence: sheet-like; 3 to 10 cm thick; drapes topography; usually at the upper part of
ignimbrite sheets with accretionary lapilli (mTacc).
Interpretation: ash-pellet bearing tuff (mTpel)
has been interpreted as from a fallout origin; ashpellets are formed in buoyant co-ignimbrite ashplumes and deposited by direct fallout (Brown et
al., 2010).
Massive agglomeratic
lapilli-tuff (mAgLT)
Lithology: matrix-supported juvenile-rich breccia in lithic- and crystal-rich lapilli-tuff matrix; it
comprises ≤ 30% of mainly black, dense juvenile blocks of varied textures including: porphyritic
black, poorly vesiculated juvenile blocks; feldspar-rich (swallow-tail texture abundant) in aphyric
groundmass blocks; glassy obsidian; mingled green and black glassy blocks with spherulitic texture
and lithophysae; scoriaceous amoeboid blocks; spatter-like and cauliflower structures; chilled-rims
and bread-crusted blocks. The clast sizes range from 1 to 50 cm. Inflated pumice is ubiquitous and
appears only at the lower levels and in low proportions; lithic lapilli abundant throughout the
lithofacies and it comprises basalt, phonolite and crystalline syenite blocks.
Structure: massive to diffuse and crudely bedded; graded to non-graded; in parts mixed with lithicbreccias (lmAg); imbrication is common (mAgf) with long axis dipping upslope; lower and upper
contacts are gradational except when mixed with lithic-breccias; thickness range from 0.5 to 5 m.
Geometry/occurrence: it can form essential parts on massive agglomerate; layers or crudely bedded
accumulations of juvenile clasts at certain levels of the deposit; it forms elongated clusters that fade
out laterally; lenticular shapes are common with lengths up to 10 meters across; diffuse layering and
imbrication in direction of flow is common when elongated shapes.
Interpretation: massive agglomeratic lapilli-tuff
(mAgLT) like lithic breccias, are consistent with
emplacement from rapidly aggrading pyroclastic
density currents in a granular-fluid based regime
(Branney and Kokelaar 1992, 2002). Most of the
blocks in this lithofacies, represent juvenile
pyroclasts/spatter that were deposited ca. 15 km
from source; hence a fallout origin is discarded.
A highly energetic eruption is invoked for the
emplacement of massive agglomerates in distal
facies; two hypotheses may be suggested: 1) the
presence of a shallow lava-lake or spatter cone
during the eruption, with subsequent disruption
by explosive magma fragmentation, convective
column and entrainment of poorly vesiculated
blocks into PDC’s. 2) The origin of the phonolite
agglutinate may have originated via intrinsic
eruption processes while emptying of magma
chamber caused partial roof collapse and
fragmentation of poorly vesicular magma that
formed the spatter clasts then incorporated into
the currents once optimum fragmentation and
highly vesiculated magma was fragmented. A
combination of both may also be possible.
Lithic-rich massive
agglomeratic lapilli-tuff
(lmAgLT) and with
directional fabric
(mAgLTf)
Lithology: lithic-rich massive agglomerate (lmAg) as mAg with an increased proportion of lithicclasts that range from lapilli to blocks of varied lithologies: basalt; phonolite; vesicular scoria and
fine-grained syenitic clasts. mAgLTf – as mAgLT and with overall directional fabric in one or more
horizons.
Structure: lmAg – as mAg with smaller percentage of interstitial matrix as this is replaced by
abundant (~30 %) lithic clasts; mAgLTf – like mAg, with crude thick layers of elongated juvenile
clasts with long axes orientated in the direction of flow; dips upslope.
Geometry/occurrence: lmAg – as mAg with sharper lower and upper contacts; mAgf – as mAg with
lateral discontinuity of imbrication due to changes in supply, palaeotopography; variability of matrixcognate clasts ratio; local intergradations with lithic-breccias (mlBr) or lapilli-tuff (mLT; Branney and
Kokelaar, 2002; references therein). Passes laterally into mAgLT, mAgf, mLT and vertically into,
mAgLT, mLT and emLT.
Interpretation: lmAg – as mAgLT with the
emphasis that dense juvenile clasts/blocks behave
similarly to accidental lithic blocks in massive
lithic-breccias (mlBr) and thus a similar
emplacement process is invoked; it involves
particle segregation during rapid deposition of
cognate clasts, fluid escape, elutriation and
overpassing of highly vesiculated pumice and
fines. mAgLTf – as mAg with variations in the
conditions of sedimentation at the flow
boundary-zone, reflected in the strength of the
directional fabric (Branney and Kokelaar, 2002).
Table 2
Picture
Type of
juvenile
Pumice
Description
Lithofacies
occurrence
dbL, mpL,
Layer/ location
Summarized interpretation
Localities
Layer 1, basal
frameworksupported pumice
lapilli
Records initial Plinian pumice-fall
deposit; high phonolite magma
fragmentation
Barranco del
Agua, Playa de
Diego Hernández,
El Puertito, Playa
Paraíso and
Barranco de
Erques (see Fig.1)
Green
pumice,
glassy
porphyri-tic
core
Matrix-supported, sub-rounded to rounded, darkgreen lapilli and blocks, microvesicular, with
crystal content of c. 3% mainly alkali feldspar
(sanidine, anorthoclase), with glassy core and
fibrous margins
dsLT, mLT,
Layer B; at 1.5 m
from base of
ignimbrite
Partially degassed green pumice
entrained into pyroclastic density
current
Most localities
Porphyri-tic
obsidian
Lapilli and blocks of sub-rounded to sub-angular
poorly-inflated glass, with conchoidal fracture and
≤20% alkali feldspars in swallowtail texture, up to
5 mm in diameter
dsLT, mLT,
emLT, mAgLT,
lmLT, mlBr
Layer B; at 1.5 m
from base of
ignimbrite
Occurs in pyroclastic density current
deposit; poorly vesiculated
phonolite glassy juvenile with
swallow-tail texture of potassic
feldspars
Most localities
Green and
black banded
Pale-green and black, mingled blocks: a) Green
glass: crystal-poor, dense, in streaks and bands,
spherulitic and with lithophysae, sharp contact
with black glass; b) Black glass: microvesicular,
crystal-rich, swallowtail feldspars, in bands with
sharp contacts
mAgLT, mlBr,
lmLT
Layer B; ~4 m
from the base of
ignimbrite
Occurs in pyroclastic density current
deposit; clasts exhibit mingling of
glasses of contrasting colour but
apparently similar composition that
probably cooled at different rates
El Puertito
Framework-supported, green to grey, highly
angular, crystal-poor, pumice-lapilli with fibrous
texture. Grades from pale and highly-inflated to
green and glassy; generally fresh
Massive
obsidian
/crystal-rich
obsidian
Sub-angular to sub-rounded blocks and lapilli of
black to dark-green glassy obsidian, with
conchoidal fracture; co-existing crystal-rich and
completely aphyric
mlBr, mLT,
mAgLT,
Layer B; 5 m from
base of ignimbrite.
Pyroclastic density current eruption;
ignimbrite flow unit 1; probably
entrained as undegassed cognate
clasts into the pyroclastic density
currents
El Puertito,
Fañabe and
Barranco de
Erques
Spatter
‘bomb- like’
clast
Black blocks to lapilli, microvesicular,
scoriaceous and crystal-rich, highly angular
(amoeboid) to sub-angular, elongated and with
fluidal shapes; bread-crusted margins; forms
imbricated and massive agglomerates (mAgf);
phenocrysts orientated in sense of clast elongation
mAgLT,
mAgLTf, mlBr,
mLT, lmLT
Layers B and D
Proximal spatter-like clasts
incorporated into PDC’s and
transported as cognate blocks,
probably behave similar to lithics in
massive lithic-breccias
El Pris and El
Puertito, Playa de
Morteros,
Barranco del
Burro and
Barranco del Agua
Brown
crystal-rich
phonolite
Sub-angular blocks, brown, crystal-rich,
vesiculated clast with intermittent black streaks.
The brown phase is highly vesicular with
approximately 30% sanidine randomly distributed
mAgLT,
mAgLTf,
lmLT, dbLT,
dbAg
Layer D, flow unit
2; ~5 m above
layer C
Slightly pumiceous phonolite glass
entrained in pyroclastic density
current
El Pris and El
Puertito
Black glassy
juvenile with
crystal
enclave
Black, sub-angular block, incipient bread-crust
texture, microvesicular, non-glassy, with phonolite
lithic-lapilli contained within; presents crystal
enclave (clusters) of approximately 60% alkali
feldspars decreasing towards the edges of clast;
crystal distribution is chaotic except from the
edges where crystals are orientated in flow
direction
mAg, mAgf,
lmLT
Layer D, flow-unit
2: 2 m above flowunit boundary
layer C
Crystal clusters in glassy
groundmass may represent material
formed previously to the eruption.
Possibly from country rock within
the magma chamber
Only seen at El
Puertito