1-20 OF 264 RESULTS FOR

microlithics

Results shown limited to content with bounding coordinates.
Follow your search
Access your saved searches in your account

Would you like to receive an alert when new items match your search?
Close Modal
Sort by
Series: Geological Society, London, Special Publications
Published: 31 March 2023
DOI: 10.1144/SP515-2020-181
EISBN: 9781786205872
... Abstract New evidence from the Ayodhya Hills, located in the western upland of West Bengal, has expanded knowledge of Late Pleistocene microlithic technology spanning 42–25 ka in South Asia. Continuous exploration for the past two decades has resulted in substantial information on technology...
FIGURES | View All (6)
Series: Geological Society, London, Special Publications
Published: 31 March 2023
DOI: 10.1144/SP515-2022-153
EISBN: 9781786205872
... Abstract The earliest occurrence of microliths in South Asia dates back to the Late Pleistocene at Mehtakheri (45 ka) and Dhaba (48 ka) in Central India, Jwalapuram 9 in Southern India (38 ka), Kana and Mahadebbara in Northeastern India (42–25 ka) and Batadomba-Lena (35–36 ka) and Fa Hien Lena...
FIGURES | View All (22)
Image
Images of thin sections of the Upper Ordovician tuffs of Salair. Plates 1–3 – the eleventh member of the Voikov Street Section: 1 – fragments with plagioclase microliths; 2 – fragments with quartz grains and plagioclase microliths; 3 – plagioclase crystal. Images: a – without analyzer, b – with analyzer.
Published: 01 March 2025
Fig. 12. Images of thin sections of the Upper Ordovician tuffs of Salair. Plates 1–3 – the eleventh member of the Voikov Street Section: 1 – fragments with plagioclase microliths; 2 – fragments with quartz grains and plagioclase microliths; 3 – plagioclase crystal. Images: a – without
Image
Back-scatter electron (BSE) images illustrating phase relations among minerals of the rhönite–kuratite series in paralavas. (a) Sample MN-1127: kirschsteinite microliths with inclusions of Ca-bearing fayalite, and few kuratite microliths in Si-Al-K and Si-Al-Ca-Fe glasses (microemulsion of quenched melts), all in interstices between microphenocrysts. Glasses, in turn, enclose goethite needles and small pyrrhotite globules. Hyalophane grows over anorthite. (b) Sample MN-1127: hyalophane and kirschsteinite microliths and euhedral kuratite crystals growing over Al-clinopyroxene microphenocrysts. Si-Al-K glass encloses numerous globules (droplets) of sub-micrometre and μm-sized Si-Al-Ca-Fe glasses, kirschsteinite microliths with Ca-bearing fayalite inclusions, pyrrhotite globules and goethite needles. (c) Sample MN-1287: zoned segregation with a pyrrhotite margin, which encloses a kuratite crystal and kirschsteinite microliths, around an aggregate of acicular goethites and an oxygen-rich Ca-F phase similar to fluorite, and calcite. (d) Sample MN-1128: euhedral crystals of a Ti-poor Fe2+-analogue of rhönite with Al-magnetite inclusions in Si-Al-K glass containing a pyrrhotite globule and numerous fine goethite needles. (e) Sample MN-1129: crystal and microlith of the Ti-poor Fe2+-analogue of rhönite in Si-Al-K glass, a palagonite aggregate which replaces Si-Al-Ca-Fe glass, and goethite. (f) Sample MN-1129: euhedral crystals of Ti-poor Fe2+-analogue of rhönite in two glasses (microemulsion of quenched Si-Al-K and Si-Al-Ca-Fe immiscible melts). Mineral names are abbreviated as Fa = Ca-bearing fayalite, Hf = hyalophane, Po = pyrrhotite, Fe-Rh = Ti-poor Fe2+-analogue of rhönite, Gth = goethite, Al-Mag = Al-magnetite, Ca-F = oxygen-rich Ca-F phase, Cal = calcite, G1 = Si-Al-K glass, G2 = Si-Al-Ca-Fe glass, and Pln = palagonite aggregate. Other symbols are the same as in Fig. 3.
Published: 01 August 2017
Fig. 12. Back-scatter electron (BSE) images illustrating phase relations among minerals of the rhönite–kuratite series in paralavas. ( a ) Sample MN-1127: kirschsteinite microliths with inclusions of Ca-bearing fayalite, and few kuratite microliths in Si-Al-K and Si-Al-Ca-Fe glasses
Image
Matrix fragments of cristobalite clinker, BSE images. a – Poorly defined microliths of sekaninaite–cordierite in glass containing acicular cristobalite, mullite, Fe and Ti oxides, sample MN-1365; b – microliths of sekaninaite in glass zones free from inclusions and partly crystallized glass zones with cristobalite, sekaninaite, and plagioclase, sample MN-1408; c–f – sample MN-1403: c – dendritic ferroindialite–indialite intergrown with cristobalite and ferrosilite and Al-magnetite inclusions, d – dendritic hopper crystals of ferroindialite in a vitreous zone enclosing acicular mullite and ferrosilite, e – sekaninaite–cordierite microliths, elongate crystals of cristobalite, and fused grains of detrital quartz with cristobalite rims, f – zones of symplectitic sekaninaite–cordierite and cristobalite in a vitreous zone enclosing acicular mullite and grains of nonidentified Si–Al–Fe phases, and Fe and Ti oxides. Scale bar is 20 μm in all panels. Sec – sekaninaite, Fe-Ind – ferroindialite, Crs – cristobalite, Gl – glass, Mul – mullite, Qtz – detrital quartz, Pl – plagioclase, Al-Mag – Al-magnetite, Ti-Mag – Ti-magnetite.
Published: 01 December 2023
Fig. 5. Matrix fragments of cristobalite clinker, BSE images. a – Poorly defined microliths of sekaninaite–cordierite in glass containing acicular cristobalite, mullite, Fe and Ti oxides, sample MN-1365; b – microliths of sekaninaite in glass zones free from inclusions and partly crystallized
Image
Representative photomicrographs illustrating the mineralogical and textural features of the Rhyolite Ridge and Argentite Canyon formations. (A-C) Porphyritic lavas from Argentite Canyon formation characterized by feldspar glomerocrysts, euhedral amphibole, and biotite in a microlitic groundmass. (D-F) Welded tuff of Argentite Canyon formation exhibiting varied fragments of lithics, plagioclase, and biotite phenocrysts in a microlithic quartzo-feldspathic groundmass. (G-I) Rhyolitic lava from Rhyolite Ridge formation showing perlitic texture due to glass hydration and overprinted by later chlorite alteration. (J-L) Lithic tuff from Rhyolite Ridge formation composed of various fragments of plagioclase, biotite, K-feldspar phenocrysts and lithics in a microlithic groundmass. Mineral abbreviations according to the International Mineral Association (IMA): Ab = albite, Amp = amphibole, Bt = biotite, Cal = calcite, Chl = chlorite, Kfs = K-feldspar, Lith = volcanic lithic fragment, Pg = paragonite, Prl = pyrophyllite, Qz = quartz.
Published: 13 May 2025
groundmass. (D-F) Welded tuff of Argentite Canyon formation exhibiting varied fragments of lithics, plagioclase, and biotite phenocrysts in a microlithic quartzo-feldspathic groundmass. (G-I) Rhyolitic lava from Rhyolite Ridge formation showing perlitic texture due to glass hydration and overprinted by later
Series: Geological Society, London, Special Publications
Published: 31 March 2023
DOI: 10.1144/SP515-2020-108
EISBN: 9781786205872
... Abstract The Spiti Valley is located in the Trans-Himalayan terrain of India, from where non-geometrical microliths have been discovered. While the Siwalik Hills have been subjected to extensive prehistoric surveys, this is the first evidence of lithic tools discovered in the Trans-Himalayan...
FIGURES | View All (9)
Image
Microlith texture, fabric, and mineralogy; all backscatter electron photomicrographs. (A) Fragments of altered biotite (b) and microcrystalline calcite (c) occur within a poorly sorted, but well compacted fine-grained wacke with an illite (gray) matrix. Scale bar: 100 μm. (B) Sandy mudrock containing angular to subrounded grains of quartz (qtz), albite (ab), and microcrystalline calcite (cc) within an illitic (ill) matrix. Scale bar: 200 μm. (C) Silty claystone containing framboidal pyrite (bright) within an illitic matrix (gray), along with rounded and possibly corroded (bottom right) siliciclastic grains. Scale bar: 50 μm. (D) Illitic microlith with ilmenite crystals (bright) associated with microveins and a stockwork-like vein fabric (arrows) with indeterminate void-fill Fe- and Si-bearing minerals. Scale bar: 30 μm.
Published: 01 September 2011
Figure 9. Microlith texture, fabric, and mineralogy; all backscatter electron photomicrographs. (A) Fragments of altered biotite (b) and microcrystalline calcite (c) occur within a poorly sorted, but well compacted fine-grained wacke with an illite (gray) matrix. Scale bar: 100 μm. (B) Sandy
Image
(A) Low Mg-calcite (cc) replacement of illite (i) matrix in a microlith. White arrows identify rounded to angular siliciclastic grains, and the black arrow identifies a rare xenocryst of apatite. Backscatter electron photomicrograph; scale bar: 100 μm. (B) Differential calcite (cc) replacement of grains within an unaltered illite (i) matrix. Note the biotite xenocryst (b). Backscatter electron photomicrograph; scale bar: 100 μm. (C) An apparent rounded grain of illitic clay (based on thin-section petrography) with framboidal pyrite (fp) occurs within the limestone interbed of the bentonite (Russell core). Scanning electron microscopy analysis shows that it possesses irregular boundaries defined by a mosaic of low-Mg microcrystalline calcite, with rounded crystal margins, that has likely displaced the host clay during growth. The white arrow demonstrates continuation of the illitic material into the calcite domain. Backscatter electron photomicrograph; scale bar: 100 μm.
Published: 01 September 2011
Figure 10. (A) Low Mg-calcite (cc) replacement of illite (i) matrix in a microlith. White arrows identify rounded to angular siliciclastic grains, and the black arrow identifies a rare xenocryst of apatite. Backscatter electron photomicrograph; scale bar: 100 μm. (B) Differential calcite (cc
Image
(facing page). Photomicrographs (a–f, scale bar = 200 μm) and BSE images (g–i, scale bar = 50 μm) showing the rock texture and some petrographic peculiarities of the olivine-leucitites of Gaussberg. (a) (sample G886), (b) (sample G895): Porphyritic texture with microphenocrysts of olivine (ol), leucite (lc) and clinopyroxene (cpx) in a glassy groundmass. The glassy groundmass contains microliths of leucite, clinopyroxene, apatite, and, unique to sample G886, dark mica and alkaline amphibole. (c,d) Clinopyroxene microphenocrysts surrounded and partially corroded by leucite microliths (G886). (e) Rim of glass bordering a large vesicle (the centre of the vesicle is above and outside the photograph): glass contains dendritic and feather crystals of phlogopite to Fe-rich phlogopite (phl) and amphibole (amph) (G886). (f) Amphibole as a product of late magmatic reaction around olivine. (g) Leucite and late phlogopite as products of magmatic reaction of the residual liquid with olivine. The lower part of the image shows a large clinopyroxene microphenocryst with a thin (light grey) Fe-rich rim and partially corroded by leucite microliths as a reaction product (G886). (h) Relic of clinopyroxene microphenocryst surrounded by leucite and mica: glassy groundmass contains skeletal crystals of mica and apatite. (i) Phlogopite to Fe-rich phlogopite with biotite (bi) dendritic ending growing from the glass bordering the large vesicle of image e (G886).
Published: 01 February 2004
with microphenocrysts of olivine (ol), leucite (lc) and clinopyroxene (cpx) in a glassy groundmass. The glassy groundmass contains microliths of leucite, clinopyroxene, apatite, and, unique to sample G886, dark mica and alkaline amphibole. ( c,d ) Clinopyroxene microphenocrysts surrounded and partially corroded
Series: Geological Society, London, Special Publications
Published: 31 March 2023
DOI: 10.1144/SP515-2020-206
EISBN: 9781786205872
... and Microlithic/Mesolithic site ( Sali 1985 , 1989 b ). The 2019 field season was carried out to understand the regional landscape and geology of the broader region in general, which covers the area roughly from 74°50′00″ to 75°50′0″ E and from 20°20′00″ to 21°05′0″ N and falls within the CTRV. The methodology...
FIGURES | View All (9)
Image
(A) Bimodal grain size of the bentonite, Russell core, showing the vitreous luster of the prominent clay matrix and silt- to sand-size dark microliths (lithic grains) and reworked biotite xenocrysts. Incident light photograph; scale bar: 300 μm. (B) Wet-sieved sand-size fraction consisting of lithic grains from the Russell core showing typical range in size, shape, and common vitreous luster. Incident light photograph; scale bar: 300 μm. (C) Biotite xenocryst with a rare zircon inclusion (bottom right) and the mold of another solid inclusion, possibly apatite. Secondary electron photomicrograph; scale bar: 100 μm. (D) Biotite xenocryst within a microlith illustrating the relic laminae of biotite (bright) within a crystalline patchwork of illite and chlorite. The biotite is encased by illite (mottled fabric), also host to other grain types. Backscatter electron photomicrograph; scale bar: 50 μm.
Published: 01 September 2011
Figure 7. (A) Bimodal grain size of the bentonite, Russell core, showing the vitreous luster of the prominent clay matrix and silt- to sand-size dark microliths (lithic grains) and reworked biotite xenocrysts. Incident light photograph; scale bar: 300 μm. (B) Wet-sieved sand-size fraction
Image
Representative photomicrographs of the studied volcanic rocks. (a) Microlithic porphyry texture; (b) glomeroporphyry texture; (c) porphyry texture; (d) sieve texture of clinopyroxene; (e) amphibole; (f) skeletal olivine. Ol: Olivine; Cpx: Clinopyroxene; Qtz: Quartz; Bt: Biotite; Pl: Plagioclase.
Published: 17 February 2023
Fig. 4. Representative photomicrographs of the studied volcanic rocks. (a) Microlithic porphyry texture; (b) glomeroporphyry texture; (c) porphyry texture; (d) sieve texture of clinopyroxene; (e) amphibole; (f) skeletal olivine. Ol: Olivine; Cpx: Clinopyroxene; Qtz: Quartz; Bt: Biotite; Pl
Journal Article
Published: 01 August 2017
Mineralogical Magazine (2017) 81 (4): 949–974.
...Fig. 12. Back-scatter electron (BSE) images illustrating phase relations among minerals of the rhönite–kuratite series in paralavas. ( a ) Sample MN-1127: kirschsteinite microliths with inclusions of Ca-bearing fayalite, and few kuratite microliths in Si-Al-K and Si-Al-Ca-Fe glasses...
FIGURES | View All (17)
Image
SEM BSE photomicrographs of zoned crystals of the rock-forming minerals from rocks of the lamproite series of the Ryabinovyi massif. A – A clinopyroxene microlith from the groundmass of the olivine–diopside–phlogopite lamproite; B – partially resorbed phenocryst of clinopyroxene from the microsyenite; C – phlogopite phenocryst from a minette; D – zoned crystal of K-felspar from the microsyenite.
Published: 01 February 2024
Fig. 9. SEM BSE photomicrographs of zoned crystals of the rock-forming minerals from rocks of the lamproite series of the Ryabinovyi massif. A – A clinopyroxene microlith from the groundmass of the olivine–diopside–phlogopite lamproite; B – partially resorbed phenocryst of clinopyroxene from
Image
Published: 01 October 1999
-poor; evidence of the presence of extraneous initial radiogenic argon. This age estimate preferred by FM Consultants. Sample 4: Slightly altered microlithic basalt. Sample 5: Slightly porphyritic, microlithic with augititic groundmass. Sample 6: Sericitization, resetting of unstable minerals
Series: Geological Society, London, Special Publications
Published: 31 March 2023
DOI: 10.1144/SP515-2020-205
EISBN: 9781786205872
... Abstract The Lower Son Valley is generally overlooked despite a lengthy history of archaeological and geological studies in the adjacent Middle Son Valley. However, recent explorations in the former have yielded a large number of Palaeolithic and microlithic sites. This paper provides...
FIGURES | View All (8)
Series: Geological Society, London, Special Publications
Published: 31 March 2023
DOI: 10.1144/SP515-2020-202
EISBN: 9781786205872
... microlithic assemblages in India; and the dating of the antiquity of human occupation of rain forests in South India and Sri Lanka. Also important is our greater understanding of the Younger Toba Tuff and the impact of the Toba megaeruption 74 ka ago on hominin populations in India. Major uncertainties...
FIGURES | View All (4)
Journal Article
Published: 01 June 1998
Jour. Geol. Soc. India (1998) 51 (6): 731–740.
...Bishnupriya Basak; G. L. Badam; Anupama Kshirsagar; S. N. Rajaguru Abstract The authors present an integrated data on the Quaternary studies carried out during the 1993-95 field seasons in a lesser known area, the Tarafeni Valley in Midnapur District, West Bengal. Microliths primarily made on chert...
Image
Composition diagrams of clinopyroxene (a–c) and phlogopite (d–f) inclusions in Cr-spinels from dunites (1) and wehrlites (2) of the Inagli massif, lamproites of the Ryabinovy massif (3). Author’s data on the composition of phenocrysts and microliths of clinopyroxene and phlogopite from lamproites of the Ryabinovy massif (4) is given.
Published: 01 November 2018
Fig. 5. Composition diagrams of clinopyroxene ( a–c ) and phlogopite ( d–f ) inclusions in Cr-spinels from dunites ( 1 ) and wehrlites ( 2 ) of the Inagli massif, lamproites of the Ryabinovy massif ( 3 ). Author’s data on the composition of phenocrysts and microliths of clinopyroxene