1 The ridge consists entirely of volcanic rock.

2 Fresh volcanic rocks are poor conductors of electricity.

3 Thus the volcanic rocks formed are drastically different from their oceanic counterparts.

4 So volcanic rocks are composed of only a few mineral groups, each group having its own characteristic atomic structure.

5 Volcanic rocks cool quickly, trap the argon, and so give good dates.

6 The important properties of these three principal volcanic rock groups can be summarized in simple tables.

7 Most volcanic rocks contain some phenocrysts - they are a bit like the pips in raspberry jam.

8 These are frequently associated with volcanic rocks of oceanic type.

9 Basalts are examples of basic volcanic rocks, while andesites are intermediate between basic and acid.

10 RioFinex examined the Ordovician volcanic rocks of County Tyrone for base metals but found only minor intersections of low-grade copper mineralisation.

11 The codename was chosen because rhyolite is a volcanic rock containing colourful pieces of quartz set in a mass of crystals.

12 Although it is one of the most widely-known volcanic rocks, obsidian lava flows are rare.

13 Unlike most volcanic rocks, obsidian does not contain phenocrysts; it is, so to speak, all glassy groundmass.

14 Warped and folded Paleozoic strata and reddish Tertiary volcanic rocks are capped with dark Quaternary basalt flows.

15 Volcanic rock can become favorable oil - gas reservoirs.

16 It's built on volcanic rock and ash.

17 Volcanic rock includes the volcanic glass obsidian.

18 Basalt is the commonest volcanic rock.

19 The Badao deposit is a typical Mesozoic volcanic rock - hosting deposit.

20 Ciweigou deposit is one of the typical volcanic rock gold deposits in the country.

21 Crystal twinning patterns in a leucite crystal from volcanic rock, observed in polarized light by Dr. Michael M. Raith of the Steinmann Institut, University of Bonn, Bonn, Germany. (Dr.

22 Volcanic rock from two eruptive sources, Taoyuan - Hongxing and southern Dapingfang weaves and superimposes reciprocally in strata.

23 Obsidian, a form of volcanic rock valued for its strength and durability, was an important resource for ancient Mesoamerican cultures including the Zapotec and Maya.

24 The perlites are volcanic rock processed to yield an expanded form.

25 Volcanic rock is widely developed both in the vertical and horizon direction in Huanghua depression.

26 Sumatra is composed of old, thick continental crust comprising volcanic rocks of Permian, Cretaceous and Cenozoic age.

27 But it has endured because it was constructed of brick and volcanic rock between 1783 and 1792.

28 Jiamuhe formation along the northwestern margin of the Junggar basin is volcanic rock bearing stratum.

29 The carrier of the modified filter medium is the volcanic rock coated with a polycondensate modifier.

30 But, with constant launch and deepgoing of exploration work of volcanic reservoir, the research methods of reservoir connected with volcanic rock is increasingly becoming mature.

31 Assorting and naming of volcanic rock is mainly based on the content of main petrogenetic mineral.

32 The Mesozoic volcanic rock is developed and in sea section, the sediment of Quaternary period is huge-thick, with complicated types and gravel commonly.

33 The purification effect of biological aerated filter stuffed with zeolite, haydite and volcanic rock for river water was studied.

34 The intermediate-acid volcanic rock is the main metallogenic mother rock. the ductile-brittle shear zone is the important ore conducting structure for the formation of gold deposit.

35 A comprehensive geophysical prediction shows that the volcanic rock in the whole area extends as strips.

36 Irruptive rock body reservoir is one of important volcanic rock reservoirs.

37 The basic volcanic rock of low potassic tholeiite series in Rucheng basin was composed of diabase, basalt and basaltic pyroclastic rocks.

38 The (examination) of the petrography shows that the volcanic terrains in Tengchong are typical of the basalt-(andesite)-(dacite) arc volcanic rock associations of the calc-alkaline series.

39 The lower level of Yingcheng volcanic rock is tholeiitic, and the upper is alkalic series.

40 Songshunangou gold deposit is located in the volcano - tectonic depression, the mineralization relates to volcanic rock.

41 Volcanic rock, clastic and metamorphic rock reservoirs integrated to form the complex petroleum accumulation region in Erleim basin.

42 The sample consisted of pebbles of gypsum and fragments of volcanic rock.

43 Major volcanic rock types of Carboniferous times are andesitic basalt, dacite, rhyolite, characterized by a bimodal volcanic suite.

44 The main rock type of the volcanic rock is trachyandesite with small amounts of trachyte, basaltic-trachyandesite and leucite basaltic-trachyandesite.

45 The Minqiao oilfield is located in the southeast of the Jinhu sag, west of Dongtai depression in the Subei basin. Volcanic rock oil reservoir has been found in the Funing Formation.

46 Sandstone reservoir and volcanic rock distribute alternately, their thicknesses are negative correlation.

47 In this springtime image, snow caps Llaima's summit, but the snow-free slopes appear in shades of purple-brown and green, likely a combination of volcanic rock and vegetation.

48 I had to do an in - class presentation on volcanic rock formation.

49 The Sierra Nevada and the Cascade Mountains meet in Plumas County, and fall color against the grey backdrop of the volcanic rock that covers the region makes for dramatic views.

50 The waters south of the island have been bubbling and fizzing with heat, sediment, bits of volcanic rock, and minerals for weeks, with the plume stretching tens of kilometers.

51 Abundant copper material was derived from volcanic rock series ( olivine tholeiite ) in the rift.

52 In this area the density value of logging response of volcanic rock correlate well with porosity.